mmiffw. 
 
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 DENTAL SURGERY. 
 A SYSTEM OF DENTAL SURGERY, 
 
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DEWEES OX THE DISEASES OF CHILDREN. Sixth edition. In 
 
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 this purpose, to this interesting, but helpless class of beings, and the manner by which their 
 duties shall be fulfilled. Arid, 'Jdly, to render available a long experience to these objects of 
 our affliction when they become diseased. In attempting this, the author has avoided as much 
 as possible, "technicality;" and has given, if he does not flatter himself too much, to each dis- 
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 DEWEES ON THE DISEASES OF FEMALES. .Fifth edition, with Addi- 
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 DUNGLISON'S PHYSIOLOGY. 
 
 HUMAN PHYSIOLOGY; illustrated by numerous Engravings. By ROBLEY 
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TREATISE 
 
 ON 
 
 SPECIAL AND GENERAL 
 
 ANATOMY. 
 
 BY WILLIAM E. HORXER, M. D. 
 
 PROCESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA MEMBER OF THE IMPERIAJ 
 MEDICO-CHIRUROICAf. ACADEMY OF ST. PETERSBURG OF THK 
 AMERICAN PHILOSOPHICAL SOCIETY, &C. 
 
 VTiiltinn adhuc restat operis, multumque restabit, nee ulli nato, post inille sa?rula 
 praerlmlitur occasio aliquid adjiciendi. 
 
 8ENECA, EPIST, 
 
 IN TWO VOLUMES, 
 VOL,. II. 
 
 FOURTH EDITION, REVISED AND IMPROVED. 
 
 CAREY, L.EA & BLANCHARD. 
 
 1836. 
 
JAN 9 '36 
 
 Eastern District of Pennsylvania, to wit: 
 
 BE IT REMEMBERED, that, on the seventeenth day of October, in the 
 fifty-first year of the Independence of the United States of America, A. D. 
 1826, WILLIAM E. HOHNER, of the said district, hath deposited in this office the 
 title of a book, the right whereof he claims as Author, in the words follow- 
 ing, to wit:- 
 
 " A Treatise on Special and General Anatomy. By William E. Horner, M. D., 
 Adjunct Professor of Anatomy in the University of Pennsylvania Member of 
 the American Philosophical Society Surgeon at the Philadelphia Alms 
 House, &c. * Multum adhuc restat operis, multumque restabit, nee ulli nato, 
 post mille szecula praecluditur occasio aliquid adjiciendi.' Seneca, Epist. In 
 Two volumes. Vol. II." 
 
 In conformity to the Act of the Congress of the United States, entitled, " An 
 Act for the Encouragement of Learning, by securing the Copies of Maps, 
 Charts, and Books, to the Authors and Proprietors of such Copies, during the 
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 curing the Copies of Maps, Charts, and Books, to the Authors and Proprietors 
 of such Copies, during the times therein mentioned,' and extending the bene- 
 fits thereof to the arts of designing, engraving, and etching Historical and other 
 Prints." 
 
 D. CALDWELL, 
 Clerk of the Eastern District of Pennsylvania. 
 
* 
 
 TREATISE ON ANATOMY. 
 
 BOOK IV. 
 
 PART II. 
 
 Organs of Assimilation. 
 CHAPTER I, 
 
 OF THE ABDOMEN GENERALLY. 
 
 THE cavity of the abdomen occupies the space between the 
 inferior surface of the diaphragm and the outlet of the pelvis; a 
 considerable part of it is, therefore, withiu the periphery of the 
 lower ribs above, and of the pelvis below. It is completely se- 
 parated from the cavity of the thorax by the diaphragm, with 
 the exception of the foramina in the latter, for transmitting the 
 aorto, the ascending cava, and the oesophagus. It is bounded, 
 below, by the iliaci interni, the psoae, and the levatores ani mus- 
 cles; on the front and sides by the five pairs of muscles called 
 abdominal; and behind by the lesser muscle of the diaphragm, 
 the Quadrati Lumborum, the lumbar vertebra?, and the sacrum. 
 The figure of this cavity is, therefore, too irregular to admit of 
 a very rigid comparison with any of the common objects of life; 
 but a little reflection, on the course of its parietes, will make it 
 perfectly understood. It should be borne in mind, that the very 
 great projection of the lumbar vertebra? forms for it a partial 
 vertical septum behind; which, in thin subjects, is almost in con- 
 tact with the linea alba in front, and may be easily distinguished 
 VOL, II. 2 
 
 ' 
 
t> ORGANS OF DIGESTION. 
 
 through the parietes of the abdomen, when the intestines are 
 empty. 
 
 The abdominal cavity varies only, inconsiderably, in its ver- 
 tical diameter, owing to the resistance of the diaphragm above, 
 and of the pelvis below ; neither does it change behind, owing to 
 the resistance of the spine, the ribs, and the muscles there. But 
 as the introduction of food, the development of gaseous sub- 
 stances during digestion, the evolution of the foetus, and many 
 other conditions, require some provision for its undergoing an 
 easy augmentation of volume; the latter occurs principally for- 
 wards and laterally, by the yielding of the muscles and by the 
 extension of their aponeuroses. The diaphragm and the abdo- 
 minal muscles, for the most part, act alternately: as the former 
 descends in inspiration, the latter relax and give way to the con- 
 tents of the abdomen: but in expiration, the abdominal muscles 
 contract, and the diaphragm is pushed upwards by the viscera. 
 In attempts at the expulsion of fasces, and in parturition, these 
 muscles contracting, and the diaphragm being fixed all at the 
 same moment, the cavity of the abdomen is actually much di- 
 minished. 
 
 The viscera contained in the cavity of the abdomen are of 
 three kinds. One kind is engaged in digestion and assimilation; 
 another in the secretion and excretion of urine; and the third in 
 generation. As these viscera are numerous, and it is of great im- 
 portance to determine with precision their position and relative 
 situation, anatomists are agreed to divide the cavity of the ab- 
 domen into several arbitrary regions. This is the more advan- 
 tageous, as the bony prominences bounding the abdomen are 
 not sufficiently numerous and distinct, to afford those obvious 
 points of relation to the viscera which they furnish in other sec- 
 tions of the body. To obtain these regions, consider a line or 
 plane as extending across the abdomen, about two inches below 
 the umbilicus, from the superior part of the crista of one ilium, 
 as it appears through the skin, to the corresponding point of the 
 other side. Strike on each side a line perpendicular to the pre- 
 ceding, by commencing at the lower end of the anterior inferior 
 spinous process of the ilium, and carrying it up to the dia- 
 phragm. Extend a fourth line across the abdomen parallel with 
 the first, and intersecting the two last where they come upon 
 
OP THE ABDOMEN. 7 
 
 the cartilages of the false ribs. It is evident that these four 
 lines or planes, two horizontal and two vertical, will, with the 
 assistance of the parietes of the abdomen, furnish nine regions: 
 three above; three in the middle, and three below. The cen- 
 tral region above, is the Epigastric; and on its sides are the 
 right and the left Hypochondriac. The central region in the 
 middle, surrounding the navel, is the Umbilical; and on its sides 
 are the right and the left Lumbar. The central region below, 
 is the Hypogastric; and on its sides are the right and the left 
 Iliac. There are also some subordinate divisions ; for example, 
 the hollow in the epigastric region, around the ensiform car- 
 tilage, is called the pit of the stomach, or Scrobiculis Cordis; 
 and for an inch or two around the symphysis pubis, is the re- 
 gion of the pubes, (Regio Pubis.) 
 
 Anatomists differ among themselves about the points of de- 
 parture and the position of the lines, or rather planes, separating 
 the regions. Some fix them at arbitrary distances from the 
 umbilicus, and others assume the points of the skeleton. The 
 umbilicus is the most fallacious mark, because its elevation va- 
 ries considerably, according to the state of distention of the ab- 
 domen, it being comparatively higher when the abdomen is 
 tumid than when it is not. Neither does it answer to take the 
 anterior ends of the last ribs as the points for the upper horizon- 
 tal line to pass through; as they, sometimes, are almost as low 
 down as the umbilicus itself. The superior anterior spinous 
 processes are also objectionable as the points of departure for 
 the vertical lines; as they leave too much room for the central 
 regions of the abdomen, and too little for the lateral: I have, 
 therefore, after some hesitation, thought proper to substitute the 
 anterior inferior spinous processes; and, especially, as the posi- 
 tion of the viscera, as almost universally described, is more in 
 accordance with this rule. 
 
 General Situation of the Viscera of the Mdomen. 
 
 When the abdomen is so opened as to leave its viscera in 
 their natural position, they will be found as follows: 
 
 1. The Liver, the largest gland of the body, is in the right 
 
ORGANS OF DIGESTION. 
 
 upper part of the abdomen, immediately below the diaphragm. 
 It occupies nearly the whole of the right hypochondriac region; 
 the upper half of the epigastric; and the right superior part of 
 the left hypochondriac. The anterior extremity of the gall- 
 bladder projects beyond its anterior margin. 
 
 2. The Spleen is situated in the posterior part of the left hy- 
 pochondriac region. 
 
 3. The Stomach, in a moderate condition of distention, occu- 
 pies the lower half of the epigastric region, and the right infe- 
 rior portion of the left hypochondriac. 
 
 4. The Smaller Intestine, when moderately distended by 
 flatus, occupies the umbilical region, the hypogastric, portions 
 of the iliac on each side, and also the upper part of the cavity 
 of the pelvis, when the viscera of the latter are empty. 
 
 5. The Large Intestine traverses the cavity of the abdomen 
 in such manner as to perform almost the entire circuit of it 
 It begins in the right iliac region by receiving the lower extre- 
 mity of the small intestine; it then ascends through the right 
 lumbar and the right hypochondriac, passes into the lower part 
 of the epigastric, or into the upper of the umbilical, according 
 to the state of distention of the stomach; thence it gets into the 
 left hypochondriac, being fixed higher up there than in the cor- 
 responding-region of the other side; afterwards it goes down 
 into the left lumbar and into the left iliac; thence it passes into 
 the pelvis, and, descending in front of the sacrum, terminates 
 in the orifice called anus. 
 
 6. The Caul, or Omentum, is a membrane, of various densi- 
 ties, in different individuals, and lies in front of the intestines. 
 Sometimes it is found spread ovsr the latter like an apron, but 
 on other occasions is drawn up into the umbilical region, form- 
 ing a ridge across it. 
 
 7. The Pancreas lies transversely in the lower back part of 
 the epigastric region. It extends from the left hypochondriac 
 
OP THE ABDOMEN. 9 
 
 region to the right side of the spine, and is placed behind the 
 stomach, so as to be covered by it. 
 
 8. The Kidneys and the Capsulse Renales, two in number 
 each, are placed in the posterior part of the lumbar region on 
 the side of the spine. 
 
 9. The Urinary Bladder and the Rectum, in the male, occupy 
 the cavity of the pelvis, and in the female between them are 
 placed the uterus, the ovaries, and the vagina. 
 
 As, in the dissection of the abdominal viscera, the subject is 
 commonly placed on its back, so the preceding description is 
 made out with a strict reference to that position. Some modi- 
 fication in the shape of the abdomen, as well as in the situation 
 of its contents, occurs in standing upright. The front of the 
 abdomen becomes more protuberant, the lumbar vertebra make 
 a greater projection forwards. The pelvis is so adjusted, in 
 order to bring the acetabula directly in the line of support to 
 the spine, that the convexity of the sacrum presents almost up- 
 wards, and the superior straight loolts forwards and upwards 
 towards the navel, so that much of the weight of the viscera is 
 thrown upon the pubes. In this attitude most of the viscera 
 descend, but more obviously the liver, from its weight, size, and 
 solidity. Portal has verified this descent by comparing the 
 thrusts of poniards into the liver in the erect, with those inflict- 
 ed in the horizontal position. He also asserts that the same 
 may be ascertained in the living body by applying the fingers 
 under the false ribs, and then directing the person to change 
 from the recumbent into the vertical position. The spleen af- 
 fords the same results when it is slightly enlarged, and the de- 
 scent of the liver and spleen will of course ensure that of the 
 stomach and intestines. According to Winslow, the pain and 
 faintness which are felt after a long abstinence, come from the 
 vacuity of the stomach and intestines, which thereby withdraw 
 their support from the liver, and permit it to drag upon the 
 diaphragm. 
 
 The presence of flatus in the stomach and intestinal canal, 
 seems to be entirely natural to them; for it is comparatively 
 
10 ORGANS OF DIGESTION. 
 
 rare to find them destitute of it, even when they contain no 
 food or faeces. The large intestine is, however, more frequent- 
 ly found contracted or empty than the small. Owing to the 
 flexible character of a considerable portion of the abdominal pa- 
 rietes, the latter, by their own contraction, as well as by atmo- 
 spheric pressure, are kept in close contact with the viscera; and 
 the viscera again, by the same influence, are kept in close con- 
 tact with one another; so that, notwithstanding the irregularity 
 of their forms and the fluctuating size of the hollow ones, there 
 is no unoccupied space in the cavity of the belly. 
 
 Several instances are reported by anatomists, in which a to- 
 tal transposition of the abdominal viscera has occurred, so that 
 those which belonged to the right side were placed in the left* 
 They are, however, exceedingly rare: in probably more than 
 fifteen hundred observations, or more, I have never met with 
 one instance of it. 
 
 CHAPTER II. 
 
 OF THE PERITONEUM, AND SEROUS MEMBRANES, GENERALLY. 
 SECT. I. OF THE PERITONEUM. 
 
 THE sides of the abdomen are lined, and its viscera are co- 
 vered by a membrane called Peritoneum.f As the reflections of 
 this membrane, by being thrown over the periphery of almost 
 every viscus of the abdomen, consequently, assume the same 
 shape ; and as it lines, without exception, the interior surface of 
 every part of the abdomen, its form is extremely complicated, 
 and can only be judged of accurately after the study of the 
 viscera is completed. For the present it will only be neces- 
 sary to give the outline of it, leaving the details to each appro- 
 priate occasion. 
 
 * Portal, Haller, Sandifort, &c. 
 
 f From 5e/T/v<r6*/ quod est circumquaque extend!. 
 
OF THE PERITONEUM. 11 
 
 In man, it is a complete sac, having no hole in it; but in wo- 
 man, its cavity communicates externally through the Fallopian 
 tubes. It has a double use: In consequence of covering the 
 viscera, it is so reflected from them to the sides of the abdomen, 
 that its processes keep the viscera in their proper places, and, 
 therefore, answer as ligaments: again, its internal surface being 
 smooth, indeed, highly polished, and continually lubricated by a 
 thin, albuminous fluid, corresponding with the synovial mem- 
 brane of the joints, the motions which the viscera have upon 
 each other in exercise, and in the peristaltic movements of the 
 bowels, are much facilitated. 
 
 The manner in which a double night-cap is applied to the 
 head, will afford the easiest conception of the reflections of the 
 peritoneum. If there were only one viscus in the belly, and that 
 of a somewhat regular outline, as the spleen, the comparison 
 would be rigid, and perfectly appreciable. One part of the cap 
 is close to the head, and compares with the peritoneal coat of 
 the spleen ; the other is loose, and is equivalent to the peritoneum, 
 where it is in contact with the parietes of the belly. It is also 
 evident from this, that none of the viscera can be said to be 
 within the cavity of the peritoneum ; that they are all on its out- 
 side; and that a viscus, in getting a coat from the peritoneum, 
 merely makes a protrusion into its cavity. Starting with this 
 simple proposition, it is easy to conceive of a second, a third body, 
 and so on, deriving an external coat from a protrusion into the 
 same sac. Admitting these bodies to be spheres, the proposition 
 is immediately intelligible; and, as a last step from it, the idea is 
 not rendered much more complex by substituting any bodies even 
 the most irregular in form, for these spheres. 
 
 Such, then, is the fact in regard to the stomach, intestines, &c.; 
 they all, with exceptions to be stated, derive an external coat 
 from the peritoneum. 
 
 The Peritoneum is, for the most part, smoothly spread upon 
 the interior surface of the abdominal muscles. It adheres to 
 them with considerable firmness by means of intervening cellular 
 substance : this adhesion, where it closes the posterior opening of 
 the umbilicus, is unusually strong. Below, the uniformity of the 
 membrane as it descends from the navel to the pelvis is inter- 
 rupted by its being reflected over the urachus, and over the re- 
 
12 ORGANS OF DIGESTION. 
 
 mains of the umbilical artery on each side. Where the urachus 
 is, it forms an oblong prominent ridge, reaching to the upper ex- 
 tremity of the bladder; and, as regards each umbilical artery, 
 the duplicature is of variable breadths in different individuals; 
 but always forms a well marked falciform process, reaching 
 from near the umbilicus to the lower side of the bladder, and di- 
 viding the inguinal region into two parts or fossae, one next to 
 the pubes, and the other nearer to the ilium. In the undistended 
 state of the bladder the peritoneum reaches to the pubes, is re- 
 flected from the latter to the upper, and then goes over the pos- 
 terior surface of the bladder. In the male, it goes from the pos- 
 terior lower end of the bladder to the rectum, but, in the female, 
 it does not descend so low there, and passes from the bladder to 
 the vagina and uterus, and afterwards to the rectum. 
 
 In the concavity of the ilium, and in the lumbar region, the 
 peritoneum is attached by long loose cellular substance, which 
 permits it to be stripped off easily, simply* by tearing. In these 
 several regions it encounters the colon, over which it is reflected, 
 and. thereby forms the Mesocolon ; thence it passes in front of 
 the kidneys, but separated from them by a thick layer of cellu- 
 lar and adipose matter, and immediately afterward it is thrown 
 into a long duplicature, extending obliquely across the lumbar 
 vertebras from above, downwards, and to the right side. This 
 duplicature includes the small intestine, and is the Mesentery. 
 
 In the highest regions of the abdomen, the peritoneum is in the 
 greater part of its extent uniformly reflected over the concave 
 surface of the diaphragm, and adheres so closely to it, as to re- 
 quire a cautious and protracted dissection for its entire removal. 
 As the remains of the umbilical vein of the fetus are still found, 
 but in a ligamentous condition, going from the navel to the under 
 surface of the liver, their existence gives rise to a broad falciform 
 duplicature of peritoneum, which passes from the upper half of 
 the linea alba and from the middle line of the diaphragm to the 
 liver. Another line of attachment, or of reflection, of this mem- 
 brane to the liver, is found all along the posterior margin of the 
 latter. In the same region, it is also reflected from the diaphragm 
 to the spleen and to the stomach. Such is the general account 
 of the course of the peritoneum. Each of the duplications has a 
 distinct name, and some peculiarity of organization or of relation, 
 
OP THE OMENTA. 13 
 
 "which will require a specific description and a frequent allusion 
 to it. 
 
 It is proved, from what has been said, that the peritoneum is 
 a single and complete sac, and that, with the exception stated of 
 the Fallopian tubes, there is no hole in it either for the passing 
 of blood vessels, nerves, or viscera. And that it is so folded over 
 the abdominal viscera, that with patience and sufficient address, 
 one might remove it from their surface and extract them, with- 
 out even laying open its cavity : an experiment said to have been 
 successfully accomplished by Nicholas Massa,* and some other 
 anatomists. 
 
 SECT. II. OF THE OMENTA. 
 
 There are four processes of the peritoneum, each of which is 
 designated under the term Omentum, Epiploon, or Caul. 
 
 1. The Omentum Minus or the Hepatico-Gastricum, extends, 
 as its name imports, between the liver and the stomach. It be- 
 gins at the transverse fissure of the liver, and proceeds from it, 
 from the right side of the lobulus spigelii, the front of which it 
 conceals, and from the inferior posterior face of the tendinous 
 centre of the diaphragm; it is attached to the lesser curvature of 
 the stomach in all the space between the cardiac and the pylo- 
 ric orifices. Its right margin reaches beyond the pylorus to the 
 duodenum, and includes the vessels going to the liver, and the 
 biliary ducts ; in consequence of which, this margin is called the 
 Capsule of Glisson. The capsule is, however, more properly the 
 condensed cellular substance within. 
 
 The two laminae which compose it are thin and transparent, 
 and have but little fat in them*; in approaching the stomach they 
 become very distinct from each other, and receive between them 
 the superior coronary vessels of the stomach. One lamina then 
 goes before the stomach and the other behind, in the form of a 
 peritoneal covering. These laminae, having covered in that way 
 the anterior and the posterior surface of the stomach, unite again 
 on the greater curvature of the latter, to form the beginning of 
 the omentum majus. 
 
 * Atiat. Liber. Introdact. an. 1539. Portal. 
 VOL. II. 3 
 
14 ORGANS OF DIGESTION. 
 
 2. The Omentum Majus or Gastro-Colicum, as indicated by its 
 name, is connected at one end all along the greater curvature of 
 the stomach, and by the other along the transverse part of the 
 colon. As it commences by two laminae, so it is continued 
 throughout in the same way. It is commonly found more or less 
 spread on the front surface of the small intestines, but occasion- 
 ally it is tucked up in the epigastric region. When fairly spread 
 out, either naturally or artificially, its course will be found as fol- 
 lows : It first of all descends from the stomach to the pelvis ; it 
 then turns upwards, so as to reverse its course, and continues to 
 ascend till it reaches the colon. Its two laminae then separate and 
 receive the colon between them, so that, in this respect, the ar- 
 rangement is entirely comformable to what happens to the sto- 
 mach. The subsequent continuation of these laminae is the 
 mesocolon, which will be more particularly described. 
 
 As the omen turn majus consists of two laminae in its whole ex- 
 tent, it is clear that it resembles a flattened bag lined by another 
 bag; so that in its whole thickness, when held between the fin- 
 gers, there are four laminae. It is an irregular quadrilateral 
 membrane, which, in corpulent subjects, is interspersed with a 
 great deal of fat ; but in such as are emaciated, it is wholly des- 
 titute of the latter ; and instead of being entire in its parietes is a 
 delicate reticulated membrane, so that the rule about the integ- 
 rity of the peritoneum is not fully accurate as applied to this sec- 
 tion of it. On the right side it is continuous with the omentum 
 colicum, and on the left with the omentum gastro-splenicum. 
 
 3. The Omentum Colicum may be considered as a continuation 
 of the omentum majus along the ascending and a part of the 
 transverse colon. In some rare fases, (for in my own observa- 
 tions I have not met with the arrangement,) its origin is conti- 
 nued downwards to the coecum, and at its left margin is extended 
 along the transverse colon to the spleen. Much more commonly 
 it is, as stated, simply an appendage of the great omentum, or its 
 right flank, advancing for a short distance along the ascending 
 colon. 
 
 It consists of but two laminae in all, commonly containing fat, 
 but in this respect subject to the same rule as. the omentum 
 majus. 
 
OF THE OMfiNTA. 15 
 
 4. The Omentum Gastro-Splenicum is the left flank or mar- 
 gin of the omentum majus, extended from the great end of the 
 stomach to the spleen. It of course consists of but two laminae, 
 which contain between them the splenic vessels and the vasa 
 brevia. 
 
 By looking for the posterior end of the gall-bladder, and then 
 passing a finger under the right margin of the hepatico-gastric 
 omentum, or, in other words, under the capsule of Glisson, where 
 it extends from the liver to the duodenum, the finger will be 
 found to have insinuated itself behind the stomach, and, by be- 
 ing directed downwards, will be thrust into the sac or cavity of 
 the great omentum. In children, where the latter is less reticu- 
 lated than in adults, and consequently more entire, a large blow- 
 pipe introduced at the same point will enable one to inflate this 
 cavity, and to separate its anterior from its posterior wall. This 
 aperture, called the foramen of Winslow, is the route by which 
 the internal or lining lamina of the omentum majus is introduced, 
 so as to make this process of peritoneum double throughout 
 its whole parietes. Though this fact of duplicity is generally 
 conceded, no author heretofore, to my knowledge, has pointed 
 out satisfactorily the means ; and for the suggestion of it, I am 
 indebted to a learned and zealous member of the profession, 
 now Professor Hodge of the University. Struck, at an early pe- 
 riod of his studies, with the difficulty of tracing a double sac to 
 the omentum majus, out of a single membrane of the peritoneum, 
 this suggestion was happily made by him to remove the difficul- 
 ties of other explanations. An attempt at a diagram formed 
 upon any other principle I have invariably seen to fail. If the 
 reader has conceived the idea, the inference will be plain, that 
 the lining lamina of the omentum majus is continued as a com- 
 mon peritoneal covering over the posterior face of the stomach, 
 and then forms the posterior lamina of the hepatico-gastric omen- 
 tum. It will also be plain that the same lamina, having reached 
 the colon in its return, continues afterwards as the upper lamina 
 of the transverse mesocolon. 
 
 From what has been said concerning the general qualities of 
 the peritoneum, it is to be understood that though it enjoys much 
 power of gradual' extension, nevertheless this quality is not suf- 
 
16 ORGANS OF DIGESTION. 
 
 ficient to enable it to endure, without a special provision, the 
 sudden and extensive dilatations to which the stomach and bow- 
 els are exposed, from the introduction of food and from the evo- 
 lution of gases during digestion. Of all the coats of these organs, 
 it is the least extensible and contractile; its rupture, therefore, 
 is guarded against by one invariable rule. For example: as 
 the muscular and other coats of the stomach dilate, the perito- 
 neum is drawn from the omentum minus and majus to cover the 
 stomach; therefore, as the stomach enlarges, the omenta dimi- 
 nish: and as the stomach decreases, the omenta, by the restora- 
 tion of peritoneum, resume their primitive size. In this way the 
 uterus, notwithstanding its great augmentation in the progress 
 of pregnancy, still keeps itself covered by peritoneum, from the 
 ability of the latter, as mentioned, to slide from one part and to 
 apply itself to another. The true intention, then, of the appa- 
 rently useless length of many processes of the peritoneum, is 
 explained, by their being a provision for the augmentation of 
 the hollow viscera of the abdomen, in the discharge of their na- 
 tural functions. Adopting this explanation as the basis of our 
 observations, we shall find that according to the probable or 
 even possible augmentation of a viscus, so are its peritoneal at- 
 tachments. The stomach, which next to the uterus enlarges 
 more than any other viscus, gets its subsidiary supply of perito- 
 neum from the length of the omentum minus and majus; the 
 colon, which is next in order, is supplied from the length of its 
 mesocolon ; the small intestines, which are next, from the length 
 of the mesentery. The latter, however, would be too long for 
 that simple purpose ; but the objection is removed by recollect- 
 ing that the mesentery has also to accommodate numerous 
 chains of lacteal glands, through'-which the chyle must pass in 
 its elaboration, before it is fit to enter into the general circula- 
 tion. The liver, being of a size almost stationary, has its peri- 
 toneal attachments proportionally short; and its peritoneal co- 
 vering, from the shortness of the connecting cellular substance, 
 is disqualified from sliding. The spleen is in the same predica- 
 ment with the liver, except that its size is not stationary; but, in 
 this case, the peritoneum presents a phenomenon entirely re- 
 markable : it wrinkles upon the contraction of the spleen. 
 
 If this mode of reasoning, derived from an arrangement of 
 
OF THE OMENTA. 17 
 
 parts which -no one denies, be correct, it follows that physiolo- 
 gists have erred sadly in the supposed uses of the omentum ma- 
 jus. That this organ is, in. fact, only subsidiary to the enlarge- 
 ment of the stomach and colon, so as to prevent the rupture of 
 their peritoneal coat, and that it is neither intended to keep the 
 belly warm, as so learned a naturalist as 'M. G. Cuvier has sug- 
 gested;* nor is it a special store-house for the wants of the sys- 
 tem during the destitution of other aliment, farther than adipose 
 matter in other parts -of the body is.t In regard to the first theo- 
 ry, it does not appear that the inhabitants of cold climates are 
 better furnished with an omentum majus than those of the torrid 
 zone : that it is better developed in winter than it is in summer ; 
 that it is tucked up in warm weather to cool the intestines, or 
 spread out in cold weather to make them more comfortable. On 
 the contrary, it is ascertained that its position is variable at all 
 seasons; that in the coldest of weather it is as often found col- 
 lected in the epigastric region, or to one side of the abdomen, as 
 it is in the warmest; consequently, its position is the result of 
 whatever motions may, for the time, have been impressed upon 
 it by the distention of the stomach, and by the peristaltic move- 
 ments of the bowels. In regard to the theory of Dr. Rush, the 
 objection is insurmountable, that children, who are equally, if not 
 more exposed to starvation and sickness than adults, never have 
 fat, except in very small quantities, in the omentum, and that 
 only along the course of its vessels. The fat is, therefore, not to 
 be viewed as an essential circumstance in the structure of the 
 omentum, as all children and many adults have it only very 
 sparingly; for the omentum being wanted as a membrane of 
 reserve to the stomach and colon, the deposite of fat in it, is in 
 obedience to one of the general laws of the system, whereby the 
 cellular substance beneath the serous membranes is disposed to 
 secrete fat as the individual advances in life ; which is exempli- 
 fied on the heart and in the pleura. Another .argument is, that 
 in the ruminating animals, where there are four stomachs, and 
 from the vegetable nature of their aliment these stomachs must, 
 in the course of digestion, be very much distended, the great 
 omentum is of proportionate magnitude.f 
 
 * XXII. Lecon D'AnaJt. Comp. 
 
 f An Inquiry into the Uses of the Omentum, by James Rush, Philad. 1809. 
 
 t Cuvier, XXII. Legon, loc. cit. 
 
18 ORGANS OF DIGESTION. 
 
 As occurs in other parts of the body, also, the fat of the omen- 
 turn accumulates in animals that take but little exercise, while it 
 is very deficient 'in such as lead an active life. 
 
 I am induced to believe that the hard knots felt in the abdo- 
 men of such persons as suffer from abdominal affections, fre- 
 quently depend upon the accumulations of the omentum majus 
 at particular but variable points. 
 
 SECT. III. GENERAL ANATOMY OF THE SEROUS MEMBRANES. 
 
 As the peritoneum presents one of the best examples of a nu- 
 merous class of membranes, called SEROUS, it will be useful at 
 this point to inquire into their general condition and properties. 
 They are, for the most part, thin, and strongly resemble com- 
 pressed cellular membrane ; having been, indeed, by some ana- 
 tomists, considered as such. They invariably assume the form 
 of perfect sacs, and as they are found in alt parts of the body, 
 they are kept distinct from each other. The arachnoid mem- 
 brane of the brain, the pericardium, the pleura, the sy no vial 
 membranes of the joints, the bursae mucosae of tendons, the peri- 
 toneum, and the tunica vaginalis testis, belong to this class. 
 They are not all of the same thickness, as some are much more 
 dense than others ; they adhere to neighbouring parts by a la- 
 mina of cellular substance, which is also of variable thickness 
 and ductility ; indeed, on some occasions, it is not entirely dis- 
 tinct, from its extreme shortness and tenuity. 
 
 As the serous membranes are only displayed over the surface 
 of the organs which they cover, after the manner of a double 
 night-cap drawn over the head ; their cavity always remains en- 
 tire, notwithstanding it is variously modified by the shape of the 
 organs protruded into it ; and has its parietes in contact, owing 
 to external compression. They are entirely distinct from the 
 essential structure of the organs covered, and are displayed over 
 those of thfc most dissimilar functions, as, for example, the intes- 
 tines and the liver. A sac of this description, then, is of infinite 
 importance in establishing between organs which border upon 
 one another a strong partition : and, consequently* in warding off 
 any injurious influence which their dissimilar natures would 
 
ANATOMY OF SEROUS MEMBRANES. 19 
 
 otherwise cause them to have upon each other. Important or- 
 gans are, therefore, invariably thus insulated, so that whether in 
 a healthy or in a diseased state, their actions are carried on 
 within themselves ; and not only so, but it is even possible, and, 
 indeed, is found in morbid dissections, every day, that an organ 
 may be diseased while its serous covering is unaffected ; or the 
 reverse. Thus, we have large suppurations in the liver, while its 
 peritoneal coat is healthy ; large accumulations of water in the 
 tunica vaginalis testis, while the testicle itself is sound ; in the 
 thorax, with sound lungs and heart ; in the abdomen, with vis- 
 cera generally sound ; in the joints, without an affection of the 
 bones. Nothing is more common than to see partial adhesions, 
 the result of inflammation, causing the opposite sides of these 
 sacs to adhere, without any evident constitutional or visceral 
 derangement ; and some of our plans of cure, as in the hydro- 
 cele, are founded upon this well established fact. 
 
 The serous membranes are throughout thin, transparent, 
 and white : in some points their tenuity is so extreme that they 
 seem to consist simply in a smooth, polished surface, spread 
 over parts ; this is strikingly the case on the interior face of the 
 dura mater, on the ventricles of the brain, and on the cartilages 
 of the joints. The evidence of their extension there, is conse- 
 quently derived principally from induction; and .from morbid 
 alteration, in which they become thickened. Their internal 
 surface, in a natural state, is always smooth, highly polished, 
 shining ; and, being also lubricated by its peculiar unctuous se- 
 cretion, the opposite parietes, when they come into contact, 
 glide freely upon each other ; a circumstance indispensable to 
 the free action of the joints, and to the peristaltic motion of the 
 bowels. Bordeu has asserted, that these remarkable characters 
 of the serous membranes depend upon the compression and the 
 friction to which they are continually exposed : but to this opi- 
 nion the argument of Bichat is unanswerable, that in their ear- 
 liest observable period in the foetus they have the same polish. 
 
 The fluid secreted from the serous membranes resembles, 
 strongly, the serosity of the blood. It is poured out continually 
 by the exhalent orifices, and in a short time afterwards is taken 
 up by the absorbents ; so that in a natural state there is seldom 
 more than sufficient to lubricate the surfaces of the membrane. 
 
20 ORGANS OF DIGESTION. 
 
 When the abdomen of an animal recently killed is exposed to the 
 air, this fluid rises in the form of a vapour. The several experi- 
 ments, as the application of heat, mineral acids, and so on, which 
 prove the abundance of albumen in the serum of the blood, pro- 
 duce the same results when applied to the secretion from the se- 
 rous membranes. 
 
 The system of serous membranes has been considered by Bi- 
 chat, and others, as only a modification of cellular membrane, for 
 the following reasons. The inflation of air into the cellular tis- 
 sue subjacent to them, reduces them to the form of cellular sub- 
 stance. Protracted maceration produces the same effects with 
 more certainty and precision. When cellular membrane is in- 
 flated, the parietes of the distended cells resemble strongly the 
 finest parts of the serous system, as the arachnoid membrane. 
 There is an identity of functions and of affections, for they are 
 both continually engaged in thegreat work of exhalation and ab- 
 sorption, and suffer in the same way from dropsical effusion, with 
 the only difference that the latter is more amassed in the one 
 than in the other. My own experience goes to prove, that drop- 
 sy very seldom manifests itself, to any extent, in the cellular tis- 
 sue without also going to the serous cavities, and the reverse. 
 The .serous membraties are also of a uniform texture, like cellular 
 substance, and present no appearance of fibres. 
 
 The serous membranes are furnished with a great abundance 
 of exhalent pores, and of absorbents, which carry on their func- 
 tions with great activity. They, when healthy, receive only the 
 colourless part of the blood, whence the uniform transparency of 
 these membranes. The existence of exhalent pores, is proved 
 by strangulating a piece of intestine with a ligature for thirty-six 
 or forty-eight hours, when they become evident, by dilating them- 
 selves so as to receive red blood. A fine coloured injection pro- 
 duces the same result; and also moistens, by the escape of its wa- 
 tery particles, the surface of the intestine, by a very fine halitus 
 or dew. The intestine of a living animal, if wiped perfectly dry, 
 will, after the same way, soon present another coat of serosityon 
 its surface. The existence of absorbents to a great extent in 
 them, may also be equally well proved, as they very readily re- 
 ceive a mercurial injection, which diffuses itself over their whole 
 surface, and causes them to have the appearance of being formed 
 
ANATOMY OF SEROUS MEMBRANES. 21 
 
 entirely of such vessels. The readiness with which fluid effused 
 into their cavities is taken up, is another proof of the same. Bi- 
 chat once saw them distended with air in a man who had be- 
 come emphysematous from poisoning. Mascagni has frequently 
 found them distended with the fluid of dropsical collections, which 
 he recognised by its colour. It happened to the same anatomist 
 to find in two bodies, where there had been an effusion of blood 
 into the thorax, the absorbents of the lungs gorged with blood. 
 This faculty of absorption may sometimes be proved to continue 
 for some hours after death, by keeping an animal in a warm 
 bath. Mascagni asserts, that he has witnessed its continuance 
 for fifteen, thirty, and even for forty-eight hours ; it is not impro- 
 bable, however, that there was some illusion in these instances. 
 
 It is more than probable that the serous membranes are en- 
 tirely deprived of red blood vessels ; the latter unquestionably ex- 
 ist, in great numbers, on the*exterior surface, where they creep 
 through the cellular substance, but they may be removed with 
 a scalpel without affecting the continuity of these membranes. 
 Again, where these membranes are free and unconnected on both 
 surfaces, as in some parts of the tunica arachnoidea, there is no 
 appearance of red blood vessels. In hernial protrusions, where 
 there is a considerable prolapse of peritoneum, the blood vessels 
 which are found abundantly about the neck of the sac do not fol- 
 low the course of the protrusion. Unquestionably some commu- 
 nication exists between the arterial system and the serous mem- 
 branes, as proved by exhalation and morbid phenomena, but the 
 mode is not well ascertained. 
 
 In common hernia and in dropsy, the serous membranes be- 
 come more thick : from my dissections I am inclined to think, that 
 this change is not so great as is generally allowed ; for most fre- 
 quently, by a careful removal of the exterior cellular substance, 
 they have been restored to their primitive condition. In other 
 cases, as in large umbilical hernias, they are so much attenuated 
 as to be found with difficulty. 
 
 The power of extension which these membranes possess, is 
 strikingly marked in dropsical effusions, in the development of tu- 
 mours, and in pregnancy ; but much of this apparent quality is 
 derived from their mode of attachment to adjacent parts, where- 
 by they are drawn from one surface to cover another. This hap- 
 VOL. II. 4 
 
22 ORGANS OF DIGESTION. 
 
 pens daily where the peritoneum is drawn from the lower part 
 of the abdomen to cover the bladder in the distentions of the lat- 
 ter ; in pregnancy, where it is drawn upon the growing uterus 
 from all the neighbouring parts; and in the distentions of the sto- 
 mach by food or flatus, where it is drawn up from the omenta. 
 The serous membranes have also a power of contraction equal to 
 that of their extension ; but it should not be confounded with that 
 condition where they are simply restored by the connecting cel- 
 lular substance, to the surfaces to which they originally belonged. 
 The sensibility of the serous membranes, from the want of 
 nerves in them, is extremely obscure in a natural state, and only 
 affords an imperfect sensation of touch. This is proved by the 
 impunity with which they may be irritated on living animals. 
 But, when the condition of inflammation is once established, they 
 feel the most acute and distressing pain. Though they resist 
 most frequently, and for a long time, disease in adjacent parts, 
 yet it not unfrequently is extended to them at last. In such 
 cases, it is generally a local instead of a universal affection, which 
 is communicated to them : Thus, in the cancer and scirrhus of 
 the uterus ; in disease of the spleen, and so on ; the portion of pe- 
 ritoneum nearest the affected organ manifests the marks of the 
 disease by preternatural adhesions and by disorganization, with- 
 out the whole membrane being involved. 
 
 As the serous system consists in many. species of sacs, so each 
 of them has some peculiarity of organization, of attachment, and 
 of vital properties, which is stated elsewhere in the account of 
 the species themselves. 
 
 CHAPTER III. 
 
 OF THE CHYLOPOIETIC VISCERA. 
 SECT. I. OF THE STOMACH. 
 
 THE Stomach ( Ventriculus, Stomachus) is a hollow viscus, 
 situated in the epigastric region, intended to receive at one end 
 
THE STOMACH. 23 
 
 alimentary matters from the oesophagus, and to transmit them, 
 at its other extremity, after digestion, into the intestinal tube, 
 where the nutritious part of the food is absorbed into the circu- 
 lation. It is a sort of conoidal sac, curved considerably up- 
 wards, and presents two Faces, two Orifices, two Curvatures, 
 and two Extremities. 
 
 The Faces of the stomach are, from their position, named 
 anterior and posterior, or, one presents to the spine and the 
 other towards the linea alba. The flat configuration is rendered 
 more obvious when the organ is empty; for when distended it 
 is rounded, and the anterior face is caused to look forwards and 
 upwards from the resistance of the spine behind. In other 
 respects they do not present any thing worthy of particular at- 
 tention.* 
 
 The two Orifices of the stomach are named Cardia and Py- 
 lorus. The first is at the left and most superior part, but re- 
 moved to the distance of two inches or more from the left ex- 
 tremity. It is generally considered a smooth uninterrupted 
 continuation of the oesophagus into the stomach, immediately 
 after the oesophagus has passed through the diaphragm into the 
 abdomen. But in a preparation by me,t of this organ, made 
 by drying, and now in the anatomical cabinet, a circular round- 
 ed pad is very perceptible at the cardiac orifice; being elevated 
 two lines or more all around, so that it makes a perfect ring of 
 from eight to twelve lines broad at its base. This pad seems 
 to be composed of a cellular substance, which is almost per- 
 fectly white, elastic, and consists of the finest filaments, resem- 
 bling carded cotton: it is placed between the lining membrane 
 of the cardiac orifice and the adjoining coat. The pylorus, 
 when viewed externally, seems like a smooth continuation of 
 the stomach into the duodenum; but when felt, there is a mani- 
 fest thickening of the part, depending upon a structure to be 
 presently explained. It points upwards and to the left side, 
 but is, by the whole thickness of the liver, lower down than 
 the cardia. 
 
 The two Curvatures are designated the great and small, or 
 
 * In some cases the posterior face of the stomach is concave to accommodate 
 it to the spine : this is best seen on inflation and drying-, 
 f Made December, 1828. 
 
24 ORGANS OF DIGESTION. 
 
 the upper and the lower. The first, forming the upper margin 
 of the stomach, is bounded at its extremities by the orifices, 
 and is very concave; its curvature is maintained both by a na- 
 tural configuration and by the small omentum. The great cur- 
 vature forms the whole inferior periphery of the organ, extend- 
 ing also from one orifice to the other. When the stomach is 
 flattened, these curvatures form very evident boundaries to the 
 anterior and the posterior faces. 
 
 The Extremities of this organ are singularly disproportionate 
 in size. That on the left forms the base of the cone, or the 
 large extremity, and projects considerably beyond the cardia 
 towards the spleen. It is a rounded cul-de-sac, or tuberosity, 
 the dimensions of which will, of course, vary according to the 
 state of distention. The right extremity, on the contrary, is 
 produced by a gradual diminution of the organ from its middle 
 to the duodenum. When the stomach has approached within 
 an inch or two of the latter, it suffers a sort of constriction, 
 which gives to the right end a more cylindrical shape. This 
 part is sometimes called the little cul-de-sac, or the antrum 
 pylori. 
 
 Where the stomach has been kept empty for some time pre- 
 viously to death, it is found not much larger than an intestine; 
 its variable magnitude, therefore, prevents any very rigid rule 
 of dimension from being applied to it; most commonly, how- 
 ever, we find it between the capaciousness of a pint and a quart 
 measure. 
 
 It is retained in its situation by its continuity with the oeso- 
 phagus and duodenum; also by the hepatico-gastric, and the 
 gastro-splenic omentum. It is in contact above, at its lesser 
 curvature, with the diaphragm, the left lobe of the liver, and 
 the lobulus spigelii; at its great extremity with the spleen, at 
 its posterior face with the pancreas, and at its greater curvature 
 with the colon and the mesocolon. 
 
 The stomach is formed by four laminae of a character essen- 
 tially differing from each other: The Peritoneal, the Muscular, 
 the Nervous, and the Mucous. 
 
 The Peritoneal Coat envelops the stomach completely, and 
 adheres closely, except at the curvatures, where, as has been 
 
THE STOMACH. 25 
 
 mentioned, a provision is made for the dislention of the organ, 
 by the looseness and the separability of the attachment of the 
 two laminse of the omen turn minus and majus. An uncovered 
 space will, consequently, be found between the lamina* at these 
 places, along which the vessels run that furnish the stomach. 
 The peritoneal coat is very thin, and is attached to the subjacent 
 muscular, by very fine cellular substance, which permits it to 
 be raised from the muscular by a careful dissection. 
 
 The Muscular Coat is intermediate in thickness to that of the 
 intestines and of the oesophagus, but its fibres are pale, are col- 
 lected into flattened fasciculi, and go in three directions. The 
 most superficial are a continuation of the longitudinal fibres of 
 the oesophagus, and are less numerous and less uniform in their 
 distribution than the circular fibres. The greater part of them 
 form a flattened broad fasciculus, which extends along the lesser 
 curvature of the stomach, from the cardiac to the pyloric ori- 
 fice. A thinner and less distinct fasciculus may be traced over 
 the great cul-de-sac, and, somewhat indistinctly, along the great- 
 er curvature, and a few others may be seen on the anterior and 
 posterior faces of the stomach. The second series consists in a 
 lamina of circular fibres distinctly covering the whole surface 
 of the organ. They are not so numerous near the cardia, but 
 become more abundant as they are examined towards the pylo- 
 rus, in the vicinity of which they are multiplied so as to form 
 a lamina of two lines or more in thickness. The circular fibres 
 are parallel with each other, and, when the stomach is much 
 distended, their fasciculi separate so as to leave interstices be- 
 tween them in many places. The individual fibres do not sur- 
 round entirely the stomach, but are rather segments of circles. 
 The third and deepest series of fibres may be called oblique, 
 and are arranged into two broad flattened fasciculi, one of which 
 is placed to the left side of the cardia, and is prolonged over 
 the anterior and the posterior faces of the stomach; while the 
 other, being to the right of the same orifice, is extended over 
 the anterior and the posterior faces of the cul-de-sac, where it 
 supplies the want of transverse or circular fibres: they are con- 
 sidered as a continuation of the circular fibres of the oesophagus. 
 The Nervous or Cellular Coat connects the muscular with the 
 mucous. It is formed from a compact, thick, and short cellular 
 
26 ORGANS OF DIGESTION. 
 
 substance, which contributes much to the general strength of 
 the organ, and serves to conduct the blood vessels and the 
 nerves to the mucous coat. 
 
 The Mucous or Villous Coat is the most internal, is not quite 
 a line in thickness, and can be readily raised up by dissection. 
 In an undistended state of the stomach it is arranged into a 
 number of wrinkles, which are very irregular in their form, 
 size, and direction, but disappear immediately on distention, or 
 at least leave but very faint traces. It is continuous with the 
 internal membrane of the oesophagus and of the duodenum, but 
 presents a surface differing from either of them, and which is 
 rendered very apparent by floating it in water. The epidermis, 
 which is continued along the internal face of the oesophagus, 
 ceases around the cardiac orifice, and, by a slight maceration, 
 may be raised up and demonstrated to terminate there. 
 
 This membrane or coat, the office of which is to secrete the 
 gastric juice for the digestion of articles of food, presents a sur- 
 face that resembles very much common velvet, from whence 
 the term villous was applied to it. It is common to find it, if 
 examined a short time after death, having, particularly along 
 the smaller curvature and at the great end, a pink and some- 
 times a deeper colour, produced by an accumulation of blood 
 in its veins. 
 
 The texture of this membrane is soft, loose, and easily lace- 
 rated. When floated in water and examined with a magnify- 
 ing glass, it is found to have a superficial honey-comb arrange- 
 ment, and to be studded with a multitude of small follicles or 
 orifices. In the vicinity of the cardiac and of the pyloric ori- 
 fices, the same arrangement is more obvious, and conducts to 
 some small muciparous glands, which are more or less apparent, 
 and called the glands of Brunner. 
 
 At the junction of the lesser extremity of the stomach with 
 the duodenum, the internal membrane is thrown into a circular 
 duplicature constituting the pyloric valve, and abridging the 
 size of the orifice. It is seen most favourably in the distended 
 and dried state, and then presents a sort of septum not unlike 
 the form x)f the iris. Around the external periphery of this 
 ring, the circular muscular fibres have a sudden augmentation 
 of number, which gives them, when viewed from the duodenum, 
 
INTESTINAL CANAL. 27 
 
 the appearance of a distinct circular muscle, occasionally called 
 the muscle of the pylorus, but it does not exist in a state so se- 
 parate as this name indicates. The opening of the valve is ge- 
 nerally circular, hut sometimes ovoidal, and it is sometimes to 
 one side. 
 
 It is very common to find the stomach divided as it were into 
 two compartments, by a contraction of its middle, resembling 
 that of an hour glass. It is said that this occurs habitually 
 during digestion; in my personal observations, however, I have 
 seen the stomach more frequently in this state when it contained 
 nothing, not even air, than when articles of aliment were in it. 
 
 The stomach is extremely vascular. Its arteries, being 
 branches of the Coeliac, are the Gastric, the Right, and the Left 
 Gastro-Epiploic, and the Vasa Brevia. The first goes along its 
 lesser curvature, the second and the third along its greater cur- 
 vature, and the last, from four to six in number, go to its great 
 cul-de-sac. They all approach it between the laminae of its 
 omenta, and undergo many divisions and subdivisions in the 
 cellular coat; they at length terminate by forming a very fine 
 and delicate vascular arrangement in the substance of the mu- 
 cous membrane, and by being successfully injected give to the 
 latter a thorough tinge of red. The veins follow the course of 
 the arteries, and like them have frequent anastomoses, but are 
 larger; they terminate either directly or indirectly in the trunk 
 of the Vena Portarum. The nerves of the stomach come from 
 the Par Vagum, and from the semi-lunar ganglion of the Sym- 
 pathetic. Its lymphatics arise from both the external and the 
 internal surfaces, and their trunks having to pass first of all to 
 the lymphatic glands, situated along the curvatures, afterwards- 
 empty into the thoracic duct. 
 
 SECT. II. OF THE INTESTINAL CANAL. 
 
 The Intestinal Canal is from thirty to thirty-five feet in length, 
 and extends from the pylorus to the anus. Owing principally 
 to a well marked difference in magnitude, it is divided by ana- 
 tomists into the Small and into the Large intestine. 
 
28 ORGANS OP DIGESTION. 
 
 Of the Small Intestine. 
 
 The Small Intestine (Intestinum Tenue] commences at the 
 pylorus; and terminates in the right iliac region by a lateral 
 aperture into the large intestine. It is four-fifths of the length 
 of the whole canal, and measures from twenty-four to twenty- 
 eight feet* When moderately distended its diameter is about 
 one inch. It retains from one end to the other an uninterrupt- 
 ed cylindrical shape, with the exception that if the two ends be 
 compared, the upper will be found larger than what is stated as 
 the medium measurement, and the lower smaller; or, in other 
 words, the intestine decreases successively from above down- 
 wards, and, as a whole, is slightly conoidal, though this diminu- 
 tion is so gradual that it is not perceptible at any given point. 
 
 The Small Intestine, like the stomach, consists of four dis- 
 tinct coats, the peritoneal, the muscular, the cellular, and the 
 mucous. 
 
 The Peritoneal Coat is complete, and forms the external sur- 
 face. It is continued afterwards in two laminae from the intes- 
 tine to the lumbar vertebrae, thereby constituting the Mesente- 
 ry. The two laminae, where they depart from the intestine, are 
 loosely connected with each other, for the purpose of allowing 
 room for the dilatation of the intestine, on the same principle 
 which is exemplified in regard to the stomach. 
 
 The Muscular Coat is next to the peritoneal. Its fibres are 
 pale, and form a lamina not so thick as common writing paper. 
 The superficial ones are longitudinal, not very distinct, and too 
 much separated to form a perfect coat. The others all run in a 
 circular direction, approaching to the spiral, and are sufficiently 
 numerous to form a perfect coat; none of them perform a com- 
 plete circuit of the intestine, but are rather segments of circles, 
 
 * This is the generally received opinion of anatomists: it would appear, how- 
 ever, to be applicable only when the intestine is left attached to the mesentery; 
 for if it be cut off and straightened, it will measure thirty-four feet, which, added 
 to eight feet of large intestine treated in the same way, will amount in all to forty- 
 two feet. If to the estimate of this length we add what is lost by the doublings 
 of the mucous coat, the entire length of surface must amount to nearly sixty feet, 
 at least, in many subjects. 
 
INTESTINAL CANAL. 29 
 
 This coat is united to the peritoneal by a thin scattered cellular 
 substance. 
 
 The Cellular Coat of the small intestine, also called the ner- 
 vous, like that of the stomach, is only a lamina of condensed 
 cellular substance, which serves as a medium of connexion be- 
 tween the muscular and the mucous coat; and also conducts to 
 the latter the blood vessels, nerves, and lacteals. 
 
 The Mucous Coat is the most internal, and when it has been 
 cleaned by maceration, exhibits an opaque pearly colour. It is 
 remarkable for having its extent very considerably augmented 
 beyond that of the other coats; by being thrown into a great 
 number of permanent folds, or duplicatures, which lie one upon 
 another successively, like the shingles upon the roof of a house. 
 These duplicatures are the Valvulae Conniventes, and are for 
 the most part about three lines in breadth. They are either 
 placed in the direction of the circumference of the intestine, or 
 are very slightly oblique; generally they go all around, but 
 some of them are segments of circles, and by being arranged 
 successively, their ends pass one another, or are connected by 
 slight elevations. They are more numerous and broad in the 
 upper than in the lower half of the intestinum tenue, and are 
 evidently intended to retard the progress downwards of alimen- 
 tary matter, and to increase the surface for absorption and for 
 exhalation. 
 
 The mucous membrane, on the side which it presents to the 
 cavity of the intestine, is furnished with a great number of de- 
 licate cylindrical projections, resembling the down on the skin 
 of an unripe peach, and called Villi, from whence the term vil- 
 lous has also been applied to this coat. These villi are to be 
 found in abundance every where; but in the upper half of the 
 intestinum tenue they are so numerous as to stud its whole sur- 
 face, and to be in contact with each other. They are from one- 
 fourth of, to a line in length; and some of them, when examined 
 with a microscope, appear flattened and fungiform. According 
 to the estimate of Meckel,* where they are thickest, every 
 square inch of intestine furnishes about four thousand of them, 
 and by extending this computation, with a proper allowance for 
 
 * Manuel D'Anat. 
 
 VOL. II.-5 
 
30 ORGANS OF DIGESTION. 
 
 diminished numbers below, their aggregate amount is about one 
 million. 
 
 Each Villus is composed of an artery, a vein, and a lympha- 
 tic; all united by cellular substance. From the extreme vascu- 
 larity of the mucous membrane, the blood vessels readily re- 
 ceive a fine injection and thereby become evident, forming a 
 very delicate vascular net-work in each of the villi. It is ascer- 
 tained that the lymphatic opens on its surface, but whether by 
 one or more orifices is yet unsettled. According to the cele- 
 brated Lieberkuhn, there is commonly but one orifice at the end 
 of each villus, and very rarely two: this assertion he considered 
 himself as having established by passing a current of air through 
 the villus till it was dried, and then slitting it open. Hewson, 
 Cruikshank, and W. Hunter, on the contrary, are said to have 
 found many more, amounting even to twenty, on such villi as 
 were gorged with chyle. The subject has been fruitful with 
 controversy to anatomists, and ranks many distinguished cham- 
 pions on each side; but as from the minuteness of the parts un- 
 der discussion and the consequent necessity of microscopical 
 observations, it is exposed to much fallacy and illusion; it can- 
 not be satisfactorily settled, though the general analogies of 
 papillary structure are in favour of the latter authorities. The 
 more important fact, however, is ascertained by the admission 
 of all, that there is a branch of the lymphatic system in every 
 villus; which has, for its function, the absorption of chyle from 
 the cavity of the intestine. 
 
 An abundance of Mucous Glands is found deposited in the 
 cellular coat of the small intestine, between the muscular and 
 the villous; the ducts of which open upon the internal surface of 
 the latter, in the interstices of the villi, and from'their smallness 
 require the intestine to be floated in water, and examined with 
 a magnifying glass, before they can be recognised. In order 
 to see the glands themselves, the intestine must be cleaned by 
 soaking it in water; it is then to be slit open longitudinally, and 
 held between the eye and the light, in which case the glands 
 appear like little points or spots in the thickness of the intestine. 
 They are more abundant in the beginning of the latter, decrease 
 about its middle, and increase again towards its termination. 
 
INTESTINAL CANAL. 31 
 
 Their structure is very simple, as they consist in a congeries of 
 blood vessels, terminating in short canals secreting mucus.* 
 
 Some of these glands are microscopical, and are called cryptae; 
 others are to be found from that size to a line in diameter, and 
 flattened. They are either alone or in clusters. The former 
 ( Glandulce Solitarice, Brunneri) are found principally about the 
 duodenum and the neighbouring portion of the small intestine. 
 The latter ( Glandule Agminatce, Peyeri) exist principally in the 
 lower part of the small intestine, and are collected into clusters 
 varying from a few lines to three or four inches in length, but 
 seldom more than from eight to twelve lines broad. They are 
 for the most part in elliptical patches, which in a healthy state 
 may be recognised rather by a slight discoloration, than by the 
 more ordinary means, and are generally situated some distance 
 from the mesentery. There are about thirty of these clusters, 
 of all sizes, in the ileum, and they are placed nearer and nearer to 
 one another, in approaching the ileo-colic junction. All of these 
 muciparous glands are too much flattened to project sensibly into 
 the cavity of the intestine, and when they do, there is reason to 
 believe that they are in a diseased state, at least in the adult: for 
 the most part, in children, the glands of Brunner may be seen in 
 the whole length of the small intestine. 
 
 The mucous coat of the small intestine is extremely vascular. 
 
 The Small Intestine, though an uninterrupted tube from one 
 end to the other, is divided by anatomists into Duodenum, Jeju- 
 num, and Ileum. There is some reason for the first name, but 
 the two latter may be very conveniently blended, as has been 
 done by some, under the term Mesenteric Portion of the intes- 
 tinal canal. 
 
 The Duodenum, named from its being about twelve inches, or 
 twelve fingers % ' breadth in length, is nearest to the stomach; or, 
 in other words, is the commencement of the canal. It is larger 
 than either of the others, and is, moreover, susceptible of great 
 dilatation, whence it has also been called Ventriculus Suceentu- 
 
 * Soemmering, de Corp. Hum. Fabrica. 
 
32 ORGANS OF DIGESTION. 
 
 riatus. Its direction is much varied: beginning at the pylorus, 
 it first of all passes upwards and to the right side, till it reaches 
 the neck of the gall-bladder; it then turns downwards, so as to 
 form a right angle with itself, and descends in front of the right 
 kidney to the third lumbar vertebra, being there placed behind 
 the superior lamina of the transverse mesocolon. It then forms 
 a round elbow, crosses the spine obliquely, under the junction of 
 the mesentery and mesocolon, in ascending from right to left; 
 and making its appearance to the left of the second lumbar ver- 
 tebra, is there continued into the mesenteric portion of intestine. 
 
 The beginning of the duodenum is moveable, and has a pe- 
 ritoneal coat continued from the lesser omentum; the descend- 
 ing and the transverse portions have no proper peritoneal coat, 
 but are only loosely fixed between the laminae of the mesocolon ; 
 the termination is both moveable and has a peritoneal covering, 
 from being at the commencement of the mesentery. 
 
 From the course assigned to the duodenum, it is evident that 
 it forms the segment of a circle, the concavity of which looks to 
 the left side. This concavity is occupied by the head of the 
 pancreas. The transverse portion crosses the spine below the 
 latter, and is separated from it by the superior mesenteric artery 
 and by the vena portarum: behind it are the crura of the dia- 
 phragm, the ascending cava, and the aorta. 
 
 The organization of the duodenum is the same with that of 
 other portions of the intestinum tenue. Its peculiarities consist 
 only in a partial deficiency of peritoneal coat, and in its aug- 
 mented size. Its internal or mucous coat is very much tinged 
 with bile, abounds in valvulae conniventes, and about four inches 
 from the pylorus is marked by a small tubercle or elevation, in- 
 dicative of the orifice of the biliary and of the pancreatic ducts. 
 The Glands of Brunner are very conspicuous in this intestine, 
 and are so numerous near .the pyloric orifice, as to form with 
 some a perfect layer. 
 
 The Jejunum and Ileum form the remaining length of the 
 small intestine, and have no external marks of difference from 
 each other. They are strung along the mesentery, and, in con- 
 sequence of their great length, are thrown into folds or t convolu- 
 tions, which give to them a complicated appearance. There is, 
 however, no difficulty in tracing them regularly from one end to 
 
INTESTINAL CANAL. 33 
 
 the other. They occupy the umbilical, the hypogastric, and a 
 part of the iliac regions, and are surrounded by the circuit of 
 the colon. The upper two-fifths is the jejunum, and the lower 
 three-fifths, the ileum. This distinction, originally introduced by 
 Galen,* from a supposition that the jejunum was more fre- 
 quently found empty than any other intestine, has no rigid ana- 
 tomical support. The only difference between the two is, that 
 the valvulae conniventes, abundant in the whole length of the je- 
 junum, become less so at the upper part of the ileum, and finally 
 disappear entirely towards its lower extremity. The distinction 
 has, therefore, been rejected by the most approved modern au- 
 thorities, such as Haller, Scemmering, Meckel, and so on. 
 
 It sometimes happens, that the intestinum tenue has one or 
 more blind pouches appended to its sides and opening into its 
 cavity. 
 
 The small intestine is supplied with blood from the superior 
 mesenteric artery ; its nerves come from the sympathetic. 
 
 The Mesentery (Mesenterium) is a process of peritoneum 
 which serves, as mentioned, to connect the intestinurn tenue to 
 the posterior parietes of the abdomen, and extends its connex- 
 ions from the left side of the second lumbar vertebra to the right 
 iliac fossa. This attachment, called the root, is about six inches 
 in length ; whereas its lower circumference, which encloses the 
 small intestine by giving it a peritoneal coat, is, of course, the 
 whole length of the bowel, (duodenum excepted,) and, conse- 
 quently, from twenty-three to twenty-seven feet in length. This 
 expansion becomes intelligible the moment that the arrangement 
 of the part is inspected, and is somewhat after the manner of a 
 ruffle, except that it is not puckered at the root. 
 
 The two laminae of peritoneum which form the mesentery, 
 contain between them the superior mesenteric artery, and the 
 corresponding portion of the superior mesenteric vein ; an abun- 
 dance of lymphatic or lacteal glands and vessels ; ramifications 
 from the solar plexus of the sympathetic nerve ; and a considera- 
 ble quantity of cellular and of adipose tissue. The superior la- 
 mina is continued directly into the mesocolon, and at the place, 
 of junction the transverse part of the duodenum is very percep- 
 tible beneath. The lower lamina descends along the posterior 
 
 * Portal, Anat. Med. 
 
34 ORGANS OF DIGESTION. 
 
 parietes of the abdomen, concealing the large blood vessels 
 there and the ureters. 
 
 Of the Large Intestine. 
 
 The Large Intestine (Intestinum Crassum) receives the effete 
 matter from the small, and is supposed also to have some pecu- 
 liar secretion of fcecal matter from the internal surface. It ex- 
 ceeds much in. its diameter the small intestine, and differs also 
 from it in not being by any means so regularly cylindrical. It 
 commences at the inferior end of the small intestine, and termi- 
 nates at the anus, describing in this course, as mentioned, a cir- 
 cle which surrounds two-thirds of the abdomen, and embraces 
 the intestinum tenue. Like the latter, though only a continuous 
 tube, it is divided into three parts ; the commencement of it, 
 which is below the insertion of the-ileum, and about two inches 
 in length, is the Coecum, or Caput Coli; the remaining portion, 
 which occupies almost its whole length, is called the Colon, 
 until it reaches the pelvis, when the name is converted into 
 Rectum. 
 
 The Mesocolon is a reflection or duplication of peritoneum, 
 that fixes the large intestine to the posterior parietes of the abdo- 
 men. This duplicature is not of a breadth so uniform as the 
 mesentery, but allows to the middle of the large intestine very 
 considerable motion, up and down, according to the distention 
 of the stomach, while the lateral portions are very much confined. 
 For example, in the right iliac fossa the mesocolon is so short 
 that the posterior surface of the gut is in contact with the iliac 
 fascia, and adheres to it by loose cellular substance ; in the right 
 and left lumbar regions the bowel is immoveably fixed in front 
 of the kidneys, but in the space between these two points, that is 
 to say, where the bowel traverses the hypochondriac and the 
 epigastric or umbilical regions, the peritoneal attachment, here 
 called, from its situation, the transverse mesocolon, is so long 
 and loose that it forms a complete and moveable septum between 
 the small intestine and the stomach. In the left iliac region, 
 again, the large intestine, after having been bound down to the 
 left lumbar, is suddenly loosened by an increased breadth of the 
 
INTESTINAL CANAL. 35 
 
 mesocolon, which permits it to form a large convolution, called 
 ifs sigmoid flexure. The mesocolon is then continued into the 
 pelvis in front of the sacrum, first of all a little to the left of the 
 middle line of the latter, and, as it descends, it gets directly in 
 front of the middle line. The portion of it in the pelvis is called 
 mesorectum, after the gut which it serves to attach. 
 
 The composition of the mesocolon is precisely the same with 
 that of the mesentery, though it be not so thick: it, therefore, 
 consists in two laminae of peritoneum, which contain between 
 them some adipose and cellular matter, along with the arteries, 
 the veins, the nerves, and the lymphatic vessels and glands be- 
 longing to the large intestine. 
 
 When the large intestine is inflated, it is rendered very ob- 
 vious that it decreases in size from its commencement to the 
 lower part of the sigmoid flexure, it then increases again in size 
 just above the anus. Its surface is arranged into three series or 
 longitudinal rows of projections, separated by transverse depres- 
 sions, the whole corresponding with an internal cellular arrange- 
 ment, by the latter surface being the reverse of the former. 
 
 Its coats, like the small intestine, are four in number ; the pe- 
 ritoneal, the muscular, the cellular, and the mucous. 
 
 The Peritoneal Coat prevails in its whole extent, with the 
 exception of the lower part of the rectum: on the ascending and 
 the descending portions of the colon, however, where the latter 
 comes in contact with the parietes of the abdomen, the perito- 
 neum does not invest it entirely ; but the transverse portion or 
 the arch, as it is called, and the sigmoid flexure, are completely 
 surrounded. 
 
 The surface of this intestine is studded with small projections 
 of various lengths, called Appendices Epiploicae, which are small 
 duplicatures of peritoneum containing fat. 
 
 The Muscular Coat is thin, like that of the small intestine, and 
 consists in two orders of fibres, the longitudinal, and the trans- 
 verse or circular. 
 
 The longitudinal fibres have the peculiarity of being collected 
 into three equidistant, flattened fasciculi or bands, of about half 
 
36 ORGANS OF DIGESTION. 
 
 an inch in breadth, which begin by a common point at the ex- 
 tremity of the coecum, and extend to the upper end of the rec- 
 tum. One of them is along the line of junction with the meso- 
 colon, another anterior, and the third inferior. These fibres, 
 being shorter than the other coats of the gut, have the effect of 
 puckering them into the internal cellular condition alluded to; 
 for, when they are cut through, the intestine is much elongated,- 
 and its cells disappear. It occasionally happens that the longi- 
 tudinal fibres, instead of being confined to the bands alluded to, 
 exist in considerable quantity over the intermediate spaces; in 
 this case the cellular arrangement is restricted, and in some in- 
 stances entirely dispensed with ; of the latter, an example is in 
 the Anatomical Museum. 
 
 The circular muscular fibres form a thin semi-transparent la- 
 mina beneath the last, and do not present any peculiarity of in- 
 terest. 
 
 The Cellular Coat is a condensed thin lamina of cellular sub- 
 stance, serving to connect the muscular with the mucous coat, 
 and to conduct the blood vessels and nerves to their terminations 
 on the latter. 
 
 The Mucous Coat lines smoothly the internal face of the cel- 
 lular, and has no doublings or folds, exclusively in it, like the 
 valvulae conniventes of the small intestine. * - The transverse 
 projections which it makes between the longitudinal bands, into 
 the cavity of the gut, and which separate the cells of the large 
 intestine from each other, are not mere duplicatures of it alone, 
 but are also constituted by the other coats. 
 
 Near its commencement this coat has the fungous appearance ' 
 of the stomach, but about the sigmoid flexure it has a plane, 
 smooth, and, to a degree, a polished surface. It has but few 
 villi, such as exist in the small intestine; indeed, by some anato- 
 mists it is denied that it has any. Its muciparous glands and 
 follicles are numerous, and the former, when somewhat enlarged, 
 project; they are unusually conspicuous about the sigmoid 
 flexure, and in the rectum. Its lacteals are not abundant 
 
 * This may be considered as the general rule: if it be examined, however,, 
 in its whole length, here and there narrow ones may be found. 
 

 VTESTINAL CANAL. 37 
 
 The mucous coat of the large intestine is very vascular, but 
 not so much so as that. of the small intestine. 
 
 Each division of the large intestine has some peculiari- 
 ties of structure and connexion; which may now be attend- 
 ed to. 
 
 The Coecum, or Caput Coli, is generally from an inch and a 
 half to two inches long, has a rounded termination below and 
 somewhat to the left, from which proceeds an intestinal pro- 
 cess, the Appendicula Vermiformis. The latter is from three 
 to four inches long, is cylindrical, has a diameter of two or three 
 lines, and consists also of the same number of coats, having the 
 same structure with other portions of the intestinal canal; its 
 base is the point from which the three longitudinal bands start. 
 It is attached by a narrow duplicature of peritoneum, a process 
 of the mesentery, which permits it to float loosely in the abdo- 
 men. It seldom contains faeces, but it is kept distended by 
 flatus. 
 
 The coecum, as mentioned, is for the most part confined to 
 the right iliac fossa, but we very frequently see it with a length 
 of peritoneal attachment permitting it to descend for a short 
 distance into the pelvis. 
 
 The Ileo-colic Valve ( Valviila Bauhini} is formed at the 
 junction of the ileum with the caput coli. This valve, destined 
 to prevent the return of faecal matter from the large into the 
 small intestine, consists in a transverse elliptical opening, or 
 slit, whose lips become approximated in the distentions of the 
 colon. The ileum runs into the left wall of the large intestine, 
 and continues its cellular and mucous coats into the correspond- 
 ing coats of the latter. The circular muscular fibres of the large 
 intestine separate to a certain degree to permit this introduction, 
 but their farther separation is restrained at each commissure or 
 corner of the lips, by a blending of the structure, aided by a 
 few ligamentous fibres, designated as the retinacula of Bauhin 
 or of Morgagni; which, however, are frequently not very dis- 
 tinct. This separation is also restrained by the two longitudinal 
 bands between which they are inserted, one of which is at the 
 posterior commissure and the other only a short distance off 
 VOL. II. 6 
 
38 ORGANS OF DIGESTION. 
 
 from the anterior. The lips themselves, formed principally by 
 the mucous membrane, approach one another after the man- 
 ner of the ship dock or canal gate; the superior is somewhat 
 broader than the inferior. Their power, as well as their 
 existence depend entirely on the tension which is kept up by 
 the natural connexions of the parts; for a very slight dissection 
 causes them to become almost effaced, and instead of forming 
 an elliptical transverse opening, to be converted into a round 
 patulous one. 
 
 
 The Colon, properly speaking, has some regional distinctions 
 which are serviceable to accurate description. The right lumbar 
 colon, which is bordered in front by the small intestine, and 
 behind, by the right kidney, extends from the ileo-colic valve, 
 to the margin of the false ribs of the corresponding side. The 
 transverse colon, bordered above by the stomach, and below by 
 the small intestine, goes from one hypochondriac region to the 
 other. It is generally found more distended than the other 
 portions. The left lumbar colon descends from the hypo- 
 chondriac region of the left side to the sigmoid flexure, being 
 bordered behind by the left kidney, and in front by the small 
 intestine. The sigmoid flexure, placed in the left iliac fossa, 
 forms a convolution, but is very indifferently described by the 
 term applied to it. It is occasionally very long and loose, and 
 terminates at the left sacro-iliac symphysis. It is not unfre- 
 quently found destitute of the partitions which prevail in other 
 parts. 
 
 The Rectum begins at the left sacro-iliac symphysis, and 
 passes obliquely downwards to the centre of the sacrum, thence 
 in front of the middle line of the sacrum, and of the coccyx, to 
 terminate at the point of the latter. It is not regularly cylin- 
 drical, but, just above the anus, is dilated into a w r ide pouch, 
 flattened from before backwards by the pressure of the bladder, 
 and very distinguishable upon the introduction of the finger, for 
 it is but seldom in a contracted state. It, of course, has a flexure 
 by adapting itself to the concavity of the sacrum, and is bound- 
 ed in front by the bladder, the prostate gland and the vesiculae 
 seminales of the male, and by the vagina and the uterus of the 
 female. 
 
INTESTINAL CANAL. 39 
 
 The peritoneum covers only the superior two-thirds of the 
 rectum, and attaches it by the short duplicature, called the me- 
 sorectum, to the front of the sacrum. A small pouch, passing 
 down between the vesiculae seminales almost to the base of the 
 prostate, is formed, as mentioned previously, by the peritoneum 
 in its course from the rectum to the bladder. 
 
 The muscular coat of the rectum has a thickness and redness 
 surpassing much that of any other intestine, and is divided very 
 clearly into two laminae, the external of which consists in lon- 
 gitudinal and the internal in circular fibres. The external forms 
 in itself a complete coat continuous with the longitudinal bands 
 of the colon, but is much increased by additional fibres. The 
 circular fibres also form a complete coat, and, just below the 
 pouch of the rectum, are multiplied so much for eight or ten 
 lines as to be a perfect internal sphincter muscle, bearing a 
 strong analogy with the pyloric muscle of the stomach. At the 
 anus, an arrangement of the muscular coat prevails, which, as 
 far as I know, has not been heretofore attended to by anato- 
 mists. The longitudinal fibres, having got to the lower margin 
 of the internal sphincter, turn under this margin between it and 
 the external sphincter, and then ascend upwards for an inch or 
 two in contact with the mucous coat, into which they are final- 
 ly inserted by fasciculi which form the base of the columns of 
 the rectum; many of the fibres, however, terminate also between 
 the fasciculi of the circular fibres. This connexion roust have 
 obviously much influence in the protrusions of the mucous coat, 
 which sometimes take place. 
 
 The mucous coat of the rectum is thick, red, and fungous, 
 and abounds in mucous lacunas and glands. It is smoothly laid 
 above, but below it is thrown into superficial longitudinal folds 
 called columns. At the lower ends of the wrinkles, between 
 the columns, are small pouches of from two to four lines in 
 depth, the orifices of which point upwards; they are occasional- 
 ly the seat of disease, and produce, when enlarged, a painful 
 itching. An original observation of Dr. Physick, on the nature 
 of this affection, and the remedy for which consists in slitting 
 them open or removing them, induced me to look for the ordi- 
 nary natural structure, which I have found to be as now de- 
 
40 ORGANS OP DIGESTION. 
 
 scribed.* The wrinkling of the anus is from the influence of 
 the external sphincter ani muscle. In some subjects, large 
 cells are formed in the cavity of the rectum by transverse 
 doublings of the mucous coat only, resembling the valvulae con- 
 niventes of the small intestine; this, however, is not the most 
 frequent arrangement, though deserving of notice. 
 
 The large intestine is supplied with blood from a part of the 
 superior mesenteric, from the whole of the inferior mesenteric, 
 and from the internal pudic artery. Its veins empty into the 
 vena portarum. Its nerves are derived from the solar and the 
 hypogastric plexus of the sympathetic. 
 
 SECT. III. ON THE MINUTE ANATOMY OF THE MUCOUS COAT 
 
 OF THE ALIMENTARY CANAL. 
 
 In the preceding account of the mucous coat of the stomach 
 and bowels, I have admitted the most generally received opi- 
 nions, as it is in every way proper for medical men to be aware 
 of them. Having been, however, much occupied, a short time 
 ago, in ascertaining the pathology of Asiatic cholera by dissec- 
 tions, the observations which I then made upon the healthy 
 and diseased structure have induced me to modify very much 
 my former views^ as will be seen in the following pages, f 
 
 The mucous coat of the alimentary canal, in a healthy state, 
 and successfully injected, appears to consist almost entirely of 
 a cribriform intertexture of veins; these veins being commonly 
 empty at death present themselves as a soft spongy structure, 
 which gives rise to the ordinary description of its sensible con- 
 dition as a velvety layer. The most minute injection of the ar- 
 teries scarcely makes itself visible among these veins when they 
 are properly injected, a straggling branch only here and there 
 exhibiting itself. The arborescence of the arteries is confined 
 to the level beneath the venous intertexture, and is there deve- 
 
 * See an interesting paper on Fistula in ano, by M. Ribes, in Mem. de la So- 
 ciete" D'Emulation, vol. 9, 1826; where the influence of this structure is al- 
 luded to. It appears that Glisson and Ruysch first described them as valves. 
 Also, an elaborate and excellent article by Dr. Reynell Coates, in the Cyclopaedia 
 of Pract. Med. and Surgery, Philada. 1835, under the term anus. 
 
 - Amer. Journ. Med. Sciences for 1835. 
 
ANATOMY OF THE MUCOUS COAT. 41 
 
 loped to an extreme degree of minuteness, being intermixed 
 with corresponding venous ramuscles, generally larger and more 
 numerous than the arteries themselves. The fine venous trunks 
 of this deeper layer have their originating extremities bent ver- 
 tically towards the cavity of the gut, and by that means receive 
 the blood of the first venous intertexture or layer, as the petrous 
 sinuses join the cavernous, or the veins of the penis arise from 
 its spongy structure. The meshes of the first venous intertex- 
 ture are exceedingly minute, and vary in a characteristic man- 
 ner in the stomach, small intestines and colon. This intertex- 
 ture is very different in its looks from a common vascular anas- 
 tomosis, and produces in the colon an appearance resembling 
 a plate of metal pierced with round holes closely bordering upon 
 each other; these holes constitute, in fact, follicles or gaping ori- 
 fices, the edges of which are rounded off, and their depth is that 
 of the thickness of the venous anastomosis being bounded be- 
 low by the arterial venous layer, and by the cellular coat of the 
 part Nothing short of an entirely successful injection will 
 exhibit this venous anastomosis as described; and it may be seen 
 either by injecting a vein or an artery, provided the injection 
 passes from the artery into the veins, but the latter process is 
 the least desirable, because we lose the benefit of a distinction 
 of colour between the two sets of vessels. 
 
 Ordinary modes of examination give no evidence of the exis- 
 tence in the alimentary canal, from the cardiac orifice of the 
 stomach to near the anus, of an epidermis; on the contrary, they 
 rather lead to a belief of its being absent, in consequence of the 
 softness, tenuity, and transparency of the mucous membrane; 
 but that it is really present, may be proved by the following 
 process: Tear off the peritoneal coat invert the part and in- 
 flate it to an emphysematous condition; the epidermis will then 
 be raised as a very thin pellicle, and may be dried in that state; 
 but as this pellicle retains the air, we hence infer that it lines 
 the follicles, and is uninterrupted by any perforations. This 
 epidermis, if the part be previously Injected perfectly, shows 
 dots of injecting matter, but no arborescence if it be inflated up 
 from the veins. In so doing the villi disappear, are in fact un- 
 folded. 
 
 The villi cannot be seen to any advantage except they be 
 
42 ORGANS OP DIGESTION. 
 
 erected by an injection, in which case those of the upper part 
 of the small intestines are found to run into each other very 
 much like the convolutions of the cerebrum, and to press upon 
 each other's sides in the same way. Some of them, however, 
 are merely semi-oval plates, the transverse diameter of which 
 exceeds the length. At the lower end of the small intestine 
 they become simply conical projections, somewhat curved, 
 with the edges bent in, and they retain this mechanism until 
 they entirely disappear near the ileo-coli6 valve. In the whole 
 length of intestine there is, however, every variety of shape, 
 from oblong curved and serpentine ridges, to the flattened cone 
 standing on its base; the first condition changing gradually to 
 the last in the descent of the bowel. Conformably to this de- 
 finition of villi, none exist either in the stomach or colon, for 
 there we have only the venous mesh. The villi of the jejunum 
 are about the thirtieth of an inch high, and those of the ileum 
 about one-sixtieth. 
 
 The superficial venous layer has great regularity in the ileum, 
 and the conical villi stand out beautifully from its partitions, or 
 in equivalent language, from the divisions of the follicles. In 
 the upper part of the small intestine the follicles are in equal 
 number to what they are in the ileum; the regularity of their 
 arrangement being interrupted by the long serpentine and oval 
 villi; but invariably the same venous intertexture exists and 
 forms in both the chief bulk of the villi, by passing into them. 
 
 In the stomach the follicles vary much in size, and there is 
 an arrangement whereby many of the smaller ones are seen to 
 open into the larger: on an average about two hundred and 
 twenty-five are found upon every eighth of an inch square, 
 which would give of course to an inch square sixty-four times 
 that amount, or fourteen thousand four hundred follicles; and 
 conceding the whole stomach to present an area of ninety 
 inches, which is probably below the mark when this organ is 
 moderately distended, as exhibited in the preparation upon which 
 this calculation is founded, the entire number of follicles is one 
 million tioo hundred and ninety-six thousand. 
 
 The great uniformity of size of these follicles in the colon, 
 and its even surface, enable us to count them with more cer- 
 tainty, and they appear to exist at the beginning of this gut at 
 
ANATOMY OF THE MUCOUS COAT. 43 
 
 the rate of about four hundred for every eighth of an inch 
 square, but in the sigmoid flexure at the rate of about two hun- 
 dred to the same area; they become, in fact, both smaller and 
 less numerous in descending towards the anus. Admitting the 
 entire area of the colon to be five hundred inches, and nineteen 
 thousand two hundred of these follicles, on an average, to exist 
 on every inch square, the aggregate number will be nine mil- 
 lions six hundred and twenty thousand. 
 
 Again, estimating the whole area of the mucous coat of the 
 small intestines at fourteen hundred and forty inches, and al- 
 lowing for interruptions occasioned by villi, about twenty-five 
 thousand follicles are found upon every square inch, and the 
 two numbers multiplied, produce thirty-six millions. 
 
 The entire number of follicles in the whole alimentary canal 
 is, by the preceding estimates, forty-six millions nine hundred 
 thousand, and upwards. I am very far from pretending to 
 have counted them all, but have made an approximation to the 
 actual number by observing sections of different portions of the 
 same subject, and verifying the observations upon other subjects. 
 The external surface of the cutis vera presents, as it were, in 
 outline the same arrangement; the venous reticular intertexture 
 appearing broader, not quite so perfect, and more shallow, and 
 forming the papillae; tjutas additional experiments are wanting, 
 it may be passed over with this transient notice; perhaps, 
 indeed, a more skilful hand in adopting the hint may perfect 
 the details. 
 
 In the stomach, the largest of these follicles is about ^\\\ of 
 an inch in diameter, and the smallest about T Jo-th. In the co- 
 lon the largest is about ^Jyth of an inch in diameter, and the 
 smallest about -^th. In the small intestines their size varies 
 in about the same ratio as in the colon, but they are much more 
 irregular in shape, being scattered more in groups in conse- 
 quence of the villi intervening: some of them penetrate oblique- 
 ly towards the foundations of the villi; hence, when examined 
 from the exterior, their distribution is more regular, and they 
 are seen lodged in the cellular coat of the gut. 
 
 I have endeavoured to keep the estimate of the number of 
 follicles below what other calculators would make it upon an 
 observation of my preparations, and a fair measurement of the 
 
44 ORGANS OF DIGESTION. 
 
 area of the alimentary canal,- lest the number may seem exces- 
 sive and incredible; I have therefore the most reasonable as- 
 surance of being within bounds on that point. I may now ask 
 their use; is it to secrete or absorb? If they are simply se- 
 cernents of mucus, the number, one would think, much greater 
 than so limited a secretion requires moreover, why is it that 
 they become smaller and less numerous towards the lower end 
 of the large intestine, where greater lubrication is required for 
 hardened faeces; in addition, are not the glands of Brunner, (so- 
 litarige,) and of Peyer, (agminatse,} amply sufficient to furnish 
 the required mucus? Again, after most sedulous observations 
 upon the villi of all kinds, finely erected by my injections, and 
 placed under most accurate, simple, and compound microscopes, 
 J find invariably a polished reflecting surface, uninterrupted by 
 foramina, either at their ends or sides, while many of these fol- 
 licles are found passing obliquely into their bases. An excel- 
 lent Woollaston's doublet, which makes the villi of the ileum 
 appear an inch long, exhibits them with a polished translucent 
 surface, without foramina, except where a villus from accident 
 has been broken, a contingency readily recognised by one in 
 the habit of viewing them. Finally, if the lacteal foramina of 
 Lieberkuhn and others, do exist in fact, why is it that the 
 raising of the intestinal epidermis by inflation does not exhibit 
 these foramina by the air escaping through them, but on the 
 contrary, admits of a dried preparation in that state, the villi 
 being completely effaced. 
 
 In these and other microscopical observations, I have been 
 much assisted by my young friend, Dr. Paul Beck Goddard, 
 who has acquired an accuracy and skill in such matters deserving 
 of confidence. 
 
 Taking into consideration these several objections to the theo- 
 ry of the follicles being secreting orifices, it appears to me that 
 a better idea of their use is called for, which suggestion is sub- 
 mitted to the profession, with the hope that a more capable per- 
 son will remove the difficulty by additional confirmation of pre- 
 ceding theories, or by the invention of a new one: for my own 
 part, I am much inclined to adopt the opinion of their absorb- 
 ing faculties. It is generally conceded that the erection and pre- 
 hension of the Fallopian tube is produced by a vascular tur- 
 
ANATOMY OF THE MUCOUS COAT. 45 
 
 gescence, in which the veins, from their number, must execute 
 an important part; in like manner as these follicles are formed 
 in the midst of veins, their orifices only become erect and pa- 
 tulous by the distention of those veins, and cannot be seen, 
 especially in the small intestine, unless an injection has suc- 
 ceeded fully; but the erection of these veins during digestion 
 puts the follicles in a similar condition; there is therefore some 
 ground of inference, that the act of the Fallopian tube in con- 
 veying a germ, and of a follicle in conveying into the thick- 
 ness of an intestine congenial matter, may be analogous. 
 
 Notwithstanding the facility with which I can detect these 
 follicles, I have failed entirely under various means of exami- 
 nation, in finding any orifices to Peyer's glands, in the dried 
 intestine; they appear to be merely small lenticular excavations 
 in its substance, and wherever a cluster of them exists, it dis- 
 turbs the arrangement of the villi, and gives to them a scatter- 
 ing unequal distribution. I would also suggest very respecful- 
 ly to anatomists whether our knowledge in regard to them is 
 sufficiently exact to render farther inquiry useless? for my own 
 part it appears that this subject requires some additional attention. 
 
 The above view, relative to the structure of mucous membrane, 
 presents at least a degree of novelty, by determining, with some 
 precision, the whole number of the G astro -enteric Follicles of 
 the human body, and how they are in every instance formed by 
 meshes of veins, while the arteries enter only inconsiderably into 
 their composition, to an amount in some measure comparable to 
 the presence of the arteries in other erectile tissues, as the corpus 
 spongiosum and cavernosum penis. In the latter it is familiar to 
 every practised anatomist, that the branches of the arteries are 
 but small, as they terminate in the cells of the penis, which are 
 to be considered as only a modification of the incipient stage of 
 venous trunks. If the corpus spongiosum were in fact spread 
 out into a thin membrane, so as to line a hollow viscus, it would 
 present no very exaggerated representation of what I have de- 
 nominated the superficial venous layer of the alimentry canal; 
 it being also admitted that within the circuit of every anasto- 
 mosis a follicle was formed. Viewed on the preparations of the 
 mucous membrane of the small and large intestines which I 
 have, these follicles appear like puncta lachrymalia disseminated 
 VOL. II. 7 
 
46 ORGANS OF DIGESTION. 
 
 by thousands over every inch square, and existing so invariably 
 upon every part that, as I have stated, the smallest calculation 
 of their numbers puts them at from forty to fifty millions. It is 
 now to be borne in mind, that it is the whole of this vascular 
 and follicular structure, endowed with the vital actions the most 
 important to life, and presenting in the aggreate an area of about 
 thirteen square feet, the size of a small breakfast table; whose 
 morbid derangements constitute the essential features of cholera. 
 It has been shown in some of my dissections, that this ap- 
 paratus in the progress of cholera is detached entirely from the 
 stomach and colon, in consequence of the excessive actions go- 
 ing on in them. The small intestines also, in some of my pre- 
 parations, exhibit in patches a similar phenomena; but as the 
 entire observation has been presented to me in its true light 
 only since the disappearance of the disease, I have no means of 
 ascertaining the extent to which they suffer in this way. 
 
 The anatomy of the muciparous system of the alimentary ca- 
 nal unquestionably requires a more exact attention than has been 
 heretofore bostowed upon it, especially so as to distinguish be- 
 tween that part which is really glandular, and the foramina or 
 follicles now under consideration. The following extract will 
 explain the difficulty which still exists in regard to a proper 
 conception of the latter. 
 
 "The mucous glands, called also follicles or cryptse mucosse, 
 are to the membranes of that name what the sebaceous follicles 
 are to the skin; that is to say, folds of the mucous membrane 
 in form of a cul-de-sac, whose orifices open upon that mem- 
 brane. These follicles have not yet been discovered over the 
 whole surface of the mucous membrane; but here, as with the 
 skin, analogy leads us to admit them. It is not long since they 
 have been discovered in the pituitary membrane, where their 
 existence had been denied. Be this as it may, we shall use the 
 same observation upon these glands that was made on the seba- 
 ceous, viz. the impossibility of making an exact dissection of the 
 capillary tissues does not allow us to discover all the forms of 
 animal matter; but wherever a particular humour is found in a tis- 
 sue, we are forced to conclude that this latter is organized in such 
 a manner as to be able to produce it, and when in place of one 
 humour we meet with many, we must acknowledge that the 
 
ANATOMY OF THE MUCOUS COAT. 47 
 
 tissue is complex. Such is precisely the case with the mucous 
 membrane of the digestive canal, and especially of the stomach, 
 which could have a form of animal matter calculated to furnish 
 digestive juices, although no gland destined to that purpose is 
 discoverable."* 
 
 This desideratum of positive evidence, instead of the induc- 
 tive, is clearly supplied to M. Broussais by my preparations. 
 In infancy, especially, the glands have a sensible thickness, 
 which enables us to see them, but the smallest of them require 
 the aid of a microscope, and appear to have been described by 
 Galeati.t As the paper is not to be had in any of the public 
 libraries of this city, I can only. quote from it on the current 
 authority of anatomical works. In a note to the anatomy of the 
 human body by Sir Charles Bell, article Intestine, it is stated 
 as follows: "It has been supposed that the fluids excreted from 
 the surface of the intestines were furnished by very minute fo- 
 ramina, (which are visible by particular preparations,) in the 
 interstices of the villi. See the letter of Malpighi to the Royal 
 Society of London on the pores of the stomach, and the paper 
 by M. Galeati in the Bologna Transactions, on the inner coat, 
 which he calls the cribriform coat. The pores, according to Ga- 
 leati, are visible through the whole tract of the canal, and par- 
 ticularly in the great intestines." Meckel designates these as 
 glandular bodies under the name of glandulx mucosae, cryptse 
 minimae. Another order of glands are those of Brunner.J They 
 are readily found in the duodenum at all ages; and particularly 
 well in infancy, as low down as the ileo-colic valve. The third 
 order are the glands of Peyer, discovered in 1677. The cele- 
 brated Ruysch appears also to have understood the existence of 
 the follicles of the stomach, and Svvammerdam to have had some 
 idea of those of the small intestines,|| and he calls them tubuli 
 glandulosi intestinorum interiores. I may here remark, that 
 the account of the villi of the small intestines given by Hedwig, 
 
 * Broussais' Physiology. First American edition, p. 419. 
 
 -j- De cornea ventriculi et intestinorum tunica. Comm Bonon. 1745. 
 
 $ Glandule intestini duodeni vel pancreas secundarius; discovered in 1715. 
 See Mangetus, Theat. Anat. where this paper is introduced with the plates illus- 
 trative of it. 
 
 See also Mangetus for the description from Peyer, with his plates. 
 
 || Mangetus Theat. Anat. Vol. I. p. 310. 
 
48 ORGANS OF DIGESTION. 
 
 in his Disquisit. Ampullarum, &c. 1797, and which appears, 
 from its introduction into Caldani's and M. Jul. Cloquet's Anato- 
 my, to have a classical value, is, judging from my own prepara- 
 tions, too much a work of the imagination, executed under pro- 
 bably some fallacious views of the part itself: a cluster of cylin- 
 drical villi, with holes at the ends, would be an anomaly, for 
 those of the upper part of the intestines are either serpentine 
 folds, as represented in my plates, with branches running into 
 contiguous folds, or semi-oval laminae; while those lower down 
 are of a flattened conical shape, somewhat bent, but in every in- 
 stance they are destitute of what has been termed by Lieberkuhn 
 an ampulla, and to my eye have uniformly polished surfaces, 
 uninterrupted by foramina. 
 
 Mascagni has also introduced views of a good kind in regard 
 to the follicular structure of the stomach and colon.* But it is to 
 Sir Everard Home, that we are indebted for one of the best papers 
 on the glandular structure of the stomach of different animals.t 
 
 As the real muciparous glands have an orifice leading into 
 each by the admission of anatomists, the follicles described 
 commonly by them, are of this description, and are not compa- 
 rable in number to the follicles found in the venous meshes. 
 The highest estimate of the number of the former, as made by 
 M. Lelut, fixes them about forty-two thousand.! In consult- 
 ing many of the distinguished modern authorities on this sub- 
 ject, there seems to be scarcely any thing in the" anatomy of the 
 intestinal canal which is presented in a more indefinite way; 
 especially in regard to the small intestines, than the difference 
 between the follicles, properly speaking, and the glands; and 
 none of them, so far as I know, have undertaken to approximate 
 the entire number of the follicles. 
 
 SECT. IV. OF THE GENERAL ANATOMY OF THE MUCOUS MEMBRANES. 
 
 The extent of the mucous coat of the alimentary canal, and 
 the important and varied sympathies which it has with most 
 other parts of the body, render useful some remarks on mem- 
 
 * Prodrome delta grande anatomia. Tab. xiii. 
 
 f Phil. Trans. 1807 and 1817: and also his Comparative Anatomy. 
 
 t Bouillaud, Tra'rt du Cholera, p. 256. 
 
GENERAL ANATOMY OF THE MUCOUS MEMBRANES. 49 
 
 branes of this kind generally. Mucous Membranes are so called 
 from the nature of the secretion which they furnish : and the 
 term having been first applied to the lining coat of the nose, a 
 similitude of character has caused its extension to that of other 
 organs. The celebrated Bichat, the founder of the science of 
 general anatomy, was the first to adopt fully, and to perceive 
 the value of this classification ; since which it has been almost 
 universally received by anatomists. 
 
 As the skin forms an external covering to the body, so mu- 
 cous membrane lines the internal surface of the hollow viscera. 
 When it is recollected that this membrane forms an internal in- 
 tegument to the whole alimentary canal, from the mouth to the 
 anus ; to all of the urinary and genital apparatus ; to the whole 
 respiratory system, from the nose down the trachea and through- 
 out the lungs ; it will be admitted that its extension exceeds much 
 that of the skin. 
 
 A mucous membrane presents two surfaces, one of which ad- 
 heres to the contiguous parts, and the other is free by being in- 
 ternal. The adherent surface is attached by a cellular structure 
 somewhat condensed. This cellular structure is principally re- 
 markable for its want of disposition to secrete fat into its inter- 
 stices ; a property of immense importance, as without it, ob- 
 structions would be continually occurring to the destruction of 
 life : it is pervaded by a multitude of fine vessels and nerves, run- 
 ning forward to be spent upon the mucous membrane ; and has 
 been unfortunately named nervous coat, by anatomists of high au- 
 thority. The strength of attachment which it furnishes is some- 
 what varied ; for example, in the small intestinal canal I have 
 often seen the mucous membrane caught at one end and entirely 
 withdrawn from the other coats, an experiment which alone can 
 give rigid ideas of its greater length, as by it all the duplicatures 
 or valvulae conniventes are stretched out. The experiment suc- 
 ceeds much more certainly by the regular pressure of a column 
 of water between the tunics of the intestine. The mucous mem- 
 brane of most organs is arranged into wrinkles and duplicatures, 
 for the purpose of augmenting its extent. This arrangement pre- 
 vails in the nose, and, as mentioned, in the oesophagus, in the 
 stomach and intestines ; to say nothing of many other instances 
 which are noticed in the description of each organ. In some 
 
50 ORGANS OF DIGESTION. 
 
 examples, they are permanent, and, in others, depend on the 
 state of contraction of an exterior muscular coat. The interior 
 face of the mucous membranes, allowance being made for the 
 inequalities just stated, moreover, presents, when closely viewed, 
 an abundance of more minute depressions and of elevations, 
 causing it to resemble velvet. Some of these depressions are so 
 large as to give it a cellular appearance, as in many parts of the 
 intestinal canal, and the gall-bladder, and have been particularly 
 described by Sir Everard Home. 
 
 In regard to organization, the mucous membranes are of a 
 soft, spongy consistence ; easily yield to mechanical violence ; 
 and depend for their strength upon the surrounding cellular coat. 
 They are not of a uniform thickness ; for example, they are much 
 thinner in the urinary and genital apparatus, than in the alimen- 
 tary canal ; they also present some varieties of consistence. They 
 yield very readily to putrefaction, and are quickly reduced to a 
 pulpy state by the action of the mineral acids. Caustics of all 
 kinds act more promptly on them than on the skin, owing to the 
 protection of the latter by a dry epidermis ; Bichat states, that in 
 the practice of the Hotel Dieu, this effect is frequently exempli- 
 fied, by the administration of lunar caustic among the common 
 people for the purpose of poisoning. The nitric acid leaving the 
 silver, quickly applies itself to the mucous membrane of the sto- 
 mach, and disorganizing it, forms a whitish eschar, which, if life 
 be preserved long enough, is finally detached in a membranous 
 form. 
 
 One of the remarkable properties of the mucous surfaces of the 
 stomach and intestines is, that of coagulating milk. According 
 to the experiments of Spallanzani, the gastric juice, in the living 
 state, assists in this change; but it is perfectly well known in do- 
 mes.tic affairs, that the dried stomach of a calf, where the juices 
 have been completely evaporated, is also productive of it. The 
 observations of the same author led him to conclude, that the 
 peritoneal and the muscular tunics of the stomach are insufficient 
 to produce this effect. 
 
 The internal surface of all the mucous membranes is furnished 
 with small projecting points or spiculae, called papillae or villi. 
 They are particularly conspicuous and numerous, as mentioned, 
 on the upper surface of the tongue and in the small intestine, 
 
GENERAL ANATOMY OF THE MUCOUS MEMBRANES. 51 
 
 and bear an analogy of function and organization with the very 
 fine papillae which are seen invariably on the surface of the 
 cutis vera. These papillae are invariably furnished with ner- 
 vous filaments, giving them a high degree of sensibility; and 
 with an abundance of blood vessels. The term papillae has been 
 more exclusively applied to the projections on the surface of the 
 tongue, from their greater size ; they are there also more distinctly 
 covered with an epidermis, frequently called epithelium, or peri- 
 glottis. The villi-, from their connexion with the process of di- 
 gestion, have been emphatically denominated the roots of ani- 
 mals. According to M. Beclard,* who has examined them upon 
 a plan of his own contrivance well suited to" accurate microsco- 
 pal observations, they are presented under a diversity of shapes. 
 Those of the pyloric half of the stomach, and of the duodenum 
 being broader than they are long, are composed of very small 
 thin laminae, having a tufted arrangement. Those of the jeju- 
 num are long and narrow, having more the form commonly 
 assigned to them, while in the lower part of the ileum and in 
 the colon they again become laminated. 
 
 It should be observed that notwithstanding the assertion of 
 Lewenhoeck, Hewson, Hunter, and others, the fact is still called 
 in question, by two of the most distinguished anatomists of the 
 present time, MM. Beclard and J. F. Meckel, whether the orifices 
 of the lacteals are, under any circumstances, visible on the sur- 
 face of the villi. Admitting that they do not open as stated, the 
 power of interstitial absorption in the mucous membrane will 
 still account for the chyle finally getting into the lacteals, as well 
 as for fluids passing into the circulation from the stomach, when 
 its continuity with the intestinal canal has been interrupted.t 
 
 The Epidermis or Epithelium of mucous membranes is very 
 distinct at their external orifices, but becomes less and less ap- 
 parent towards the interior of the body, until finally it cannot be 
 distinguished; and anatomists generally consider that it is entirely 
 deficient, notwithstanding the assertion of Haller to the contrary. 
 It is a matter of common observation, that when the interior of 
 mucous membranes is exposed by an eversion for a long time, to 
 
 * Anat. Gen. p. 253. 
 
 j- Should the suggestion of the absorbing powers of the gastro-enteric follicles 
 which I have proposed in Section third, be correct, it will dispose of the diffi- 
 culties and opposing opinions alluded to in this paragraph, 
 
52 ORGANS OF DIGESTION. 
 
 the action of the atmosphere ; they take on more of the structure 
 of skin, and become evidently covered with a cuticle which pro- 
 tects them and diminishes their secretion. This is exemplified 
 in eversion of the vagina from prolapsed uterus, in elongated and 
 tumid labia interna, and in other ways: restore the parts to their 
 natural situation, and they are brought back to their original 
 structure. In the partial prolapse of the mucous membrane of the 
 rectum, from piles, corresponding circumstances occur. From 
 this we infer, that the full development of cuticle depends very 
 much upon the degree of exposure which any surface of the 
 body has to undergo. The reverse also takes place: shut up or 
 close any surface of the skin so that it is put in the condition of 
 an interior cavity, and it immediately begins to assimilate it- 
 self to a mucous membrane. This is proved by the tendency in 
 young children to a detachment of the cuticle, or excoriation of 
 the opposed surfaces of the deep wrinkles about their thighs and 
 in their perineum ; a tendency obviated by the practice of nurses 
 of covering these surfaces with powdered starch. It is also 
 manifested frequently in the dressing of wounds with sticking 
 plaster, where an incautious approximation of the contiguous 
 surfaces of the skin, not only is followed by excoriation, but even 
 'by ulceration; a fact, the importance of which was formerly set 
 in proper relief by Dr. Physick in his surgical lectures, and of 
 which I have seen an example in a case of extirpated female 
 mamma. The state of this question is, in fine, such that I think 
 we may safely admit the existence of a very thin epidermis on 
 the alimentary canal, but so pulpy that it cannot be distinguished 
 except by the process alluded to in Section third of this Chapter. 
 
 The mucous membranes vary in colour from a very light pink 
 to a deep red, which is owing to the blood that circulates in 
 them. In cases of suffocation, they become almost brown from 
 the congestion of blood in them, while in fainting they turn white 
 from the desertion of the latter. These vessels after having pe^ 
 netrated the thickness of the membrane, ramify with extreme 
 minuteness on its surface. In consequence of this superficial si- 
 tuation, the vessels being unsupported on one side, are exposed 
 to rupture from slight concussions; in this way hemorrhage is 
 produced in the lungs from coughing, and bleeding at the nose 
 from blows upon the head. 
 

 GENERAL ANATOMY OF THE MUCOUS MEMBRANES. 53 
 
 Exhalent orifices exist in great numbers in the mucous mem- 
 branes : this is especially the case in the lungs, where the pul- 
 monary perspiration, as it is called, is very obvious to common 
 observation. Elsewhere, this discharge is so much blended with 
 the mucus of the part, that it is difficult to appreciate its quantity. 
 From the superficial situation of the blood vessels, it is clear that 
 the exhalent orifices or pores, have but a short course to run. 
 This is considered by Bichat as a satisfactory reason for the 
 tendency of the blood to escape through them, or to ooze out 
 where there is no rupture. 
 
 Absorbents exist also in great numbers, as proved by the ab- 
 sorption of chyle, of watery drinks from the intestinal canal, and 
 by the inhalation of the vapour of spirits of turpentine into the 
 lungs, rapidly communicating the particular smell of this article 
 to the urine. There are, moreover, cases recorded of obstructed 
 urethra, where the urine has been almost entirely absorbed by 
 the mucous coat of the bladder. 
 
 In regard to nerves, the mucous membranes are well furnished 
 with them. Bichat has remarked that wherever these mem- 
 branes are situated near the surface of the body and enjoy com- 
 mon sensibility, they are almost wholly furnished from the cen- 
 tral portions of the nervous system, as the brain and spinal 
 marrow: this is exemplified in the conjunctiva, the pituitary 
 membrane, the palate, the glans penis, &c. On the contrary, 
 the sympathetic nerve furnishes the intestines, the bladder, and 
 the excretory tubes generally. 
 
 Mucous Glands, as they are called, exist throughout the sys- 
 tem of mucous membranes, being situated either under them or 
 in their thicknesses. From them is derived the mucilaginous 
 fluid which lubricates so abundantly their interior surfaces, so 
 as to facilitate the passage of extraneous bodies, and, at the 
 same time, to protect the membrane from mechanical violence. 
 These glands are of various sizes, from that of the tonsils and 
 the muciparous glands on the lips, cheeks, and root of the tongue, 
 to the almost imperceptible cryptae of the bladder and urethra. 
 Their shape is either lenticular, rounded, or that of a pouch. 
 The two former have their parietes of a sensible thickness, but 
 the last are too thin, to be distinguished from the mucous mem- 
 brane itself. For the most part, the excretory duct of these 
 
 VOL. II. 8 
 
54 ORGANS OF DIGESTION. 
 
 glands is short and patulous, so as to lead directly into the sub- 
 stance of the gland. This is remarkably the case with the ton- 
 sils, which consist in a congeries of these follicles ; and with the 
 glands on the root of the tongue. In some animals they are so 
 numerous as to form almost a distinct lamina to the intestines ; 
 after the manner of the human subject, on the palate and parietes 
 of the mouth. 
 
 The Mucosity discharged from these glands is one of the prin- 
 ciples of animals, and, as is well known, exists also to a great 
 extent in some vegetables. When perfectly pure and fluid, it is 
 white, transparent, inodorous, and insipid. It is insoluble in al- 
 cohol, but soluble in acids. Water forms more than nine-tenths 
 of it, the remainder is mucus, properly speaking, blended with 
 some neutral salts of soda and potash. 
 
 The mucous membranes are exposed to a multitude of mor- 
 bid alterations, such as polypus, scirrhus, cancer, phlegmor- 
 rhagiae or serous fluxes, blennorrhagiae or mucous fluxes, inflam- 
 mation in all its forms, gangrene, ulcerations, and congestions. 
 
 CHAPTER IV. 
 
 OF THE ASSISTANT CHYLOPOIETIC VISCERA. 
 SECT. I. OF THE LIVER. 
 
 THE Liver (Hepar, Jecur] secretes the Bile, and is the largest 
 glandular body in the human frame. It, as mentioned, occupies 
 the whole of the right hypochondriac region, the upper half of 
 the epigastric, and, as it becomes thinner in going towards the 
 left side, it occupies a small space in the right superior part of 
 the left hypochondriac region. Its whole superior face is in 
 contact with the diaphragm; on the left it is bounded by the 
 spleen, and below by the stomach and the transverse colon ; be- 
 hind it, are the vertebral column and the ascending cava. 
 
 The shape of the liver is like one half of an ovoidal body cut 
 into two in *the direction of its long diameter, and having the 
 thick end turned to the right side. It is about ten inches in 
 
THE LIVER. 55 
 
 length by six or seven wide, and weighs from four to five pounds 
 in the adult. Its colour is a reddish brown, generally; though, 
 on its under surface and about its edges, broad, blue or black 
 patches are constantly met with, which do not indicate any 
 morbid derangement. 
 
 Its upper surface is of a uniform convexity, rather more pro- 
 minent at the right posterior part than elsewhere; adjusts itself 
 accurately into the concavity made by the under surface of the 
 diaphragm; and is unequally divided from before backwards by 
 the suspensory ligament. The anterior margin is thin, and is 
 notched where the suspensory ligament begins ; the posterior 
 margin is much thicker, and has near its middle a broad de- 
 pression, to fit it to the projection of the vertebral column. The 
 ascending vena cava forms a superficial sulcus upon this mar- 
 gin, and frequently there is a complete canal through the sub- 
 stance of the liver for transmitting it. The right extremity is 
 very thick, and almost fills the hypochondriac region of that 
 side, while the left extremity is reduced to a thin, tapering, and 
 flexible edge. 
 
 The under surface of the* liver is much more irregular than 
 the upper; it is traversed in an antero posterior direction, in a 
 line corresponding with the attachment above of the suspensory 
 ligament, by the umbilical fissure, (Sulcus Umbilicalis) which 
 extends from the notch in the front edge to the depression be- 
 hind, and obtains its name from having accommodated in the 
 fcetal state, the umbilical vein, now converted into a round liga- 
 mentous cord. In the posterior part of this fissure is likewise to 
 be seen, in the same condition, what remains of the ductus ve- 
 nosus. The anterior portion of the umbilical fissure is not un- 
 frequently converted into a complete canal, by a portion of he- 
 patic substance crossing it like a small bridge. The transverse 
 fissure (Sulcus Transversus, Intermedius] is situated in the middle 
 of the under surface of the liver, and extends along a third or 
 fourth of the long diameter of the latter. It begins somewhat to 
 the left of the umbilical fissure, and crossing it at right angles, 
 proceeds towards the right extremity. It contains the vena por- 
 tarum, the hepatic artery, and the hepatic duct ; all of which 
 are bound to each ether by a close cellular substance. 
 
 The suspensory ligament above, and the umbilical fissure be- 
 
56 ORGANS OF DIGESTION. 
 
 low, give occasion to divide the liver into Lobes; right and left; 
 of which the right is by much the largest, and accommodates 
 almost entirely the transverse fissure, having also on its under 
 surface some subordinate elevations, to wit, the Lobulus Spigelii 
 and the Lobulus Quartus, together with the Gall-Bladder. 
 
 The Lobulus Spigelii is placed between the transverse fissure 
 and the posterior margin of the liver, to the right of the poste- 
 rior end of the umbilical fissure. Its shape is somewhat prisma- 
 tic, bifurcating in front ; one of the elongations is a papilla over- 
 hanging the transverse fissure, and is, therefore, considered as 
 one side of the gateway (porta) opened for the vena portarum ; 
 the other elongation is a small ridge, sometimes called Lobulus 
 Caudatus, and is lost gradually on the under surface of the great 
 lobe, by inclining to the right. 
 
 The Lobulus Quartus, or Anonymus, is not by any means so 
 elevated as the last, but having a flattened surface, is placed in 
 front of the transverse fissure, between the fore end of the um- 
 bilical fissure and the gall-bladder ; its posterior extremity is the 
 second porta of the Liver, and is just opposite to that furnished 
 by the Lobulus Spigelii. 
 
 The liver, from being completely enveloped in peritoneum, has 
 a smooth glossy appearance. The reflections of this membrane, 
 from it to the parietes of the abdomen, form the ligaments, as 
 they are called, which consist each of two laminae. The Fal- 
 ciform Ligament, or Suspensory, containing in its anterior mar- 
 gin *the remains of the umbilical vein, now called Ligamen- 
 tum Teres, begins at the umbilicus, extends from it along the 
 linea alba and the middle line of the diaphragm, and, as men- 
 tioned, is reflected to the upper surface of the liver, from the an- 
 terior to the posterior margin. The Right Lateral Ligament is 
 situated behind, and departs from the back part of the diaphragm 
 to the posterior margin of the right lobe. The Left Lateral Li- 
 gament also goes from the back part of the diaphragm, and is 
 attached along the posterior margin of the left lobe. Where the 
 suspensory ligament inclines on each side into the lateral, it 
 passes with so much obliquity as to leave some portion of the 
 posterior margin of the liver uncovered by peritoneum ; the lat- 
 ter, where it describes the periphery of this space, has been ra- 
 ther unnecessarily designated as the Coronary Ligament. 
 
THE LIVER. 57 
 
 In addition to the peritoneal coat, the liver has another, con- 
 necting it with the peritoneum, and seeming to be only condensed 
 cellular substance, which also penetrates into the substance of 
 the gland, and holds its constituent parts together. It is parti- 
 cularly well seen within the circle of the coronary ligament. 
 
 Of the Organization of the Liver. 
 
 The Liver is made extremely vascular by the ramifications of 
 three kinds of blood vessels, the vena portarum, the Hepatic Arte- 
 ry, and the Hepatic Veins. The two first convey the blood to 
 it, and the third removes it again, into the general circulation, by 
 emptying into the ascending vena cava. There are also branches 
 of the hepatic duct, lymphatic vessels, and nerves. 
 
 The glandular substance is fragile and easily lacerated ; when 
 torn it assumes the appearance of a congeries of spherical or po- 
 lyhedrical grains, called acini from their resemblance to small ber- 
 ries: they are united in mass by the elongations of the cellular 
 coat, and traversed by the trunks of the blood vessels. Each of 
 these granulations is about the size of a millet seed, and is a re- 
 presentative of the entire gland, as its structure is complete in 
 itself; being formed by the terminations of the blood vessels, and 
 by the origin of a branch of the hepatic duct, called the porus 
 biliarius. When examined with a microscope, it is said that 
 these acini are composed of a yellow and of a brown-looking sub- 
 stance ; it has not, however, occurred to me to see the distinction 
 in a very satisfactory way, though it is recognised by anatomists 
 of high authority.* 
 
 The Vena Portarum having arisen from the junction of all 
 the veins of the stomach, intestines, pancreas and spleen, is 
 about three inches in length when it reaches the transverse fis- 
 sure, by going over the duodenum and under the pancreas. It 
 immediately divides into two branches, called collectively the 
 Sinus Venae Portarum, which is at right angles with the trunk 
 of the vein; the right branch being the shortest and largest, is 
 distributed by radiating trunks to the right lobe of the liver; 
 
 * Bichat, Meckel, &c, 
 
58 ORGANS OF DIGESTION. 
 
 the left branch is distributed, after the same manner, to the left 
 lobe, to the lobulus spigelii, and to the lobulus quartus. Some 
 of its branches anastomose with the hepatic veins, which ac- 
 counts for the ease with which an injection will pass from one 
 to the other. Other branches of a smaller description anasto- 
 mose with the pori biliarii, but with less freedom than in the 
 preceding case; and lastly, the most delicate ramifications are 
 spent upon the cortical or yellow matter of the acini, without 
 penetrating to the brown.* 
 
 The Hepatic Artery is a branch of the cceliac, and in ap- 
 proaching the transverse fissure divides into three or more 
 branches, that penetrate the substance of the liver, between the 
 sinus portarum and the ducts as they come out; one branch 
 goes to the right lobe, another to the left, and a third to the 
 lobulus spigelii. There is some variety in regard to the precise 
 mode of distribution, and their division into subordinate rami- 
 fications frequently occurs before they get fairly into the sub- 
 stance of the liver. When there, they seem to be intended for 
 the nourishment of this organ, according to the observations of 
 several able anatomists; and follow the ramifications of the vena 
 portarum and of the biliary ducts, forming upon them a very 
 delicate and complicated tissue of anastomosing vessels; some 
 of which, probably the vasa vasorum, communicate with the 
 vena portarum. 
 
 The Biliary Pores (Pori Biliarii} or the commencing rami- 
 fications of the biliary duct, take their origin in the acini; and, 
 as is said, upon the boundary between the two kinds of matter, 
 avoiding the brown and passing through the cortical. t The 
 larger branches converge into their respective trunks succes- 
 sively or in pairs; while the primordial, or most minute ones, 
 converge several of them to the same point, giving a penicillous 
 appearance. It is asserted that a fine injection passes more 
 readily from them into the lymphatics than into any other order 
 of vessels; which may account for the promptitude of jaundice 
 upon an obstruction of the hepatic duct. 
 
 * Mnppes, I. F. Meckel, loc. cit; 
 t I. F. Meckel, loc. cit. 
 
THE LIVER. 59 
 
 The Hepatic Veins arise in the acini from the capillary ter- 
 minations of the vena portarum and the hepatic artery. Their 
 hranches are sucessively accumulated into three large trunks, 
 the collective area of which vastly exceeds that of the vessels 
 bringing the blood to the liver. Two of these trunks come 
 from the right lobe and one from the left, to empty into the 
 ascending cava, while it is still in contact with the liver, im- 
 mediately below the diaphragm; just below the preceding trunks 
 there are five or six, sometimes more, small hepatic veins, 
 coming from the posterior margin of the liver, and from the 
 lohulus spigelii. The hepatic veins are destitute of valves, and 
 remarkable for the thinness of their parietes. An injection 
 passes readily from them into the other systems of vessels. 
 They may be recognised by their insulated course, by their 
 consisting in trunks which converge from the periphery of the 
 liver to the vena cava, while all the other vessels diverge from 
 the transverse fissure to the periphery, and consequently cross 
 the course of the hepatic veins. 
 
 At the bottom of the transverse fissure of the liver is to be 
 found a condensed cellular fibrous tissue, which invests the vena 
 portarum, the hepatic artery, and the biliary ducts ; and, as they 
 all keep together in their ramifications, this tissue follows them 
 throughout the substance of the liver, and thereby forms sheaths 
 for them. It may be considered as continuous with the processes 
 sent in from the cellular coat ; and, contrary to the opinion of 
 Glisson, whose capsule it has been called, it is devoid of muscu- 
 lar structure.* 
 
 Of the Gall Bladder. 
 
 The Gall Bladder (Cistis Fellea) is a reservoir for the bile se- 
 creted by the liver. It is fixed on the under surface of the great 
 lobe, to the right of the umbilical fissure, and removed from the 
 latter by the lobulus quartus.t It is an oblong pyriform sac, 
 
 * An elaborate work on the minute anatomy of the liver has lately appeared, 
 from the English press, by Francis Kiernan, Esq. R. C. Surgeons, London, 1833, 
 in which there are some peculiar notions of structure. It is highly creditable to 
 the zeal of the author and well worthy of perusal. 
 
 j- I have seen an instance where it was to the left of the umbilical fissure, on 
 the small lobe. The latter was much longer than common. Dec. 1 830. 
 
60 ORGANS OF DIGESTION. 
 
 having its anterior extremity or fundus projecting somewhat be- 
 yond the anterior margin of the liver, while the posterior end 
 reaches to the transverse fissure. Its long diameter inclines 
 slightly to the right side, so that it is not precisely in an ante- 
 ro-posterior line. It varies in its shape in different subjects, be- 
 ing much more spheroidal in some than in others. Its fundus 
 is rounded and obtuse, while the posterior end is gradually re- 
 duced to a narrow neck, which is bent up on itself, so as to re- 
 tard the flow of a fluid through it. Its upper surface is in con- 
 tact with the substance of the liver, and is received into a broad 
 shallow fossa, while the lower surface is projecting, and by 
 coming in contact with the transverse colon, tinges it with bile, 
 by transudation after death. 
 
 The Gall Bladder has three coats, a peritoneal, a cellular, and 
 a mucous one. 
 
 The Peritoneal Coat is not complete, but only covers that part 
 of the sac not received into the fossa on the under surface of the 
 liver ; it is, therefore, a continuation of the peritoneal coat of the 
 latter ; sometimes, however, the gall bladder is so loosely at- 
 tached to the liver that it almost hangs off from it, in which case 
 the peritoneal coat is nearly complete. 
 
 The second coat is condensed cellular membrane. Through 
 it ramifies a great number of lymphatics, and blood vessels ; be- 
 low, it attaches the peritoneal to the mucous coat, and above, 
 the latter to the liver. 
 
 The Mucous Coat is alw r ays tinged of a deep green or yellow, 
 by the bile which it contains percolating after death ; for it is 
 said to be, before that, of a light colour. This coat is thrown 
 into irregular tortuous folds or wrinkles of extreme delicacy, in 
 the intervals of which are many round or polyhedrous cells, 
 causing it to look, when floated in water, like a fine honey comb; 
 such as are about the fundus of the sac are superficial, and not 
 so distinct ; but those near its middle and about the neck, are a 
 line or a line and a half deep. In the neck or apex, and in the 
 beginning of the cystic duct, are from three to seven, sometimes 
 twelve, semilunar duplicatures of the internal membrane, which 
 also retard the flux and afflux of any fluid, though they do not 
 afford so much resistance to the ingress as to the egress of it. 
 
THE LIVER. 61 
 
 These duplicatures are sometimes arranged into a spiral valve, 
 projecting from the inside of the duct, and forming two or three 
 turns.* Very small mucous follicles exist over the internal face 
 of this membrane, the discharge of which fills the gall bladder 
 when the secretion of bile has been interrupted by diseased ac- 
 tion, as in yellow fever, or by scirrhus of the liver. 
 
 The artery of the gall bladder is a branch of the hepatic. Its 
 veins empty into the vena portarum. Its nerves come from the 
 sympathetic, and its lymphatics join those of the liver. 
 
 Of the Biliary Ducts. 
 
 A succession of very fine branches having arisen from the aci- 
 ni of the liver, these branches are united into three or four trunks 
 by the time they reach the transverse fissure. These trunks then 
 coalesce into a single one, the Hepatic, of eighteen or twenty 
 lines in length, and about the diameter of a writing-quill. The 
 Hepatic Duct is then joined at a very acute angle with the duct 
 from the gall-bladder, which is somewhat shorter and smaller ; 
 the union of the two forms the Common Duct, (Ductus Commu- 
 nis Choledochus.) The latter is larger than either of the others 
 singly, and is three or three and a half inches long ; it descends 
 behind the right extremity of the pancreas through its substance, 
 passes for an inch, obliquely, between the coats of the duodenum, 
 becoming at the same time diminished in diameter ; and, finally, 
 ends by an orifice still more contracted, on the internal face of 
 this gut, on its second turn, and about three or four inches from 
 the stomach. The orifice is marked by a small surrounding tu- 
 bercle somewhat obscured by the valvulae conniventes. 
 
 The Biliary Ducts are situated, as mentioned, along the right 
 margin of the lesser omen turn, and have the vena portarum and 
 the hepatic artery to their left. 
 
 The bile ducts are formed by two coats; the external is a 
 fibrous, lamellated, and very extensible membrane, while the in- 
 ternal is mucous, having the same structure with that of the gall 
 bladder, of which it is in direct continuation. In the Cystic Duct, 
 
 * Discovered latterly by M. Amussat of Paris. M. Amussat has also detected 
 muscular fibres in the gall bladder and biliary ducts, in which we see an analogy 
 with other hollow viscera. Am. Med. Jour. vol. ii. p. 193, 
 VOL. II. 9 
 
92 ORGANS OF DIGESTION. 
 
 and at the lower part of the Common Duct, are several longitu- 
 dinal folds. The Common Duct sometimes receives, just before 
 it empties into the duodenum, the Pancreatic Duct. 
 
 Of the Bile. 
 
 This secretion from the liver, is of a deep yellow, sometimes 
 green colour : when recent, it is thin and fluid ; but after it has 
 been conveyed to the gall bladder, and permitted to remain there 
 for some time, it becomes as thick as molasses, and increases also 
 in the intensity of its colour and in bitterness. Some anatomists 
 have believed that there was a more direct communication be- 
 tween the liver and the gall bladder than that through the hepa- 
 tic and the cystic duct ; but repeated and close observations have 
 proved the opinion to be erroneous, or, at least, destitute of pro- 
 per proof: it is, therefore, clear, that the difference between the 
 hepatic and the cystic bile, depends upon the watery particles 
 being removed from the latter by the absorbing power of the in- 
 ternal coat of the gall bladder. 
 
 According to Berzelius, the chemical analysis of bile furnishes 
 about eighty parts of water, eight of a particular substance which 
 assumes a resinous condition on the application of an acid : three 
 of mucus ; and nine of saline matters ; of which soda is a princi- 
 pal constituent. 
 
 SECT. II. OF THE SPLEEN. 
 
 The Spleen (Lien. Splen) is situated deeply in the posterior 
 part of the left hypochondriac region, and is bounded above by 
 the diaphragm, below by the colon, and on the right by the great 
 end of the stomach, and by the pancreas. It is not ascertained 
 that it secretes any thing. 
 
 Its colour varies from a deep blue to a dark brown. In shape 
 it resembles the longitudinal section of an oval, being flat or very 
 slightly concave on the surface next to the stomach, and convex 
 on that contiguous to the diaphragm. Occasionally its margins 
 are notched, but this is not invariably the case. Its flat surface 
 is slightly depressed longitudinally in the centre, where the blood 
 vessels enter it by six or eight foramina. 
 
THE SPLEEN. 63 
 
 Several spleens sometimes exist in the same individual, in which 
 case the supernumerary ones are not larger than nutmegs. The 
 common size of this organ is about four and a half inches long, 
 by two and a half or three wide, in which case it has a solid 
 firm feel ; but it very often exceeds these dimensions ; its transi- 
 tion and varieties of magnitude are so frequent, that no settled 
 rule can be established. In its inordinate enlargements I have 
 seen it only slightly smaller than the liver, its texture in this case 
 is soft and easily lacerated. 
 
 It is fixed in its place by three lines of reflection or processes 
 of peritoneum, whose names indicate sufficiently their places of 
 attachment. They are the Gastro-Splenic Ligament or Omen- 
 turn, in which are the vasa brevia of the stomach ; the Splenico- 
 Phrenic ; and the Splenico-Colic. These reflections, by being 
 continued over the spleen, give it a complete peritoneal coat, 
 which is raised up with more difficulty than the corresponding 
 membrane of any other viscus of the abdomen, and is common- 
 ly thrown into very small inequalities or wrinkles. 
 
 The internal or proper coat of the spleen is a grayish, com- 
 pact, extensible, and elastic membrane, the use of which is evi- 
 dently to sustain the natural shape of the organ, and to support 
 its parenchymatous structure. It sends in processes to accom- 
 pany the blood vessels, and from its internal face there proceeds 
 a multitude of lamellae and of fibres, which traverse its cavity 
 in every direction, and reduce it into a cellular condition, not 
 unlike the spongy structure of bones. 
 
 The spleen, in proportion to its size, is furnished to a remark- 
 able degree with blood. The largest branch of the creliac artery 
 runs to it along the superior margin of the pancreas, forming 
 numerous serpentine flexures, and distinguished for its thickness ; 
 it divides into several trunks for penetrating into the spleen, and 
 enters by the foramina in the fissure. The veins come out by 
 a number of trunks equal to what the artery is divided into ; 
 they assemble then into a single trunk, which attends the artery 
 along the pancreas, and is remarkable for the tenuity and ex- 
 tensibility of its coats. The splenic vein is destitute of valves, 
 and empties into the vena portarum. The spleen has also lym- 
 phatic vessels; and is furnished with nerves from the solar 
 plexus. 
 
64 ORGANS OF DIGESTION. 
 
 Of the Intimate Structure of the Spleen. The Splenic artery 
 having penetrated into this organ, is divided and subdivided into 
 a radiating succession of very fine branches, which, according 
 to the injections of Ruysch, do not anastomose with each other ; 
 in consequence of which, one part is sometimes finely injected 
 and ndt another, of which, in my own observations, 1 have had 
 an example. The veins, on the contrary, do anastomose, not 
 only as regards the collateral branches of the same primitive 
 trunk, but also by the collateral branches of different trunks. 
 These anastomoses are not large. The arteries terminate freely 
 in the veins, as may be proved by fine injections, and by the 
 microscope. 
 
 The mass of the spleen, upon superficial examination, seems 
 to consist in a dark brown pulp, which is contained in the cells 
 dividing the cavity of the internal coat, and may be easily de- 
 monstrated by tearing the spleen, and scraping it with a, knife 
 handle. MM. Assolont and Meckel believe, that blood, besides 
 being in the arteries and veins, is placed in a state of particular 
 combination and of intimate union with the other organic ele- 
 ments of this viscus, and with a large quantity of albumen; and 
 that this combination of the blood forms the dark brown pulp 
 alluded to. The great quantity of albumen in the pulp, is rea- 
 dily proved oy the hard coagulum which it forms, when steeped 
 in alcohol. But a. question has arisen whether the pulp be ex- 
 travasated in the cells which contain it, or whether it be still re- 
 tained in the extremities of the blood vessels. Superficial exa- 
 mination is in favour of the first, but M. Marjolin denies it on 
 the following grounds: that injections, cautiously made, pass 
 immediately from the arteries into the veins; and that the 
 spleen, when successfully injected and "-frozen, does not exhibit 
 ice in the interstices of its vessels, while their capillary ramifi- 
 cations, distended by the injected fluid, are distinctly seen. 
 From these he concludes that the glandular structure of the 
 spleen is formed essentially of arterial and venous capillary ves- 
 sels with very delicate and extensible coats, and that they com- 
 municate with one another without the intermedium of any cell; 
 that the extreme tenuity of these vessels, and their extensibility 
 in every direction, are sufficient to explain the augmentation of 
 
THE SPLEEN. 65 
 
 volume of the spleen, under certain circumstances, as well as 
 the promptitude of its diminution under others. 
 
 In addition to this pulp, many observers have met in the 
 spleen with an abundance of rounded corpuscles, varying in size 
 from an almost imperceptible magnitude to a line or more in dia- 
 meter.* They are of a gelatinous consistence, soft, grayish, and 
 semi-transparent, and either cluster together, or are widely sepa- 
 rated. By Malpighi, they were considered glandular, and, by 
 Ruysch,t as convoluted vessels. Professor Scemmering, from the 
 following paragraph, seems to join in the opinion of the latter: 
 " Qui nonnunquam occurrunt, acini vel glomeruli, microscopii 
 ope accuratissime explorati nihil sunt, nisi vasorum fasciculi, vel 
 teretes penicilli aut cirri vasculosi." According to the observa- 
 tions of Sir Everard Home, they swell considerably after an ani- 
 mal has finished drinking. 
 
 The spleen, from having no excretory duct, and, consequently, 
 from our inability to ascertain whether it secretes, has its nature 
 and uses shrouded in mystery. No single theory concerning it 
 has ever been generally adopted, for speculations have multiplied 
 in proportion to the obscurity of the subject. The idea, howe- 
 ver, on the use of this body, which to me is most reasonable, is, 
 that it acts a subsidiary part to the liver. It would seem, indeed, 
 as a general rule in regard to glandular structures and such other 
 highly vascular organs of the body as have an intermittent func- 
 tion, that the blood which is sent to them during their state of 
 activity, should be passed off through a different channel, while 
 they are in a state of repose. This does a double service, it pre- 
 vents superfluous secretions, and it also keeps up the vascular 
 equilibrium of the body, as there must be always in readiness a 
 quantity of blood sufficient for the supply of any secretion which 
 may be wanted for the time. 
 
 This proposition will derive some additional illustrations from 
 the fetal state. The kidneys being then inactive the glandula? 
 renales take off their blood, and thereby prevent what would 
 otherwise be a very inconvenient secretion of urine ; again, the 
 lungs being also then inactive, the circulation through them is 
 proportionately reduced, and the superabundant blood is con- 
 
 * Malpighi, Ruysch, Hewson, Home, Dupuytren, Meckel, 8cc. 
 f Epist. Anat. IV. 
 
66 ORGANS OF DIGESTION. 
 
 ducted through the thymus gland. But as the full functions of 
 the lungs and of the kidneys are established upon birth, and con- 
 tinue uninterrupted during life, their supplementary organs, the 
 thymus gland, and the capsulae renales, are not wanted, and they 
 wither away after the early period of infantile existence is passed. 
 
 In regard to the liver, its functions also suspended during the 
 fetal state, are of an intermittent kind throughout life, the spleen 
 may, therefore, be considered a vicarious organ for it during the 
 whole period of existence, receiving its blood during the continu- 
 ation of uterine life, and, in the intermission of action, during 
 common life. The spleen is, therefore, an organ useful to the 
 foetal and to the perfect state, and we, consequently, never see 
 it in the collapsed and dwindled condition of the thymus gland, 
 and renal capsule. 
 
 The same reasoning which applies to the spleen will also ap- 
 ply to the Thyroid Gland, for the latter may be considered as ex- 
 ecuting for the salivary glands during foetal and perfect existence, 
 what the spleen does for the liver. For it is ascertained, that 
 the salivary glands are inactive during foetal existence, have only 
 an intermittent action during perfect life, and, therefore, proba- 
 bly stand in need of a supplementary organ during their periods 
 of inactivity. 
 
 SECT. III. OF THE PANCREAS. 
 
 The Pancreas (Pancreas] secretes saliva, and is the largest of 
 the salivary glands. It is fixed in the lower back part of the epi- 
 gastric region ; and extends horizontally across the spine, being 
 separated from it by the lesser muscle of the diaphragm. It is 
 connected to the spleen on the left; at its right extremity is sur- 
 rounded by the curvature of the duodenum ; is bounded in front 
 by the stomach, which conceals it ; and is placed between two 
 laminae of the mesocolon. 
 
 The pancreas is about six or seven inches long, two wide, and 
 flattened before and behind. Its figure would be represented by 
 a parallelogram, were it not that its right extremity is enlarged 
 considerably into a head or tuber, to which Winslow gave the 
 n'ame of the Lesser Pancreas. The anterior face of this organ is 
 turned obliquely upwards, and is covered by the superior lamina 
 
THE PANCREAS. 67 
 
 of the mesocolon. The posterior face looks obliquely downwards, 
 and is in contact with the aorta, the vena cava ascendens, the 
 superior mesenteric vessels, and several nerves : along the supe- 
 rior margin of this face exists a long superficial fossa, occupied 
 by the splenic artery and vein. 
 
 With the exception of the loose covering given by the mesoco- 
 lon, the pancreas has no peritoneal coat; neither has it an 
 appropriate tunic, unless we consider as such the lamina of con- 
 densed cellular membrane which envelops it, and sends in pro- 
 cesses between its lobules, as in the case of the salivary glands in 
 the neck. 
 
 Of the Minute Structure of the Pancreas. This body, like the 
 other glands, which discharge saliva, is of a light gray or pink 
 colour. It consists in lobules of various forms and sizes, united 
 by an intermediate cellular tissue, and having their interstices oc- 
 cupied by numerous blood vessels. These lobules, by a slight 
 maceration, may be separated and resolved into small granular 
 masses, constituting integral portions of the gland. 
 
 The arteries of the pancreas come principally from the splenic, 
 as it cruises along the superior margin. The veins empty into 
 the splenic, and thus, finally, into the vena portarum. It is fur- 
 nished with nerves from the solar plexus, and has lymphatics. 
 
 The excretory duct of this gland (Ductus Wirsungii) arises, by 
 very fine roots or tubes, from each of the small granular masses. 
 These tubes coalesce into larger ones, which run transversely 
 from the periphery towards the centre of the gland, inclining 
 slightly, at the same time, towards the right. These secondary 
 tubes finally discharge successively into a single one, which runs 
 the whole length of the gland nearly in its middle. The single 
 tube, by these additions, enlarges continually from left to right, 
 being small where it begins at the splenic extremity of the pan- 
 creas, and about the size of a crow-quill at the duodenal. At the 
 latter place, it is joined by the duct of the lesser pancreas, which 
 is derived after the same rule as itself. The pancreatic duct, al- 
 most immediately afterwards, empties into the ductus communis 
 choledochus, or runs at the side of the latter, and makes a dis- 
 tinct opening- near it into the duodenum, at the posterior part of 
 the second curvature. 
 
BOOK V. 
 
 OF THE URINARY ORGANS. 
 
 THE Urinary Organs, (Organa Uropoietica^ being destined 
 to secrete and convey the urine out of the body, consist in the 
 Kidneys, the Renal Capsules, the Ureters, the Bladder and the 
 Urethra. 
 
 Of the Kidneys. 
 
 The Kidneys (Renes] are two glandular bodies for the secre- 
 tion of the urine, fixed one on either side of the spine. They 
 are in the back part of the lumbar regions, have their internal 
 edges inclining very slightly forwards, and extend from the 
 upper margin of the eleventh dorsal to the lower margin of the 
 second lumbar vertebra; the right, however, is ten or twelve 
 lines lower than the left, owing to the thick posterior margin 
 okthe right lobe of the liver, which presses it downwards. The 
 kidneys are covered in front by the peritoneum and the lumbar 
 portions of the large intestine, but in such a manner as to be 
 separated from them, in corpulent subjects, by a surrounding 
 layer of fat; behind, they repose upon the lower part of the 
 great muscle of the diaphragm, upon the quadrati lumborum, 
 and upon the upper end of the psose magni muscles. 
 
 The kidney is a hard solid body, of a brown colour; in shape 
 
 it is a compressed ovoid, excavated on the margin which it 
 
 presents to the spine, and bears a very strong resemblance to 
 
 the common kidney bean. Its flat surfaces present forwards 
 
 VoL.IL 10 
 
70 URINARY ORGANS. 
 
 and backwards, and the broad end of the ovoid is above. Its 
 periphery is smooth, so that one does not see from an external 
 examination the lobules or internal divisions. The excavation 
 of the kidney, called its fissure, (hiium renale) occupies about 
 one-third of its long diameter, is bevelled in front, and leads to 
 the very interior of the gland; conducting its blood vessels and 
 excretory duct, which have to pass through a quantity of cellular 
 and adipose matter. The kidneys are generally of equal size, 
 being about four inches long, and two wide; and each one weighs 
 three or four ounces. They have no ligaments for keeping 
 them in position, but depend for the latter upon the adjacent 
 cellular "adhesions and blood vessels. 
 
 The kidney being destitute of a peritoneal coat, has a well 
 marked capsule which envelops it entirely and penetrates into 
 its fissure for some depth, where it is perforated with foramina 
 for transmitting the blood vessels and the ureter. This capsule 
 is white, semi-transparent, fibrous, strong, and elastic: it adheres 
 to the surface of the kidney by delicate cellular and vascular 
 filaments, which are so weak that they permit it to be stripped 
 off without difficulty, and when so removed, some indications 
 of the original lobulated condition of the organ are seen. 
 
 The kidney receives from the aorta one or more branches, 
 called the renal or emulgent arteries, which divide as they ap- 
 proach the fissure; and having got into the substance of the 
 gland are distributed by innumerable twigs to all parts of it. 
 Some terminate in veins, others in the substance of the organ, 
 and others, again, in the excretory tubes. The veins equal in 
 number the arteries, and are somewhat larger. When both, or 
 even one, of these systems of blood vessels is injected with 
 wax and corroded, its branches are so abundant as to retain the 
 form of the gland. In engaging in the fissure of the kidney, 
 the arterial ramifications are in front, the veins in the middle, 
 and the commencement of the ureter behind.* The artery on 
 the right side is longer than that on the left. The reverse is 
 the case with the emulgent veins, as they empty into the vena 
 cava ascendens. This arrangement is owing to the relative 
 
 * This rule is subject to frequent variations, 
 
THE KIDNEYS. 7l 
 
 position of the aorta and the vena cava ascendens, as the first is 
 on the left side of the spine, and the last on the right side. 
 
 The nerves come from the solar plexus of the sympathetic, 
 and adhering to the arteries cannot be traced very far through 
 the glandular structure. The quantity of lymphatics is consi- 
 derable. 
 
 Of the, Minute. Structure of the Kidney. When the kidney 
 is cut open longitudinally, it obviously consists of two kinds of 
 substance, differing in their situations, colour, consistence and 
 texture. The one nearest to the periphery of the gland is called 
 from its position Cortical, (Subslantia Corticalis, Glandulosa,) 
 while the other, being more internal, is designated as the Me- 
 dullary or Tubular, (Substantia Medullaris; Tubulosa; Fi- 
 brosa.) 
 
 The Cortical or Secretory Substance forms the whole circum- 
 ference of the kidney, and, on an average, is about two lines in 
 thickness: but it is thicker at some points; as from its internal 
 face processes converge towards the centre of the gland, which 
 separate the tubular part into as many distinct portions of a 
 conoidal shape. It is composed principally of arteries and veins 
 ramifying, among small graniform corpuscles that secrete the 
 urine, and are very distinct when viewed with a microscope. 
 It tears with facility, thereby presenting this granular appearance, 
 and is of a dark, or reddish brown colour, varying considerably, 
 however, according to the cause of death. 
 
 The granular corpuscles which form the mass of the cortical 
 or secretory substance, are, individually, imperfectly visible to 
 the naked eye, and appear like rounded points. 
 
 The celebrated Ruysch, who was distinguished for the suc- 
 cess of his injections, and for the acuteness of his vision, de- 
 clared that they consisted wholly in the very fine extremities 
 of arteries and veins having a penicillous arrangement; while 
 Malpighi and Schumlansky viewed them as purses or small 
 sacs of a glandular character, specifically suited to secrete urine, 
 and upon whose parietes the blood vessels ramified. From 
 these granuli or acini the incipient extremities of the tubuli 
 uriniferi take their rise. 
 
72 URINARY ORGANS. 
 
 The Tubular or Conoidal portion, consists in from twelve to 
 eighteen conoidal fasciculi (Pyramided MalpighiancE} present- 
 ing their rounded bases towards the cortical matter, and en- 
 closed in it, while their apices converge to the central cavity of 
 the kidney, the surface of which they form. The bodies of 
 these pyramids, as just mentioned, are separated by processes 
 of the cortical matter; but their apices are free, and project from 
 the internal surface of the kidney so as to resemble as many 
 small nipples, whence they are called Papillas Renales. Fre- 
 quently two of the pyramids coalesce so as to form but one 
 papilla together; in such case the latter generally preserves a 
 duplicate appearance. The papillae are arranged into three ver- 
 tical rows, one before, one in the middle, and another behind; 
 those of the foremost row are turned backwards; those of the 
 middle look inwards; and those behind look forwards. Not un- 
 frequently there is a small depression (foveola] on the very 
 summit of the papilla. The tubular part is of a lighter colour 
 and harder than the cortical, but the difference in these respects 
 is not always manifest. 
 
 The conoidal fasciculi may each be considered, along with its 
 appertaining cortex, as a sort of distinct gland, or at least as a 
 lobe; for upon them depend the lobulated appearance of the 
 kidneys of a foetus, and of animals. Each cone, when analyzed, 
 is found to consist in a collection of tubes (Due/us Urinifm 
 Bellini] converging from the circumference of the kidney to 
 the apex of the papilla. These tubes are more numerous near 
 the base, in consequence of their successive junction in approach- 
 ing the apex:* their terminating orifices, on the latter, appear 
 like small pores, from which the urine can be squeezed in little 
 drops. 
 
 In the early part of the course of the ductus uriniferi, while 
 they are still in the cortical matter, they are wound up in a 
 very serpentine and tortuous manner, and are distinguished by 
 the name of Cortical Canals, (Ductus Ferrenii.^) They com- 
 monly go alone, winding their way in the cortical substance 
 until they reach its most interior face; they then become straight, 
 
 Schumlansky, Dis. de Struct. Renum, Strasburg, 1788. 
 
 A. Ferrein; sur la Structure des reins et du foie, Mem. de Paris, 1749. 
 
THE KIDNEYS. 73 
 
 form the medullary substance, and have the name of the con- 
 duits of Bellini.* 
 
 Some of the calculations on this subject are not a little curious. 
 It was ascertained by Ferrein that in each of the conoidal fas- 
 ciculi (Pyramides Malpighianse) there were, at least seven hun- 
 dred subordinate cones or pyramids; and as the number of co- 
 noidal fasciculi is generally about fifteen, these pyramids would 
 amount to ten thousand five hundred. Again, each of the sub- 
 ordinate pyramids (Pyramides Ferrenii) is composed of many 
 hundred uriniferous tubes, and, by the observations of Eysen- 
 hardt,| each of these tubes consist of twenty smaller ones. 
 
 The arteries of the kidneys, in ramifying minutely through 
 its structure, adopt the following arrangement. They first of 
 all pass through the processes sent inwards from the cortical 
 matter between the Pyramids of Malpighi, or large cones, and, 
 having got into the cortical matter, they divide into very fine 
 twigs, which form arcades around the bases of the pyramids 
 of Ferrein, and pass between them.J These arcades have but 
 few anastomoses with each other, and their branches go almost 
 exclusively to the cortical substance, very few of them being 
 found on the tubular. Their branches radiate from the con- 
 vexities of the arches so as to surround the base of each cone, 
 and to penetrate to the surface of the kidney. Some of these 
 branches terminate in corresponding veins, and others on the 
 granular corpuscles, or acini. The connexion between the cor- 
 puscles and the arteries, has been compared to that between 
 grapes and the stems on which they grow, so as to form a bunch. 
 The veins penetrate the substance of the kidney, and have a 
 similar distribution; but they are much larger than the arteries, 
 and have free, large and numerous anastomoses. A connexion 
 of the corpuscles with the veins is not quite evident, and, even 
 if it does exist, remains yet to be proved; at least, in the opinion 
 of some anatomists: the fact, however, is well established, that 
 fine injections will readily pass from the veins into the tubuli 
 uriniferi. 
 
 In one instance, I found in a young female subject one of the 
 
 * L. Bellini, de Structure Renum. Florence, 1662. 
 
 f De Struct. Renum. Obs. Micros. Berlin, 1818. t Schumlansky. 
 
74 URINARY ORGANS. 
 
 kidneys in the pelvis in front of the rectum. A similar case 
 has been seen by Professor Hensinger;* and I have met with 
 several instances of a coalition across the spine, of the two 
 kidneys, so as to present the appearance of a bilobed organ. 
 
 Of the Excretory Duct of the Kidney, or the Ureter. 
 
 The Ureter is a canal which conveys the urine from the kid- 
 ney to the bladder. It commences in the centre of the kidney 
 by an enlargement called pelvis, which branches off into three 
 or four portions, (calices} one above, one below, and one or two 
 intermediate. Each of these calices is divided, at its free ex- 
 tremity, into three or four short funnel-shaped terminations, 
 (Infundibula.) Each of these terminations embraces by its 
 expanded orifice, the base of a papilla, so as to permit the latter 
 to project into it, and thereby to distil its urine there. Very 
 frequently the number of papillae exceeds that of the infundi- 
 bula, in which case two of the former project into one of the 
 latter. 
 
 The pelvis of the kidney having emerged at the fissure be- 
 hind the vessels, from being expanded and somewhat conoidal 
 in shape is reduced to a cylindrical canal, which, properly 
 speaking, is the ureter: the latter is about the size of a goose- 
 quill and descends through the lumbar region, between the pe- 
 ritoneum, and the psoas magnus muscle. It dips into the pelvis 
 by crossing in front of the primitive iliac vessels and the in- 
 ternal iliac, crosses the vas deferens at the back of the bladder, 
 and penetrating obliquely the coats of the latter, terminates in 
 an orifice ten or twelve lines behind that of the neck of the 
 bladder. 
 
 The excretory duct of the kidney is formed by two coats. 
 The external is a condensed, fibrous, and cellular tissue, but is 
 destitute of any thing like muscle. The internal is a thin mu- 
 cous lamina, which can be raised up without much difficulty, 
 and is continuous, at its lower end, with the internal coat of the 
 bladder; at the upper end, it is supposed by some anatomists to 
 be reflected over the papilla?, and even to pass for some distance 
 
 * Am. Med. Jour. Vol. iii. p. 442. 
 
THE KIDNEYS. 75 
 
 into the tubuli uriniferi. This duct has considerable powers of 
 extension, as manifested by its transmitting large calculi from 
 the kidney, and also, by its general enlargement in some cases 
 of obstructed urethra; its sensibility is exquisite when irritated 
 by a calculus passing down it. 
 
 Of the Renal Capsules. 
 
 The Renal Capsules (Capsulae Renales, Penes Succentu- 
 riatij) are two small bodies, one on either side, placed upon 
 the upper end of the kidney. They 'are of a yellowish brown 
 colour tinged with red, have no excretory ducts, and are more 
 distinctly developed and softer in the perfect foetus than in the 
 adult; whence they are ranked among those organs, as the thy- 
 mus gland, and others; which, having some peculiar value in 
 fcetal existence, are perhaps unnecessary to that of the adult.* 
 They are of a triangular pyramidal shape, flattened before and 
 behind, and rest by a concave base upon the kidney; they are 
 about fifteen lines high and as many wide. 
 
 They are surrounded by a proper coat of lamellated con- 
 densed cellular tissue, which, by detaching inwards its prolon- 
 gations, keeps the parts of these bodies together, and marks out 
 their divisions. In the centre of the renal capsule, a cavity 
 may, from time to time, be found; but, according to my own 
 observations, nothing is less certain than its existence; and, in 
 the opinion of Meckel, when found, it is the result of cadaverous 
 decomposition. In the foetus it contains a reddish viscid fluid, 
 which seems to consist in a large share of albumen, as it coagu- 
 lates with alcohol; in children, this fluid becomes yellow; in 
 adults it is dark brown; and in old people it is either entirely 
 deficient, or in a remarkably small quantity. 
 
 Of the Minute Structure of the Capsulae Renales. The 
 arteries of these bodies come from the emulgents, from the 
 phrenics, and from the aorta. The veins of the right one ter- 
 minate in the cava ascendens, and of the left in the emulgent. 
 Each one is divisible into lobes, and by a slight maceration 
 
 * This opinion has recently been confirmed in a dissection of a foetus, where 
 1 found the capsulx renales, though the kidneys were absent. 
 
76 URINARY ORGANS. 
 
 may be reduced into lobules and small granulations. The ex- 
 ternal part is rather more consistent and yellow than the in- 
 ternal. The granulations seem to have an intimate connexion 
 with the veins, as they are easily penetrated by fluid injections 
 from the latter. 
 
 Reputed excretory ducts for these bodies have been found 
 going to the testicles, to the pelvis of the kidneys, and to the 
 thoracic duct, but no weight is now attached to such assertions. 
 
 Of the. Bladder. 
 
 The Bladder ( Tesica Urinaria,) is the reservoir for the urine, 
 and is placed in the pelvis, just behind the symphysis of the 
 pubes. When pressed upon, as it commonly is, by the ad- 
 jacent viscera, it is flattened somewhat before and behind; but 
 removed from the body and inflated, it is an elongated sphere 
 or an oval; the greatest diameter of which is vertical, in regard 
 to the linea ileo-pectinea. The superior end of the bladder is 
 called the upper fundus, and the lower end the inferior fundus; 
 the latter is rather more obtuse than the other; and between 
 the two is the body. The neck of the bladder is its place of 
 junction with the urethra. The form of the bladder is influ- 
 enced by age and by sex; in very young infants it is cylindroid, 
 and owing to the smallness of the pelvis, rises up almost wholly 
 into the abdomen. In the adult woman, who has frequently 
 borne children, it is nearly spherical, has its greatest diameter 
 transverse,* and is more capacious than in man. 
 
 The bladder is bounded in front by the pubes, above by the 
 small intestine, behind by the rectum, and below by the pro- 
 state gland and the vesiculae seminales. From its superior end 
 there proceeds to the umbilicus a long conical ligament, the 
 urachus, which is placed between the linea alba and the perito- 
 neum, and produces a slight elevation or doubling of the latter. 
 In mankind, the urachus is solid: some very rare cases, how- 
 ever, are reported, in which it has been hollow, so as to permit 
 the urine to flow through it from the bladder. This vicious 
 conformation has generally been attended with a congenital ob- 
 struction of the urethra.! When the anterior parietes of the ab- 
 
 * H. Cloquet, Anat. Descrip. f Sabatier, Anat. vol. iii. p. 19. 
 
THE BLADDER. 77 
 
 domen are put upon the stretch; a semi-lunar fold of the peri- 
 toneum, as formerly mentioned, is seen to proceed, on either 
 side of the urachus, from the lateral surface of the bladder al- 
 most to the umbilicus. These folds contain, in their loose edge, 
 the fibrous remains of the umbilical arteries of the foetus, called, 
 subsequently to uterine life, the Round Ligaments of the blad- 
 der, though they have little or no influence on its position. 
 The bladder is also fixed in its situation by the pelvic aponeu- 
 rosis, a membrane elsewhere described with the organs of ge- 
 neration. , 
 
 The bladder consists of four coats: the Peritoneal, the Mus- 
 cular, the Cellular, and the Mucous. 
 
 The Peritoneal Coat is very imperfect, and is derived from 
 the part of the peritoneum which descends from the anterior 
 parietes of the abdomen into the pelvis. It covers the upper 
 and the posterior face of the bladder, and then passes to the 
 rectum, by sinking down between these two organs, so as to 
 form the small pouch beneath the lower fund us of the bladder; 
 the apex of this pouch reaches within an inch of the base of the 
 prostate. The upper margin of this pouch next to the bladder, 
 forms a strong horizontal doubling, stretching across the pelvis, 
 when the rectum is empty, and is on a level with the posterior 
 end of the vesiculse seminales. Being connected to the subja- 
 cent muscular coat by a thin lamina of loose cellular membrane, 
 the peritoneum may be dissected off without difficulty. In con- 
 siderable distentions of the bladder, it is reflected from the up- 
 per end of the latter to the abdominal muscles in a line much 
 above the pubes; whereby a good opportunity is afforded of 
 reaching, with an instrument, the cavity of the bladder without 
 injuring the peritoneum. 
 
 The Muscular Coat is of a thickness intermediate to thatof 
 the stomach and of the oesophagus, and its fibres are pale. 
 They pass in very varied directions,* and are collected into 
 flattened fasciculi, leaving interstices between them, through 
 which the internal coat is occasionally caused to protrude, in 
 .strictures and other obstructions of the urethra. These fasci- 
 
 * Santorini, Septemd. Tabul. 
 VOL. II. 11 
 
7S URINARY ORGANS. 
 
 culi, for the most, part, arise about the neck of the bladder, and 
 ascending upwards, before, behind, and laterally, terminate at 
 the superior fundus in the base of the urachus. Within these, 
 which may be considered as the longitudinal fibres of the blad- 
 der, there are others forming a thinner lamina, whose course is 
 transverse, or oblique: they serve to connect the preceding. 
 As the muscular fibres are collected at the neck of the bladder, 
 and at the urachus, there is, of course, an increased thickness at 
 these points. 
 
 The Cellular Coat consists in a^ close, dense, lamellated, and 
 filamentous tissue, very extensible and difficult to tear. It is 
 impervious to water, adheres closely to the muscular coat with- 
 out, and to the mucous within, so as to form a strong bond of 
 union between them. It is pervaded by many vessels and 
 nerves, which it conveys to the mucous coat. 
 
 The Mucous Coat is also called the villous, but is much more 
 smooth than the corresponding one of the stomach. It is white, 
 with a slight tinge of red, and abounds with mucous follicles, 
 which, though small and scarcely discernible in a natural state, 
 are rendered very obvious by disease. It stretches with much 
 facility, but, like other mucous membranes, does not restore 
 itself readily, and is rather thrown, in the contracted state of 
 the bladder, into wrinkles or folds, having a diversified course, 
 and of a fugitive character, as they disappear, again upon the 
 next distention. It is very vascular. 
 
 The internal face of this coat presents, at its inferior part, the 
 following appearances: 
 
 1. TheVesical Triangle ( Trigonus Lieutaudi, Trigone Ve- 
 sicale) is placed immediately behind and below the neck of the 
 bladder, occupying the space between it and the orifices of the 
 ureters. It is an equilateral triangle of an inch in length, its 
 surface is smooth, is not affected materially in extent either by 
 the dilatation or the contraction of the bladder, and is elevated 
 so as to be sufficiently distinct and well defined. 
 
 2. The anterior angle of the triangle looks into the orifice of 
 the urethra, and is generally so elevated that it has obtained 
 the name of Uvula Vesicse; it is, however, simply a projection 
 
THE BLADDER. 79 
 
 of the mucous membrane depending upon the subjacent third 
 lobe of the prostate; which, at this point, is not unfrequently 
 much enlarged in the aged, and then presents a great difficulty 
 in the introduction of a catheter. 
 
 3. Tlje Orifices of the ureters form the posterior angles of the 
 triangle, and are contracted somewhat below the size of Ihe ca- 
 nals themselves. They are said, by Mr. Charles Bell,* to be 
 furnished each one with a small fasciculus of muscular fibres, 
 which runs backwards from the orifice of the urethra, just be- 
 neath the lateral margins of the triangle, and, in its contraction, 
 will stretch the orifice of the ureter so as to permit an easy pas- 
 sage of the urine into the bladder. The retrogradation of the 
 urine is prevented by the ureter passing obliquely, for six or 
 eight lines, between the muscular and mucous coat; there is 
 something also in the obliquity of the orifice itself which as- 
 sists in this effect; as I have ascertained by removing the mus- 
 cular coat entirely, at this point, and dissecting up the ureter, 
 notwithstanding which, the bladder, when inflated, still retained 
 its contents. Where the ureter penetrates the muscular coat, I 
 have in several instances found a layer of longitudinal muscular 
 fibres enveloping it for half an inch, or an inch. 
 
 4. The Inferior Fundus of the bladder (bas-fond of the French) 
 is a depression of the general concavity of the bladder, of about 
 six lines in depth, placed between the base of the triangle and 
 the posterior side of the bladder. In the erect position, calcu- 
 lus, when one has it, lodges there. 
 
 5. The Internal Orifice of the neck of the bladder resembles 
 strongly that of a Florence flask, modified, however, by the 
 projection of the uvula vesicse, which makes is somewhat cres- 
 centic below. The neck of the bladder penetrates the prostate 
 gland, but, at its commencement, is surrounded by loose cellu- 
 lar tissue containing a very large and abundant plexus of veins.t 
 The internal layer of muscular fibres is here .transverse; and 
 they cross and intermix with each other in different direction's, 
 
 * Med. Chir. Trans. Vol. iii. 
 
 f Mascagni, Anat. Univ. Str. Prim. Tab. Spec. Fig. V. 
 
80 URINARY ORGANS. 
 
 forming a close compact tissue, which has the effect of a parti- 
 cular apparatus for retaining the urine, and is called Muscu- 
 lus Sphincter Vesicae Urinarise. Generally, anatomists have 
 not considered this structure as distinct from the muscular coat 
 at large; but Mr. Charles Bell, of London, whose reputation as 
 an anatomist is well established, gives the following account of 
 it: 
 
 "Begin the dissection by taking off the inner membrane of 
 the bladder from around the orifice of the urethra. A set of 
 fibres will be discovered on the lower half of the orifice, which, 
 being carefully dissected, will be found to run in a semicircular 
 form round the urethra. These fibres make a band of about 
 half an inch in breadth, particularly strong on the lower part 
 of the opening, and, having mounted a little above the orifice, 
 on each side, they dispose of a portion of their fibres in the 
 substance of the bladder. A smaller and somewhat weaker 
 set of fibres will be seen to complete their course, surrounding 
 the orifice on the upper part; to these sphincter fibres a bridle is 
 joined, which comes 'from the union of the muscles of the ure- 
 ters."* 
 
 After repeated observations on this point, I have come to the 
 conclusion that Mr. Bell has indicated a real structure; but my 
 own dissections have resulted as follows: The inferior semi- 
 circumference of the neck of the bladder is surrounded by a 
 thick fasciculus of muscular fibre, half an inch wide, running 
 in a transverse direction, and having its ends attached to the 
 lateral lobes of the Prostate Gland, being above the third lobe 
 of the latter. This fasciculus is perfectly distinct from the or- 
 dinary muscular fibre of the bladder, and resembles in its tex- 
 ture the musculo-fibrous coat of the arteries. The superior se- 
 micircumference is also surrounded by a thin layer of muscular 
 fibres of an ordinary kind, forming a broad, thin band of a cre- 
 scentic shape, the lower ends of which are insensibly lost in the 
 adjacent muscular coat of the bladder by being spread out. And, 
 lastly, beneath the mucous membrane of the vesical triangle 
 there is a triangular muscle of the same size as the triangle with 
 elongated angles, the anterior angle of which may be traced to 
 
 * Diseases of the Urethra, &c. p. 10. Lond. 1820. 
 
THE BLADDER. 81 
 
 the posterior part of the caput gallinaginis, and the posterior 
 angles to the orifices of the ureters and the adjacent part of the 
 bladder. The texture of this muscle is r also, like that of the 
 musculo-fibrous coat of the arteries. When a bladder is recent, 
 this detail of structure is made out with difficulty: it requires 
 to be previously hardened in spirits of wine. That a power 
 exists in the neck of the bladder of retaining completely the 
 urine, has been satisfactorily demonstrated to me in a case of 
 fistula in perineo, which was presented to the notice of Dr. 
 Physick and myself, a few years ago.* Occasionally there ex- 
 ists on each side of the neck of the bladder, passing from it to 
 the pubes, a muscle of half an inch in breadth, the effect of 
 which is to draw the neck of the bladder towards the symphysis 
 pubis. 
 
 As the urethra of the male performs the double office of con- 
 ducting both semen and urine, it will be described more pro- 
 perly along with the organs of generation. 
 
 The urine has a considerable number of constituents, the pro- 
 portion of which varies according to age, health, and other cir- 
 cumstances. Water forms about nine-tenths of it, the remainder 
 is an animal matter insoluble in alcohol; uric and lactic acids; 
 lactate of ammonia; sulphate of potash and of soda; hydrochlo- 
 rate of soda and of ammonia; phosphate of soda and of lime; and 
 fluate of lime. 
 
 * Chapman's Med. and Phys. Journ. 1824. 
 
BOOK VI. 
 
 Organs of Generation. 
 
 CHAPTER I. 
 
 OF THE ORGANS OF GENERATION IN THE MALE. 
 
 THE Male Organs of Generation consist in the Testicles and 
 in the Penis, with their appendages ; or, in the language of some 
 anatomists, in the Formative and in the Copulative Organs; which 
 distinction has been applied to both sexes. 
 
 SECT. I. OF THE PENIS. 
 
 The Penis, (Membrum Virile, Menlula,) from performing the 
 two offices, one of which is the conducting of urine from the 
 bladder, and the other the projection of semen into the female, 
 has, accordingly, a peculiarity of structure, which allows it to 
 assume a state of collapse or of erection. Its shape is almost 
 cylindrical, but terminating in front by an obtusely pointed ex- 
 tremity, named Glans. It adheres by its posterior end or root 
 to the bones of the pelvis, at and below the symphysis pubis. 
 
 It is formed by common integuments, by condensed cellular 
 tissue, by the Corpus Cavernosum, and by. .the Corpus Spon- 
 giosum. 
 
 The skin on the penis is more thin and delicate than it is on 
 most other parts of the body, and is furnished with a considera- 
 ble number of sebaceous follicles or glands about the root of the 
 organ, with hairs 'growing from the centre of them. This same 
 
84 ORGANS OF GENERATION. 
 
 skin, in passing to the abdomen over the pubes, is somewhat pro- 
 truded by a subjacent deposite of fat and cellular matter, causing 
 an appearance corresponding with the mons veneris of the fe- 
 male; and is also generally thickly covered with short curly 
 hair, which, as the individual advances in life, proceeds in a 
 pointed direction to the umbilicus. The skin of the penis is but 
 loosely connected to the organ, so that it slides readily back- 
 wards and forwards, and by its elasticity is well suited to the 
 varying states of erection and collapse. At the anterior ex- 
 tremity it is thrown into a duplicature or fold; the Prepuce, 
 (Preputium,) the internal lamina of which being fixed circularly 
 to the penis, some distance back from the point, permits a con- 
 siderable portion of that extremity of the penis, called the Glans, 
 to remain uncovered when the prepuce is drawn back. The 
 under middle part of the prepuce is attached to the extremity of 
 the glans by a vertical longitudinal duplicature, called the Frse- 
 num, which extends to the orifice of the urethra. 
 
 The skin does not actually stop at the circumference of the 
 glans, but is continued smoothly over it, modified, however, so 
 much in its structure, as to be much more adherent, soft, deli- 
 cate, vascular, and sentient: its cuticle there is a thin epithelium, 
 readily separated by maceration. The projecting circular and 
 oblique shoulder of the glans, behind which the skin becomes 
 firmly joined to the penis, is called the Crown, (Corona Gldndis.) 
 The contracted portion, behind the corona, is the neck, (Collum.) 
 On the surface of the neck and the posterior face of the corona, 
 the skin is furnished with an abundance of small glandular masses 
 or follicles, (Glandulce Odorifera Tysonii,) which secrete the thick 
 white sebaceous matter, (Smegma praputei,} that accumulates 
 when personal cleanliness is not attended to. 
 
 The penis, in addition to other modes of attachment to the 
 bones of the pelvis, is fixed by the Ligamentum Suspensorium. 
 The latter is a triangular vertical fibrous lamina, which proceeds 
 downwards from the symphysis pubis to the dorsum of the penis ; 
 and, according to Mr. Colles, envelops this organ to the glans, 
 forming its cellular coat, and being continued into the fascia su- 
 perficialis abdominis. Posteriorly, it is lost insensibly on the 
 fascia of the thighs, covering the adductor muscles. At its ori- 
 
THE PENIS. 85 
 
 gin it is occasionally furnished with muscular fibres; one strongly 
 marked instance of which has been presented to me in my own 
 dissections. 
 
 The Corpus Cavernosum of the penis, forms by much the most 
 considerable portion of the whole organ. Externally, it is a 
 white fibrous membrane, of a dense structure, enjoying extensi- 
 bility and an extreme degree of contractility. Its external 
 fibres pass, for the most part, longitudinally, except about the 
 root, where they are blended with the periosteum of the bone, 
 and with the tendons of the muscles. This coat of the penis is 
 occasionally called its elastic ligament. It arises by two conical 
 crura, from the internal face of the crura of the pubes and ischia, 
 to within a little distance of the anterior part of the tuber ischii. 
 At the lower part of the symphysis pubis these crura join and 
 form a body; which, when stripped of its connexions, resembles 
 two cylinders lying along side of each other, united ; and which 
 terminate in common, anteriorly, by a truncated cone, covered 
 obliquely by the glans. At the posterior part of the corpus ca- 
 vernosum, in its centre, there is a septum, almost complete, also 
 of the same elastic substance, which separates the two halves 
 from each other; but, anteriorly, this septum is more imperfect, 
 having an arrangement like the teeth of a comb, whence the 
 term Septum Pectiniforme has been given it. This septum is 
 continued at its margins into a layer of circular fibres, consti- 
 tuting the internal coat of the corpus cavernosum. 
 
 In the middle of the corpus cavernosum, above, is a longitudi- 
 nal depression for lodging the veins of the penis, and, in the same 
 manner, there is another below, for the corpus spongiosum ure- 
 thrae. The cavity of this membrane is filled by a spongy tissue, 
 that arises from its internal face, and is formed of filaments and 
 little laminae ; they, by crossing each other, make a multitude of 
 cells, which have a perfectly free communication with one an- 
 other, and generally are somewhat occupied by blood. A fine 
 injection through the artery of the corpus cavernosum will fill 
 these cells and return through the veins ; from which cause the 
 cells may be considered as intermediate to the two orders of 
 vessels. This opinion is the more probable from the cells being 
 lined by a thin menibrane like the internal one of the veins, and 
 VOL. II. 12 
 
86 ORGANS OF GENERATION. 
 
 which is easily seen near the septum by tearing the spongy part 
 from it. 
 
 The Corpus Spongiosum Urethrae extends from ten or twelve 
 lines behind the junction of the crura of the corpus cavernosum, 
 to the anterior extremity of the penis. Externally, it has a coat 
 resembling that of the corpus cavernosum, except that it is thin- 
 ner, and in its centre is the canal for the passage of urine. Be- 
 tween the canal and the coat is a spongy structure, much finer 
 than that of the corpus cavernosum, and though the cells com- 
 municate freely, still they have the appearance of convoluted 
 veins. The corpus spongiosum is not of equal diameter in its 
 whole course, for its commencement in the perineum, where it 
 is pendulous, is enlarged into what is termed the Bulb ; from this 
 it diminishes gradually to the anterior end, where it is again en- 
 larged into the glans penis. 
 
 The Urethra is a canal, whose length varies according to the 
 degree of erection in the penis, and extends from the neck of the 
 bladder to the extremity of the glans. It is curved, and receives 
 in its course the ductus ejaculatorii, the excretory ducts of Cou- 
 per's glands, and the mucous lacunae of its own internal mem- 
 brane. The first part of this canal which traverses the prostate 
 gland is from fifteen to eighteen lines in length, and is called the- 
 Prostatic Portion: it is well supported by this body, although its 
 own sides are very thin. On its inferior surface is a doubling 
 which constitutes the Verumontanum or Caput Gallinaginis. On 
 either side of the caput gallinaginis the canal of the urethra is 
 depressed into something like a cul-de-sac, where are to be found 
 the lacunae of the prostate gland. 
 
 Between the Prostate and the Bulb is the membranous part 
 of the urethra, about eight or ten lines long; it is unprotected, 
 except by a soft covering, which seems in some measure to be 
 a mixture of gelatinous matter and muscular fibre. The former 
 was considered by Littre as a glandular body which secreted a 
 viscid humour into the interior of the canal ; the latter, probably, 
 is the part described by Winslow as the inferior prostatic mus- 
 cle ; which, arising on each side of the membranous part of the 
 urethra, goes to be inserted into the corresponding branch of the 
 
THE PENIS. 87 
 
 pubes near the symphysis. The membranous part of the urethra 
 does not get into the end of the bulb, but penetrates it from 
 above, half an inch or more occasionally, from its extremity, 
 just below the junction of the crura of the corpus cavernosum. 
 
 The canal varies in its dimensions: at its commencement, 
 which is synonomous with the neck of the bladder, it is large ; 
 it then contracts at the back of the caput gallinaginis, and imme- 
 diately enlarges in the fore part of the prostate, at the sides of 
 the caput. The membranous part is small ; the canal then en- 
 larges in the bulb. In the body of the penis the canal is suc- 
 ' cessively diminished, till it comes almost to the glans, when it is 
 so remarkably enlarged again as to get the name of Fossa Na- 
 vicularis ; it terminates, finally, by a short vertical slit at the 
 extremity of the glans. 
 
 In the whole length of the canal there are two whitish middle 
 lines, one above, and the other below ; and in the membranous 
 and spongy portions, excepting the fossa navicularis, longitudinal 
 folds of the lining membrane exist, which are effaced by disten- 
 tion. In the upper part of the canal there are a great many 
 mucous lacunae ;* Loder has marked about sixty-five : there is 
 one particularly large in the upper surface of the fossa navicu- 
 laris, which, it is said, has stopped the point of a bougie, and 
 been mistaken for stricture.! 
 
 Mr. Shaw Ras described a set of vessels immediately on the 
 outside of the internal membrane of the urethra ; which, when 
 empty, are very similar in appearance to muscular fibres. He 
 says, he has discovered that these vessels form an internal 
 spongy body, which passes down to the membranous part of the 
 urethra, and forms even a small bulb there.f His preparation, 
 being a quicksilver injection of the part, is certainly a very sa- 
 tisfactory demonstration of its existence ; yet, in my own obser- 
 vations, where the blow-pipe has been resorted to, it has rather 
 appeared to me to be the cellular membrane connecting the 
 canal of the urethra' with the corpus spongiosum. 
 
 * Tabula Anat. 
 
 f Sir Everard Home has lately communicated to the Royal Society a highly 
 interesting paper on the structure of the lining membrane of the urethra. From 
 his microscopical observations he is induced to think that it is muscular. 
 
 t Med. Chir. Trans.' vol. x. 
 
88 ORGANS OF GENERATION. 
 
 The arteries of the penis come from the internal pudic ; some 
 of its veins follow the course of the arteries, and others collect 
 into the two venae dorsales penis ; the nerves come from the in- 
 ternal and external pudics. 
 
 SECT, II. OF THE MUCOUS GLANDS AND APPARATUS. 
 
 The Seminal Vesicles ( Vesicula Seminales) are two convoluted 
 tubes, one on each side, two inches in length, placed on the 
 lower fundus of the bladder, between it and the rectum, and be- 
 hind the prostate gland. At their anterior extremities they ap- 
 proach very nearly to each other, being only separated by the 
 intervention of the vasa deferentia. They are fixed to the blad- 
 der, and surrounded by a thick mass of adipose and cellular 
 matter, with many blood vessels, principally veins, passing 
 through it. 
 
 When inflated and dried, they present the semblance of cells, 
 but are, in fact, long tubes; which, by being convoluted, are 
 reduced to the apparent dimensions mentioned. When dissected 
 and stretched out, they are four or five inches long, by three 
 lines in diameter. 
 
 There are also several pouches on each side of the long tube 
 which increase the number of cells. The convolutions are pre- 
 served by the intermediate cellular tissue. These bodies consist 
 of two coats : an external, which is fibrous and cellular ; and an 
 internal, which is mucous, being a continuation of the lining 
 membrane of the urethra. They are commonly filled by a drab- 
 coloured thick fluid, supposed to be a mixture of the semen, with 
 their own proper secretion, though, of this, Mr. Hunter doubted.* 
 The excretory duct of each vesicle is about a line and a half 
 long, when it joins in the substance of the prostate with the vas 
 deferens of the same side ; a common canal (ductus ejaculalorius) 
 is thus formed, which runs parallel with its fellow, below the ure- 
 thra.! 
 
 * Observations on the Animal (Economy. 
 
 f Lately, in a dissection executed at the university by Dr. Togno, a muscle 
 was found on the inferior surface of the seminal vesicles arising from the pros- 
 tate gland, and inserted into them. This is said to be a common arrangement in 
 some animals. 
 
MUCOUS GLANDS. 89 
 
 The Ductus Ejaculatorius is about eight or ten lines long, and 
 opens by an oblong orifice, at the lateral anterior face of the 
 Caput Gallinaginis : it is larger behind than before, which gives 
 it a conical shape, and allows fluids injected to pass freely from 
 the vas deferens to the vesicula, and the reverse. 
 
 The Prostate Gland (Glandula Parastala*} is a body about 
 the size and form of a horse chestnut, fixed on the neck of the 
 bladder, and penetrated by the urethra, which traverses it much 
 nearer its superior than its inferior surface. The base of it is 
 turned backwards, and the point forwards ; its inferior surface 
 rests upon the rectum ; it is rendered concave by that circum- 
 stance, and its sides, in the distentions of this organ by faeces, 
 are overlapped by it. The Prostate has, posteriorly, a notch in 
 its centre, which divides it into two lateral lobes, and by raising 
 the Vesiculae Seminales, we see where their excretory ducts pe- 
 netrate the gland, and separate from the body of it, the little tu- 
 bercle, to which Sir Everard Homef has particularly called the 
 attention of the profession, and considered as a ' Third Lobe ; it 
 being certain that it is frequently the seat of disease and tume- 
 faction. 
 
 On the under surface of the canal formed in the prostate, by 
 the urethra, is the oblong elevation called the Verumontanum, or 
 Caput Gallinaginis. It commences a little in front of the uvula 
 vesicse, and, being broader and higher behind, comes to a point 
 very gradually before ; it is about eight or ten lines long. Along 
 the posterior part of this ridge is a long cleft, being the orifice of 
 a lacuna, first observed by Morgagni ; and in front of it are the 
 orifices, bordering upon each other, of the ductus ejaculatorii. 
 
 The prostate consists in a condensed, white, extensible, though 
 easily lacerated fibrous cellular tissue, within which are placed 
 a great number of mucous follicles, that have from eight to twelve 
 ducts, or, according to Loder, from thirty-two t6 forty-four, pass- 
 ing obliquely forwards, and terminating in the urethra, as stated, 
 at the sides of the urethral crest, or caput gallinaginis. The 
 fluid secreted is thick, ropy, white, and semi-transparent, in a 
 healthy state. The prostate is surrounded by a fibrous capsule, 
 to be described. 
 
 * From Vs-Xjtt/, sto. | Diseases of Prostate. 
 
90 ORGANS OF GENERATION. 
 
 The lacunae of the third lobe penetrate the coats of the blad- 
 der, behind the caput gallinaginis. 
 
 Of the Glands of Couper. These glands are also intended for 
 the secretion of mucus, or a fluid very much like it, into the ca- 
 nal of the urethra. They are two in number, one on each side, 
 and are situated in advance of the prostate, between the laminae 
 of the triangular ligament, at the point where the bulb of the 
 urethra adheres to it. Commonly, they are about the size of a 
 garden pea, but not unfrequently much smaller, and, in some in- 
 stances, cannot be found at all, which induced Hiester to declare, 
 that he had searched for them fruitlessly. They are yellowish, 
 hard, and consist of several lobules united together. Each one 
 has an excretory duct that receives readily a bristle, and passes 
 obliquely forwards, between the corpus spongiosum and the ca- 
 nal of the urethra, to terminate in an oblique orifice in the latter, 
 about, an inch distant from the gland. 
 
 One or more glands, of the same description, and discovered 
 by Littre, are occasionally found just in front of Couper's. They 
 also discharge their secretion into the adjacent part of the ure- 
 thra. In my own dissections I have not met with them. 
 
 SECT. III. OF THE TESTICLES. 
 
 The Testicles (Testes, Didymi) are two in number, one for 
 each side of the scrotum. Being the seat of the secretion of 
 sperm or the male prolific liquor, their function is of the first im- 
 portance in the act of generation. They are of an oblong oval 
 form, somewhat compressed laterally ; and present their edges 
 forwards and backwards. From being suspended near the mid- 
 dle of their posterior edge by the spermatic chord, the upper 
 end points somewhat forwards, while the lower one is directed 
 in the same degree backwards. They are about an inch and a 
 half long, by one inch in breadth, and eight or nine lines in thick- 
 ness. They are of equal size generally, but in case of a diffe- 
 rence it is in favour of the right; the latter is also remarkable 
 for being suspended higher than the left, a feature in ancient 
 statuary so universal, as to prove the vigilance and 'accuracy 
 of the sculptors of those days, in regard to the proportions and 
 
THE TESTICLES. 91 
 
 peculiarities of the human form. " Two obvious advantages 
 attend this arrangement: one, that of the testicles passing each 
 other without collision when the thighs are brought together ; 
 and another, the facility of keeping the penis to one side, instead 
 of straight forward in the middle line of the body."* 
 
 The testicle is enveloped by several tunics; they are the 
 Scrotum, the Dartos, the Tunica Vaginalis, and the Tunica Al- 
 buginea. 
 
 The Scrotum is merely a continuation of the common skin 
 from the inner side of the thighs, the perineum, and the penis, 
 and is common to the two testicles. It is a symmetrical bag, 
 and the two halves are marked off from each other by a middle 
 line or elevation of the skin, called the Raphe, which begins in 
 the perineum at the anus, and, winding around ttye scrotum, is 
 continued along the under surface of the penis to the prepuce. 
 
 The skin of the scrotum is thin, darker than elsewhere, but 
 has a thick, strong epidermis ; it has many sebaceous follicles in 
 it, and is sparingly furnished with hair. It is very extensible, as 
 manifested in fatigue, and by hydrocele ; and may be contracted 
 again so as to draw the testicles close under the pubes, though 
 for the latter power it principally depends upon the subjacent 
 coat. Its surface is covered with wrinkles, for the most part 
 transverse, and ending at the raphe : they are effaced during its 
 great distentions in hernia and dropsy, and then it has a smooth 
 shining surface. 
 
 The Dartos is placed within the scrotum, and forms two dis- 
 tinct sacs or tunics, one for each testicle. It arises from the 
 inferior margins of the crura of the ischia and of the pubes, and 
 lines the scrotum till it reaches the raphe ; it is then reflected 
 upwards to form the partition between the testicles, (septum 
 scroti,) and terminates at the corpus spongiosum urethras. This 
 membrane, according to the observations of MM. Chaussier, 
 Lobstein, and Breschet,t does not exist in the scrotum till the 
 descent of the testicle, and then appears to be an expansion of 
 the gubernaculum testis. 
 
 * gir A. Cooper on the Testis. 1830. 
 
 f Dictionnaire des Sciences Med. tome viK. 
 
92 ORGANS OF GENERATION. 
 
 It receives a considerable number of blood vessels, which, 
 owing to the thinness of the skin, may be seen in the living body, 
 ramifying through its substance: its general appearance is, 
 therefore, reddish. It is destitute of fat, and consists in long 
 fibres much matted together, and passing in every direction : 
 they are easily separated by distention with air or water, and 
 by slight maceration. Its powers of contraction are exceeding- 
 ly well marked upon the application of cold to the scrotum, from 
 which cause it has been considered by many anatomists as 
 muscular : the only distinct evidences, however, which I have 
 met with of a resemblance to the latter, have been found gene- 
 rally on its posterior face, near the perineum.* From its equi- 
 vocal character, J. F. Meckel has very ingeniously suggested 
 that it forms the transition from cellular to muscular tissue, and 
 that there exists between it and other muscles the same relation 
 that there is between the muscles of the superior and of the in- 
 ferior orders of animals. Among the latter, the fibrous structure 
 is indistinctly marked, and is masked by gelatine; an element of 
 the cellular tissue which envelops and conceals the fibrine, an 
 element of the muscular tissue. 
 
 The fibres of the cremaster muscle, which are next in order, 
 form a very imperfect covering to the testicle, and belong rather 
 to the spermatic chord: what remains to be said concerning 
 them will be more properly introduced into the account of the 
 latter. The cellular substance that connects the dartos and the 
 cremaster with the tunica vaginalis forms a compact and perfect 
 lamina, sometimes spoken of as the Tunica Vaginalis Communis 
 Testis. There is one for each testicle, which it surrounds en- 
 tirely, as well as its chord, and connects the chord to the mar- 
 gins of the abdominal rings, as stated in the account of them. 
 At its upper end it is continuous with the cellular substance that 
 unites the peritoneum to the parietes of the abdomen, as may 
 be proved by inflating it, when the air will penetrate according- 
 ly through the abdominal canal. 
 
 The Peritestis, or Tunica Vaginalis, was originally a process 
 
 * Since the first edition, I have dissected one subject, (January, 1830,) where 
 the fibres were evidently muscular, though interwoven. 
 
THE TESTICLES. 93 
 
 of peritoneum, communicating with the cavity of the latter through 
 the abdominal canal ; but in the adult, it appears as a complete 
 and distinct sac. As it is very rigidly comparable to a double 
 night-cap drawn over the head, we accordingly find that the tes- 
 ticle, along with the epididymis, is pushed into it from behind. 
 That portion of the tunica vaginalis which is in contact with the 
 testicle, or rather with the tunica albuginea, adheres so closely 
 that it cannot be separated, except very partially, and in shreds ; 
 but it may be detached easily from the epididymis, with the con- 
 volutions of which it is in immediate contact. This sac is longer 
 and larger than the testicle itself, from which cause it ascends 
 for several lines above the superior end of the gland, and the 
 free part hangs loosely about it. Its cavity may, with but little 
 force, be injected so as to hold an ounce or two of fluid. 
 
 This membrane is smooth and polished on the surface forming 
 its cavity, and contains a small quantity of serous halitus, which 
 allows the opposed surfaces to glide freely upon one another. Its 
 exterior connexion with the dartos is so slight that it may be 
 withdrawn without dissection, with the exception of an adhesion 
 at the lower end of the testis arising from the remains of the gu- 
 bernaculum : in such case, however, it still continues to be in- 
 vested by the tunica vaginalis communis, from which it can only 
 be removed by a special dissection. 
 
 The Tunica Albuginea is the proper coat of the testicle, is in 
 immediate contact with its glandular structure, and serves to 
 maintain its shape, as well as to protect it from pressure. From 
 its internal surface proceed many membranous, horizontal fibres, 
 which form partial partitions of its cavity (SeptulcB Testis) and 
 incline towards its posterior part, where they terminate in a lon- 
 gitudinal projection, called Corpus Highmorianum. The latter 
 is of a prismatic shape, somewhat broader above than below, 
 and is of but little consequence, except that it was once errone- 
 ously supposed to be a sinus, into which the seminiferous tubes dis- 
 charged. Sir Astley Cooper proposes to call this the mediastinum 
 testis, and considers the Corpus Highmorianum as being formed 
 by an inflection of the tunica albuginea. The Septulae Testis, 
 he asserts, really envelop the seminiferous tubes, by forming bags 
 which support, confine, protect, and nourish .the tubular struc- 
 VOL. II. 13 
 
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THE TESTICLES. 05 
 
 backwards to penetrate the corpus Highmoriamnn and the tunica 
 
 albuginea. f these vasa efferentia is then convoluted upon 
 
 nical body, called Conns Vasculosus, which pre- 
 
 :ts base backwards. Each cone, at its base, has its tube 
 
 entering successively into the tube of which the Epididyrnis is 
 
 Notwithstanding the extreme tenuity of these several arrange- 
 ments in the excretory ducts of the testicle, they may be entirely 
 filled with quicksilver from the vas deferens ; but the task is one 
 of great difficulty, and rarely* succeeds. 
 
 The epididyrnis is the prismatic arch which rests vertically on 
 the back of th' and adheres to it by the reflection of the 
 
 tunica vaginalis. It is enlarged at both ends, the upper of which 
 formed by the Coni Vasculosi, is called the Globus Major, 
 and the lower enlargement is the Globus Minor. It is formed of 
 a single convoluted tube, of the fourth of a line in diameter. 
 After this tube has got to the lower end of the globus minor it 
 .ics less convoluted, enlarges, turns upwards on the inner 
 f the epididymis, and obtains the name of Vas Deferens. 
 Before it reaches the top of the epididymis it has become per- 
 fectly straight, or almost so. There is a blind duct which be- 
 gins at the top of the epididymis and terminates below ; the ob- 
 ject of it is not understood. 
 
 Of the Spermatic Chord. 
 
 The Spermatic Chord is a fasciculus of about half an inch in 
 diameter, which may be felt very readily through the skin of the 
 scrotum, passing from the upper end of the testicle to the exter- 
 nal abdominal ring. It is formed by the Vas Deferens : the Sper- 
 matic Artery and Veins : the Lymphatics of the Testicle ; and 
 i being covered in by the Tunica Vaginalis Com- 
 munis, and by the Cremaster Muscle. 
 
 The Cremqster Muscle, also called the tunica elythroides,* be- 
 ing derived from the internal oblique and the transverse muscle of 
 the abdomen,t forms a very complete envelope to the chord from 
 
 * E/.y7^r, a sheath. f See Abdominal Muscles. 
 
96 ORGANS OF GENERATION. 
 
 the abdominal ring to the testicle. But when it reaches the lat- 
 ter its fibres spread out and become indistinct upon the tunica 
 vaginalis communis,, as they there consist in small, pale, scat- 
 tered fasciculi ; many of which terminate insensibly, while others 
 form on the front of the tunica vaginalis loops, having their 
 convexities downwards. This muscle draws the testicle up- 
 wards, an action very different from the corrugation of the 
 scrotum. 
 
 The Vas Deferens, or the proper 'excretory duct of the testicle, 
 is a white tube of about a line and a half in diameter, and has a 
 cartilaginous feel. Its parietes are thick, as its cavity will not 
 receive a body larger than a bristle, without being put upon the 
 stretch. It traverses a long space, and in doing so, first passes 
 at the back of the chord from its commencement to the internal 
 abdominal ring : having reached the latter, it then abandons the 
 spermatic artery and vein, and dipping into the pelvis, by the 
 side of the bladder, goes between the lower fundus of the latter 
 and the ureter. It then converges towards its fellow, along the 
 under extremity of the bladder, at the inner margin of the vesi- 
 cula seminalis, of the same side, and finally terminates in the ure- 
 thra near the neck of the bladder, by forming the Ductus Ejacu- 
 latorius with the assistance of the duct of the adjoining vesicula 
 seminalis. About two and a half inches from its termination, it 
 enlarges and becomes somewhat tortuous. 
 
 This duct consists of two coats : the external one is hard, com- 
 pact, and, occasionally, fibres are seen in it ; but its structure is 
 not very evident, and is peculiar. The internal is a mucous 
 membrane. 
 
 For the description of the remaining portions of the chord, 
 see Spermatic Artery, Vein, Lymphatics, and Plexus of Nerves. 
 
 The Testicles undergo a remarkable change in their position, 
 from the earliest development of their rudiments to the perfect 
 foetal state. They are not formed in the scrotum, but in the ab- 
 domen just below the kidneys ; from which position they are 
 gradually transferred. About the middle of the third month of 
 gestation they are two lines long, and placed behind the perito- 
 neum, to which they loosely adhere. The vas defer ens then, in- 
 
MUSCLES AND FASCIA OF THE PERINEUM. 97 
 
 stead of rising up on the side of the epididymis, goes straight 
 down into the pelvis. At this period may be seen the guberna- 
 culum testis, discovered by J. Hunter,* which becomes more dis- 
 tinct in a few weeks afterwards, and assumes a triangular appear- 
 ance. This gubernaculum has the office of drawing the testicle 
 down into the scrotum ; its point commences in the upper part of 
 the latter, somewhat below the external abdominal ring ; it passes 
 through the abdominal canal, ascends upon the iliac us internus 
 muscle, and is attached by its base to the inferior end of the tes- 
 ticle. In front of the gubernaculum, a process, or small pouch 
 of peritoneum, passes through the abdominal canal to the upper 
 part of the scrotum. By the contraction of the gubernaculum, 
 the testicle is brought, about the seventh or eighth month, into 
 the scrotum, by sliding down behind the pouch. The lower end 
 of the pouch, at which the testicle is finally arrested, becomes 
 the tunica vaginalis testis. 
 
 As soon as the testicle has reached the scrotum, the neck of 
 the pouch has a tendency to close and to become obliterated, 
 which is commonly accomplished at the period of birth ; yet it 
 sometimes remains open for a longer time, and becomes the oc- 
 casion of congenital hernia. Very generally, at birth, the orifice 
 of the pouch will receive the end of a probe to the depth of a line 
 or two ; but all below is perfectly closed, and has its structure 
 so condensed and altered, that na one, from a view of it alone, 
 would suppose that the cavity of the tunica vaginalis had ever 
 communicated with that of the peritoneum.t 
 
 SECT. IV. OF THE MUSCLES AND FASCIA OF THE PERINEUM. 
 
 Perineal Fascia. 
 The Perineal Fascia is placed just beneath the skin of the peri- 
 
 * Mecl. Comment. Lond. 1777. 
 
 j- The explanations and anatomy of this process have been treated at large in 
 the following works : 
 
 Girardi, Tabul. II. adj. Septemd. Tab. Santorini. 
 
 Hunter, Observations on certain parts of the Animal (Economy. W. Hunter, 
 Med. Commentaries. 
 
 Edwardi Sandifort, Opusc. Anat. 
 
 Wrisberg Comment. Medic. Physiolog. &c. 
 
98 ORGANS OP GENERATION. 
 
 neum, and covers the muscles. It occupies nearly all the space 
 between the anus and the posterior margin of the scrotum, and 
 between the rami of the pubes and the ischia on each side : it is 
 very firmly fixed to these bones, and is gradually blended with 
 the cellular substance of the posterior part of the scrotum. This 
 fascia is rather thin, but, in case of a rupture of the posterior part 
 of the urethra, prevents the urine from showing itself in the peri- 
 neum, and drives it into the cellular structure of the scrotum. 
 In abscesses of the perineum, it also prevents the fluctuation from 
 being very evident. 
 
 The Musculus Erector Penis, 
 
 Is so situated, as to cover the whole of the crus of the penis 
 which is not in contact with the bony margin of the pelvis. It 
 arises, therefore, tendinous and fleshy, from the anterior part of 
 the tuber ischii; its fleshy fibres adhere to the internal and exter- 
 nal margins of the ramus of the ischium, and of the pubes, and 
 proceed upwards; just before the union of the crura of the pe- 
 nis, they end in a flat tendon which is lost on the side of the 
 corpus cavernosum of the penis.* 
 
 Its use is not well understood. 
 
 The Musculus Accelerator Urince, 
 
 
 Lies on the bulb and back part of the corpus spongiosum ure- 
 thras : it is a thin muscle, consisting of oblique fibres. 
 
 It arises by a pointed production from the side of the body of 
 the penis ; its origin is continued obliquely across the inferior sur- 
 face of the crus penis, where the latter begins to form the body 
 of the penis. It arises, also, for an inch from the inner side of 
 the ramus of the pubes, between the crus penis and the triangu- 
 lar ligament of the urethra. The muscles of the opposite sides 
 are inserted into one another by a white line, which marks the 
 middle of the bulb of the urethra ; and by a point, into the ante- 
 rior extremity of the sphincter ani, where they are joined by the 
 transversi perinei. 
 
 * The late Dr. Lawrence informed me that he had frequently found muscular 
 fibres between the bone and the cms penis. 
 
MUSCLES OF THE FASCIA AND PERINEUM. 99 
 
 In order to see the origin of these muscles very distinctly, se- 
 parate them from each other in the middle line, and dissect them 
 from the corpus spongiosum. Cut transversely through the cor- 
 pus spongiosum about three inches before the triangular liga- 
 ment, and dissect it clearly from the corpus cavernosum, turning 
 it downwards so that it may hang by the membranous part of 
 the urethra. By putting the two acceleratores on. the stretch, it 
 will be seen that besides the origins mentioned, they arise, also, 
 from each other by a tendinous membrane that is interposed be- 
 tween the corpus spongiosum and cavernosum ; so that they lite- 
 rally surround the back part of the urethra, constituting a com- 
 plete sphincter muscle for it. This account of the accelerator 
 urinae being peculiar to myself, is adopted from a strong analogy 
 between it and the sphincter vaginae. 
 
 The two muscles are considered by M. Chaussier as forming 
 but one : in that case its origin will be reversed, and commence 
 in the middle line of the perineum instead of terminating there. 
 As this muscle, and the erector penis, touch by their contiguous 
 faces, it is difficult to get into the membranous part of the ure- 
 thra in lithotomy without cutting through the muscular fibres of 
 one or the other. 
 
 It propels the urine and semen forward. 
 
 The Musculus Transversus Perinei, 
 
 As its name implies, passes directly across the perineum ; it 
 arises from the inner side of the ischium, just at the origin of the 
 erector penis, and is inserted where the sphincter ani and acce- 
 leratores join. 
 
 I have observed that when the lower part of the accelerator 
 was extended much below its usual line, and strongly developed, 
 that the transversus was very irregular in its origin and course ; 
 consisting frequently of a few fibres which did not deserve the 
 name of a distinct muscle, and lying almost unappropriated in 
 the adipose matter of the part. 
 
 Occasionally, a fasciculus of muscular fibres exists, called, by 
 Albinus, Transversus Perinei Alter, which arises in front of the 
 transversus : it seems generally to be a fasciculus loosened of 
 
100 ORGANS OF GENERATION. 
 
 the accelerator urinae muscle, and is inserted into the perineal 
 junction just behind it. 
 
 The use of these muscles seems to be to contribute to fix the 
 bulb of the urethra. 
 
 The Musculus Sphincter Ani, 
 
 Consists in a plane an inch thick, of elliptical fibres immediate- 
 ly beneath the skin of the anus, and which surrounds the latter 
 in order to keep it closed. The long diameter of the ellipsis is 
 extended from the coccyx towards the symphysis pubis, and 
 has its angles very much elongated : the anterior may be traced 
 terminating insensibly in the posterior face of the scrotum. It 
 has two fixed points, the last bone of the os coccygis behind, and 
 the perineal union of the other muscles in front ; its lateral dia- 
 meter occupies about one-half of the space between the tuberosi- 
 ties of the ischia, and it is in the middle of this space. 
 
 Besides closing the orifice of the rectum it will draw the bulb 
 of the urethra backwards, or the point of the os coccygis for- 
 wards. 
 
 The Musculus Coccygeus, 
 
 Belongs to the interior of the pelvis. It arises by a small, 
 tendinous, and fleshy beginning, from the spine of the ischium, 
 and, lying on the anterior face of the anterior sacro-sciatic liga- 
 ment, it is inserted into the side of the last bone of the sacrum, 
 and of all those of the os coccygis. 
 
 It draws the os coccygis forwards. 
 
 It frequently happens that there is on each side a small fasci- 
 culus of muscle arising from the inferior bone of the sacrum in 
 front, and inserted into the bones of the coccyx ; it is called 
 Sacro-Coccygeus. 
 
 A large quantity of adipose and cellular matter exists on the 
 side of the rectum, between it and the parietes of the pelvis, con- 
 cealing the perineal surface of the levatores ani muscles. 
 
MUSCLES AND FASCIA OF THE PERINEUM. 101 
 
 The Musculus Levator Ani, 
 
 Arises, fleshy, from the back of the pubes near its symphysis, 
 and from near the superior margin of the foramen thyroideum 
 above the obturator internus muscle. It also arises from the 
 aponeurosis pelvic a, where this membrane is extended as a 
 thickened semi-lunar chord from the superior margin of the thy- 
 roid foramen towards- the spinous process of the os ischium. 
 This second part of the origin of the levator ani is defectively 
 described in most books on anatomy. It is then seen to cross 
 obliquely, as far as the spine of the ischium, that portion of the 
 obturator internus which arises from the plane of the ischium. 
 
 From this extensive origin the fibres converge and descend 
 backwards, and have three distinct places of insertion; the pos- 
 terior fibres are inserted into the two last bones of the os coccy- 
 gis; the middle, and by far the greater, number, are inserted 
 into the semi-circumference of the rectum be'tween its longitu- 
 dinal fibres and the circular fibres of the sphincter ani; and, 
 finally, the most anterior fibres pass obliquely downwards and 
 backwards on the side of the vesical end of the membranous 
 part of the urethra, and on the side of the prostate gland, and 
 are inserted into the common place of junction of the perinea! 
 muscles. 
 
 The Triangular Ligament of the Urethra, 
 
 Is a membrane which fills up the space below the symphysis 
 of the pubes, and answers there as a septum between the peri- 
 neum and the pelvis: when closely examined, it is seen to con- 
 nect itself to the internal edges of the rami of the pubes and 
 ischia on the inner posterior sides of the crura penis as far down 
 as the beginning of the latter. At its lower edge its ligamentous 
 character is not so well defined. On its anterior surface is the 
 bulb of the urethra, and just at the extremity of the latter, en- 
 closed by the ligament, and adhering to it, are Couper's Glands. 
 In contact with it behind, and adhering, is the prostate gland, 
 covered by its fibrous capsule, which is a continuation of the 
 pelvic aponeurosis over it. A perforation exists in it, through 
 VOL. II. 14 
 
102 ORGANS OF GENERATION. 
 
 which passes the membranous part of the urethra. This open- 
 ing is not very apparent, in consequence of its edges being con- 
 tinued a little distance on the canal ; but by detaching them the 
 whole becomes well defined. 
 
 The relative situation of the bulb and of the membranous part 
 of the urethra is such, that the former goes towards the anus, 
 while the latter passes upwards towards the neck of the bladder ; 
 they, consequently, form a considerable angle with each other. 
 The membranous part of the urethra is much the deepest, the 
 recollection of which is all-important in lithotomy, as it teaches 
 us to avoid the one, and to cut into the other. It may also be 
 observed, that the hole in the triangular ligament is an inch be- 
 low the symphysis pubis. 
 
 By removing the upper corner of the triangular ligament, we 
 are made acquainted with another just behind it, which is total- 
 ly distinct. This ligament is half an inch broad, is thick and 
 strong, particularly at its lower edge, and is very firmly attached 
 laterally to each of the pubes, just below the symphysis: it is a 
 continuation of the ligamentous union of the symphysis pubis. 
 Mr. Colles calls it pubic ligament, with great propriety. I would 
 suggest, as somewhat more expressive, the term Inter-Pubic Li- 
 gament ; * as it serves to distinguish it from another called Pubic, 
 which is above the pubes, and described in the account of the 
 recti abdominis muscles. The breadth of this having been 
 stated at half an inch, it is obvious that the hole in the triangu- 
 lar ligament is half an inch below its lower edge. 
 
 Pelvic Fascia. 
 
 The Pelvic Fascia (Aponeurosis Pelvica) connects the bladder 
 to the sides of the pelvis. " This fascia descends from the ileo- 
 pectineal line to about midway in the depth of the pelvis; here 
 it is reflected from the surface of the muscle, (the Levator Ani,) 
 and applies itself to the prostate gland and bladder on the body 
 of which it is ultimately lost. At the angle of its reflection, this 
 fascia appears particularly strong and white, but becomes more 
 weak and thin as it lines the muscle and covers the bladder. In 
 
 * See Symphysis Pubis. 
 
MUSCLES AND FASCIA OP THE PERINEUM. 103 
 
 tracing this membrane it will be seen that from the pubes just 
 below the symphysis, a pointed production of it, constituting its 
 anterior margin, is fixed into the side of the neck of the bladder. 
 This pointed production on each side is called, by most anato- 
 mists, the anterior ligaments of the bladder. Between them, 
 just beneath the symphysis of the pubes, a pouoh large enough 
 to receive the end of the finger, is formed by the union of the 
 fasciae of the two sides: this pouch connects the middle anterior 
 part of the neck of the bladder to the lower margin cf the sym- 
 physis pubis."* 
 
 This fascia adheres closely to the periosteum of the pubes, 
 between the upper margin of the thyroid foramen and the crista 
 of the pubes ; about the middle third of the linea innominata it is 
 obviously a continuous membrane with the iliac fascia which 
 covers the iliacus internus muscle; but behind this, again, it 
 arises from the remaining third of the linea innominata. 
 
 The portion of this fascia which Mr. Colles speaks of as pap* 
 ticularly strong and white, forms a bow, the concavity of which 
 looks upwards^ one end of the bow being fastened to the pubes 
 above the foramen thyroideum, and the other end to the ischium 
 above its spine. The perineal surface of this bow is an impor- 
 tant point of the origin of the levator ani. Above the bow this 
 fascia is very thin, for the fibres of the obturator internus can be 
 readily seen through it. 
 
 At the bow the fascia divides into two laminae; one pursuing 
 its course to the bladder and rectum, the other covers the lower 
 part of the obturator internus muscle, and thereby constitutes 
 the obturator fascia. The levator ani is interposed between the 
 two laminae. The aponeurosis pelvica also forms a bow or se- 
 mi-lunar edge in front of the sacral nerves. The triangular li- 
 gament and this fascia are so identified in forming the capsule of 
 the prostate, that the latter, in description, may be referred either 
 to the one or the other, or to both, according to the fancy of the 
 describer. 
 
 * Colics' Surgical Anatomy. 
 
104 ORGANS O.F GENERATION. 
 
 CHAPTER II. 
 
 OF THE ORGANS OF GENERATION IN THE FEMALE. 
 
 THE Copulative Organs in the female are, the Vulva and the 
 Vagina; the Generative are the Uterus and the Ovaria. 
 
 SECT. I. OF THE VULVA. 
 
 The term Vulva is applied to the most superficial of the co- 
 pulative organs, and consists in the Mons Veneris, the Labia 
 Externa, the Labia Interna, the Clitoris, the Vestibulum, the 
 Orificium Urethrae, the Fourchette, and the Fossa Navicularis. 
 
 The Mons Veneris is the protuberance on the fore part of the 
 pubes. Its size varies considerably, according to the state of 
 obesity of the subject, in consequence of its being formed by a 
 deposite of fat between the skin and the bone: in corpulent 
 women it is very large and prominent, whereas, in such as are 
 much emaciated, it simply describes the outline of the bones. 
 The skin, there, is abundantly furnished with sebaceous glands, 
 seated in the cellular texture beneath it, and about the size and 
 shape of millet seed. At the age of puberty a growth of hair 
 takes place upon it, which is not so long as the correspondent 
 growth upon men, and is not so much disposed to spread itself 
 over the lower part of the abdomen as life advances. In wo- 
 men who have abused coition, it is. said that these hairs become 
 much curled. 
 
 The Labia Externa are a continuation of the mons veneris 
 downwards in the form of an oblong eminence on either side. 
 Their elevation is produced in the same way by a deposite of 
 fat beneath the skin. They are somewhat broader and more 
 prominent above than below. On the side which is next to the 
 thigh, the integument is common skin, sparingly covered with 
 hair; but on the other face it is a mucous membrane, being a 
 continuation of that of the vagina. The skin here, as well as 
 
THE VULVA. 105 
 
 at the commencement of every mucous membrane, is insensi- 
 bly changed into the latter. They have many sebaceous glands 
 externally, and mucous glands internally, upon them. 
 
 Much cellular membrane, like that of the scrotum, is found 
 in their interior structure; whereby they enjoy great extensibi- 
 lity in order to favour the dilatation of the parts in parturition. 
 The rima which exists between them is the Fissura Vulvas of 
 authors, and is about twice the length of the orifice of the vagi T 
 na; this arrangement of it gives increased facility to the expul- 
 sion of the fostus. 
 
 The Fourchette or Frenulum Vulvse, is situated at the poste- 
 rior commissure of the labia externa, and is a thin, narrow 
 transverse duplicature of skin; which, owing to its weakness, is 
 most frequently ruptured at the first act of parturition, and then 
 disappears. 
 
 The Clitoris bears, in some respects, a resemblance to the penis 
 of the male, but is by ho means so large. It is situated imme- 
 diately below the symphysis pubis, and consists in a cylindrical 
 body of three or four lines in diameter, with two crura. The 
 body is an inch long; the crura are likewise of the same length, 
 and arising from the internal face of the crura of the pubes, 
 unite beneath the symphysis so as to form the body. The 
 body is not straight, but has the anterior half bent downwards 
 and forwards. The exterior covering, or capsule of the clitoris, 
 in its texture, resembles the elastic ligamentous membrane of 
 the corpus cavernosum penis; and is, moreover, filled within by 
 a similar cavernous or cellular structure, which is divided into 
 two equal parts by a septum pectiniforme, and is susceptible of 
 distention during sexual excitement. The clitoris is supplied 
 also with blood vessels and nerves like the penis, and is held 
 up to the under part of the symphysis pubis by a suspensory 
 ligament. 
 
 The anterior extremity of the body of the clitoris is found in 
 the rima or fissura vulvae, about an inch below the upper com- 
 missure 6*f the labia externa. It projects somewhat, and bears 
 a general resemblance in shape with the end of the penis, 
 whence its name of glans clitoridis; but it has not the same or 
 
106 ORGANS OP GENERATION. 
 
 i 
 
 ganization, excepting the delicacy, the extreme sensibility, and 
 the vascularity of the skin which covers it. The clitoris has no 
 corpus spongiosum, neither is it concerned, like the penis, in 
 conveying the urine from the bladder. Its glans is covered by 
 a doubling of skin called the prepuce, and is likewise furnished 
 with the glandulae Tysoni, from which is discharged a smegna, 
 or sebaceous fluid, as in the male. The prepuce does not fur- 
 nish a regular well defined fraenum. 
 
 The Erector Clitoridis muscle corresponds with the erector 
 penis. It arises from the ascending ramus of the ischium, and, 
 covering the inferior face of the cms clitoridis, runs as far for- 
 wards as the commencement of the body. 
 
 The Labia Interna, or Nymphae, are two duplicatures of the 
 mucous membrane of the vulva, which pass down, one on each 
 side, from the clitoris. The prepuce of the latter terminates, 
 on either side, in the labia; while the latter are continued up- 
 wards, by a narrow process, to the under surface of the glans 
 clitoris. They arise, all along their base, from the internal sides 
 of the labia externa, or majora; and being wider in the middle 
 than elsewhere, they terminate insensibly about half-way down 
 the orifice of the vagina. Between the laminae of each one is 
 placed a vascular cellular substance, susceptible of distention and 
 of partial erection during sexual excitement. In young sub- 
 jects, their vascularity communicates a vermilion tinge, which 
 is lost and becomes brownish in the progress of life. As they 
 are effaced during parturition, their chief use seems to be a pro- 
 vision for the great distention of the vulva, which then occurs. 
 
 The labia interna are about half an inch broad in the natural 
 state, and do not project obviously beyond the labia externa, ex- 
 cept in cases of extreme emaciation, where the prominence of 
 the latter has been destroyed by a removal of its fat. They 
 are, however, very subject, as the individual becomes old, to a 
 pointed elongation, increasing their breadth to an inch, or an 
 inch and a half; and to become thickened and indurated. A 
 tribe of Hottentots, the Boschismans, living near the Cape of 
 Good Hope, are uniformly subject to this enlargement; which, 
 for a long time, was represented, by travellers, as an organ su- 
 peradded to what is common in the human species. 
 
THE VAGINA. 107 
 
 The Vestibulum is a depression of twelve or fifteen lines 
 long, between the labia interna; it is bounded above by the cli- 
 toris, and below by the orifice of the vagina. It is abundantly 
 furnished with mucous lacunae. 
 
 The Urethra of the female has its external orifice (Orificium 
 Urethra) in the inferior part of the vestibulum, about one inch 
 below the glans clitoridis, and is generally marked by a slight 
 rising, which is easily distinguished by the sensation of touch 
 alone; its margin is often bounded by a little caruncle on each 
 side. The urethra itself is an inch long, larger and much more 
 dilatable than that of the male, its course is obliquely down- 
 wards and forwards from the neck of the bladder; passing under 
 the symphysis of the pubes, and being slightly curved from that 
 cause. It consists of two membranes, a lining and an external 
 one. The lining membrane is a continuation of that of the 
 bladder; it is thrown into several longitudinal folds, and has 
 many mucous follicles in it. The external coat of the urethra 
 consists of condensed laminated cellular membrane, having a 
 strong affinity with muscular fibre: the principal direction of 
 the fibres is transverse, forming a cylindrical body of half an 
 inch in its transverse diameter, and which has given the idea of 
 the existence of a prostate gland in the female: the lower and 
 lateral surfaces of this cylinder are in contact with the vagina, 
 forming a protuberance into its cavity; and the upper surface is 
 firmly connected to the triangular ligament of the pubes. Im- 
 mediately behind the neck of the bladder, we find the vesical 
 triangle with its muscle, as in the male, excepting that the an- 
 terior angle of it goes to the anterior end of the urethra. 
 
 The Fossa Navicularis is that portion of the rima vulvas 
 which is below the vestibulum, and anterior to the orifice of 
 the vagina. 
 
 SECT. II. OF THE VAGINA. 
 
 The Vagina is a thin membranous canal which leads from the 
 vulva to the uterus. It is from four to six inches in length, dif- 
 fering according to age and pregnancy, and being much shorter 
 
108 ORGANS OF GENERATION. 
 
 in women who have borne children than in virgins. It is placed 
 between the bladder in front, and the rectum behind, being 
 flattened by them so as to bring its anterior and posterior sur- 
 faces into contact. Its anterior extremity is the smallest of the 
 two; and presents its greatest diameter vertically, while that of 
 the posterior is transverse. As it follows accurately the central 
 line of the pelvis, it is, consequently, curved with its concavity 
 forwards. Its anterior parietes are shorter than the posterior, 
 both from the smaller depth of the pelvis in this direction, and 
 from the mode of connexion with the uterus. 
 
 The vagina is formed by two tunics; a fibrous and a mucous 
 one. The first is external, of a light red colour, highly elastic, 
 and seems to consist of condensed cellular membrane, the fibres 
 of which are much intermixed, and pass in every direction. It 
 is vascular, and immediately adjacent to the large venous sinuses 
 of the pelvis. The mucous membrane being a continuation of 
 that of the vulva, is at and near its anterior orifice of a vermi- 
 lion tinge; while, posteriorly, it is grayish and frequently 
 spotted, so as to give it a marbled appearance: its thickness di- 
 minishes as it recedes from the external orifice; and upon be- 
 ing floated in water many mucous lacunae are observable upon it. 
 The internal surface of the vagina is commonly covered with 
 the mucus which comes from its lacunae. On the anterior or 
 pubic portion, it is divided longitudinally by a middle ridge, 
 which commences by a sort of tubercle just below the orifice 
 of the urethra, and proceeds backwards, becoming indistinct as 
 it approaches the uterus. Transverse ridges formed in the same 
 way by folds of the mucous membrane, arise from the sides of 
 the last at its anterior portion, and give a roughness to that part 
 of the vagina. The inferior side, or that next to the rectum, 
 has the same kind of arrangement of the mucous membrane, but 
 not so distinct. In a majority of subjects, the uterine half of 
 the vagina is perfectly smooth, but the rule does not always 
 hold. 
 
 The Corpus Spongiosum Vaginae is an erectile tissue, like that 
 of the penis, and closely resembles in structure the corpus 
 spongiosum urethras. It is placed at the anterior end of the va- 
 
THE VAGINA. 109 
 
 gina, on its outer circumference, just below the clitoris, and at 
 the base of the labia minora or interna. It is an inch broad, 
 and a line or two thick, adheres closely to the fibrous coat of the 
 vagina, and extends around the superior semi-circumference of 
 the orifice, but not around the inferior. It is frequently called 
 Plexus Retiformis. 
 
 The Sphincter Vaginae Muscle surrounds the anterior orifice 
 of the vagina, and covers the plexus retiformis. It is about an 
 inch and a quarter wide, and arising from the body of the clito- 
 ris and the crus of the pubes, behind tbe crus of the clitoris, 
 passes backwards and downwards to be inserted into the dense, 
 white substance, in the centre of the perineum, common to these 
 muscles, the tranversi perinei and the anterior point of the 
 sphincter ani. There is a strong analogy between it and the 
 accelerator urinas of the male. 
 
 The Transversus Perinei of the female, has the same circum- 
 stances of origin and insertion as in the male, but is not quite 
 so strong. 
 
 On each side of the orifice of the vagina, near its middle, is 
 frequently found a mucous gland, the size of a garden pea: it 
 corresponds with Couper's gland of the male subject. 
 
 The Hymen,* one of the attributes of the virgin state, is 
 placed at the anterior orifice of the vagina for the purpose of 
 closing it, and commonly remains until it is ruptured by vio- 
 lence. In all cases, except where there is an unnatural adhesion, 
 it leaves a small orifice for the passage of mucus and of men- 
 strual blood. In my own observations, I have found it most 
 frequently crescentic, the convexity of the crescent presenting 
 downwards, and the horns upwards; but in some cases, it is to 
 one side. Next in frequency to the lunated is the circular shape, 
 where it surrounds completely the orifice and leaves a hole in 
 its own centre. There are some other varieties, such as its be- 
 ing fleshy, fasciculated, unequally divided into two portions, and 
 
 * J. G. Tolber. Diss. de Variet. Hymen. Haller, Icon. Anat. Fasc. i. Albin. 
 Acad. Annot. Lib. iv. Santorini, Septemd. Tab. 
 VOL. II. 15 
 
110 ORGANS OF GENERATION. 
 
 so on, which are narrated by different writers. Being simply a 
 duplicature of the mucous membrane, it is generally so weak as 
 to be ruptured at the first act of copulation, or even from 
 slighter causes during infancy; but occasionally, it becomes 
 thickened, and so strong as to require division with the knife. 
 After the rupture of the hymen, its place is indicated in subse- 
 quent life by from two to six small tubercles, called Carunculas 
 My rti formes, which are its remains. 
 
 The peritoneum, in descending from the uterus, anteriorly, 
 touches the top of the vagina for a little distance, and is then 
 reflected to the bladder, but posteriorly, almost the upper half 
 of the vagina has a peritoneal coat before this membrane is re- 
 flected to the rectum. The attachment of the vagina to the 
 bladder is strong and close just about the urethra, but its con- 
 nexion with the rectum is by rather loose cellular substance. 
 
 .SECT. III. OF THE UTERUS, AND ITS APPENDAGES. 
 
 The Uterus, or Womb, is a compressed pyriform body, the 
 larger end of which stands upwards, while the lower is directed 
 downwards, and is attached to the vagina. Unimpregnated, it 
 is two and a half inches long, and one and a half in diameter at 
 its widest part. The posterior face is very convex, while the 
 anterior is almost flat, or very slightly convex. It is about one 
 inch in thickness. It is divided by anatomists into fundus, 
 bodv> and neck. The fundus is formed by its superior ex- 
 tremity, and comprises the space between the orifices of the 
 Fallopian tubes; the neck is the lower cylindrical portion, of 
 about an inch in length; and the body is the part intermediate 
 to the two. On the exterior circumference of the uterus there 
 are no marks or lines distinguishing these several portions from 
 each other. 
 
 The uterus, being destined to lodge the foetus from a short 
 period after conception to the moment of birth, has a cavity 
 ready for its reception. The shape of this cavity bears some 
 general, but not a rigid resemblance to that of the organ itself, 
 and is so much flattened as to have its anterior, and posterior 
 parietes in contact, or nearly so. The cavity of the body is an 
 equilateral triangle of eight or ten lines in diameter; the sides 
 
UTERUS, AND ITS APPENDAGES. Ill 
 
 of the triangle are bent inwards in parabolic curves, in such a 
 way as to present their convexities to the cavity of the uterus: 
 this, of course, occasions an apparent elongation of the angles. 
 The inferior angle is continued into the cavity of the neck, 
 while the two superior run into their respective Fallopian tubes. 
 From this arrangement it happens that the parietes of the uterus 
 are only two or three "lines thick on the angles of the triangular 
 cavity, while at the middle they are from four to six lines. The 
 cavity of the neck has not its anterior and posterior sides so 
 near together as that of the body; and is rather cylindrical, 
 being smaller, however, at the upper and lower ends than in 
 the middle. This arrangement gives to its sides a paraboloid 
 curvature which presents its convexity outwards, differing in 
 that respect from the corresponding curvature in the cavity of 
 the body. 
 
 The cavity of the neck terminates in the vagina by an orifice 
 about the size of a small writing-quill, but ovoidal, and pre- 
 senting its long diameter transversely. This orifice i* the Os 
 Tineas, or Orificium Externum Uteri; frequently, without ap- 
 parent disease, I have seen it conoidal, with its base, half an inch 
 in diameter, presenting downwards. The upper orifice, where- 
 by the cavity of the neck communicates with that of the body, 
 is not subject to such fluctuations in size: it is occasionally called 
 Orificium Internum Uteri, and is generally somewhat larger 
 than a small writing-quill. The os tincse is bounded before and 
 behind by the lips of the uterus, formed by the projection of 
 the neck into the vagina. For the most part the anterior side 
 of the vagina is directly continuous with the anterior lip; so 
 that its projection is very inconsiderable, and, indeed, not ap- 
 preciable to the finger: at the same time, this lip is rather thicker 
 than the posterior. The projection of the latter, on the contrary, 
 is always well marked, because the vagina, instead of being 
 inserted into its ridge, is joined to the posterior surface of its 
 base. 
 
 The cavity of the uterus is lined by a very thin mucous mem- 
 brane, a continuation of that of the vagina. This membrane is 
 of a light pink colour, which changes to a vermilion during the 
 period of menstruation; it is furnished with villosities, which, 
 though seen with difficulty in the usual way, may be rendered 
 
112 ORGANS OF GENERATION. 
 
 apparent, by floating the uterus in water; and it adheres so 
 closely to the substance of the uterus, that it seems to form an 
 inseparable portion of it, which can neither be dissected nor ma- 
 cerated off entirely, as in the case of other mucous membranes. 
 This membrane is smoothly laid upon the cavity of the body, 
 and gives it a polished shining surface. On the cavity of the 
 neck, it is wrinkled along the anterior and the posterior parts; 
 there being a longitudinal line running along the centre, and on 
 each side of this line transverse or oblique elevations or dupli- 
 catures. This arrangement presents an arborescent appearance, 
 technically called the arbor vitae. In the interstices of these 
 duplicatures there are some small mucous glands or lacunae, 
 which, as their orifices are exposed to obliteration from inflam- 
 mation or some other irritation, become distended into small 
 spherical sacs by the accumulation of their habitual secretion. 
 Naboth, from seeing them in this state, mistook them for eggs, 
 or the rudiments of the foetus, and the error has been comme- 
 morated by their being called Ovula Nabothi. 
 
 The uterus is covered completely by the peritoneum; in the 
 reflection of the latter, from the rectum to the bladder, it ad- 
 heres to the uterus by a subjacent cellular substance, which al- 
 lows it to be dissected off without difficulty. The same dupli- 
 cature of peritoneum which encloses the uterus, is also reflected 
 from each of its lateral margins, by their whole length, to the 
 corresponding side of the lesser pelvis, and forms the Lateral 
 or the Broad Ligament, (Ligament a Later alia, Lala.) The 
 peritoneum, in passing from the uterus forwards to the bladder, 
 forms, on each side, a duplicature, not very distinct, and de- 
 pending, in a measure, upon the state of the bladder; this con- 
 stitutes the Anterior Ligament. The same membrane, in 
 passing from the back of the uterus to the rectum, and in co- 
 vering the posterior superior end of the vagina, also forms, on 
 each side, a duplicature, denominated the Posterior Ligament; 
 they are always better seen than the anterior. Muscular fibres 
 are said to be found, occasionally, between the laminae of these 
 several duplicatures, running in the direction of the latter:* 
 
 * J. F. Meckel, vol. ii. p. 605. 
 
UTERUS, AND ITS APPENDAGES. 113 
 
 they have not been presented to me in such a way as to arrest 
 my attention. 
 
 The broad ligaments, along with the uterus, form a transverse 
 septum, passing from one side of the pelvis to the other; and 
 contain, between their laminae, the arteries and the veins which 
 belong to the uterus and ovaries. 
 
 Besides the duplicatures of peritoneum, the uterus is retained 
 in its position by the Ligamenta Rotunda, one on each side. 
 These round ligaments arise from the sides of the uterus, a lit- 
 tle below the insertion of the Fallopian tubes, and going between 
 the laminae of the broad ligament, reach, finally, the internal 
 abdominal ring: they then traverse the abdominal canal and the 
 external ring after the manner precisely of the spermatic chord, 
 and terminate by several fasciculi in the fatty cellular matter of 
 the rnons veneris and of the labia majora. The round ligaments are 
 rather smaller in the middle than at either extremity: they con- 
 sist of a condensed cellular or fibrous structure, and have many 
 blood vessels in them. It has been asserted,* that they con- 
 tain strongly marked muscular fibres; some of which come from 
 the uterus, and others from the broad muscles of the abdomen. 
 No evidence of this fact has as yet been presented to me, though 
 I do not deny it; and, indeed, I think it probable, that such 
 fibres may be developed there during gestation. 
 
 The texture of the uterus is very compact, and of a cartila- 
 ginous feel; it is composed of fibrous matter, intermixed with 
 a great many blood vessels. In regard to its fibrous structure, 
 there is no subject in anatomy on which opinions are more di- 
 vided, or more authoritative and numerous on both sides of 
 the question. Some deny its existence at any period, while 
 others admit it as a constant condition: others, again, limit its 
 duration only to the period of pregnancy. Without dwelling 
 on the value of the several doctrines, and the means and obser- 
 vations tending to support them, it may be sufficient here to 
 mention that the structure of the uterus takes on very impor- 
 tant and strongly marked changes, in passing from the unim- 
 pregnated state to that of advanced gestation. In the first the 
 fibres look ligamentous and pass in every direction, but so as to 
 
 * J. F. Meckel, loc. cit. 
 
114 tfRGANS OP GENERATION. 
 
 permit the uterus to be lacerated more readily from the cir- 
 cumference to the centre than in any other course: it, indeed, 
 manifests an indisposition to be torn in a laminated manner. 
 The fibres, moreover, break off short, are separated by the blood 
 vessels, and seem to contain, in their interstices, something like 
 fibrine. 
 
 In the impregnated state, on the contrary, the vessels become 
 immensely increased in size, the laminated structure becomes 
 very evident, and submits readily to the tearing of one layer 
 from the other: these lamina consist of fibres, which are princi- 
 pally parallel with each other. The muscular nature of these 
 fibres seems to be sufficiently proved, by their powerful con- 
 traction in the expulsion of the foetus, and on being irritated by 
 the introduction of the hand. They are, however, not red like 
 other muscles, but of a very light colour as those of the bladder 
 and intestines; and are collected into fasciculi of peculiar flatness 
 and looseness. The development of this muscular structure is 
 not, however, limited to the pregnant state, but it is disposed to 
 manifest itself on all occasions which produce an increased size 
 in the uterus. This fact was first excmplied to me in a small 
 scirrhus of a virgin uterus, presented by Dr. Hugh L. Hodge,* 
 and has been still farther confirmed in a case, where the scirrhus 
 was five or six inches in diameter; also in a virgin uterus, very 
 much enlarged from scirrhus, presented by Dr. Charles D. 
 Meigs. A similar fact has been noticed by Lobstein, of Stras- 
 burg, where the tumour was also steatomatous. 
 
 The fibres of the uterus, examined near the term of pregnan- 
 cy, consist in two planes separated by the large blood vessels; 
 one within and the other without. These layers are readily 
 divisible into subordinate laminae, intermixed with one another, 
 but yet to a considerable extent separable. The external layer 
 is thicker than the internal, and both have an increased thick- 
 ness at the fundus; while they are much diminished, and in- 
 deed indistinct, at the cervix. 
 
 The fibres generally are either circular or longitudinal, but 
 many of them are oblique. The exterior surface of the exter- 
 nal plane, is composed principally of longitudinal fibres, within 
 
 * Now Professor of Midwifery in the University of Pennsylvania. 
 
UTERUS,'AND ITS APPENDAGES. 115 
 
 which are the circular. The inner plane, on the contrary, has 
 the circular fibres external, and the longitudinal internal. In 
 both planes the circular fibres are more abundant at the fundus, 
 .and the longitudinal upon the body of the uterus; but, generally 
 speaking, there are collectively more longitudinal than circular 
 fibres. 
 
 Of the Fallopian Tubes. 
 
 The Fallopian tubes ( Tubas Fallopianae) are two membranous 
 canals, one on either side, fixed in the superior margin of the 
 broad ligaments of the uterus. They serve to conduct the ru- 
 diments of the embryo from the ovarium into the uterus. They 
 are about four inches long, and extend from the upper angle of 
 the uterine cavity to the side of the pelvis: their outer extre- 
 mity is loose, and hangs upon the posterior face of the broad 
 ligament over the ovarium, consequently, inclines downwards, 
 thereby forming an angle with the other portion. 
 
 At their uterine extremities the Fallopian tubes are about the 
 size of the vas deferens, resemble it strongly, and scarcely ad- 
 mit a hog's bristle; but having proceeded about one-half of their 
 length, they begin to enlarge, and continue to do so rapidly for 
 an inch, until they reach the size of a writing-quill; they then 
 contract again somewhat, and immediately afterwards expand 
 into a broad trumpet-shaped mouth. The latter has an oblique 
 orifice, the edge of which is extremely irregular, by being re- 
 solved into a number of ragged fringe-like processes, of unequal 
 size and length; and which, as a whole, are called Corpus Fim- 
 briatum or Morsus Diaboli. One of the longest of these pro- 
 cesses adheres to the external end of the ovarium. 
 
 The Fallopian tube is covered by the peritoneum, and con- 
 sists of two coats: the external is fibrous, and bears sufficient 
 resemblance to the structure of the uterus to be considered a 
 continuation of it; the internal is mucous, and is likewise a con- 
 tinuation of the corresponding one of the uterus. The external 
 end of the tube, which is called Pavilion by the French anato- 
 mists, is flaccid, thin, and generally in a collapsed state, as it is 
 formed solely by, the mucous membrane, assisted by the peri- 
 toneum, neither of which furnishes resistance sufficient to keep 
 
116 ORGANS OP GENERATION. 
 
 it expanded; but, as many blood vessels enter into its composi- 
 tion, their turgescence, in sexual excitement, probably commu- 
 nicates a certain degree of erection. 
 
 Of the. Ovaries. 
 
 The Ovaries, (Ovaria, Testes Muliebres,} two in number, 
 one on either side, are situated on the posterior face of the broad 
 ligaments, by a duplicature of which they are surrounded, and 
 are twelve or fifteen lines below the Fallopian tubes. Their 
 shape is that of a compressed ovoid, about half the size of the 
 male testicle; their long diameter is horizontal; they are sus- 
 pended from the broad ligament rather by the edge than by the 
 flat surface, so that they project, and are to a considerable de- 
 gree pendulous. Their distance from the uterus varies from 
 an inch to an inch and a half, and from the internal end of each 
 one, there proceeds a small vascular fibrous chord, the Liga- 
 ment of the Ovarium, which is inserted into the uterus, some- 
 what below the origin of the Fallopian tube. * 
 
 From their being the seat of conception, they have, in the 
 youthful and healthy female, a pliancy and succulency, indi- 
 cative of their state of preparation for the act; but in advanced 
 life they diminish much in volume and becpm'e hard and dry. 
 Their surface, originally smooth or slightly embossed, is sub- 
 sequently rendered uneven, by repeated acts of conception, 
 leaving on it a number of cicatrices or small stellated fis- 
 sures. 
 
 They are of a light pink colour. Within the peritoneal coat 
 is another, the Tunica Albuginea, of a strong, compact, fibrous 
 texture, like the same coat of the testicle, and sending inwards 
 many processes. 
 
 The structure of the ovarium is not ascertained with entire 
 satisfaction, though the grosser arrangement of it is known. 
 But few females, of such as are presented in our dissecting 
 rooms, have these parts ^in a state fit for study, owing to age, 
 disease, or excessive sexual indulgence: my best opportuni- 
 ties have been derived from post mortem examinations, in pri- 
 vate, of individuals of from fourteen to twenty, where the virgin 
 state had been preserved. When an ovarium of the latter kind 
 
THE OVARIES. 117 
 
 can be got, by cutting through the tunica albuginea simply, and 
 then tearing open the organ, it will be found to consist of a 
 spongy tissue, abundantly furnished with blood vessels from 
 the spermatic artery and vein. In this spongy tissue are from 
 fifteen to twenty spherical vesicles (Qvula Graafiana) varying 
 in size from half a line to three lines in diameter; the larger 
 ones are nearer the surface, and from having caused the absorp- 
 tion of the tunica albuginea, may sometimes be seen through 
 the peritoneal coat, and give to the surface of the ovarium its 
 embossed condition. The vesicles contain a transparent fluid 
 supposed to be, or to have within it, the rudiments of the em- 
 bryo. As the vesicles are evolved they advance from the centre 
 to the circumference. Their parietes are thin, transparent, 
 and have creeping through them minute arterial and venous 
 ramifications.* 
 
 The Organs of Generation in the female are supplied with 
 blood principally from the internal pudic and other branches 
 of the hypogastric artery: their veins run into the hypogastric. 
 Their nerves come from the sacral and from the hypogastric 
 plexus. 
 
 The Bladder and the Rectum, with unimportant exceptions, 
 are the same in both sexes. The Levator Ani, the Coccygeus, 
 and the Sphincter Ani, are also similar. The pelvic aponeu- 
 rosis in the female, besides connecting the bladder to the sides 
 of the pelvis, is attached to the anterior part of the vagina. The 
 triangular ligament of the urethra also exists, but under circum- 
 stances somewhat modified by the close connexion of the urethra 
 with the vagina. 
 
 * In an ovary exhibited to me by Dr. Hopkinson, there were thirty-six ve- 
 sicles. 
 
 VOL. II. 16 
 
118 ORGANS OP GENERATION. 
 
 CHAPTER III. 
 
 OF THE LACTIFEROUS GLANDS, OR BREASTS. 
 
 THE Breasts (Mammas) of the female, are intended for the 
 secretion of milk, and thereby to maintain the connexion be- 
 tween mother and infant, for some time after the uterine life of 
 the latter is passed. All mammiferous animals exercise this 
 function: in birds there is a sort of substitute for it, in the 
 changes which take place in the first stomach or crop during 
 incubation. In the male subject, there is, also, a small glandular 
 body on each side, which has the same organization as in the 
 female, but is in miniature, and always remains in a collapsed 
 state, with some rare exceptions, when it has been known to 
 expand in volume, and to furnish a secretion, as in the female.* 
 
 The Breasts are two in number, one on either side; they are 
 situated on the same level, in front of the pectoralis major mus- 
 cle, and between the arm-pit and the sternum. They are he- 
 mispherical, and have their base united to the muscle by a thin 
 lamina of loose, extensible, cellular substance, containing, even 
 in corpulent women, but little fat. The skin which covers the 
 front of this gland is very fine and thin, so that the blood which 
 circulates in its veins may be readily seen. Between the skin 
 and the front surface of the gland, there is a considerable thick- 
 ness of cellular adipose matter, which, from its superabundance 
 
 * In a male patient, now resident in the Philadelphia Alms House, the pheno- 
 menon of a full evolution of the glandular structure in both breasts is manifested. 
 The individual (James Mclntyre) is forty-five years of age, the breasts are as large 
 as those of a nursing woman, but the nipples are not proportionately evolved. 
 Though his frame is robust, and well set, the voice is feminine ; his external or- 
 gans of generation are about the size of those of a boy of fourteen or fifteen. 
 Thinking that there might be an internal state approaching to hermaphrodism, he 
 informed me, on inquiring, that in earlier .life lie had the common inclinations for 
 the female. He also informed me that this unusual development took place seven 
 or eight years ago, owing to an excessive salivation; but as he has a reserve on the 
 subject, this statement may, probably, be received with some qualifications. I 
 have also seen a second case, in which the voice is weak and .feminine, but the 
 genital organs have not been examined. July, 1826. 
 
LACTIFEROUS GLANDS. 119 
 
 in certain individuals, gives to them an appearance of having 
 the glands enormously enlarged. There is, however, a great 
 variety in the size of the glandular structure itself; for in fe- 
 males who are youthful and giving suck, they are much larger 
 than in such as have passed the period of child-bearing, and 
 whose health is impaired. When all the fatty matter has been 
 removed from a breast, and it is permitted to repose upon a ta- 
 ble, its hemispherical shape disappears, and it then seems rather 
 a flattened circular disk, of from four to five inches in diameter. 
 
 The mamma is of a very light pink colour; and though very 
 flaccid and yielding on being handled, its texture is actually ex- 
 tremely tough, and is cut only by much force. With the ex- 
 ception of bone, it dulls the knife sooner than any other tissue 
 of the body. Its grosser arrangement consists in lobes of dif- 
 ferent sizes, united in such a way by cellular texture, that, though 
 they can be pulled somewhat apart, they cannot be entirely se- 
 parated without injury. These lobes, when examined through 
 the skin, give to the gland a knotted feel, and are sometimes 
 partially affected by inflammation, so as to become still more 
 distinct. The Lobes are composed of Lobuli, which are resol- 
 vable by maceration and particular modes of treatment, into 
 small graniform masses (acini) about the size of millet seed, 
 and which contain the ultimate glandular arrangement. The 
 acini themselves consist of very small oblong vesicles, united 
 by cellular substance, and by the common blood vesels; and are 
 said to be very apparent by the aid of a microscope in a lac- 
 tescent gland.* 
 
 Excretory Ducts (Ductus Galactophori, Lactiferi] of this 
 gland are numerous.f They are of an arborescent shape, and be- 
 gin by very fine extremities or ramuscles in the acini ; the ramus- 
 cles from several acini coalesce into a larger branch; several 
 branches unite to form one still larger, and so on, successively, 
 until a lactiferous duct, constituting, as it were, the body of the 
 tree, is formed by this assemblage. These trunks vary considera- 
 bly in size, according to the number of tributary branches, and 
 having got towards the centre of the gland near the nipple, from 
 
 * Marjolin, Manual D'Anat. J. F. Meckel, Manual D'Anat. 
 f Alex. Kolpin, Dfss. Inaug. de Struct. Mam. Cuboli, Append, ad Septemd. 
 Tab. Santorini. Girardi, Append, ad Septemd. Tab. Santorini. 
 
120 ORGANS OF GENERATION. 
 
 two to four of them, according to Cuboli, run into a common stock 
 or root, called a Lactiferous Sinus. These Sinuses are in all about 
 fifteen: they are only a few lines long, and differ in size; some not 
 being larger than a lactiferous duct, while others have a diameter 
 of from two to three lines. The sinus at the end next to the nipple 
 terminates in a sort of rounded cul-de-sac; but from the extremity 
 of the sac a conoidal tube arises which runs through the nipple, 
 and conducts the milk: the point of this tube is very fine, and 
 ends on the top of the nipple. This tube, from its shape, is suited 
 to the retention of milk; in addition to which, it is sometimes 
 dilated in the middle, is curved when the nipple is not in a state 
 of erection or stretched out, and terminates by an external ori- 
 fice, which is so small as to be seen with difficulty by the naked 
 eye. 
 
 The excretory ducts of the breast, under which term may be 
 comprehended the lactiferous -ducts, the sinuses, and the conoi- 
 dal tubes in the nipple, are formed by a soft, thin, and semi-trans- 
 parent membrane, very capable of extension and of contraction. 
 The trunks generally go deeply through the substance of the 
 gland, and are tortuous, but do not anastomose laterally with 
 one another; whence it happens that the lobes and lobules of 
 the gland are arranged into sections, each of which has its ap- 
 propriate excretory duct. In order to make a complete injec- 
 tion of the gland, each sinus must be separately injected through 
 its conoidal tube. This rule is not, however, of universal ap- 
 plication, as in some experiments performed by the elder Meckel 
 upon women advanced in pregnancy and during lactation, he 
 succeeded in forcing mercury through one sinus, by its ramifi- 
 cations, into those of another : this route was supposed to have 
 .been through the finest extremities of the ducts. The whole 
 gland itself may, however, from the infrequency of this circum- 
 stance, and from the difficulties and partial condition of these 
 anastomoses, rather be considered as a congeries of smaller 
 glands kept distinct by the interposition of cellular substance be- 
 tween their lobes ; but joined, in one respect, by having the ter- 
 minations of their excretory tubes collected into one bunch in 
 the nipple. This latter circumstance seems to be only a provi- 
 sion for the more convenient sucking of the infant. 
 
LACTIFEROUS GLANDS. 121 
 
 The excretory ducts are no where furnished with valves, 
 which accounts for the facility with whfch they may be injected 
 backwards from the nipple. An opinion was entertained by 
 Haller, and by other anatomists after him, that some of these 
 ducts originated in the surrounding cellular substance, but this 
 has been refuted by the researches of Cuboli. Some, anatomists 
 have thought that there is a direct communication between the 
 ends of the lactiferous tubes and the arteries, veins, and lym- 
 phatics. Mascagni, after a very successful injection of the gland, 
 whereby its vesicles were filled with quicksilver, not meeting 
 with such an occurrence, was induced to think that when the 
 communication did happen, it was produced by rupture. 
 
 The Areoldj 
 
 In virgins is a rose-coloured circle, which surrounds the base 
 of the papilla or nipple. In women who have borne children, 
 or in those whose age is advanced, it becomes of a dark brown. 
 The skin of the areola is extremely delicate, and on its surface, 
 particularly in pregnant or nursing females, there are from four 
 to ten tubercles, which sometimes form a regular circle near its 
 circumference, and in other subjects are irregularly distributed. 
 Each of these tubercles has near its summit three or four fora- 
 mina, which are the orifices of the excretory ducts of a little 
 gland forming the tubercle. The areola consists of a spongy 
 tissue beneath which there is no fat; it is susceptible of disten- 
 tion during lactation, or from particular excitement. 
 
 The greater number of anatomists have considered these tu-. 
 bercles as intended only for the secretion of an unctuous fluid 
 which lubricates the areola and nipple, and protects them from 
 excoriation by the sucking of the infant. It is said, however,* 
 that when some time has elapsed after a repast, or when there 
 has been a long interval to the nursing of the child, milk flows 
 from them abundantly; but that in inverse circumstances a 
 transparent, limpid fluid is distilled in small drops : all of which 
 would tend to prove that they are of the same nature with the 
 
 * J. F. Meckel, 
 
122 ORGANS OF GENERATION. 
 
 mammas themselves, being only smaller. In addition to them, 
 it is said, that the areola and the nipple are furnished with a 
 great number of sebaceous glands, which do not elevate them- 
 selves above the surface, and which may be found on and near 
 the tubercles. 
 
 The Papilla, 
 
 Is the truncated cone in the centre of the mamma, of the same 
 colour with the areola, and surrounded by it. The lactiferous 
 tubes terminate on its extremity. It is collapsed and in a very 
 pliable state for the most part, but when excited it swells, be- 
 comes more prominent, and of a deeper colour. Its skin is 
 rough, and provided with numerous and very small papillae. 
 Its internal structure consists of the extremities of the lactiferous 
 tubes united by condensed cellular membrane. 
 
 The mamma is supplied with blood from the external thoracic, 
 intercostal, and the internal mammary arteries. Its veins attend 
 their respective arteries. The nerves come from the axillary 
 plexus and from the intercostals. The lymphatics run into the 
 internal mammary, intercostal, and axillary trunks. 
 
BOOK VII. 
 
 Of the Organs of Respiration. 
 
 THE Organs of Respiration are the Larynx, the Trachea, 
 and the Lungs. 
 
 CHAPTER I. 
 
 OF THE LARYNX. 
 
 The Larynx is an irregular cartilaginous tube that forms the 
 upper extremity of the windpipe. It is situated immediately be- 
 low the os hyoides and the root of the tongue, where it may be 
 felt readily through the integuments, and by its prominence con- 
 tributes to the outline of the neck. Its position is such, that it is 
 bounded behind by the pharynx, which is interposed between it 
 and the vertebrae of the neck ; and laterally by the primitive ca- 
 rotid arteries and the internal jugular veins. It gives passage 
 to the air which is inhaled into the lungs or exhaled from them, 
 and also contributes essentially to the production of the voice. 
 Its special use, on the latter occasion, has induced some anato- 
 mists to give it a description apart from that of the other organs 
 of respiration ; but as the function of voice is subordinate to that 
 of respiration, I have preferred an observance of its most natu- 
 ral and local connexions. 
 
 Five distinct cartilages form the skeleton of this structure : the 
 
124 ORGANS OP RIPIRATIOi\. 
 
 os hyoides, which is common to it and to the root of the tongue, 
 also contributes to its superior part, in a manner which will be 
 presently mentioned. The cartilages are one Thyroid, one Cri- 
 coid, one Epiglottis, and two Arytenoid. 
 
 The Thyroid Cartilage (Cartilago Thyroidea) is the largest of 
 the five, and being placed about one inch below the os hyoides, 
 produces in the upper part of the neck the prominence called 
 Pomum Adami. It consists in two lateral halves, which in 
 most individuals are perfectly symmetrical, and are continuous 
 with each other on the middle line of the body. These tw* 
 sides form at their line of junction an angle projecting forwards, 
 and resembling that of the canal or hydraulic gate : the superior 
 part of the angle is more prominent than the inferior; particu- 
 larly in the male subject. The sides pf this body lean outwards, 
 by which its transverse diameter above is increased. 
 
 The angle is terminated above by a deep notch, from which 
 the superior margin begins to form a curvature, on either side, 
 like the letter S ; the inferior margin is also somewhat curvefl, 
 but to a smaller degree. The posterior margin of each half is 
 nearly straight, but is elongated above, with the aid of the upper 
 margin, into a long process, the Cornu Majus; and below with 
 the aid of the inferior margin, into another process not so long, 
 Cornu Minus. By the latter, the thyroid cartilage is articulated 
 by ligamentous fibres called the lateral crico-thyroid ligament, to 
 the side of the cricoid cartilage, which thereby becomes the ful- 
 crum of many of its motions. 
 
 The internal surface of each half of the thyroid cartilage is 
 flat; but the exterior surface is slightly marked by the sterno- 
 thyroid and the thyreo-hyoid muscles. 
 
 The Cricoid Cartilage (Cartilago Cricoidea] is placed below 
 the thyroid, and is the base of the larynx. It is an oval ring, of 
 an unequal thickness and breadth. 
 
 Its inferior margin is nearly straight and horizontal, and is 
 connected to the first ring of the trachea; it is also thinner than 
 the superior: the latter is very oblique, and rises from before 
 backwards and upwards so abruptly, that the breadth of the cri- 
 coid cartilage behind becomes three times as great as it is in 
 
THE LARYNX. 125 
 
 front, under the inferior margin, of the thyroid cartilage. The 
 superior margin has on each side, behind, a little head, or con- 
 vexity, which receives the base of the corresponding arytenoid 
 cartilage, and forms with it a ball and socket joint. 
 
 The interior surface of the cricoid cartilage is smooth, and 
 covered By the lining membrane of the larynx. Its exterior 
 surface is flattened on each side behind, by the posterior crico- 
 arytenoid muscles; it is marked also laterally by other muscles, 
 and by the inferior cornu of the thyroid cartilage. 
 
 .The cricoid cartilage is embraced by the inferior margin of 
 the thyroid, but in such a way that a triangular interval is left 
 in front between the two cartilages. 
 
 This interval is filled by a ligament adhering to its margins 
 called the middle Crico-Thyroid, to distinguish it from the li- 
 gamentous junction between the inferior cornua of the thyroid, 
 and the sides of the cricoid. The middle ligament has some 
 small apertures in it for the passage of blood vessels and of 
 nerves. It is the part commonly cut in the operation of laryn- 
 gotomy. 
 
 The Arytenoid Cartilages (Cartilagines JJrytanoidecK] re- 
 semble triangular pyramids curved backwards, and about six 
 lines long. They are placed on the upper margin of the cri- 
 coid cartilage behind. The anterior face of each is uneven, and 
 divided into two concavities; the posterior face forms a single 
 cylindrical concavity; and the internal face, by which it approx- 
 imates its fellow, is nearly flat. When joined together, the 
 two cartilages resemble the mouth or spout of a pitcher, from 
 whence their name. Their bases are hollowed into a small gle- 
 noid cavity, for articulating with the cricoid cartilage. 
 
 A synovial capsule is reflected over the articulation, between 
 the arytenoid and the cricoid cartilage: this capsule is strength- 
 ened by a few scattered ligamentous fibres. 
 
 The Epiglottis Cartilage (Epiglottis] is situated on the pos- 
 terior face of the base of the os hyoides, being enclosed partial- 
 ly by the two sides of the thyroid cartilage. Its general form 
 is that of an oval disk; the upper margin of it is thin and round- 
 VOL. II. IT 
 
126 ORGANS OF RESPIRATION. 
 
 ed, and the lower part is elongated into a pedicle which adheres 
 to the entering angle of the thyroid cartilage. 
 
 Its surfaces, though nearly flat, are not fully so; for, anterior- 
 ly, it forms a cylindrical convexity, and posteriorly, a cylindri- 
 cal concavity, from side to side. When nicely stripped of its 
 covering, a number of very small foramina are seen to exist in 
 it, which give passage principally to the ducts of muciparous 
 glands. Its connexions, aided by its natural elasticity, keep it 
 in a vertical attitude behind the base of the tongue; its round- 
 ed margin is elevated above the latter, and overlooks it. 
 
 
 
 In addition to the preceding cartilages, there are always two, 
 and sometimes four others. On the top of each arytenoid is to 
 be found one, (Corniculum Laryngis:) it is somewhat trian- 
 gular and elongated; its inferior face is attached by a few liga- 
 mentous fibres to the end of the arytenoid; it is included in the 
 soft parts, and is very moveable. The others, when they exist, 
 are found on the margin of the glottis, in the duplicature of the 
 membrane which is extended from the side of the epiglottis to 
 the tip of the arytenoid cartilage. 
 
 From the whole superior margin of the thyroid cartilage in- 
 cluded between its greater cornua, there proceeds upwards a 
 thin lamina of somewhat condensed cellular substance, which is 
 attached to the inner margin of the base and. of the cornua of 
 the os hyoides their whole length. It fills completely the space 
 between the os hyoides and the thyroid cartilage. This mem- 
 brane is called the middle Thyreo-hyoid Ligament, (Ligament. 
 Thyreo-Hyoid. Medium,) though its ligamentous character is 
 by no means well developed. It completes the periphery of 
 the larynx in the space alluded to, and, from its thin yielding 
 nature, presents no obstacle to the motions of the os hyoides 
 and of the thyroid cartilage upon each other. 
 
 The posterior margin of this membrane, on each side, is 
 bounded by a long, rounded, fibrous chord, the Lateral Thyreo- 
 Hyoid Ligament, (Ligamenlum Thyreo-Hyoideum Laterale.) 
 The latter is extended from the cornu major of the thyroid car- 
 tilage to the tuberculated extremity of the os hyoides, and. fre- 
 quently contains, about its centre, a small, oval cartilage or 
 
THE LARYNX. 127 
 
 bone, (Cartilago-Triticea,) not quite so large as a grain of 
 wheat. 
 
 Immediately under the body of the os hyoides, between its 
 concave face and the middle thyreo-hyoid ligament, is a small 
 sac or cell formed between the laminae of the ligament, and fre- 
 quently extending itself downwards as far as the notch of the 
 thyroid cartilage; it is flat about four or five lines in its trans- 
 verse diameter, and presents a shining surface. I have never 
 seen a fluid in it in the natural state; its secretion, however, 
 sometimes becomes excessive, and it is then elongated down- 
 wards over the front of the thyroid and of the cricoid cartilage, 
 as far as the isthmus of the thyroid gland. In this state it fre- 
 quently forms a small fistulous opening, at its lower end, through 
 the skin, which is marked by a fold of the latter across the 
 neck. The true pathology of the disease was first pointed out 
 by Dr. Physick, who cures it, in some cases, by the introduc- 
 tion of lunar caustic, and in others by extirpation. 
 
 The Thyreo-Arytenoid Ligaments are two in number, on 
 each side of the larynx; one above the other, at the distance of 
 three lines. The inferior is extended from the anterior angle 
 of the base of the arytenoid cartilage to the inferior part of the 
 entering angle of the thyroid, and, by converging towards its 
 fellow, is inserted there in contact with it. Its fibrous structure 
 is very distinct. It also bears the name of Ligamentum Vo- 
 cale, from its bordering the rima glottidis. The superior thy- 
 reo-arytenoid ligament arises from the middle of the anterior 
 edge of the arytenoid cartilage, and is also inserted into the en- 
 tering angle of the thyroid; it is more distant from its fellow 
 than the lower one, and goes almost parallel with it; so that the 
 opening between the two is both larger and more like an ob- 
 long. Its fibrous structure is less distinct than that of the lower. 
 Both the upper and the lower ligaments are covered by a re- 
 flection of the lining membrane of the larynx, and are small, 
 round fibrous threads, which are rendered more or less tense by 
 the action of the small muscles of the larynx. 
 
 The superior thyreo-arytenoid ligament is attached, in its 
 whole length, by a triangular fibro-muscular layer to the pedi- 
 cle of the epiglottis: the posterior margin of this layer is dis- 
 
128 ORGANS OF RESPIRATIOJf. 
 
 tinctly muscular, and must have the effect of drawing the liga- 
 ment upwards. 
 
 There are several pairs of muscles belonging to the larynx. 
 
 1. The Thyreo-Hyoideus, as observed in the former account 
 of this muscle, looks like a continuation of the sterno-thyroideus. 
 It arises, obliquely, from the side of the thyroid cartilage by the 
 ridge, there; and running upwards, it is inserted into a part of 
 the base, and into nearly all the cornu of the os hyoides. 
 
 When the thyroid cartilage is fixed, it draws down the os 
 hyoides; but when the latter is fixed, it draws up the thyroid 
 cartilage. 
 
 2. The Crico-Thyroideus arises, tendinous and fleshy, from the 
 the anterior lateral surface of the cricoid cartilage, and passes 
 upwards and backwards, to be inserted into the inferior cornu 
 of the thyroid cartilage, and the adjacent part of its inferior 
 edge. 
 
 Use, to draw these cartilages obliquely together. 
 
 3. The Crico-Arytenoideus Posticus arises from the back of 
 the cricoid cartilage, occupying its excavation, and is inserted 
 into the posterior part of the base of the arytenoid cartilage. 
 
 It draws the arytenoid backwards, and makes the ligaments 
 tense. 
 
 4. The Crico-Arytenoideus Lateralis arises from the side of 
 the cricoid cartilage, and is inserted into the side of the base of 
 the arytenoid. 
 
 Use, to draw the latter outwards, and open the chink of the 
 glottis. 
 
 5. The Thyreo-Arytenoideus arises from the posterior face 
 of the thyroid cartilage, near its angle, and the middle crico- 
 thyroid ligament, and is inserted into the anterior edge of the 
 arytenoid cartilage. 
 
 Use, to relax the ligaments of the glottis. 
 
THE LARYNX. 129 
 
 6. The Arytenoideus Obliquus arises from the base of one 
 arytenoid cartilage, and is inserted into the tip of the other. 
 It is a very small fasciculus, and sometimes only one muscle 
 exists. 
 
 Use, to close the chink of the glottis. 
 
 7. The Arytenoideus Transversus is always a single muscle, 
 which arises posteriorly from the whole length of one arytenoid 
 cartilage, excepting a little part of the tip, and is inserted, in a 
 corresponding manner, into the other. It fills up the cylindri- 
 cal concavity of the arytenoid cartilages. 
 
 Use, to close the chink of the glottis. 
 
 8. The Thyreo-Epiglottideus consists in a few fibres, and 
 arises from the posterior face of the thyroid cartilage near its 
 entering angle. It is inserted into the side of the epiglottis. 
 
 Use, to draw the epiglottis downwards. 
 
 9. The Aryteno-Epiglottideus consists also in a few indis- 
 tinct fibres, and arises from the superior lateral parts of the ary- 
 tenoid cartilage. It is inserted into the side of the epiglottis. 
 
 Use, to draw the epiglottis downwards. 
 
 These two last muscles are generally so small and undefined, 
 that they cannot be satisfactorily distinguished from the adja- 
 cent soft parts. 
 
 On the posterior face of the thyroid cartilage, of the middle 
 thyreo-hyoid ligament; and on each side of the epiglottis carti- 
 lage, surrounding its lower part with the exception of its poste- 
 rior face, there is an accumulation of cellular and adipose sub- 
 stance. In the lower part of this substance there are several 
 small glandular bodies, sometimes insulated and sometimes col- 
 lected together, which detach their prolongations into the fora- 
 mina of the epiglottis cartilage, and seem to open thereby on 
 its laryngeal surface: they are mucous glands. 
 
 The Arytenoid Gland, which is also muciparous, is situated 
 in front of the arytenoid cartilage, in the duplicature of the mu- 
 
130 ORGANS OP RESPIRATION. 
 
 cous membrane which passes from the side of the epiglottis car- 
 tilage to the arytenoid. It is a small body of a grayish colour, 
 resembling the letter L, and consists in distinct grains; it is 
 supposed to have its excretory ducts opening into the larynx. 
 It is frequently wanting. 
 
 The Interior Face of the Larynx is lined by a mucous mem- 
 brane, continuous above with that of the mouth and pharynx, 
 and below with that of the trachea. Where it is reflected from 
 the base of the tongue to the epiglottis cartilage, it forms, as 
 described, a well marked vertical fold or fraenum in front of 
 the middle of the latter, and on each side of this middle fold 
 there is another, not so distinct, but varying in different sub- 
 jects. Beneath the middle fold is the strong fibre-muscular 
 connexion with the root of the tongue.* The three folds form 
 two pouches in front of the epiglottis, in which food is some- 
 times lodged. The mucous membrane also forms the duplica- 
 ture on each side already alluded to, which passes from the la- 
 teral part of the epiglottis cartilage to the arytenoid of the same 
 side of the body. This duplicature forms the superior boundary 
 of the cavity of the larynx, and is very soft and extensible, per- 
 mitting freely the epiglottis to be depressed and to rise again 
 into its vertical position. The duplications of the two sides, 
 taken together, form an oblong oval opening into the larynx, 
 passing very obliquely upwards and forwards to the epiglottis, 
 and terminated behind by a notch between the cornicula laryn- 
 gis. At the latter place the mucous membrane is wrinkled and 
 loose, so as to permit, by its extensibility, free motion to the 
 arytenoid cartilages. 
 
 * A muscle of a triangular shape has lately been observed by the English ana- 
 tomists,f situated in front of the epiglottis, passing to it from the base of the os 
 hyoides: it is called Hyo-Epiglottideus. The observations on its existence have 
 not yet been repeated sufficiently often to determine whether it belongs to the 
 normal structure of the body or not; and in my own dissections, for the purpose 
 of ascertaining its existence, it has not occurred. Albinus, Scemmering, and 
 others, speak of the occasional existence of muscular fibres there. A strong mus- 
 cle is found there in the lower animals, as stated in the description of the tongue, 
 vol. 1st. 
 
 1 Am. Med. Jour. vol. v. p. 475. 
 
THE LARYNX. 131 
 
 After adopting the preceding arrangement, the lining mem- 
 brane of the larynx passes downwards; it covers smoothly the 
 posterior face of the epiglottis, adhering closely to it; but, when 
 it reaches the thyreo-arytenoid ligaments, it is tucked in be- 
 tween the upper and the lower one, so as to form, on either side, 
 an oblong pouch, the bottom of which is broader than its ori- 
 fice between the ligaments. This pouch is the ventricle of 
 Galen, or of Morgagni, or of the larynx; it projects into the 
 fatty glandular matter on the posterior face of the thyroid car- 
 tilage, and has its base resting on the thyreo-arytenoid muscle. 
 Its superior end reaches almost as high as the upper margin of 
 the thyroid cartilage, and it has some small fasciculi of muscular 
 fibre on its interior which seem appropriated to its use. The 
 continuation of the membrane afterwards lines smoothly the 
 cricoid cartilage, and abounds there in mucous follicles. 
 
 That portion of the larynx which is formed by the thyreo- 
 arytenoid ligaments, and the pouches between them, is the 
 structure essential to the formation of voice. The opening be- 
 tween the two lower ligaments is the Rima Glottidis, and the 
 space between the upper ligaments and the duplicature of the 
 mucous membrane passing from the arytenoids to the epiglottis 
 cartilage, may be termed the Glottis. 
 
 The Epiglottis Cartilage is principally useful in preventing 
 articles of food from falling into the glottis, either in swallow- 
 ing or in vomiting. The strength of its muscles, however, does 
 not seem to be sufficient to draw it down over the glottis, as- 
 many physiologists suppose; on the contrary, I am induced to- 
 believe that the glottis is rather*ftrawn upwards to it. If, on 
 any occasion, it be depressed or bent down over the glottis, the 
 position must be caused by mechanical pressure from the bulk 
 of the article swallowed. But the latter explanation is not suf- 
 ficient to account for the swallowing of fluids, or of a very small 
 body, as a pill or a crumb of bread. 
 
 Impressed with these objections, and unsatisfied with the 
 common theory, I had an opportunity, in a dissection a few 
 years ago, of witnessing a position of these parts which afforded 
 a satisfactory explanation. The subject was a robust, muscular 
 man, who had died suddenly. The upper orifice of the glottis 
 was closed and protected, but by an arrangement precisely the 
 
132 ORGANS OF RESPIRATION. 
 
 
 
 reverse of the received opinion; for the epiglottis, retaining its 
 naturally erect position, with a slight inclination backwards, had 
 the opening of the glottis drawn up so as to come in contact 
 with its posterior face. The cricoid cartilage, as has been men- 
 tioned, slopes on its superior margin upwards and backwards; 
 the front surfaces of the arytenoid cartilages, in their natural 
 position, are nearly on a line with this slope, or a continuation 
 of it; the whole may, therefore, be considered in the light of 
 an oblique plane, rising up behind the epiglottis cartilage. By 
 a very slight additional elevation of this plane along with the 
 rotatory motion of the thyroid cartilage upon its lesser cornua, 
 the plane is caused to come in contact with the posterior face 
 of the epiglottis, and thereby to close the upper opening of the 
 glottis. 
 
 The principal agents in this motion are the thyreo-hyoid mus- 
 cles, the contraction of which, causing the larynx to ascend, the 
 opening of the glottis is'brought up behind the epiglottis, and' 
 thereby secured from the introduction of food into it. Whether 
 the food be passed from the mouth into the stomach, as in 
 swallowing, or from the stomach into the mouth, as in vomiting, 
 is equally unimportant; and the security is the same, whether 
 the article be small or large, fluid or solid. Several years ago, 
 I dissected a gentleman who had symptoms of sore throat with 
 swelling of the neck, superadded to those of pulmonary con- 
 sumption: during the existence of his sore throat, in addition 
 to the usual difficulty of swallowing, he was frequently affected 
 in the act, with strangulation to an alarming and distressing de- 
 gree. In the dissection, it was found that an abscess, of con- 
 siderable extent, existed between the os hyoides and the thyroid 
 cartilage, ancl involved the thyreo-hyoid muscles. Without 
 knowing at the time the value of this observation, I arn'now 
 persuaded that the strangulation arose from the inactivity of 
 the thyreo-hyoid muscles. In some ulcerations of the epiglottis 
 cartilage, which I have had an opportunity of seeing, the up- 
 per circular portion, which projects above the root of the tongue 
 has been lost; if the accident be confined to that extent only, 
 deglutition is not much impaired, because still enough of the 
 epiglottis is left to perform the office assigned to it, as the up- 
 per part is less essential. The cases of its reputed loss by wounds, 
 
THE TRACHEA. 133 
 
 must be considered as applying themselves to this upper portion 
 only, because a wound low enough to remove the whole body, 
 would cause such a destruction of the rima glottidis, as to 
 produce ah embarrassment of respiration, incompatible with 
 life. * 
 
 It is probable that the inferior constrictors of the pharynx, as 
 well as the stylo-pharyngeal muscles, assist in this use of the 
 thyreo-hyoidei. 
 
 There is a well marked difference in the larynx of the two 
 sexes. In the female, it is generally smaller by one-third than 
 it is in the male; the thyroid cartilage is also less prominent, in 
 consequence of its two halves uniting at an angle more obluse, 
 the pomum Adami is, therefore, seldom conspicuous. The rima 
 glottidis is also smaller in women. 
 
 The nerves of the larynx come principally from the superior 
 and the inferior laryngeal branches of the par vagum. 
 
 CHAPTER II. 
 
 OF THE TRACHEA, AND THE GLANDS BORDERING UPON IT. 
 SECT. I. THE TRACHEA. 
 
 THE Trachea, or Aspera Arteria, is a cylindrical canal of four 
 or five inches in length and about nine lines in diameter, com- 
 municating with the lungs for the transmission of air. It opens 
 into the larynx above, by being attached to the inferior mar- 
 gin of the cricoid cartilage, and terminates in the thorax oppo- 
 site the third dorsal vertebra, by two ramifications called Bron- 
 chia. In this course it is situated over the middle line of the 
 neck, beneath the sterno-thyroid muscles, and separated from 
 them by the deep-seated fascia of the neck and the adipose mat- 
 ter beneath it. It is placed in front of the oesophagus, between 
 the primitive carotid arteries and the internal jugular veins. 
 When it has got into the thorax, it inclines slightly'to the right 
 VOL. II. 18 
 
134 ORGANS OF RESPIRATION. 
 
 side as it passes behind the curvature of the aorta. Of its two 
 branches, the right bronchia is larger than the other; it is also 
 less slanting, and an inch long before it divides; it sinks below 
 the right pulmonary artery, to penetrate the lung about the 
 fourth dorsal vertebra. The left bronchia being an inch longer, 
 sinks into the lung of the left side, below the corresponding 
 pulmonary artery, and opposite the fifth dorsal vertebra. The 
 bronchise then divide and subdivide very minutely through the 
 lungs. 
 
 Very dissimilar structures enter into the composition of the 
 trachea; they are cartilage, ligamentous fibre, muscle and a mu- 
 cous membrane. 
 
 The Cartilage preserves the cylindrical shape of the trachea, 
 and consists in from sixteen to twenty distinct rings, which are 
 deficient in the posterior third of their circumference. Each 
 ring is about two lines broad, and half a line thick, and is kept 
 apart from the one above and below it by a small interstice; 
 sometimes, however, they run into each other. 
 
 There is an almost uniform similitude between these rings; the 
 principal departure from which is observed in the first being ra- 
 ther broader in front than the others, and in the last ring, which, 
 by its corset-like shape in front, contributes to the beginning of 
 each bronchia. 
 
 The rings of the Bronchia? are, like those of the trachea, defi- 
 cient in their posterior third, and the same arrangement holds 
 during their primitive ramifications in the lungs. But as they sub- 
 divide more and more, the cartilages do not succeed each other 
 so closely, and are smaller segments of circles, they are not re- 
 gularly deficient at the posterior third; but, in place of the latter, 
 the whole periphery of the bronchial ramification is cartilage, 
 and the latter consists in several pieces put end to end. The 
 pieces become, after awhile, more and more scattered and small- 
 er, till they finally disappear, and the bronchia is simply mem- 
 branous.* At the orifice of each branch of the bronchia, there is 
 a semiflunar cartilage, forming rather more than one half of its 
 circumference, and having its concave edge upwards. The whole 
 arrangement resembles somewhat the pasteboard to an eared 
 bonnet, and is evidently to keep the orifice open. 
 
THE TRACHEA. 135 
 
 The Ligamentous Structure of the trachea and of the bron- 
 chiae is very evident between the proximate margins of the car- 
 tilaginous rings, and fills up the intervals between them so as to 
 make the tube perfect. This tissue may be traced over the sur- 
 faces of the rings, forming their perichondrium, so that they may 
 be considered as embedded in it. It does not exist, satisfactorily, 
 in the human subject, in the interval behind, where a third of 
 the ring is defective, its place being supplied by a condensed cel- 
 lular substance; but in the bullock it is there also. In the small- 
 er ramifications of the bronchiae, where a complete circle is 
 formed by the juxta-position of the several little cartilaginous seg- 
 ments, it is probable that this tissue contributes to the whole pe- 
 riphery of the ramification. 
 
 It possesses great elasticity, which is manifested by the rapid 
 shortening of the trachea, when its two extremities are stretched 
 apart and then suddenly let loose. And it is the continuance of 
 this quality of elasticity, in the minute ramifications of the bron- 
 chiae, which proves the existence of this tissue there, even when 
 it cannot be very distinctly seen. 
 
 The Muscular Structure of the trachea exists at the cartilagi- 
 nous deficiency in its posterior third, and consists in a thin mus- 
 cular plane whose fibres pass transversely between the interrupt- 
 ed extremities of the cartilaginous rings of the trachea and of the 
 bronchiae. These transverse fibres begin at the first ring, and 
 exist all the way down to the lungs : they rise from the internal 
 faces of the rings, and the intermediate elastic ligamentous tis- 
 sue ; about a line beyond their extremities. Anteriorly, they are 
 covered by the lining membrane of the trachea, and posteriorly, 
 by the cellular tissue just spoken of. 
 
 In the lungs, where the cartilages become scattered and irre- 
 gular, the muscular fibres are said, by J. F. Meckel, and by M. 
 Reisseissen,* to perform the whole circuit of the bronchial rami- 
 
 * De Fabrica Pulmonis. Berlin, 1822. M. Laennec says (Traite, de 1' Ausculta- 
 tion, Paris, 1826, vol. ii. p. 189,) that he has sought in vain to verify these obser- 
 vations of Reisseissen, but that the manifest existence of circular fibres upon 
 branches of a middling' size and the phenomena of many kinds of asthma, induce 
 him to view, as a thing well established, the temporary occlusion of the small 
 bronchial ramifications, by a spasmodic contraction of their parietes. 
 
136 ORGANS OF RESPIRATION. 
 
 fication, and to be visible even beyond the existence of tbe carti- 
 laginous pieces. Soemmering expresses a doubt of this arrange- 
 ment.* It is very difficult in such minute structure to arrive at 
 a satisfactory conclusion ; careful observations, latterly made, 
 have, however, induced me to adopt the same conviction as Reis- 
 seissen. Longitudinal fibres are also said by Portal to exist be- 
 tween the contiguous margins'of the cartilaginous rings, but the 
 fact is far from being ascertained.t 
 
 The use of this muscular tissue has been pointed out, by Dr. 
 Phyc-ick, as follows : " In expectoration, it diminishes the caliber 
 of the air tubes, so that the air having to pass out with increased 
 rapidity through them, its momentum will bring up the inspissated 
 fluid which may be in its way." This very ingenious theory has 
 subsequently been advanced by M. Cruveilheir, of Paris, possibly 
 without a knowledge of his having been anticipated ; but cer- 
 tainly not without the claims of the eminent individual to whom 
 we owe it, having been established by its publication.! 
 
 The Mucous Membrane of the trachea lines its whole interior 
 periphery, from the larynx to the bronchiae, and is continued, un- 
 der the same circumstances, through the latter to their minute 
 divisions. It adheres very closely to the contiguous structure, and 
 is continued, in the substance of the lungs, beyond the traces of 
 any of the other tissues which compose the trachea ; it indeed 
 terminates in the air cells. It is very vascular, like other mu- 
 cous membranes; and also, like them, the venous appears to pre- 
 vail over the arterial vascularity. A successful minute injection 
 makes it look as if it consisted of a tissue of blood vessels; thin 
 and red, it presents an abundance of slightly elevated longitudi- 
 nal folds: one of the latter, conspicuous for its greater size, ex- 
 ists at the commencement of the left bronchia, and is yet more 
 developed in the still-born infant. 
 
 The exterior circumference of the mucous membrane is stud- 
 
 Extimje autem vel pcsticz ejus fibrze per longittidinem, a cartilagine cricoi- 
 dea ad pulmones usque descendant uc, vel in ipsis trachea ramis haud parura 
 conspicui sunt. De Corp. Hum. Fabrica. 
 
 f Anat. Med. 
 
 t Wistar's Anatomy, 3d edition, vol. ii. p. 64. Phil. 1821. 
 
THE THYROID GLAND. 137 
 
 ded with muciparous glands, about the size of millet seed. These 
 glands are particularly conspicuous and abundant on the poste- 
 rior part of the trachea and of the bronchiae, where the deficien- 
 cy of the cartilaginous rings is supplied by the membranous struc- 
 ture only ; and more of them exist at the lower part of the tra- 
 chea and upon the roots of the bronchia? than elsewhere. They 
 are placed behind the muscular layer, which their excretory 
 ducts have to penetrate. Besides occupying these situations, they 
 are found in the interstices between the cartilaginous rings, but 
 here they are much smaller. The mucous membrane abounds 
 so much in the orifices made by their excretory ducts, that it 
 looks cribriform, which appearance is increased by floating it in 
 water. 
 
 About the origins of the bronchiae, there is a considerable num- 
 ber of black coloured lymphatic glands, called Bronchial, which 
 it is easy to distinguish from the preceding by their colour and 
 much greater size. 
 
 There are two more glands of a different character, which, 
 though they do not enter into the composition of the trachea, yet, 
 from their locality, are most conveniently studied at this time : 
 they are the Thyroid and the Thymus. 
 
 SECT. II. OF THE THYROID GLAND. 
 
 
 
 The Thyroid Gland (Glandula Thyroided) is placed on the 
 first and second rings of the trachea, and on the sides of the 
 larynx. 
 
 It consists in a middle portion, which is thin, of variable mag- 
 nitude in different individuals, sometimes entirely wanting, and 
 which, being stretched across the upper part of the trachea just 
 below the larynx, is called its isthmus; and of two lobes, one on 
 each side, which, being flattened and ovoidal, are extended up- 
 wards on the side of the larynx, and downwards on the side of 
 the trachea and of the oesophagus. Frequently from the superior 
 part of the isthmus, and most commonly on its left side, a small 
 pyramidal process runs upwards in front of the cricoid and of 
 the thyroid cartilage, and is attached, by ligamentous fibres to 
 
138 ORGANS OF RESPIRATION. 
 
 the os hyoides ; this process, however, varies much in size and 
 length : I have never seen it double. According to Morgagni 
 and Meckel, its existence is much more common than its ab- 
 sence, which corresponds with my own observations. The thy- 
 roid gland, when extended, measures about three inches from 
 side to side. 
 
 It is covered in front by the sterno-hyoid and thyroid muscles, 
 and laterally by the omo-hyoid and the sterno-mastoid. Em- 
 bracing the trachea and the sides of the larynx, its lobes repose 
 upon the primitive carotids, and the internal jugular veins. 
 
 The thyroid gland has a capsule which is not very easily raised 
 up, but serves to give it a polish ; it is also invested by the con- 
 densed cellular membrane of the part called fascia profunda 
 colli. Its surface is smooth and uniform. It is of a dark brown 
 colour. When cut into or torn, it is seen to consist of several 
 lobules adhering to each "other: but this arrangement is not very 
 distinct, except in an enlarged or diseased state ; and may be 
 traced most easily by following the course of the large blood ves- 
 sels, which pass in the interstices between the lobules. The lat- 
 ter contain many small vesicles, or cells, filled with a transparent 
 or yellowish and somewhat unctuous fluid ; the cells are fre- 
 quently in a collapsed state, which prevents them from being ma- 
 nifest to the naked eye. 
 
 There are four considerable arteries which supply this body, 
 two on each side, one coming from the external, carotid and the 
 other from the subclavian. The veins follow the course of the 
 arteries for the most part. Bichat has made a very interesting 
 remark on the subject of its blood vessels ; that, notwithstanding 
 their size and number, and minute ramifications in it, much less 
 blood remains in its capillary system than in that of the liver or 
 kidney, as is proved by the quantity of water it tinges in mace- 
 ration; he, therefore, infers that the capillary system is less abun- 
 dant. 
 
 Anatomists have sought in vain for one or more excretory 
 ducts to this body, and some have imagined that they had found 
 them terminating in the trachea, or in the larynx. Santorini con- 
 sidered the pyramidal process, from the isthmus as the desired 
 duct. The emphysema with which the gland has sometimes 
 been affected, was supposed to be a proof of its communicating 
 
THE THYMUS GLAND. 139 
 
 with the trachea by excretory tubes ; but it is more probable that 
 the air was forced into the cellular substance, uniting its lobules, 
 and not into the structure itself of the gland. The settled opi- 
 nion now seems to be, that whatever fluid it secretes is conveyed 
 away by the lymphatic vessels. Meckel has suggested, that as 
 this gland is more voluminous proportionately in early infancy, 
 particularly its pyramidal process, possibly the duct may be ob- 
 literated when the gland begins to be restrained in its growth ; 
 but if this were the case, the duct ought to have been found 
 during the period indicated. The probability is, that it is a di- 
 verticulum of blood from the salivary glands during the inter- 
 in ittence of their action ; and from the marked sympathy between 
 it and the brain in goitre, it may exercise a corresponding func- 
 tion on this organ during its intervals of repose. 
 
 Duverney* has described a small azygous muscle on the mid- 
 dle line of the body, coming from the under margin of the base 
 of the os hyoides, and running over the middle of the thyroid 
 cartilage, to be inserted into the upper margin of the isthmus of 
 the thyroid gland. Soemmering calls it Levator Glandulae Thy- 
 roideae, and speaks of it as being found more frequently on the 
 left side, and about half of the breadth of the thyreo-hyoideus. 
 After many special examinations for it I have found it in but few 
 instances ; I, therefore, consider it rare ; though without a close 
 attention to structure, the pyramidal process of the isthmus of 
 the gland may, from the similitude of colour and position, be 
 very readily mistaken for it, which I have reason to believe is 
 frequently the case.f Some few fibres are often found going to 
 the isthmus of the gland from the crico-thyroid, and the thyreo- 
 hyoid muscles, or from the thyroid cartilage. 
 
 SECT. III. OF THE THYMUS GLAND. 
 
 This body (Glans Thymus) is placed between the trachea and 
 
 * Essai D'Anatomie en tableux imprimes, pi. IV. Paris, 1745. 
 
 f The unassisted eye, in a strong light, is generally sufficient to determine the 
 structure; but in case of doubt, by boiling the gland, if there be muscular fibres 
 along this process, their longitudinal and parallel direction will become evident: 
 they also may then be torn asunder, so as to be made still more distinct; whereas, 
 the vesicular structure of the gland is not susceptible of division into fibres, 
 
140 ORGANS OF RESPIRATION. 
 
 the upper extremity of the sternum. It is irregularly triangular, 
 its broadest part being above, and the narrower below. In the 
 adult, it is in a collapsed and shrivelled state, and scarcely pre- 
 sents a vestige of what it once was ; it is, therefore, only in the 
 infant that it can be satisfactorily studied. 
 
 At birth, it is much larger, not relatively, but actually, than it 
 is in the adult, and extends from the body of the heart up to the 
 thyroid gland. It is of a very soft consistence and of a pink co- 
 lour. It is surrounded by a capsule of cellular substance, which, 
 when removed, permits the gland to be resolved into two lobes, 
 one on either side, which adhere to each other. These lobes 
 may be separated with facility into lobules, and contain a whitish 
 fluid. 
 
 A good Essay on the structure of this gland, has latterly been 
 published by the distinguished British surgeon and anatomist, Sir 
 Astley Cooper,* illustrated by excellent plates. From this it ap- 
 pears that the lobules of the gland are formed of vesicles of va- 
 rious sizes, all discharging into a duct which runs from one end 
 of the gland to the other, the consistence of which duct is ex- 
 tremely feeble. .This duct and the vesicles may be filled with 
 an injection, by means of a pipe introduced into the substance of 
 the gland. A large lymphatic trunk passes from the gland, on 
 each side, into the transverse vein. 
 
 Sir Astley thinks, or, rather, asks, whether this gland does not 
 prepare a fluid for foetal nourishment, in the absence of proper 
 chylification, during foetal life? inasmuch as all the elements of 
 the blood are upon chemical analysis, found in the fluid contained 
 in its cavities. 
 
 It is visible in the third month of gestation, and continues to 
 grow till the end of the second year of extra-uterine life. It then 
 collapses, and its structure is effaced about the twelfth year; its 
 remains are scarcely distinguishable subsequently from the sur- 
 rounding cellular substance. No excretory duct has been found 
 for it, unless we .may consider as such the lymphatic trunk al- 
 luded to by Sir Astley Cooper, and, though it clearly belongs to 
 foetal and infantile existence, its use is problematical. The pro- 
 bability is, that it is a diverticulum of blood from the lungs 
 
 * London, 1832. 
 
THE LUNGS. 141 
 
 during their state of quiescence in foetal life, and until their struo 
 ture becomes confirmed and proportionately evolved*. 
 
 CHAPTER III. 
 
 OF THE LUNGS. 
 
 The Lungs (Pulmones) are the essential seat of the process 
 of respiration, and occupy the greater part of the cavity of the 
 thorax, as formed by the- ribs and the intercostal muscles on 
 the sides, by the sternum and its cartilages in front, by the 
 dorsal vertebrae behind, and by the diaphragm below. They 
 are two bodies, placed one on either side of the thorax, and se- 
 parated from each other by the heart and its great vessels. As 
 the heart is the only organ of much volume which is also in- 
 cluded in the cavity of the- thorax, the size of the lungs is in a 
 direct relation with the capacity of the latter;, and may, therefore, 
 be known by external indications in the living body. It is 
 probable that there is no void) or only a very small one, be- 
 tween the sides of the lungs and the sides of the thorax. 
 
 Each lung forms an irregular cone, the apex of which is above, 
 and the base below; the latter, from resting upon the diaphragm, 
 is, consequently, oblique from before backwards and downwards, 
 and is also concave. The surface which reposes against the pe- 
 riphery of the side of the thorax, is uniformly rounded, but that 
 which looks towards its fellow, is concave, from being pressed 
 in by the heart. From the oblique direction of the diaphragm, 
 the vertical diameter of the lung behind, when it is fully dis- 
 tended, goes from the first to the last rib, and is, consequently, 
 much more considerable than the vertical diameter in front, 
 which extends only from the first rib to the inferior end of the 
 second bone of the sternum, or, in other words, to a level with 
 the tendinous centre of the diaphragm. 
 
 The left lung is divided into two lobes by a deep fissure, 
 VOL. II. 19' 
 
142 ORGANS OP RESPIRATION. 
 
 which begins behind, on a level with the fourth dorsal vertebra, 
 and runs obliquely downwards and forwards to the anterior 
 margin of its base. A deep fissure in a nearly similar situation 
 is observed on the right lung; but from it another fissure branches 
 out forwards, by which the right lung is divided into three lobes. 
 The internal face of the left lung is also rather more concave 
 than that of the right, from the side of the heart projecting into 
 it. The right lung is more voluminous than the left, which 
 corresponds with the greater size of the bronchia on this side, 
 but its vertical diameter is not so great, from the pressure of 
 the liver from below. 
 
 Near the middle of the internal face of each lung are to be 
 seen the points of connexion with the bronchia, and with the 
 pulmonary vessels. Before these the anterior margin is thin, 
 and more or less winding where the lung is introduced between 
 the heart and the front parietes of the thorax. When the lungs 
 are fully inflated, only a very small portion of the pericardium 
 can be seen here between them. The posterior margin is thick, 
 and rounded where it rests against the vertebral column. 
 
 The whole rounded circumference of the lung as well as its 
 base, though they are in contact with the parietes of the thorax, 
 do not adhere at any point to them. The connexion of the 
 lung, constituting its root, as it is called, and by which it is 
 maintained in its situation, is entirely on the side of its concave 
 face, where the pulmonary vessels and bronchia enter, and 
 though other attachments are frequently found springing from 
 different points of the thorax, they are purely the results of 
 disease. 
 
 Of the. Texture of the Lungs. 
 
 Each lobe of the lungs is divided into a great many distinct 
 lobules, which adhere together by intermediate cellular tissue. 
 The marks of these divisions are apparent on the surface by 
 lines running in different directions, but they are made still 
 more distinct by tearing them asunder. The Lobules are sub- 
 divided into very fine air vesicles or cells, which may be con- 
 sidered as the terminations of the ultimate branches of the 
 bronchia. The opinion is generally held, that the cells do not 
 
THE LUNGS. 143 
 
 communicate laterally with one another, as the cells of the bones, 
 but only with the ramifications of the bronchia, to which they 
 respectively belong. Recent preparations, however, have in- 
 duced me to abandon this idea, and to conclude that the cells 
 of the lobules individually communicate, but not those of dif- 
 ferent lobules. I have succeeded in proving this by distending 
 the air cells with tallow, and, after the lung was dried, by re- 
 moving the tallow with spirits of turpentine. This process 
 shows the cells of their natural size, and communicating freely. 
 
 In tracing the terminations of the bronchise, in the substance 
 of the lungs, the parietes of these canals are observed to become 
 very thin, and especially after the cartilaginous structure has 
 ceased. The ramifications seem then to be composed almost 
 entirely of muscular fibres, and a lining of mucous membrane: 
 the latter is smooth, polished, and so thin that it is a mere film, 
 about the thickness and transparency of the peritoneum, where 
 it covers a small intestine. Longitudinal folds may still be 
 traced in the length of the mucous membrane, and, with the aid 
 of a lens, mucous follicles are very perceptible, in innumerable 
 quantities all over it. It may also be remarked, that the bronchiae 
 do not end by a regular succession of proportionately finer and 
 finer branches; but that a bronchial trunk, of some lines in 
 diameter, sends off in different directions to the contiguous lo- 
 bules, branches about the size of a bristle, which are followed 
 with much difficulty, owing to their collapsing; the probability 
 is, however, that each one of these branches belongs to a lobule, 
 and discharges into its cells, in a manner resembling a blow- 
 pipe fixed to the side of a small piece of sponge. In my pre- 
 parations, these terminating tubes of the bronchiae, the size of 
 bristles, are seen very distinctly; but there is no appearance 
 of the penicillous arrangement, which would be apparent if 
 each air cell had its own specific branch of the bronchia running 
 to it. 
 
 Besides the ramifications of the bronchiae, the substance of the 
 lungs is composed of numerous blood vessels and lymphatics, and 
 is well supplied with nerves. 
 
 The blood vessels are of two kinds, the pulmonary and the 
 bronchial. The pulmonary artery, coming from the right ven- 
 tricle of the heart, divides under the arch of the aorta into two 
 
144 ORGANS OP RESPIRATION. 
 
 large branches : one for the right lung, and the other for the left. 
 The right branch is larger than the left. Each of these branches 
 havkig reached the upper part of the root of its respective lung, 
 begins there to distribute itself in large trunks, which divide and 
 Subdivide throughout the substance of the lung. The terminating 
 branches finally become capillary, and ramify in the parietes of 
 the fine cells, where the blood which they carry, from being dark- 
 coloured and venous, is so altered, as to have the arterial quali- 
 ties restored to it, and to become of a bright red. From the ul- 
 timate branches of the pulmonary artery, arise the first branches 
 of the pulmonary veins. These are successively accumulated 
 into two large trunks on each side, which, issuing at the lower 
 part of the root of the -lung, go to qpen into the left auricle of 
 the heart* It has been remarked by Mr. Bqyer, that the two 
 pulmonary veins are less -capacious than the pulmonary artery of 
 the same side, in which they manifest a peculiarity of blood ves- 
 sels, differing from what exists in other parts of the body. The 
 pulmonary artery and veins are distributed in company with the 
 branchiae. From the observations of Professor Mayer, it ap- 
 pears that valves exist in the pulmonary veins, contrary to the 
 general opinion of anatomists. They are found where smaller 
 trunks join the larger ones, at an acute angle, but there are none 
 when they join at a right angle.* 
 
 The second order of blood vessels, being the bronchial, also 
 consists in arteries and in veins, and are for the nourishment of 
 the lungs. They, too, attend the branches of the bronchia?. The 
 arteries pervade the substance of the lung by innumerable fine 
 branches, and anastomose with the pulmonary arteries. The 
 bronchial veins also anastomose with the pulmonary veins, but, 
 finally, come out in small trunks from -the root of the lung, and 
 empty into the vena azygos. 
 
 The Lymphatics of the lungs are numerous ; after traversing 
 the black bronchial glands, those of the left side empty into the 
 thoracic duct, and those of the right into the large lymphatic 
 trunk coming from the right upper extremity. 
 
 The nerves come principally from the par vagum. Some of 
 them are distributed with the bronchia, and may be traced ea>si- 
 
 * Am. Med. Jour. vol. in. page 186. 
 
THE LUNGS. 145 
 
 ty far along its branches, forming beautiful anastomoses around 
 them : their texture there resembles much that of the sympathe- 
 tic : they are thought to be, finally, spent upon the mucous mem- 
 brane : others seem to be more specifically appropriated to the 
 vessels. 
 
 It will now be understood that the root of each lung is formed 
 by the pulmonary artery, the two pulmonary veins, and the bron- 
 chia, covered by the pleura, where the latter extends from the 
 lung to the pericardium. The relative situation is such that the 
 pulmonary artery is above, the bronchia in the centre and be- 
 hind, and the pulmonary veins below. 
 
 The lung of the adult is of a light pink colour, with specks or 
 patches of black : in early life there is much less of the latter, 
 and in advanced life it becomes more abundant. 
 
 The texture of the lung is so light and spongy after an animal 
 has once breathed, that its weight is very inconsiderable when 
 compared with its volume. Its cells are left much distended, 
 even when the animal is dead ; and, notwithstanding from its 
 unusual elasticity, it expels a great quantity of air when the tho- 
 rax is opened, and is thereby reduced to a third of its size during 
 life ; yet it retains enough air to make it float in water, or even 
 in spirits of wine. The quantity of air which the lungs contain 
 differs very considerably in different individuals, depending en- 
 tirely on the capaciousness of the thorax. Its medium amount 
 is computed at one hundred and forty-five cubic inches ; thir- 
 ty cubic inches of which are changed at every act of respira- 
 tion. 
 
 Of the Pleurte. 
 
 Each lung has a perfect covering, called Pleura, t& which rt 
 is indebted for its shining surface. This membrane is also re- 
 flected from the internal surface of the lung to the adjacent side of 
 the pericardium, and is then spread over the interior periphery 
 of that half of the thorax to which it belongs, by lining the ribs 
 and intercostal muscles, and covering the convex face of the 
 diaphragm. There are, therefore, two pleurae, each of which is 
 confined to its appropriate half of the thorax, so as to line its 
 cavity and to cover its lung. The pleura, as other serous mem- 
 branes, is a thin membranous sac. Its circumference is entire, 
 
146 ORGANS OF RESPIRATION". 
 
 like that of an inflated bladder; there is, therefore, no point or 
 line at which one may exclusively begin an account of its course 
 and attachments. To commence, however, at the sternum; the 
 pleura goes thence outwardly to line the lateral parietes of the 
 thorax, as formed by the cartilages of the ribs, the ribs them- 
 selves, and the intercostal muscles. In this way it may be 
 traced around to the dorsal vertebras, and over the convex sur- 
 face of the diaphragm. In proceeding along the first rib, which 
 is very oblique, it forms a sort of bulging bag, which projects 
 towards the trachea, lines the lower part of the scalenus an- 
 ticus muscle, and receives the upper extremity of the lung. 
 The pleura, having reached the dorsal vertebrae from the ribs, 
 passes from their sides forwards to the posterior part of the pe- 
 ricardium, a very small portion of which it covers. It then 
 goes upon the posterior face of the pulmonary vessels and of 
 the bronchia to the lung; and applies itself closely to the latter. 
 It then covers the part of the lung posterior to the pulmonary 
 vessels, and continues to advance along the rounded surface of 
 the lung, to its anterior margin: it then passes over the internal 
 surface of the lung, which is anterior to the pulmonary vessels. 
 It afterwards covers the front of the pulmonary vessels and of 
 the bronchia, and gets in a very short space to the pericar- 
 dium. It then passes forwards on the side of the latter, and 
 having got near its middle line, goes from it to the sternum, and 
 reaches the line from which the description of its course com- 
 menced. 
 
 There is no important difference between the two pleurae 
 either in their mode of reflection or in the organs to which they 
 are attached, so that the description of one will apply to the 
 other. The portion of each pleura covering the lung is called 
 Pleura Pulmonalis, and that portion which lines the thorax is 
 the Pleura Costalis. A duplicature of the pleura commences at 
 the inferior margin of the pulmonary veins, and descending as 
 far as the diaphragm, attaches the inferior portion of the poste- 
 rior margin of each lung to the side of the pericardium in front of 
 of the vertebrae. This duplicature is the Ligamentum Pulmo- 
 nis. It is longer on the left lung than on the right, by reason 
 of the greater vertical diameter of the former. 
 
 From what has been said it will now be readily understood, 
 
THE LUNGS, 147 
 
 that the whole cavity of the thorax is divided vertically into 
 two halves, by that portion of the two pleurae which advances 
 from the spine towards the sternum. This septum is called the 
 Mediastinum, and the heart, enveloped by the pericardium, is 
 placed in its centre, and separates the two pleurae widely apart. 
 It has been found useful by anatomists, for descriptive purposes, 
 to subdivide the mediastinum into three portions or regions. 
 One, passing from the front of the pericardium to the posterior 
 face of the middle line of the sternum, is the Anterior Medias- 
 tinum; another, passing from the posterior face of the pericar- 
 dium to the dorsal vertebrae, is the Posterior Mediastinum; and 
 a third, which is within the circuit of the first ribs, is the Supe- 
 rior Mediastinum. This division, though evidently arbitrary, 
 is indispensable to a correct account of the relative situation of 
 very important organs placed between the two pleurse. 
 
 1. The Anterior Mediastinum is less important than the other 
 two; the portions of the two pleurae of which it consists are al- 
 most in contact, and contain between them some loose cellular 
 substance by which they adhere together, and by cutting through 
 which, after a longitudinal section of the sternum, they are 
 easily separated from one another. The upper part of this sep- 
 tum contains the remains of the thymus gland; its lower part 
 leaves the middle line of the sternum, and inclines to the left 
 side; and when the sternum is narrow below, it is attached to- 
 the anterior ends of the cartilages of the lower true ribs. 
 
 2. The Posterior Mediastinum, where it leaves the vertebrae- 
 to reach the pericardium, passes off from a line nearer the heads 
 of the ribs on the left side, than on the right. The descending 
 portion of the thoracic aorta is contained within this septum, on 
 the left side of the dorsal vertebrae. The oesophagus is in its 
 middle in front of the vertebrae above, but, in descending, it 
 crosses in front of the aorta, and inclines to the left side of the 
 dorsal vertebrae. The vena azygos occupies the right side of 
 this mediastinum, and, after ascending, forms an arch over the 
 root of the right lung, and terminates by joining the descending 
 cava. The thoracic duct, after entering the thorax between the 
 crura of the diaphragm, ascends in front of the dorsal vertebrae 
 
148 ORGANS OP RESPIRATION. 
 
 between the aorta and the vena azygos, and behind the oesopha- 
 gus, till it reaches the third dorsal vertebra; it then inclines to 
 the left side, and mounting into the root of the neck near the 
 vertebrae, it, finally, forms an arch, which, by advancing for- 
 wards, terminates in the angle formed by the junction of the 
 left internal jugular and subclavian veins. The par vagum 
 nerve, of both sides, is also in the posterior mediastinum. 
 
 3. The Superior Mediastinum is bounded in front by the up- 
 per part of the sternum, behind by the upper dorsal vertebrae, 
 and laterally by the first ribs. The cavity is conoidal, with the 
 base upwards, but is too peculiar to admit of a rigid comparison 
 with any thing else. The pleurae are reflected downwards from 
 the internal edge of the first ribs, not abruptly, but in a round- 
 ed bulging manner, receiving there, as mentioned, the tip or 
 apex of the lungs. In order to understand well the position of 
 the pleurae, it must be borne in mind that the upper rib is placed 
 very obliquely downwards and forwards, at an angle of about 
 forty -five degrees with the spine; consequently, the pleura, on 
 being reflected from its whole internal edge, is much higher at 
 the head of the rib than it is at the anterior extremity of the 
 same. This cavity is continuous, of course, with that of the an- 
 terior mediastinum in front, and also with that of the posterior 
 mediastinum behind. 
 
 The remains of the thymus gland are where this cavity joins 
 the anterior mediastinum: a part of the gland is, indeed, in each 
 of these cavities just below the transverse vein. In contact 
 with the right pleura is the descending Vena Cava. The com- 
 mon trunk of the Left Subclavian, and Internal Jugular, called 
 the Transverse Vein, or Vena Innominata, after crossing in an 
 oblique descent behind the upper portion of the sternum, joins 
 the descending cava an inch above the place where the latter 
 penetrates into the pericardium. Behind the transverse vein 
 are the top of the arch of the aorta, the arteria innominata, the 
 left carotid, and the left subclavian. The trachea, with the oeso- 
 phagus behind it, descends along the middle line in front of the 
 spinal column. The arteria innominata crosses the front of the 
 trachea from left to right in ascending; it is in contact with the 
 transverse vein, and more superficial than either of the other 
 
THE LUNGS. 149 
 
 arteries. The phrenic nerve, passing at the internal edge of the 
 scalenus anticus, between the subclavian artery and vein, de- 
 scends vertically in contact with the pleura. The par vagum 
 passes along the side of the trachea, and afterwards behind the 
 corresponding bronchia, having got into the superior mediasti- 
 num between the subclavian vein and artery: its inferior laryn- 
 geal branch encircles the subclavian artery on the right side, and 
 the arch of the aorta on the left. 
 
 The internal surface of the pleura is smooth and polished, and 
 is moistened and kept lubricated by an unctuous serum, the na- 
 tural quantity of which is merely sufficient to allow the parts to 
 slide freely upon each other. In dropsy of the chest, it is aug- 
 mented frequently to such an amount as to cause the collapse of 
 the lung by pressing upon it. 
 
 In the cellular tissue, between the pleura and pericardium, as 
 well as on the diaphragm, adipose matter, in considerable abun- 
 dance, is found in corpulent persons advanced in age. 
 
 The blood vessels of the pleura costalis are derived from those 
 which supply the parietes of the thorax, as the intercostals and 
 phrenics. -They ramify in the subjacent cellular substance, and 
 end by exhalent orifices on the internal face of the pleura, from 
 which a minute injection is poured out very copiously. 
 
 VOL. II. 20 
 
BOOK VIII. 
 
 OF THE CIRCULATORY SYSTEM. 
 
 FART I. 
 
 Of the General Anatomy of the Circulatory System. 
 
 CHAPTER I. 
 
 GENERAL CONSIDERATIONS. 
 
 THE Circulatory or the Vascular System, consists in a conge- 
 ries of tubes, or cylindrical canals, which convey the blood to 
 and from every part of an animal body, and therefore, enter into 
 the texture or composition of almost every portion of it. In all 
 animals there seems to be a necessity for the alternate reception 
 and discharge of alimentary materials ; in the higher orders, this 
 is effected through the agency of the vascular system ; but in the 
 most simple animals this system does not exist, and their whole 
 fabric being soft and permeable, nutritious matter is introduced 
 by a direct absorption, or a species of capillary attraction, after 
 the manner of a sponge, or any other porous body, and is dis- 
 charged by a process equally simple.* It is probable that there 
 are some parts of the human body whose mode of nutrition is 
 analogous to the latter ; as, for example, the articular cartilages, 
 the hair, nails, and so on ; for many observations tend to prove 
 that all these organs have an interstitial circulation. 
 
 * Hunter on the Blood. Beclard, Anat. Gen. 
 
152 CIRCULATORY SYSTEM. 
 
 In many animals, the blood is propelled from a central point, 
 called the heart, to all parts of the body, and then returns again 
 to the heart. The first movement is executed through canals 
 called arteries, and the second through veins. It is the most 
 simple scheme by which a circulation can be carried on through 
 a sanguiferous system, and requires a heart with only two cavi- 
 ties ; one for propelling blood into the arteries, or departing tubes, 
 and another as a reservoir for receiving the blood of the return- 
 ing tubes, or the veins. The two cavities must be near each 
 other, and have a valvular opening between them, which will 
 permit the blood to pass from the venous into the arterial reser- 
 voir ; but not from the arterial into the venous. A circulation of 
 this simple cast is found in fish, and in animals generally whose 
 respiration is effected on the surface of the body ; but in man, 
 and in other warm-blooded animals, where respiration is carried 
 on interiorly by means of the lungs, their circulatory apparatus 
 is double ; one part being for the lungs, and the other part for 
 the body generally. 
 
 In man, the heart consists of four cavities : two auricles, or re- 
 servoirs of venous blood, and two ventricles, into which the ve- 
 nous blood is transmitted, and which, in their functions, may be 
 compared to the forcing-pump of a fire-engine. The circulation 
 is effected in the following manner : The blood contained in the 
 right auricle of the heart flows into the right ventricle, and from 
 the latter it is forced through the pulmonary -artery into the 
 lungs. It returns from the lungs through the four pulmonary 
 veins, and is received into the left auricle of the heart; from the- 
 latter it flows into the left ventricle, and is propelled from it into 
 the aorta. The aorta then distributes it through the whole body 
 by an infinitude of small branches ; from the latter it is collected, 
 by corresponding veins, into two trunks, the Ascending and the 
 Descending Cava. The ascending vena cava brings the blood 
 from the lower extremities and from the abdomen ; the descend- 
 ing vena cava brings the blood from the head and neck, the up- 
 per extremities, and the parietes of the thorax. These two trunks 
 finally discharge the blood into the cavity from which it started, 
 to wit, the right auricle. The same round is then renewed, and 
 continues to be repeated during the whole course of life. It is 
 
GENERAL CONSIDERATIONS. 153 
 
 customary for anatomists to call the route of blood from the 
 right ventricle, through the lungs, to the left auricle inclusively, 
 the lesser or the pulmonary circulation ; and that which begins 
 at the left ventricle, goes through the whole body, and ends in 
 the right auricle, the greater circulation. 
 
 The blood contained in the veins of the greater circulation, in 
 the right auricle and ventricle, and in the pulmonary artery, is 
 of a dark brown or reddish colour; while that contained in the 
 pulmonary veins, in the left auricle and ventricle, and in the 
 aorta and its ramifications, is, from being vivified by respira- 
 tion, of a carmine or vermilion complexion. The celebrated 
 Bichat has, upon this difference of colour, founded his division 
 of the whole circulating system into two parts; one containing 
 black blood, " Systeme vasculaire a sang noire ;" the other red 
 blood, " Systeme vasculaire a sang rouge." This division 
 having general physiology for its object, affords a well marked 
 distinction, suited to such discussions. 
 
 The lymphatics also are a part of the circulatory system, but 
 as they do not commonly convey red blood, the consideration 
 of them will be introduced subsequently. " They take a very 
 active part in the animal economy, whether natural or diseased, 
 and seem, in many actions, to be the antagonists of the arteries; 
 while the veins are much more passive, being principally em- 
 ployed in returning the blood to the heart."* 
 
 The largest vascular trunks are situated near the centre of the 
 body and limbs, on the side upon which flexion is accomplished, 
 while those near the surface are generally small. Most com- 
 monly there are one artery, one or two veins, and several lym- 
 phatics, all together. 
 
 The arterial system in its external configuration may be com- 
 pared to a tree, the trunk of which is attached to the heart, and 
 which by a continued succession of divisions and subdivisions 
 reaches to every part of the body. There are no means of esti- 
 mating rigidly the collective area of the branches in proportion 
 to that, of the trunk, but a little observation on the size of the 
 primitive branches will satisfy one of a great excess on the part 
 of the latter; and as the rule is maintained throughout, there 
 
 * Hunter, loc. cit. 
 
154 CIRCULATORY SYSTEM. 
 
 must finally be an immense disproportion. We have then rea- 
 son to believe, that if all the branches were assembled into a 
 single cavity, this cavity would be somewhat like a cone, the 
 apex of which would be next to the heart. The same rule 
 holds in regard to the venous system, it being observed, how- 
 ever, that the latter has two trunks connected with the heart in- 
 stead of one. The general rule is, therefore, established through- 
 out the vascular system, that the collective area of the branches 
 is always greater than that of the trunk from which they pro- 
 ceed.* By the same rule the circulation in the branches must 
 
 * I am indebted to a scientific friend, Mr. Erskine Hazard, for the following 
 computation, by actual measurement, of the arteries, from which it 'appears 
 that in many of them, at least, the area of the trunks is greater than that of 
 the branches near them. 
 
 The Left Carotid at the Aorta 'is .42 
 
 Its diameter at the branching is .43 
 
 Increase of diameter .01 
 
 Its square at the Aorta is - 1764 
 
 Each Carotid branch measures .28, and the sum of their squares 
 
 is -'---- 1568 
 
 The difference of the areas of the Carotid and its branches is 12 per cent, 
 in favour of the Carotid. 
 
 Diameter of Aorta near the Iliacs .64 
 
 Its square 4096 
 
 Diameter of Left Iliac .40 
 
 Its square 1600 
 
 Diameter of Right Iliac - - - - - .37 
 
 Its square ------- 1369 
 
 Sum of their squares - - - - 2969 
 Aorta largest by nearly 38. per cent., or 1127 
 
 Square of Right Iliac, as above, 1369 
 
 Ditto External Iliac - 900 
 
 Ditto Internal do. 729 
 
 1629 
 
GENERAL CONSIDERATIONS. 155 
 
 be more languid than in the parent trunks, as this circulation is 
 retarded both by additional friction and by having to fill up a 
 
 Branches largest by nearly 19 per cent, or 260 
 
 Square of Left Iliac, as above, 1600 
 
 Ditto Internal Iliac 961 
 
 Ditto External do. 900 
 
 1861 
 
 Branches largest by above 16 per cent., or .... 261 
 
 Great Sinus of Valsalva 13456 
 
 Innominata 2601 
 
 Carotid 1444- 
 
 Subclavian 1024 
 
 Aorta beyond 3600 
 
 Sinus greater than all, by 4787 
 
 or 55 per cent. 
 
 Comparison of the areas of the Iliac Arteries, with that of the Aorta, half ah 
 inch above them, in decimals of an inch. 
 
 Greatest diameters 
 
 Left Iliac. 
 .354 
 
 Aorta. 
 
 .556 
 
 Right Iliac. 
 
 .390 
 
 Least do. 
 
 .290 
 
 .410 
 
 .290 
 
 Sum of diameters 
 
 .644 
 
 .966 
 
 .680 
 
 Mean diameters - 
 
 .322 
 
 .483 
 
 .340 
 
 Their squares 
 
 - 103684 
 
 233289 
 
 115600 
 103684 
 
 Sum of the squares of the 
 Square of the 
 
 Iliacs 
 Aorta - 
 
 . 
 
 219284 
 233289 
 
 Aorta larger than the Iliacs 14005 
 
 or nearly 6 T \ per cent. 
 
 As the areas of circles are to each other as the squares of their diameters, it 
 follows that the aorta will contain, in a given length, nearly 6^ per cent, more 
 than the two iliacs; and, consequently, the blood must flow that much faster 
 
156 CIRCULATORY SYSTEM. 
 
 larger canal.* The course of rivers exemplifies this continual- 
 ly; while confined to narrow channels, they rush tumultuously 
 through them, but when they begin to expand themselves into 
 capacious basins, or to be divided into a multitude of smaller 
 channels, the current becomes slower, and in some cases imper- 
 ceptible, though the fact is clear, that an equal volume of wa- 
 ter is every where descending in the same period of time. 
 
 The moisture conferred upon all parts by the circulation of 
 the blood, bears a sufficient analogy to the effects of irrigation 
 upon ground. The water may be conducted to the latter by a 
 canal, which is finally divided into an infinitude of streamlets, 
 which ramify every where, and from the porosity of their beds 
 percolate laterally, so that the whole field, even to its most 
 minute atom, is kept moistened. The streamlets, afterwards, 
 successively assemble again into a single canal, which bears off 
 their superabundant water. From the nature of the particles of 
 blood, many of them are confined to their proper channels, and 
 can never pass off by percolation into the tissue, through which 
 the blood vessels ramify. This may be proved by the fact that 
 the red globules of blood have a diameter of from the two- 
 thousandth to the five-thousandth part of an inch, a size incon- 
 siderable as it is, yet too large to permit their flowing through 
 elementary fibres or atoms; whereas serum, or the water of the 
 blood, may, from the extreme fineness of the particles, be ab- 
 sorbed by any tissue whatever; a circumstance entirely un- 
 questionable, both from daily observation, as, for example, in 
 soaking a piece of dried meat or a bone; and from the reflec- 
 
 through the iliacs than through the aorta, as the same blood has to be disposed of 
 in both in the same time. By this means the power of the heart is continued 
 much farther through the system, as each artery is large enough to supply its 
 branches with but little friction. The interior surfaces of the above iliacs are, 
 together, 2.0806 inches, while that of the aorta is but 1.518 inches, or only three- 
 fourths of the rubbing surface. Independently of this circumstance, it is found 
 that there is a greater difference in the quantities of fluids passing through aper- 
 tures of different sizes than there is in the areas of the respective apertures. 
 This is accounted for by there being less friction between the particles of fluids 
 than there is between these particles and a solid; and, in the larger apertures, a 
 smaller proportion of the particles comes in contact with the solid. 
 
 * It is computed that the blood moves 5233 times slower in the capillaries than 
 in the aorta. 
 
GENERAL CONSIDERATIONS. 157 
 
 tion, that the air itself will hold a certain quantity of water in 
 solution. 
 
 A question then arises whether the moisture of parts not sup- 
 plied with red globules of blood, comes in the living body ex- 
 clusively from infiltration or from a peculiar set of vessels called 
 exhalents, often talked of, but as yet never seen? That the 
 lateral porosities of blood vessels are large enough to allow 
 watery fluids to exude, is readily proved by injecting water 
 into the blood vessels of a limb, or of any other part, when the 
 latter invariably becomes cedematous. It is in this way even 
 possible to inundate a living animal, as I have seen accomplished 
 by M. Magendie, in Paris. This moisture requires a change, 
 and by continued additions would become superabundant: as it 
 has been thrown out of the common current of the circulation 
 and could not be removed in any other way, the lymphatic sys- 
 tem has, therefore, been added for the purpose. In the lower 
 orders of animals, who are destitute of the blood vessels, the 
 interstitial change of moisture goes on without lymphatics. 
 
 No part of the human body is exempt from moisture, but 
 it is furnished by smaller streams, and is also less abundant 
 in some textures than in others; for example, though blood 
 vessels susceptible of conveying red blood do ramify through 
 tendons and ligaments, yet they are not numerous, apparently; 
 not more so, indeed, than what is sufficient to keep up by a de- 
 posite of serum, the flexibility of those parts. The vascularity 
 of a part "during life may be ascertained by a simple process 
 after death, the most vascular always lose proportionately of 
 their bulk by drying; for example, a muscle shrinks more than 
 a tendon, a gland more than a muscle. 
 
 Besides the operation of the lymphatics, much of the super- 
 abundant moisture is carried off by insensible perspiration and 
 evaporation from the surface of the body: the latter process, 
 however, is much restrained by the peculiar character of the 
 cuticle, without which it would become excessive, probably 
 so much so as to exceed any supply of fluid through the 
 stomach. 
 
 The red globules of the blood, besides their less obvious uses, 
 VOL. II. 21 
 
158 CIRCULATORY SYSTEM. 
 
 unquestionably serve to inspissate the serous or watery part, 
 by an intimate mixture with it, and thereby put a certain re- 
 straint upon its extravasation. They also, from their size, serve 
 to keep open the channels through which the blood circulates. 
 So much associated is the existence of red globules with regular 
 blood vessels, that there are but few examples of animals having 
 the former, without also having the latter; whereas, in animals 
 whose circulating fluid has not red globules, but is a mere serum, 
 the entire destitution of regular blood vessels is very common, 
 and their circulation, if the name be deserved, consists simply 
 in the transmission of moisture from one pore to another, as oc- 
 curs in a rag or in a sponge, by mere capillary attraction. Such 
 animals form a numerous class in the chain of organized beings, 
 and have a gelatinous consistence. 
 
 A remarkable feature in the vascular system, both arteries 
 and veins, is the disposition of trunks to run into one another; 
 or, in other words, to form an anastomosis, whereby, if the 
 blood should be cut off by one route, it may still be supplied 
 through another. These communications are frequent in the 
 head, in the neck, in the thorax, in. the abdomen, and in the 
 extremities; they exist, indeed, wherever the blood vessels do, 
 and become more numerous as the blood vessels are smaller, or 
 more removed from the centre of the circulation. It is unne- 
 cessary here to specify instances, as the more remarkable ones 
 will be mentioned at a proper time. But some estimate may 
 be made of their importance, and of the facility of communica- 
 tion established by them, when it is remembered that cases 
 have occurred of obstructed aorta, without the circulation ceasing 
 in the parts of the body beyond it: the same has occurred to the 
 venae cavae, and to the thoracic duct also." 
 
 The extreme vascular ramifications are called Capillaries, 
 (Vasa Capillaria,) and they form the connexion between the 
 arteries and veins; or, by being intermediate to the two, they are 
 the ultimate terminations of the arteries, and the commencing 
 roots of the veins. From the extreme tenuity of these vessels, il is 
 
 * lU'cl.ml, A int. Gen. 
 
GENERAL CONSIDERATIONS. 159 
 
 impossible to indicate where the arteries terminate and the veins 
 begin; yet their continuity with the capillary system has been 
 repeatedly demonstrated, by throwing injections from the one 
 into the other system, and by microscopical observations made 
 on the transparent parts of living animals, as the mesentery and 
 web foot of frogs, and the tail of fishes. These facts are suffi- 
 ciently substantiated by the observations of Malpighi, Lewen- 
 hoeck, Prochaska, and a crowd of others; yet there are anatomists- 
 who hold a contrary doctrine, and admit the parenchyma of the 
 ancients (an indefinable something, conceived, however, to be 
 spongy) as a point of termination for the arteries, and of com- 
 mencement for the veins. 
 
 Though the capillaries are all too fine to be seen distinctly 
 without the microscope, yet they are found to have several gra- 
 dations of size. The largest of them are those which only escape 
 the naked eye, experience successive divisions, whereby their 
 diameters are reduced from admitting a file of several globules 
 of blood to the caliber of one globule only.* The capillaries 
 have also frequent anastomoses with one another. Sometimes 
 the artery is simply doubled on itself, and immediately becomes 
 a vein: on other occasions, several capillary arteries run into- 
 the same vein. When these communications are unduly en- 
 larged, they constitute what has been called by Mr. John Belt 
 the aneurism from anastomosis, a frequent mark in young chil- 
 dren, and which, when it has developed itself fully, has a spon- 
 gy structure resembling the erectile tissues, as the corpus caver- 
 nosum penis, &c. As there is a double circulation, so there is 
 a double capillaVy system, one for the lungs and the other for 
 the body generally: to these may be added a third, which exists 
 in the liver, between the hepatic extremities of the vena porta- 
 rum and the hepatic veins. 
 
 The texture of the capillary vessels is too fine to admit of 
 much scrutiny, but they appear as simple cylindrical excavations 
 in the substance of the part to which they belong. It is not 
 improbable, that they may be uninterrupted continuations of the 
 internal coat of the arteries into that of the veins. They have 
 striking powers of extension and of contraction, and are easily 
 
 * Bcclard, loc. cit. 
 
160 CIRCULATORY SYSTEM. 
 
 irritated. An emotion of the mind, as a sentiment of shame or 
 a feeling of resentment, quickly causes those of the face to become 
 turgid with blood. Local stimuli cause congestions in them. 
 Cold, the application of a weak acid, or fear, causes them to con- 
 tract; though, under the influence of the heart, they are less so 
 than larger vessels. Their innumerable channels cause a compa- 
 paratively languid circulation of the blood in them, for reasons 
 mentioned; and by furnishing it with more places of contact with 
 their parietes, put it more under nervous influence than it is 
 elsewhere. 
 
 These vessels are not equally abundant in all the textures of 
 the body. Their quantity may be ascertained by the redness 
 which a part acquires by inflammation, as well as by fine injec- 
 tions: the latter proof is preferable, as, in the former, it is diffi- 
 cult to distinguish them from the extravasations which also oc- 
 cur at the same time. The celebrated injections of Ruysch, 
 from their unusual minuteness, induced him to think that every 
 solid portion of the body was vascular, yet he admitted that 
 some portions were more vascular than others, thereby con- 
 ceding to his antagonists, that some points at least were not 
 formed by blood vessels. In the microscopical examinations 
 on living animals, for example, the frog, it is seen that in their 
 feet the smallest capillaries are separated by distinct intervals, 
 while in the mucous membrane of the lungs the finest needle 
 cannot have its point inserted without opening several of them.* 
 The younger an animal is, the more vascular are its parts: but, 
 on the contrary, as it advances in age, the proportion of parts 
 not susceptible of injection increases, while the capillaries dimi- 
 nish in number. In cold-blooded animals, it is very evident 
 that some of these capillaries, or arterio-venous communications, 
 are large enough to admit a file of several red globules abreast, 
 while others allow a single file only. As a general rule, their 
 diameter may be stated at from one to five globules of red 
 blood.t 
 
 The nutrition of the body depends upon an alternation of ex- 
 halation and of absorption; but it is still undetermined, whether 
 
 * Bcclartl, Anat. Gen. -j- Beclard, loc. cit. 
 
GENERAL CONSIDERATIONS. 161 
 
 there be any vessels whatever whose especial office is that of 
 exhalation, and which produce the several secretions and ex- 
 halations. If there he such, they are generally designated by 
 the term exhalents, and their diameters are too small to transmit 
 the red globules of blood; their function is, consequently, to 
 give passage to the serous particles only. This subject has been 
 much agitated by anatomists, and marshals the best authorities 
 on both sides. Among the distinguished advocates in the affir- 
 mative, are Boerhaave, Haller, and Bichat; and opposed to them, 
 are Prochaska, Mascagni, and Richerand. The leading facts of 
 the former are; The microscopical observations of Lewenhoeck, 
 who speaks of vessels admitting only serous globules; the phe- 
 nomena of inflammation, which render red, parts naturally 
 white and transparent; the difficulty of conceiving how the 
 nourishment of certain parts can be maintained, whose capillary 
 system of red blood is so limited, in proportion to points not 
 susceptible of it. The opinion of Mascagni and others to the 
 contrary, is: That those exhalents, if they existed, should be 
 seen readily, inasmuch as they are within the range of a mi- 
 croscope, whose powers enable one to examine a body much 
 smaller than a red globule of blood; that injections should pe- 
 netrate them, instead of being limited to vessels whose existence 
 is sufficiently confirmed by examination in the living state; that 
 if during inflammation they do seem to be injected with red 
 blood, the appearance is delusive, and depends upon the exist- 
 ing capillaries being dilated so as to receive more red blood 
 than usual, upon the formation of new vessels, and upon san- 
 guineous infiltration; and, as to membranes naturally white, as 
 the conjunctiva, the colour depends upon the'capillaries, while 
 in a healthy state, being so small that they do not admit the red 
 globules in a file sufficiently numerous to be perceived by tha 
 eye, the globules being, probably, then conducted in a series of 
 one only, or in a single file, like a string of beads. It is, there- 
 fore, much more reasonable not to admit the existence of ves- 
 sels which it is very doubtful whether any one has seen. 
 
 When a watery injection is pushed into a blood vessel, it in 
 a little time shows itself as a fine dew upon the surface of the 
 serous and mucou.s membranes; in the cellular membrane, and 
 elsewhere. According to many anatomists, it has gone through 
 
162 CIRCULATORY SYSTEM. 
 
 the system of exhalents, and, indeed, presents itself to sight in 
 very much the same way that exhalation occurs in the living 
 state. From the view which has just been taken, it becomes 
 more probable, that this perspiration is executed through the 
 interstices or pores of the vessels. In the dead state it is merely 
 a mechanical result, a simple straining of the fluid; whereas, in 
 the living body it is a vital function, continually modified by 
 the peculiar vital powers of the organ or membrane where it 
 occurs; and, therefore, presents itself under the form of the dif- 
 ferent secretions. The question of the ex'halents being a dis- 
 tinct set of vessels, does not, however, appear to be one of 
 much consequence; because, if they do exist, they must be very 
 short and very small; and the assumption of their existence does 
 not throw any light upon the function of secretion. For the 
 latter is still an incomprehensible vital process, and as far as 
 we have any idea about it, it is quite as easy to conceive of its 
 being performed in the parietes of the capillaries, as in the 
 mouths of a distinct set of vessels, whose length is too short to 
 admit of an estimate. 
 
 Besides the supposed existence of a general system of exha- 
 lent vessels, some anatomists have thought that there was a spe- 
 cies of them acting particularly as nutritive vessels. According 
 to Boerhaave, every part must, therefore, be vascular. Mascag- 
 ni thought that the extreme arterial ramifications are not only 
 furnished with exhaling, but also with nutritive porosities ; and 
 that there are every where orifices of absorbing vessels, to con- 
 tain the nutritive molecules. The theories of Bichat and of 
 Prochaska, do not differ materially from the latter. Whatever 
 may be the mode of existence, and the route of nutriment to the 
 several parts of the body, the operations involved are entirely 
 too subtle even for microscopic observation. We, therefore, 
 can only understand, in a general way, that the blood vessels 
 deposite, and the lymphatics absorb, by invisible avenues in the 
 cellular substance, the molecules of composition and of decom- 
 position in our organs.* It is to this power that the name of 
 vital force has been given, and especially that of the force of 
 formation, (nisus formations.) 
 
 The arteries, though commonly said to be cylindrical canals. 
 
 * Bcclard, loc. cit. 
 
GENERAL CONSIDERATIONS. 103 
 
 are not exactly so, but, as they recede from the heart, increase 
 somewhat in diameter, even where they do not send off any 
 branches. In this way the arteries of the umbilical chord are 
 evidently larger as they get nearer the placenta; and the sper- 
 matic arteries of a bull as they get nearer to the testicle. Ob- 
 servations made on the carotid arteries of the camel, and of the 
 swan, by Mr. Hunter,* tend to prove the same disposition in 
 them. It is probable th'at the rule extends to all arteries through- 
 out the system, but it cannot be ascertained with so much cer- 
 tainty, because of the close succession of branches which they 
 send off. 
 
 Arteries have within themselves a power of increase connect- 
 ed with the exigencies of the part to which they go : thus, the 
 uterine arteries increase much in their capacity during pregnan- 
 cy, while the hypogastric, from which they are derived, aug- 
 ment inconsiderably, and the primitive iliacs not in an appre- 
 ciable manner. In animals of the deer kind, whose horns are 
 deciduous, the same augmentation of arterial trunks occurs 
 while the horn is growing. Tumours are supplied in the same 
 way. But in all these cases, after the exigency is passed, the 
 vessels diminish to their primitive size. 
 
 With the exception of the semi-lunar valves at the orifice of 
 the pulmonary artery and of the aorta, there are no others in 
 the whole arterial system. These valves permit the blood to 
 pass in the direction of the circulation, but not backwards, as 
 they are closed immediately upon the cessation of the contrac- 
 tion of the ventricles. The tricuspid valve of the heart, and 
 the semi-lunar of the pulmonary artery, are naturally not so per- 
 fect in their closure as those on the other side of the heart, but 
 permit a small quantity of blood to retrograde.! As life ad- 
 vances, the valves of the aorta are much disposed to ossifica- 
 tions and derangements of different kinds, which render them 
 much less perfect than those of the pulmonary artery. 
 
 * On the Blood and Inflammation. | Hunter, loc. cit. 
 
104 CIRCULATORY SYSTEM. 
 
 CHAPTER II. 
 
 OF THE TEXTURE OF THE ARTERIES. 
 
 THE arteries are composed of three coats ; an external, a mid- 
 dle, and an internal. 
 
 The External Coat, also called Cellular, is, in fact, condensed 
 cellular substance formed into a cylinder. Its fibres run in eve- 
 ry direction, so as to be perfectly interwoven with one another. 
 The exterior periphery of this coat is continued into the adja- 
 cent cellular substance, but its internal face is united more close- 
 ly to the middle coat; not, however, so tightly as to prevent a 
 slight sliding of the one upon the other, and to forbid their easy 
 separation by a knife. Scarpa is not disposed to admit this as 
 one of the coats of arteries, and says that it only serves as an 
 exterior envelope, and retains them in their places. This coat 
 manifests its fibrous character in not being disposed to secrete 
 fat, and is more distinct in the large arterial trunks. It has con- 
 siderable strength and elasticity, both circularly and longitudi- 
 nally, and is remarkable for its whiteness. If an artery be sur- 
 rounded by a tightly drawn ligature, the middle and the internal 
 coats will be completely cut through by it, while the external 
 coat remains entire. This coat, then, answers the purpose of a 
 strong investing fascia,* in which respect it may be considered 
 as a sheath to the proper arterial structure, though the term 
 sheath is commonly applied to the cellular membrane on its 
 outer side. 
 
 The Middle Coat of the arteries is called the Muscular, the 
 Proper, the Tendinous, and so on. It is of a light yellowish 
 tinge, and decreases continually in thickness, with but few ex- 
 ceptions, from the heart to the ends of the arteries; it is, how- 
 ever, proportionately thicker in the small arteries than in the 
 large ones. Its fibres are circular, but do not individually per- 
 form the circuit of the vessel. They are parallel to each other, 
 
 * Jones on Hemorrhage. 
 
TEXTURE OF THE ARTERIES. 165 
 
 and adhere laterally by very slender ties. In the larger arte- 
 ries, this coat may be divided into several laminae, though the 
 division is entirely artificial. There are no longitudinal fibres 
 whatever in it ; the consequence of which is, that an artery di- 
 vested of its external coat, yields more readily in the direction 
 of its length than of its circumference. 
 
 The middle coat has a firmness, whereby, even when an ar- 
 tery is emptied, the cylindrical shape is still retained. Its cha- 
 racter seems to be the result of a mixture of elastic and of mus- 
 cular properties derived from a state of tissue entirely peculiar ; 
 but which some anatomists have been very desirous of ranging 
 under the head of muscles, others under that of ligaments, and 
 a third, under both united. The celebrated John Hunter, whose 
 observations were generally made with the most scrupulous at- 
 tention to perfect exactitude, were often repeated, so as to make 
 one confirm another ; and who has received that sanction of 
 greatness in which one's posthumous reputation becomes more 
 exalted than the living ; bestowed much attention on this sub- 
 ject. He was induced to believe that this middle coat was 
 formed by a muscular lamina internally, and an elastic one ex- 
 ternally; which distinction might be rendered evident by cutting 
 a contracted artery through transversely, when the muscular 
 coat would be found projecting beyond the other. He acknow- 
 ledges, however, that he never could discover the direction of 
 the muscular fibres: though he supposed them to be oblique, be- 
 cause their degree of contraction was greater than a straight 
 muscle could produce. 
 
 The elastic contraction of an artery, is manifested both in the 
 direction of its length and of its circumference; for, when put 
 upon the stretch in either way, it has the ability of returning to 
 its original dimensions after the distending force ceases. The 
 Muscular contraction, however, only occurs in the circumference, 
 and not at all in the length: by it the caliber of arteries is re- 
 duced to a very small diameter, if an animal be slowly bled to 
 death. If, in this contracted condition, an artery be slit open 
 longitudinally, the elastic coat will, at the cut margin, project 
 beyond the other, which Mr. Hunter considers as another way 
 of ascertaining the existence of the two tunics. But if this same 
 artery be then stretched transversely, the muscular coat will 
 VOL. II. 22 
 
166 CIRCULATORY SYSTEM. 
 
 project beyond the other ; for the reason, that if a muscle, after 
 death, be elongated by force, it has no power of returning from 
 that state, but will remain precisely as it is: whereas, elasticity 
 being a property of matter enjoyed quite as fully in the dead as 
 in the living state, the elastic coat of the artery returns to the 
 medium condition. 
 
 Mr. Hunter, with a view of satisfying himself on these several 
 points, had a horse bled to death, so as to obtain the vessels at 
 their minimum of contraction. A circular section of the aorta 
 measured, at first, five inches and a half, and, on being stretched, 
 it lengthened to ten inches and a half; being let alone, it con- 
 tracted to six inches, at which it remained stationary; the dif- 
 ference between six inches and ten and a half was then the 
 amount of its elastic power, while only half an inch of contrac- 
 tion was due to the muscular stratum, or, in other words, an 
 eleventh of the whole. 
 
 A section of the iliac artery, measuring two inches in circum- 
 ference, on being allowed to contract after stretching, measured 
 two and one-third inches; it, therefore, gained one-sixth the 
 amount of its muscular contraction. A section of the axillary 
 artery gained one-eighth of the carotid, two-thirds of the ra- 
 dial artery, doubled its primitive extent. From all which the 
 inference was drawn, that the power of recovery in a vessel is 
 greater, in proportion as it is nearer the heart, but lessens as the 
 distance increases, which shows the decrease of elastic, and the 
 increase of muscular power. 
 
 The elastic coat gives a middle state to an artery, or has a 
 continued tendency to it; if, therefore, the artery be too much 
 dilated, it contracts it, and if it be too much contracted, it dilates 
 it, all of which is readily exemplified by a cylinder of gum elastic, 
 which, whether compressed or dilated, has only one state of re- 
 pose, to which it immediately returns on being left to itself. 
 Mr. Hunter supposed, that a certain degree of elasticity is con- 
 tinued to the very end of every artery, from this quality being 
 better suited to sustain a permanent resistance than muscular 
 power; as a pipe of lead, from its want of elasticity, finally 
 becomes stretched and useless under the pressure of a column 
 of water, whereas, one of iron, from being elastic, always re- 
 acts efficiently. It is this elasticity in the arteries, which 
 
TEXTURE OF THE 'ARTERIES. 167 
 
 causes the blood, at a little distance from the heart, to flow 
 through them in a continued jetting stream when they are 
 opened, although it is supplied to the aorta by interrupted strokes. 
 In this way, as the artery is more distant from the heart, the 
 stream becomes proportionately regular. 
 
 " The muscular power of an artery renders a smaller force 
 of the heart sufficient for the purposes of circulation; for the 
 heart need only act with such force as to carry the blood through 
 the larger arteries, and then the muscular power of the arteries 
 takes it up, and, as it were, removes the load of blood while the 
 heart is dilating. In confirmation of this remark, it is observa- 
 ble in animals whose arteries are very muscular, that the heart 
 is proportionably weaker, so that the muscular power of the ves- 
 sels becomes a second part to the heart, acting where the power 
 of the heart begins to fail, and increasing in strength as that de- 
 creases in power."* 
 
 The Internal Coat of the arteries" is designated by the terms 
 Nervous and Arachnoid. It is continued from the ventricles of 
 the heart, in the left one of which it is of unusual thickness. It 
 is the duplication of this membrane with some fibres interposed, 
 that composes the semi-lunar valves of the aorta and of the pul- 
 monary artery. Its internal face is smooth, polished, and moist- 
 ened with a kind of humidity which permits the blood to flow 
 through with diminished friction. In the larger arterial trunks, 
 some small longitudinal wrinkles are observable in it ; and when 
 an artery has been cut through, as in amputation, it is disposed 
 to retract in small transverse wrinkles. It is, therefore, not 
 very extensible, but has, according to the experiments of Sir 
 Everard Home,t a considerable degree of solidity t and strength. 
 
 Ossifications of this membrane are very frequent after the age 
 of sixty. 
 
 In addition to the tunics mentioned, cellular substance, vessels, 
 and nerves enter into the structure of arteries. 
 
 The Cellular Substance is not abundant, and serves principally 
 
 * Hunter, loc. cit. 
 
 f Transactions for the Improvement of Medical and Surgical Knowledge, 
 vol. i. 
 
168 CIRCULATORY SYSTEM. 
 
 to unite the sides of the circular fibres to one another, and to 
 join the internal to the middle coat. 
 
 The Vessels ( Vasa Arteriarum) consist both in arteries and in 
 veins, and come from the adjacent trunks, instead of from those 
 on which they ramify. They may be made very distinct by a 
 fine injection, or by laying them bare in the living body ; when 
 in a little time after exposure, they begin evidently to carry red 
 blood, and to grow turgid as in inflammation. The difference 
 in the colour of the blood distinguishes these arteries from the 
 same kind of veins. Both arteries and veins may be traced very 
 well into the middle coat, but not upon the internal, though the 
 changes which occur in the latter, from disease and upon the 
 application of ligatures, prove clearly that exhalation and ab- 
 sorption are continually going on there. For in inflamed arte- 
 ries, an exhalation is seen upon their internal surface, and when 
 a coagulum has been produced by ligature, it is finally ab- 
 sorbed. 
 
 The Nerves of the arteries, according to Wrisberg and Be- 
 clard, are numerous and considerable, form around them a plex- 
 us resembling that of the par vagum around the oesophagus, and 
 follow them into the interior of our organs, with the exception 
 of the brain ; which has them only to its surface. They are 
 proportionately more abundant in the aortic than in the pulmo- 
 nary system; also upon the smaller than upon the larger arte- 
 ries. The arteries of the head, of the neck, of 'the thorax, and 
 of the abdomen, are supplied from the sympathetic nerve, while 
 those of the extremities are supplied from the nerves of the spi- 
 nal marrow. 
 
 The passing of the blood through the arteries is accompanied 
 with a pulsating motion, which, for the most part, is exactly 
 synchronous with the contraction of the left ventricle, and de- 
 pends upon an increased quantity of blood thrown into them at 
 the moment. The dilatation of the artery may be both seen and 
 felt: " but were we to judge of the real increase of the artery 
 by this, we should deceive ourselves; for when covered by in- 
 teguments, the apparent effect is much greater than it really is 
 in the artery itself; for in laying such an artery bare, the nearer 
 we come to it, the less visible is its pulsation; and, when laid en- 
 tirely bare, its motion is hardly either to be seen or felt. This 
 
TEXTURE OF THE VEINS. 169 
 
 apparent diastole of the artery is augmented in proportion to the 
 solid matter covering it, whence tumours over large arteries 
 have considerable motion given to them, and have often been 
 supposed to be aneurismal. Arteries, in fact, during their dias- 
 tole or dilatation, increase much more in length than in width, 
 and are thrown into a serpentine course: instead, therefore, of 
 the term diastole, it should rather be called the elongated state."* 
 Mr. Parry, of Bath,t has denied that the arteries dilate at all 
 during their diastole: his opinion, however, is peculiar, though, 
 in an experiment performed some years ago upon the carotid 
 artery of a calf, its correctness appeared to me then to be fully 
 proved. 
 
 There is no part of the human body which presents more fre- 
 quent varieties, in different individuals, than the arteries. These 
 varieties are found, in their place and manner of origin, in posi- 
 tion, and in the number of their ramifications. They are com- 
 paratively rare in the trunks of the first order, more common in 
 those of the second, and still more usual in those of the third and 
 fourth. From these causes, discrepancies are continually found 
 in the descriptions of the most approved authorities, and must 
 last so long -as writers repose upon a partial experience, instead 
 of referring to what has been most generally observed. 
 
 CHAPTER III. 
 
 OF THE TEXTURE OF THE VEINS. 
 
 THE veins, from their duty of receiving the blood in all parts 
 of the body from the extreme arteries, and returning it to the 
 heart, by successively collecting it into the two venae cavag, may 
 be more appropriately compared to the roots of a tree, than to 
 its branches. The variations in them as well as their anasto- 
 moses, are more frequent than in the arteries. 
 
 They are more numerous than the arteries ; for, in addition to 
 
 * J. Hunter, loc. cif. 
 
 f Experimental Inquiry on the Pulse, 18161819. 
 
170 CIRCULATORY SYSTEM. 
 
 two venous trunks attending each artery wherever the structure 
 of the part is intended for locomotion, as in the extremities, and 
 in some places upon the trunk of the body, there is a very abun- 
 dant class of veins which pre superficial or subcutaneous, and 
 which, when filled properly with injecting matter, form a fine 
 vascular network over the whole surface of the body.* These su- 
 perficial veins, in some places, form trunks even larger than such 
 as attend the arteries, and especially in the extremities. Besides 
 the excess in number, the veins which attend the arteries ( Vena 
 Comites) have a capaciousness which, in many cases, is double 
 that of the latter. From these several circumstances, it results 
 that the area of the venous system vastly exceeds that of the ar- 
 terial. 
 
 In some cases the veins follow precisely the course of the ar- 
 teries, one for one, as in the greater number of the viscera of 
 the abdomen, where they have common points of entering and 
 departure. Sometimes two arteries discharge into one vein, as 
 in the penis, the clitoris, and the umbilical chord ; sometimes 
 they pursue a course entirely different from the arteries, as in 
 the pia mater. For the most part they are less tortuous than 
 the arteries. 
 
 The veins, when injected, assume a cylindrical shape, yet 
 they differ materially from the arteries, in having much thinner 
 coats, and in being so pliable that they collapse by their own 
 weight. In the lower extremities, however, near the feet and 
 upon them, as the veins sustain the pressure of a long column of 
 blood ; they have additional thickness and strength, so as to ap- 
 proximate them more to the arterial structure. This provision 
 will be found occurring in most places where they have much 
 duty to perform. 
 
 " They are similar to the arteries in their structure, being com- 
 posed of an elastic and muscular substance : the elasticity pre- 
 serves them in some degree in a middle state, although not so 
 perfectly as it does in the arteries. The muscular power adapts 
 the veins to the various circumstances, which require the area to 
 be within the middle state, and assists the blood in its motion to- 
 wards the heart."t 
 
 * Pauli Mascagni Anatom. Univers. Pisis, 1823. 
 f Hunter, loc. cit. 
 
TEXTURE OF THE VEINS. 171 
 
 The External Coat is thinner and not so strong as that of the 
 arteries ; in other .respects, the resemblance is sufficiently close 
 not to require any particular comment. 
 
 The Middle Coat, near the entrance of the larger veins into 
 the heart, is distinctly muscular.* It is formed of soft extensible 
 fibres, many of which, when the vein is held up to the light, ap- 
 pear longitudinal, while the most internal are circular: there are 
 difficulties, however, in the separation of these fibres, which pre- 
 vent their course from being accurately ascertained. Bichat and 
 Meckel assert, that the whole of them are longitudinal, and that 
 there are none circular. 
 
 This coat, in the human subject, is much thicker in the system 
 of the ascending than of the descending cava ; it is also thicker 
 in the superficial than in the deep-seated veins. In some sub- 
 jects it is much better developed than in others. In certain parts 
 of the body it is entirely deficient, as in the sinuses of the dura 
 mater, and has its place supplied by this membrane ; the same 
 deficiency exists in the sinuses of the bones. 
 
 The Internal Coat is more delicate and extensible than the 
 corresponding one of the arteries, is less liable to rupture, and 
 less disposed to ossification. It is thrown into a considerable 
 number of duplications, forming valves. Each valve is of a se- 
 micircular shape ; is connected by its convex edge to the vein, 
 while the straight edge is loose, and turned towards the heart. 
 When the veins are injected backwards, these valves may be 
 forced in the larger trunks, and give them a knotted appearance. 
 The valves are commonly in pairs, but in certain veins, as the 
 crural and the iliac, there are three of them together ; very rare- 
 ly do they amount to four. In some instances there is but a 
 single one ; this arrangement is more frequent at venous orifices, 
 as the great coronary vein of the heart, the vena cava ascen- 
 dens, the vena azygos. They are frequently found reticulated as 
 if they had been lacerated, whence it has been supposed that the 
 fibres which cross the sinuses of the dura mater are an elemen- 
 tary approach to them. 
 
 * Beclard, loc. cit. 
 
172 CIRCULATORY SYSTEM. 
 
 The valves are more abundant in the superficial than in the 
 deep-seated veins, but they do not exist every where. There are 
 none in the branches of the vena portarum, excepting the vasa 
 brevia : none in the spine, in the umbilical vein, the cervical veins, 
 the kidneys, womb, ascending and descending cava, or in the 
 median vein. The valves are proportionately more abundant in 
 the lower extremities. 
 
 From the tenuity of the parietes of the veins, the blood may 
 be readily distinguished circulating through them. Their coats, 
 like those of the arteries, are vascular, or have the vasa vaso- 
 rum. The arteries come from the nearest small trunks, while 
 the corresponding veins do not empty immediately, but second- 
 arily, into the trunk, whos parietes they supply. They are well 
 furnished with veins. 
 
 Their elasticity, both transversely and longitudinally, is well 
 marked ; but they are not so extensible in the latter direction as 
 the arteries, while they are more so transversely. There can be 
 no doubt of their spontaneous powers of contraction, for it is 
 abundantly proved by their diminishing much in volume upon 
 the application of cold ; moreover, when a venous trunk, dis- 
 tended with blood, is intercepted by two ligatures, and then punc- 
 tured, it empties itself entirely and rapidly. 
 
 The circulation in the veins is produced, in a principal degree, 
 by the contraction of the heart ; their own contraction may also 
 favour this motion, as well as lateral pressure from contiguous 
 parts. As the movement of the blood in the smaller arteries is 
 so uniform as to be almost without pulsation, so the latter disap- 
 pears entirely in the veins. It is not clear that this circumstance 
 depends exclusively on the friction experienced by the blood in 
 passing through the capillaries, but is probably rather owing, as 
 Mr. Hunter has suggested, to the veins receiving their blood from 
 different arteries, some of whose channels are more circuitous 
 than others, and, consequently, their blood arrives at different 
 times. The momentum of the heart, then, even if it did impinge 
 upon those channels, would not be synchronous upon the venous 
 trunk, but would be divided in such a way as to produce a tre- 
 mour or confused motion. The larger veins, however, have near 
 the heart a pulsation during the contraction of the auricles, 
 
THE BLOOD. 173 
 
 arising from the arrest of their circulation at the moment. 
 During inspiration, the vacuum created in the thorax hurries on 
 the blood to the heart, but in expiration it is somewhat im- 
 peded.* 
 
 It has sometimes happened, that a large vein near the heart 
 being opened by an accident or an operation, a strong inspira- 
 tion has caused the introduction of air, which, being carried to 
 the heart, has produced instant death. It lately occurred in Pa- 
 ris to the celebrated surgeon Dupuytren. 
 
 CHAPTER IV. 
 
 OF THE BLOOD. 
 
 THE Blood, in the human subject, and in many animals, is of 
 a red colour. It is about the consistence of thin size, has a pe- 
 culiar smell, a nauseous and slightly saline taste, and is some- 
 what heavier than water; its specific gravity being about 105> 
 and its temperature in the living body is from 96 to 98 of Fah- 
 renheit. Its quantity is variously estimated at from eight to one 
 hundred pounds, so that there would seem to be no very exact 
 means of ascertaining this point. 
 
 So long as it continues to circulate, or while it is still flowing 
 from an opened vessel, it has, to common inspection, the appear- 
 ance of a homogeneous fluid ; yet, after it has been drawn a few 
 minutes, and permitted to remain at rest, it assumes a thick ge- 
 latinous condition, expressed by the term coagulation, and by 
 
 * This ancient observation has lately been renewed, with additional interest 
 and details, by M. Barry of Paris. See a Report of MM. Cuvier and Dumeril, con- 
 cerning the Influence of the Atmosphere on the Circulation of the Blood, in the 
 Philadelphia Journal of the Medical and Physical Sciences, July, 1826. M. Bar- 
 ry has probably assigned too much importance to this influence, as it is certain 
 that the circulation may go on veiy well where no vacuum is produced at inter- 
 vals in the thorax; for example, in the foetus, in incubation, and in fish. 
 
 VOL. II.-23 
 
174 CIRCULATORY SYSTEM. 
 
 \vhich it ceases to be any longer fluid. The coagulation begins 
 'on the surface of the mass, and by a thin pellicle, which shows 
 itself in three or four minutes ; commonly at the end of twenty 
 minutes the coagulation is complete throughout, but this rule 
 varies according to the state of the body at the moment ; and 
 the coagulation is more protracted when the quantity of blood is 
 large and has been drawn through a large orifice, than where it 
 is small, and has been evacuated through a small orifice. This 
 change has scarcely taken place, when a spontaneous separa- 
 tion follows, whereby it is resolved into a watery part called Se- 
 ^rum, and into a thick condensed mass called Cruor or Crassa- 
 mentum. The serum first shows itself on the surface of the co- 
 agulum, in small drops, which quickly increasing in number and 
 size, finally run together, a^id form a mass of fluid exceeding 
 considerably that of the crassamentum. The separation into se- 
 rum and crassamentum-, though sufficiently evident after a few 
 hours, yet requires some days for its complete accomplishment ; 
 for the coagulum still continuing to contract, expels more and 
 more of the serum. 
 
 The peculiar complexion of the blood depends upon a red co- 
 louring matter consisting in globules. This matter does not seem 
 to be an indispensable -constituent, as many animals are entirely 
 deprived of it, and such as naturally are possessed of it, may 
 "have its quantity very much reduced by repeated bleedings. The 
 ^colouring matter is generally an ingredient of the crassamentum, 
 so that the whole of the latter has a red appearance ; yet there 
 are some conditions of the body in which a spontaneous separa- 
 tion of it takes place, more or less completely. For example, in 
 inflammatory diseases the blood does not coagulate so soon as in 
 health ; and the red globules, from being naturally heavier than 
 the other constituents of the crassamentum, subside to its bottom 
 and leave it of a white semi-transparent colour. It is this white 
 part upon which depends the whole property of coagulating, and 
 which has been called coagulating lymph. We have, therefore, 
 three constituents of blood manifested by its own spontaneous 
 'changes ; the serum, the red globules, and the coagulating lymph. 
 
 Coagulation, contrary to popular opinion, is not assisted by cold, 
 fout rather retarded by it : heat assists it.* If the heat be raised 
 
 * Hunter on the Blood. Hewson. 
 
THE BLOOD. 175 
 
 to 120, blood will coagulate five minutes sooner than if left at 
 its natural standard, and even sooner than if its temperature ba 
 reduced to 50. If Wood be frozen quickly, before it has time 
 to coagulate, on being thawed it returns to the fluid state, and 
 will coagulate afterwards. The contact of air does not produce 
 coagulation. Dr. Physick, in order to ascertain this point con- 
 clusively, took a glass tube, which had a stop cock at each 
 end, and attached one of its ends to the vein of a dog. A 
 current of blood was then conducted through the tube, and 
 while it was flowing, the far stop cock was closed, and im- 
 mediately afterwards the other; thus, a column of blood was 
 obtained which had not touched the aii\ After permitting it 
 to remain a proper time, the tube was broken asunder, and 
 the blood found coagulated as usual. Rest is not indispensa- 
 ble to the process, for blood, if shaken in a vial, will still co- 
 agulate. The division of the blood into small masses expe- 
 dites coagulation. Therefore, when it flows slowly from the 
 blood vessels, falls from some height, or runs for a distance 
 over the surface of a dish, it coagulates sooner than under op- 
 posite circumstances. The latter are then auxiliary to the blood 
 manifesting the sizy coat, one of the concomitants of inflam- 
 mation ; because, if the coagulation be very rapid, it will pre- 
 vent the constituents of the crassamentum from separating from 
 one another, by entangling the red globules, in the coagulating 
 lymph. 
 
 After death the blood is coagulated in the veins, though not 
 so perfectly or generally as is supposed, for there are no sub- 
 jects which do not bleed from their large veins, when the latter 
 are opened. 
 
 There are many modes of death which prevent entirely the 
 coagulation of the blood in the vessels, for example, where life 
 is destroyed by a paroxysm of excessive anger ; by electricity ; 
 by lightning ; by a blow upon the stomach ; by certain fevers 
 of a typhoid character. Many chemical articles prevent its co 
 agulation on being mixed with it. 
 
176 CIRCULATORY SYSTEM* 
 
 SECT. I. OF THE SERUM OF THE BLOOD, 
 
 Serum is common to the blood of all animals, and is consi- 
 dered, by Mr. Hunter, to be more abundant in such as have red 
 globules. It is, generally, of a lighter specific gravity than the 
 crassamentum. I have, however, often seen the latter floating 
 in it, which shows the contrary in some instances. Though its 
 separation commonly depends upon the coagulation of the latter, 
 yet that process is not indispensably necessary, as was once 
 witnessed, by Mr. Hunter, in a lady, in whom the serum was 
 disengaged from the crassamentum, while the latter was yet 
 in a fluid state. The phenomena of dropsy, also, prove the 
 same point. 
 
 Serum, though very fluid, is not so much so as water. It is 
 a light yellow or straw colour, varying, somewhat, in different 
 subjects. It contains a large quantity of albumen, or matter re- 
 sembling the white of an egg. It also consists of water, of soda 
 uncombined, and of some of the salts of soda, jthe presence of 
 all which may be manifested in several ways. For example, 
 when exposed to a heat of 140 degrees of Fahrenheit, it becomes 
 Opaque, and at 160 or 165 coagulates firmly. During this pro- 
 cess, a great deal of air is disengaged from it. It is also coagu- 
 lated by spirits of wine, by all the mineral acids, by corrosive 
 sublimate, and by many other articles, all of which prove the 
 presence of albumen. Mr. Brande considers this liquid albumen 
 as an albuminate of soda, with an excess of its base, and that its 
 fluidity depends on the excess of soda; when, therefore, the lat- 
 ter is removed or neutralized by an acid, the albumen coagu- 
 lates. Under the action* of the Galvanic pile, like the influence 
 of heat, the soda produces mucus, by blending with a part of 
 the albumen ; and the remainder of the latter, not being able to 
 retain its fluidity after the abduction of the soda, coagulates. 
 
 This mucus is, probably, the part which Mr. Hunter speaks 
 of as retaining its fluidity when other portions of the serum are 
 coagulated by heat. It is observed in meat either roasted or 
 boiled, and comes from it as a thin, limpid fluid, somewhat 
 tinged with the red globules. The older the animal is, the 
 greater is its comparative quantity: in lamb, there is scarcely 
 
COAGULATING LYMPH OF THE BLOOD. 177 
 
 any of it, whereas, in mutton five or six years old, it is abun- 
 dant ; the same rule seems to hold in regard to the human sub- 
 ject This serosity, or mucus, is coagulable by Gourlard's Ex- 
 tract* 
 
 The serum is not always transparent, but sometimes wheyish 
 and thin: when it settles, it often throws up a white scum like 
 cream. This more frequently occurs in pregnant women, though 
 it is not confined exclusively to either sex, or to any known con- 
 dition of body. The specific gravity of the globules composing 
 this scum varies ; for though it generally floats on the surface 
 of the serum, it does not always: it also sometimes swims, and, 
 on other occasions, sinks in water. It has been erroneously 
 considered as chyle not yet assimilated, or as absorbed fat or 
 oil. It is, probably, this substance which presents itself under 
 the form of microscopic globules in the coagulum of serum ; 
 and, when serum has been kept for several days, is deposited in 
 the form of globules at its bottom. These globules present a 
 singular motion of ascent and descent in the serum ; upon the 
 application of heat to it by holding it in the hand. It is said 
 that albumen, coagulated, presents a very close resemblance to 
 fibrine.f 
 
 The presence of soda uncombined in the serum, is readily as- 
 certained by an infusion of red cabbage, (Brassica oleracea,) or 
 the juice of the flag, (iris versicolor,) which are both made green 
 by it. Sulphur combined with ammonia, is also found in it. 
 Owing to the presence of sulphur, serum has the effect of black- 
 ening silver when left in it, and also has its power of dissolving 
 the oxydes of mercury, iron, copper, and other metallic prepa- 
 rations. 
 
 SECT. II. OF THE COAGULATING LYMPH OF THE BLOOD. 
 
 Coagulating lymph, or fibrine, when circumstances are suita- 
 ble for collecting it, freed from the red globules, offers the ap- 
 pearance of a semi-transparent body of a very light drab colour; 
 it is elastic and strong, and, when subjected to the microscope, 
 has the appearance of muscular fibres, by being composed of 
 
 * Hunter, loc. cit. f Beclard, loc. cit. 
 
178 CIRCULATORY SYSTEM. 
 
 colourless globules. Like muscle, it also, when macerated in 
 water, resolves itself into those globules before it putrefies. 
 
 If the blood, while flowing from an animal, be collected, and, 
 at the same moment, stirred round and round with a rough stick, 
 the fibrine will gather upon the latter in a fibrous form, so as to 
 resemble a mass of entangled and knotted packthread. The 
 fibrine may be afterwards washed almost white, and, at any 
 rate, so as to clear it entirely from the red globules. 
 
 The fibrine, when dried, loses greatly in its bulk and weight, 
 by the evaporation of the serum from it, so that the proportion 
 which it seems to bear to the whole mass of blood is much less 
 considerable than one would suppose from seeing it in the sim- 
 ple coagulated state. 
 
 The coagulating lymph of the blood being common, probably, 
 to all animals, w 7 hile the red particles are not, we must suppose 
 it from this alone to be the most essential part; and, as we find 
 it capable of undergoing, in certain circumstances, spontane- 
 ous changes, which are necessary to the growth, continuance, 
 and preservation of the animal ; while to the other parts we can- 
 not assign any such uses, we have still more reason to suppose 
 it the most essential part of the blood in every animal."* 
 
 SECT. III. OF THE RED GLOBULES OF THE BLOOD. 
 
 The particles of blood upon which its red colour depends are, 
 by a majority of observers, considered to be globular, and while 
 the blood circulates they float about in the lymph and serum. 
 They are of the same size in animals of the same species, and 
 have no tendency to run into each other, as globules of mercury 
 would. They are plastic, by which they can assume an ellip- 
 tical shape when they circulate through vessels of a very small 
 size. 
 
 According to the microscopical observations of Mr. Bauer, 
 each globule is one two-thousandth part of an inch in diameter, 
 but Capt. Kater does not consider it to exceed one five thou- 
 sandth part of an inch.t There seems, however, to be a great 
 
 * Hunter, loc. cit. f Phil. Trans. 1818. 
 
RED GLOBULES OF THE BLOOD. 179 
 
 uncertainty in these estimates of form and of size, inasmuch as 
 different observers do not agree among themselves. Father 
 Delia Torre considered them as flat circles or rings, with a 
 perforation in the centre, while Mr. Hewson, in ascribing the 
 same shape, represented them as hollow or vesicular, with a red 
 dot in the middle. Mr. Bauer, on the contrary, considers that 
 the dot, or colouring matter of the globule, is placed upon its 
 periphery. As the colour is supposed to depend upon particles 
 of iron, Dr. John Mason Good has wittily suggested, that, ac- 
 cording to Mr. Hewson, we have the wheels of life moving upon 
 iron axles, whereas, according to Mr. Bauer, they only have 
 iron tiers.* 
 
 It has been observed that the red globules are the heaviest 
 part of the mass of blood, and are, therefore, always disposed to 
 subside to the bottom of the crassamentum, though, from the 
 quick coagulation of the latter, they can seldom do it before they 
 become entangled in it, and thereby fixed to a certain place. 
 They do not invariably retain their form, but are readily dis- 
 solved in water. They are, of course, insoluble in serum. Urine 
 does not dissolve them ; neither does a solution of muriate of soda, 
 of sal ammoniac, Epsom salts, nitre, diluted sulphuric or muria- 
 tic acid : the latter, however, deprives them of colour. 
 
 The solution of red globules in water is manifested by the mix- 
 ture becoming of a fine transparent red, and the process takes 
 place almost immediately. On the contrary, when the globules 
 refuse to be dissolved, a rnuddy mixture is formed. When they" 
 are dried in serum, and afterwards soaked again in it, they do 
 not resume the globular form. They have more substance than 
 the coagulating lymph, for they do not lose so much of their bulk 
 by drying. 
 
 Notwithstanding the doubts that have been raised on the sub- 
 ject, it seems now to be very well ascertained, that iron is the 
 colouring principle of the red globules of the blood, though it 
 cannot be detached in the coloured state, owing to the absolute 
 necessity of using strong heat, or concentrated acids to destroy 
 the substance with which it is combined. The iron is an oxide 
 with a small quantity of the sub-phosphate, but a knowledge of 
 
 '* Study of Medicine, vol. ii. p. 25. 
 
180 CIRCULATORY SYSTEM. 
 
 this fact does not enable the chemist to imitate red globules by 
 mixing these chemical substances with albumen. The process 
 by which Berzelius obtains iron from the blood, consists in 
 placing a clot of the latter upon blotting paper, whereby its se- 
 rum is absorbed. The clot being afterwards put into water, its 
 colouring matter is dissolved, while the lymph remains entire ; 
 by removing then the lymph, and evaporating the water, the co- 
 louring matter is obtained, which, on being reduced to ashes, 
 renders about one to two-hundredth part of its weight in iron. 
 
 The chemists also inform us, that fibrine, albumen, and the co- 
 louring matter, all resemble one another so closely, that they are 
 only modifications of one and the same substance ; and that each 
 of them yields, upon decomposition, phosphate and carbonate of 
 lime, though these ingredients cannot be detected by tests ap- 
 plied to the entire mass of blood. 
 
 " It is difficult to determine by what means the iron, or the 
 sulphur, or the elementary principles of calcarious earth, obtain 
 an existence in the blood. If these materials were equally dif- 
 fused throughout the surface of the earth, we might easily con- 
 ceive that they were introduced through the medium of food. 
 But as this is not the case, as some regions, like New South 
 Wales, at least, on this side the Blue Mountains, contain no lime- 
 stone whatever, and others, no iron or sulphur, while all these 
 are capable of being obtained apparently as freely from the blood 
 of the inhabitants of such regions, as from that of those who live 
 in quarters where such materials enter largely into the natu- 
 ral products of the soil ; it is, perhaps, most reasonable to con- 
 clude that they are generated in the laboratory of the animal 
 system itself, by the all-controlling influence of the living prin- 
 ciple."* 
 
 The red globules, according to the opinion of Mr. Hunter, 
 from not being pushed into the extreme arteries, where the 
 coagulating lymph reaches, and from not being found in all ani- 
 mals, do not contribute to the growth and to the repair of the 
 system. But they seem to be connected with strength, in such 
 animals as have them, as the strength acquired by exercise in-. 
 
 Good, loc, cit. 
 
RED GLOBULES OF THE BLOOD. 181 
 
 creases their proportion and occasions them to he carried abun- 
 dantly into parts which previously, from a debilitated state, re- 
 ceived them but partially, if at all. This fact is well known ta 
 graziers, who keep their quantity in certain animals, as veal, re- 
 duced by quietude and frequent bleeding. 
 
 Their source is not understood, though many conjectures on 
 the subject have been hazarded. Mr. Hunter's opinion was, 
 that they do not appear to be formed in those parts of the blood 
 already produced, but rather to rise up in the surrounding parts; 
 as, in the incubated egg, they exist in the form of a zone, com- 
 posed of dots, previously to the formation of vessels. This fact 
 ought to quiet all speculations about their coming from the 
 spleen, thymus gland, and so on. 
 
 VOL. JI. 24 
 
BOOK VIII. 
 
 PART II. 
 
 Of the, Special Anatomy of the Circulatory System. 
 
 CHAPTER I. 
 
 OF THE HEART AND PERICARDIUM. 
 
 THE Heart, (Cor,) the centre of the circulation, is situated in 
 the thorax, between the sternum and the spine; being bounded 
 on its sides by the lungs, and below by the tendinous centre of 
 the diaphragm. It is a hollow muscular organ. 
 
 The heart is of a conoidal shape, but flattened on the surface 
 which lies upon the diaphragm. This flat surface is on a hori- 
 zontal line with the lower end of the second bone of the ster- 
 num; the base of the cone is towards the vertebrae, and looks 
 obliquely backwards to the right side, while the apex is about 
 the junction of the left fifth rib with its cartilage. Being placed 
 between the right and the left pleura, in the mediastinum, it is 
 surrounded by its own proper capsule called the pericardium. 
 Its common weight is about six ounces. Its greatest length, to 
 wit, that from the apex to the base, is about five and a half 
 inches, four of which are taken up by the ventricles: its base is 
 about three and a half inches in diameter. 
 
 The heart is divided into four cavities; two auricles and two 
 ventricles: the places where the partitions are placed between 
 these cavities are marked on the surface of the heart by fissures, 
 sufficiently distinct to be immediately recognised. The two 
 auricles form the base of the heart, the ventricles constitute its 
 
184 CIRCULATORY SYSTEM. 
 
 body, and the anterior end of the left ventricle, by being ex- 
 tended somewhat beyond the right, forms the apex. The right 
 auricle and the right ventricle are the two cavities which are 
 nearest to the right side of the body, while the left auricle and 
 the left ventricle are the two cavities nearest to the left side. 
 it will, however, be understood, from the general observations 
 already made, that the relative situation of these cavities is such 
 that the right ones are in front of the others, and present ob- 
 liquely forwards to the right side, while those on the left side 
 look obliquely backwards to the left side. This position of the 
 heart makes it encroach more upon the left cavity of the thorax 
 than it does on the right; from which cause its pulsations may 
 be very easily distinguished where the left ribs join their carti- 
 lages, while on the right side of the sternum there is scarcely 
 ever a perceptible pulsation. 
 
 The Pericardium is covered on its sides by the pleura, and 
 reposes on the tendinous centre of the diaphragm, to which it 
 adheres by close compact cellular substance, particularly at its 
 periphery. When the latter attachment is cut through, a sepa- 
 ration of the remainder is easily effected. Behind, the pericar- 
 dium is opposed to the bronchias and the resophagus. 
 
 The pericardium does not adhere to the heart, except at the 
 base of the latter; it is, therefore, a loose capsule in, by far, the 
 greater part of its extent. It not only surrounds the heart, but 
 also the roots of the large arteries and veins connected with it. 
 Thus, it includes the aorta, as high up as the great vessels pro- 
 ceeding from its arch; from the latter, it passes to the trunk of 
 the pulmonary artery, and also includes it, causing the aorta and 
 the pulmonary artery to lie close together. The posterior face 
 -of these vessels is not covered so high up as the anterior face. 
 The pericardium also invests the descending vena cava for an 
 inch above its junction with the right auricle: it likewise in- 
 vests the trunks of the pulmonary veins, and the ascending cava 
 as it rises above the diaphragm. The pouches which it forms 
 at the base of the heart, in passing from one of these vessels to 
 another, are the cornua of some anatomists. It cannot be con- 
 sidered as pierced for the passage of these vessels, but is lost in- 
 sensibly on their parietes; being continued into the cellular co- 
 
THE HEART. 185 
 
 vering of the arteries, in accompanying them to a great dis- 
 tance.* 
 
 The pericardium is a double membrane, or consists of two 
 layers, an internal and an external one. The external mem- 
 brane, to which the preceding description is especially applica 
 ble, resembles strongly the dura matter, but is thinner; it is, 
 therefore, white, semi-transparent, fibrous, and inelastic. Its 
 thickness is greater on the sides than below, where it rests upon 
 the diaphragm, or above, where it goes along the great vessels: 
 its fibres are irregularly disposed and interwoven, but many 
 may be traced longitudinally. 
 
 The internal membrane lines the external, and gives the po- 
 lish to its cardiac surface; it is then conducted along the sur- 
 face of the several vessels that have been mentioned, to the 
 heart, over the whole of which it is spread, and adheres to it 
 by cellular substance, frequently containing much adipose mat- 
 ter: it also causes the heart to have a smooth shining surface. 
 This is a very delicate thin serous membrane; and secretes a 
 fluid, transparent and somewhat unctuous, like that of the joints, 
 but not so consistent; which lubricates the surface of the heart 
 and permits it to play freely within its pericardium. This fluid, 
 in a natural state, seldom exceeds a tea-spoonful, though two 
 ounces, or a little more, are not considered sufficient evidence 
 of a pathological state: its augmentation constitutes a dropsy. 
 
 After death, we find the pericardium lying loosely upon the 
 heart, from the vacuity, and consequently diminished bulk of 
 the latter; but while the circulation is going on, the heart fills 
 and distends it. A striking resemblance is observable between 
 the condition of the pericardium and the moveable articulations. 
 Its external membrane corresponds with the strong fibrous cap- 
 sule that passes from one bone to the other; while the internal 
 is the synovial bag, which scarcely assists in the strength of the 
 apparatus, but secrete's a fluid to render motion easy. Several 
 instances are on record of a total absence of pericardium. 
 
 The Right Auricle (Auricula Dextra, anterior] is an oblong 
 cuboidal cavity. It is joined at its posterior superior angle by 
 
 * Sabatier, Trait. d'Anat. vol. ii. p. 284. 
 
186 CIRCULATORY SYSTEM. 
 
 the descending vena cava, and at. its posterior inferior angle by 
 the ascending vena cava. The structure of the auricle, between 
 these two points, seems to be only a continuation of that of the 
 veins. These veins enter with a direction slightly forwards, so 
 that their columns of blood are noi directly opposed to each 
 other. In front of this continuation of U}e -two veins, the auri- 
 cle is dilated into a pouch called its sinus; the upper extremity of 
 the latter, just in front of the descending cava, is elongated into 
 a process with indented edges, that hangs loose, and has some 
 general resemblance to the ear of an animal, from which it is 
 probable that the term Auricle has been derived. 
 
 The exterior surface of this cavity is smooth and uniform, but 
 its internal surface is varied at several places. About midway 
 between the orifices of the two cavae is found a transverse pro- 
 minence, the Tuberculum Lovveri, which is occasioned by the 
 continuous structure of the veins meeting at an obtuse angle. 
 This cavity is separated from the left auricle only by a thin sep- 
 tum, which is common to the two auricles. On the septum, 
 below its middle, is a superficial circular depression, the Fossa 
 Ovalis; it is more distinct above than below, and varies much 
 in its dimensions. It is surrounded by an elevated margin, com- 
 posed of muscular fibres, and called its Annulus, or the Isthmus 
 of Vieussens. The septum of the auricles is thinner at the fos- 
 sa ovalis than elsewhere, and is frequently perforated by one or 
 more foramina. I have, in several instances, seen a hole there, 
 large enough to transmit the finger. On similar, occasions, from 
 the valvular arrangement of the opening, it is probable that the 
 blood of the two auricles is still kept distinct. The fossa ovalis 
 always presents this foramen in the foetal state. 
 
 Just below the fossa ovalis is found the Eustachian valve, 
 consisting in a duplication of the lining membrane of the auri- 
 cle. It is crescentic, but varies much in its dimensions and 
 shape. Its left extremity commences at the left inferior mar- 
 gin of the annulus ovalis; it then extends itself along the front 
 of the orifice of the ascending cava, where the latter is con- 
 nected with the auricle, but never to an extent sufficient to ar- 
 rest the circulation there. Sometimes it is reticulated at its 
 margin, and half an inch wide; on other occasions, it is scarcely 
 
THE HEART. 187 
 
 developed. Its loose edge looks upwards, and to the right side. 
 Its office in the foetus is clearly, according to the opinion of Sa- 
 batier, to direct the blood of the ascending cava through the fo- 
 ramen ovale. In the adult, it may, on the general principle of 
 venous valves, oppose itself to the introduction of refluent blood 
 into the ascending cava; but this office cannot be very impor- 
 tant, as the valve is frequently scarcely visible at that age. 
 
 At the lower part of the right auricle, just to the left of the 
 Eustachian valve and very near it, is the orifice of the large co- 
 ronary vein of the heart: it is protected by a small semi-lunar 
 valve, (Valvula Thebesii,) formed also by a duplication of the 
 lining membrane of the auricle. This orifice will admit a quill 
 of common size very readily. 
 
 Between the right auricle and ventricle is a round hole, of 
 more than an inch in diameter, for the passage of the blood; it 
 is the Ostium Venosum. Its margin, on the auricular side, is 
 smooth and rounded. 
 
 The parietes of the right auricle are formed by muscular 
 fibres. On the sinus these fibres are collected into small trans- 
 verse fasciculi, called Musculi Pectinati, from their resembling 
 the teeth of a comb. These fasciculi, though slightly united 
 by other fibres, yet leave between them deep interstices, by 
 which the external and the internal membrane of the heart come 
 into contact. The parietes of the auricle are about one line in 
 thickness. Its muscular structure is continued for a short dis- 
 tance, on the two venae cavse. There are several orifices of 
 small veins on the internal surface of this cavity, and in greater 
 abundance around the fossa ovalis; they belong to the system 
 of coronary vessels, and are the foramina Thebesii. 
 
 The right Ventricle ( Ventriculus Dexter, anterior.) The 
 general form of this cavity, which receives the blood from the 
 right auricle, is that of a triangular pyramid, curved somewhat 
 backwards, and having its base downwards. It forms the great- 
 er part of the anterior surface of the heart, and is about three 
 lines in thickness. It is bounded on its posterior face by the 
 left ventricle, from which it is completely separated by a thick 
 septum. 
 
 The internal surface of this cavity is covered by muscular fasci- 
 
188 CIRCULATORY SYSTEM. 
 
 culi, of very irregular shapes and dimensions, designated under 
 the term of Columnse Carnese: some of the latter go from one side 
 to the other; others contribute to the mechanism of the valvu- 
 lar apparatus between it and the right auricle; but the greater 
 portion is employed in forming a complicated reticular texture 
 over the internal face of the ventricle. Those connected with 
 the valve vary from four to eight in number: they are rounded, 
 of different lengths and sizes, and detach from their projecting 
 extremities several small rounded tendinous chords, (chordae 
 lendinese,") which are inserted into the floating edge of the valve. 
 These chords sometimes form an intertexture among them- 
 selves. 
 
 The Valve, between the ventricle and the auricle, consists in 
 a duplicature of the lining membrane of the ventricle, arising 
 uninterruptedly from around the ostium venosum, at the left 
 margin, which is there somewhat tendinous. This Valve is 
 called the Tricuspid, (Valvula Tricuspis, Triglochis,) because 
 its loose margin is divided into three points or processes. One 
 of these points, which is at the anterior external margin of the 
 orifice, is much larger than the other two and more distinct in 
 its boundaries. The edges of these processes form a sort of re- 
 ticulated work along with the adjoining ends of the tendinous 
 chords: by this arrangement they are always kept expanded 
 and in the cavity of the ventricle. 
 
 The opening for the pulmonary artery is placed above the 
 ostium venosum; at this point, the cavity of the ventricle, in- 
 stead of being reticulated, is made smooth, for the more ready 
 transmission of blood. The orifice of the pulmonary artery is 
 round, and about twelve lines in diameter; it is furnished with 
 three valves, called from their shape Semi-lunar or Sigmoid. 
 Each valve is a semicircular plane, formed from the lining 
 membrane of the artery, and attached to the latter by its semi- 
 circumference. The diameter of the plane is loose, and, instead 
 of being straight, has each semi-diameter of a curved or fes- 
 tooned shape: in the centre of its edge is a small cartilaginous 
 body, the Corpusculum Aurantii, which, when the valve is 
 thrown down by the reaction of the artery, comes in contact 
 \vith the corresponding bodies of the other valves, so that they 
 serve as mutual abutments. Between the outer face of each 
 
THE HEART. 189 
 
 valve and the artery there is a pouch, attended with a slight 
 dilatation of the artery, and called the Sinus Valsalva. Between 
 the coats of each valve there is an additional fibrous substance, 
 for the purpose of strengthening it. 
 
 The Pulmonary Artery, immediately after its origin, goes 
 upwards and backwards to the under part of the curvature of 
 the aorta, and there divides into two trunks, one for each lung. 
 These trunks separate widely, and from the middle of their fork 
 proceeds a ligamentous substance, the remains of the Ductus 
 Arteriosus of the foetus, to the aorta posteriorly to the origin 
 of the left subclavian artery. The right Pulmonary artery is 
 both longer and larger than the left, and passing transversely 
 behind the aorta and the descending cava, then penetrates the 
 substance of the lung to be distributed as mentioned. The left 
 pulmonary artery passes to the lung in fn>nt of the descending 
 aorta. Though the pulmonary artery is quite as large as the 
 aorta, its parietes are thinner. 
 
 The left Auricle, (Auricula Sinistra, posterior,) in the na- 
 tural situation of the heart, is concealed by the right auricle 
 and the ventricles. Its figure is more regularly quadrangular, 
 or square, than that of the right, and into each of its angles is 
 introduced a pulmonary vein, their being two on each side. 
 Sometimes, however, the latter join together previously, so that 
 the two have but a common orifice. Its tip, or ear-like portion, 
 is situated at the left side of the pulmonary artery, and is longer, 
 narrower, more crooked, and more notched at its margins than 
 the corresponding portion of the right auricle. 
 
 The parietes of this cavity are muscular, and somewhat 
 thicker than those of the right; they are smooth and uniform, 
 both externally and internally, with the exception of its ap- 
 pendix or ear-like portion, in which the muscu-li pectinati pre- 
 vail. The term sinus venosus or sinus pulmonalis- of anato- 
 mists, only means that part of the cavity into which the pul- 
 monary veins empty. The septum between the auricles, when 
 viewed on this side, has the place of the fossa ovalis marked 
 out principally by its diaphanous condition. Occasionally, 
 there is some appearance of the valve which once existed 
 there. 
 
 VOL. IL 25 
 
190 CIRCULATORY SYSTEM. 
 
 At the inferior part of the anterior side of this cavity is found 
 the opening between it and the left ventricle, also called Ostium 
 Venosum; it is circular, and rather more than an inch in dia- 
 meter, resembling strongly the corresponding orifice of the right 
 side of thfe heart. 
 
 The Left Ventricle (Ventriculus Sinister, posterior) in the 
 shape of its cavity resembles a long ovoidal or conical body. 
 Its parietes are generally three times as thick as those of the 
 right ventricle, amounting to about eight lines: it is thicker, 
 however, at its inferior than at its superior part, as it gradually 
 decreases in approaching the aorta. 
 
 Its internal surface is arranged on the same principle with 
 that of the right ventricle, being roughened by the presence of 
 numerous fleshy columns (Columnas Carneae) some of which 
 are connected with the valvular apparatus between it and the 
 left auricle; others form an intricate reticular texture on its 
 sides, and a few pass from one side to the other. As this sur- 
 face approaches the orifice of the aorta, it becomes smooth, 
 so that no impediment may be afforded to the passage of the 
 blood. 
 
 The Ostium Venosum, on the side of this cavity, has its mar- 
 gin looking tendinous, and furnished with a duplicature of the 
 lining membrane that surrounds it. This duplication, by being 
 severed on its loose edge into two divisions, obtains the name 
 of Mitral Valve, (Valvula Mitralis.) Its margin is secured 
 from being pushed into the left auricle by several chordae ten- 
 dineae, which are attached by their other extremities to four or 
 five columnar carneae projecting from the surface of the ven- 
 tricle. The whole internal arrangement of this cavity indicates 
 a great increase of strength over that of the right side: in the 
 robustness of its fleshy columns, the number and size of its ten- 
 dinous chords, and the greater thickness of its valve. The 
 upper division of the mitral valve is placed immediately below 
 the orifice of the aorta, and is considerably broader than the 
 other, so that when it opens to admit bloed, it is in some mea- 
 sure thrown over the aortic orifice. There is less of an in- 
 tertexture among the tendinous chords here than on the right 
 
THE HEART. 
 
 191 
 
 side of the heart: they cluster more, and, owing to the 
 breadth of the extremities of the fleshy columns, are more pa- 
 rallel. 
 
 The Septum of the Ventricles is of considerable thickness, 
 being formed almost exclusively by the continuation of the 
 fibres of the left ventricle. Where the large columnar carnese 
 elevate themselves on its surface, its thickness is increased. Its 
 shape is somewhat triangular. It forms a round projection into 
 the right ventricle, while its other surface, which presents to 
 the left, is concave to the same degree. It is rather thinner as 
 is approaches the auricular septum than elsewhere. Its fibres 
 near the apex are less closely connected to each other. 
 
 The Orifice of the Aorta is furnished with three semi-lunar 
 Valves, which, in the mode of their arrangement, correspond 
 precisely with those of the pulmonary artery. They are, how- 
 ever, thicker, and the Corpuscula Aurantii are larger. The 
 Sinuses of Valsalva, attended with a slight dilatation of the ar- 
 tery, exist in the same way. Just beyond the margins of the 
 right and of the left valves are observed the orifices of the two 
 ' coronary arteries. The orifice of the aorta is somewhat tendi- 
 nous, which marks out the distinction of structure between it 
 and the ventricle.* 
 
 Of the Texture of the Heart. 
 The Heart, with the exception of the membrane which lines 
 
 * Mr. Erskine Hazard has furnished me with the following- estimate on the 
 action of these valves: 
 
 If the diameter of the artery be put = 10, the 
 length of the superior edge of the valve will also 
 be 10. The arc, occupied by the valve will be 
 10.47 = 120 of the circle. The valves, when 
 open, will either assume the form at B, or that of 
 the double chord of 60, as at A. In either case, 
 being .47 shorter than the arc, they cannot come 
 in contact with it, and must, therefore, leave room 
 for the blood to get behind them, and depress 
 the valves. For the same reason, they cannot 
 close the orifice of the coronary arteries. The 
 chord of 120 would be 8.67. 
 
192 CIRCULATORY SYSTEM. 
 
 its cavities, and of the serous lamina of pericardium which co- 
 vers its surface, consists entirely of muscular fibres. 
 
 The sides of the auricles, as stated, are much thinner than 
 those of the ventricles. In the right auricle, the stratum of 
 muscular fibres is uniform in its venous portion, but on the 
 sinus is arranged into the parallel fasciculi called the Musculi 
 Pectinati; a circular fasciculus surrounds the orifice of the de- 
 scending cava. In the left auricle, the stratunvpf muscular fibres 
 forms a uniform layer, and is also thicker than on the right 
 side. These fasciculi commence on the pulmonary veins and 
 run transversely across the auricle, with the exception of the 
 more deeply seated, which are irregular, and crossed upon each 
 other. The septum of the auricles is also formed by a muscular 
 stratum. 
 
 In the ventricles, the superficial fasciculi observe a spiral 
 course, and many of those belonging to the left ventricle may 
 be traced over the right; as the fibres are more deeply situated, 
 they become shorter and more interwoven. In the septum, 
 between the ventricles, the fibres of the two cavities are much 
 interlocked; but, with some trouble, may be partially separated. 
 The fibres of the columnse carneaB are too irregular in their 
 course to admit even of a general description. It would appear, 
 however, that they are a continuation of the superficial spiral 
 fibres of the ventricles which penetrate into the interior of the 
 heart at it's apex, and leave there a small foramen which is 
 closed only by the pericardium, externally, and the lining 
 membrane of the heart. M. Gerdy asserts, that all the fibres 
 of the heart arise from, and are inserted into, the tendinous 
 rings forming the ostia venosa and the orifices of the arteries; 
 having in the mean time traversed the course which is peculiar 
 to the several fasciculi, according to their being superficial, in 
 the middle or deep-seated.* 
 
 All the cavities of the heart are lined by a serous membrane, 
 resembling that of the blood vessels. 
 
 * For a veiy detailed exposition of the Structure of the Heart, see Wolff Act. 
 Acad. Petrop. 1781:; and Gerdy, Journal Complementaire du Diet, des Sc. Med. 
 vol. x. p. 97. 
 
THE HEART. 193 
 
 Of the Blood Vessels of the Heart. 
 
 The Heart is furnished with both arteries and veins, which be- 
 long to its nutritious system. 
 
 The arteries, called Coronary, arise, as observed, from the 
 trunk of the aorta, somewhat above the margins of the semi-lu- 
 nar valves ; so that when the latter are applied against the aorta, 
 the orifices of these arteries are still visible. 
 
 The Right Coronary Artery begins above the anterior valve, 
 and passes to the right, beneath the pulmonary artery ; it then 
 shows itself in the upper part of the fissure, between the right au- 
 ricle and right ventricle, and follows the course of this fissure to 
 the flat side of the heart. It detaches, as it goes along, several 
 small branches, which come off at right angles from it. One set 
 of these branches is distributed upon the right ventricle, and ano- 
 ther set upon the right auricle. Small branches are also sent 
 from it to the root of the pulmonary artery, and to. that of the 
 aorta. 
 
 The Left Coronary Artery begins above the left semi-lunar 
 valve. While its root is still obscured by the pulmonary artery, 
 it divides into two principal branches, of which the anterior runs 
 in the fissure on the upper part of the septum of the ventricles to 
 the apex of the heart, and in this course distributes branches to 
 the right and left ventricles : those to the right anastomose with 
 the branches of the right coronary artery, which go to the same 
 ventricle. The other branch goes along the groove, on tHe sep- 
 tum, between the left auricle and left ventricle, and reaches the 
 under surface of the heart ; and in this course distributes many 
 branches to the left auricle and left ventricle, both on their upper 
 and under surfaces. It anastomoses freely with the branches of 
 the trunk that run along the upper part of the septum. 
 
 In consequence of the frequency of the anastomoses between 
 the two coronary arteries, injecting matter thrown into one very 
 readily finds its way into the other. 
 
194 CIRCULATORY SYSTEM. 
 
 The Coronary Veins receive the blood, which is distributed by 
 the coronary arteries through the substance of the heart. 
 
 The Great Coronary Vein ( Vena Coronaria Maxima Cardis) is 
 formed by the union of several trunks, which run from the apex 
 towards the base of the heart. One of them begins at the apex, 
 goes along the superior fissure of the septum of the ventricles, 
 and then winds to the left side, between the left auricle, and the 
 left ventricle : while in the latter position, it is joined by several 
 trunks corning from the left ventricle and the left auricle : it, 
 finally, empties into the lower part of the right auricle, just in 
 front, as mentioned, of the orifice of the ascending cava ; being 
 there covered by its own valve. 
 
 The Lesser Coronary Vein ( Vena Coron. Minor Cardis) lies in 
 the inferior fissure of the septum of the ventricles. It begins at 
 the apex, and, going backwards, collects the blood from the flat 
 surface of the heart, principally on the right ventricle. It dis- 
 charges into the great coronary vein, just before the latter ter- 
 minates in the auricle. 
 
 Besides the preceding veins, some of a smaller size exist on 
 the right ventricle, and about the root of the aorta and pul- 
 monary artery, and empty by several orifices into the right au- 
 ricle. There are also some veins of a still smaller size, which 
 open into all the cavities of the heart by little orifices, called the 
 Foramina of Thebesius : by Mr. Abernethy they are considered 
 as being larger when the lungs are diseased.* 
 
 The Nerves of the Heart come principally from the cervical 
 ganglions of the sympathetic, and follow the course of the coro- 
 nary arteries. It has been doubted whether these nerves are 
 actually distributed in the substance of the heart, from the pre- 
 sumption, that as they cannot be traced beyond the third order 
 of branches of the coronary arteries, they are limited to them. 
 But, as the ramifications of the sympathetic are bestowed exclu- 
 sively upon the branches of the circulatory system, Meckel has 
 
 * London Philosophical Transactions, 1798. 
 
BRANCHES FROM THE ARCH OF THE AORTA. 195 
 
 very properly suggested, that the heart being also supplied with 
 nerves from the same source, it follows that there can be no de- 
 parture from the general rule, as the heart is nothing more than 
 the fibrous portion of the blood vessels more completely deve- 
 loped. 
 
 While the circulation continues, as both auricles contract at 
 the same instant, whereby the blood is thrown into the ventri- 
 cles, and as immediately afterwards the ventricles contract si- 
 multaneously also, whereby the blood is forced into the aorta and 
 the pulmonary artery, so it is the contraction of the ventricles 
 which causes the heart to strike against the parietes of the tho- 
 rax. For, as was first pointed out by Dr. W. Hunter, the blood 
 which is forced through the large arteries, by extending them 
 diminishes their curvature, or brings them more into a straight 
 line, in which effort the heart bounds up from the tendinous cen- 
 tre of the diaphragm. The filling of the auricles, while this is 
 going on, also assists in protruding the heart forwards. The 
 French anatomists assert, that during the contraction of the ven- 
 tricles, their extremity is elevated or bent upwards on the body 
 of the heart, which will also increase the momentum of the stroke 
 against the thorax. 
 
 CHAPTER II. 
 
 OF THE ARTERIES. 
 SECT, I. THE AORTA AND THE BRANCHES FROM ITS CURVATURE. 
 
 THE Aorto is the trunk of the arterial system. Having arisen 
 from the superior posterior end of the left ventricle, its root 
 passes beneath the pulmonary artery, and is entirely concealed 
 in front by it. Keeping to the right, it emerges from the base of 
 the heart, between the right auricle and the trunk of the pulmo- 
 nary artery, being bounded on the right side by the descending 
 
196 CIRCULATORY SYSTEM. 
 
 cava. Continuing its ascent, it forms a curvature with the con- 
 vexity upwards, and the summit of which rises to within eight 
 or twelve lines of the superior edge of the sternum. This cur- 
 vature is in front of the third and fourth dorsal vertebras, and its 
 direction is nearly marked out by a line drawn from the anterior 
 extremity of the third right rib, to the posterior end or tubercle 
 of the third one on the left side. In this course, therefore, the 
 aorta passes over the right pulmonary artery, across the left 
 bronchia, and applies itself to the left side of the spine, about the 
 third or fourth dorsal vertebra. It is this curvature which ob- 
 tains the name of the Arch of the Aorta, (Arcus Aortce.) 
 
 Near its origin, where the aorta is still within the pericardium, 
 it has very commonly, especially in persons advanced in age, a 
 dilatation, which is called the great sinus to distinguish it from 
 the lesser sinuses, or those of Valsalva. This dilatation is use- 
 ful in diminishing the resistance arising from the curvature of 
 the aorta, to the current of blood, or rather it is a provision for 
 doing away with the effects of this friction, whereby a larger 
 current of blood becomes a compensation for diminished velo- 
 city. The ascending portion of the arch is to the right of the 
 vertebral column, the descending portion to the left, and the mid- 
 dle or horizontal part goes in front of the trachea. 
 
 The aorta, in its descent down the thorax, is placed in the 
 posterior mediastinum, and is covered on one side by the left 
 pleura, while the other side is in contact with the left surface of 
 the bodies of the dorsal vertebras. At the lower part of the tho- 
 rax it inclines towards the middle line of the vertebrae, in order 
 to reach the hiatus aorticus of the diaphragm, through which it 
 penetrates to the abdomen. In the abdomen it descends in front 
 of the lumbar vertebrae, somewhat inclined to their left side ; and 
 at the intervertebral space between the fourth and fifth vertebras 
 of the loins, or somewhat above it, it ceases, by being divided 
 into two large trunks, the Primitive Iliacs ; one for each lower 
 extremity, and the corresponding side of the pelvis. 
 
 In this course of the aorta, from the heart to the loins, it first 
 gives off the branches which supply the head and the superior 
 extremities : then, those which supply the sides of the thorax ; af- 
 terwards, in the abdomen, it detaches the trunks which supply 
 the viscera and the sides of the latter cavity. 
 
BRANCHES FROM THE ARCH OF THE AORTA. 197 
 
 The Coronary Arteries are, strictly speaking, the first branches 
 of the aorta, but as they belong especially to the heart, their de- 
 scription is associated with it. In all the space between them 
 and the superior convexity of the aortic arch no branches are 
 given off; but as the aorta is crossing the trachea three conside- 
 rable trunks arise from it, which are distributed upon the head 
 and the upper extremities principally. They are, the Arteria 
 Innominata, the Left Primitive Carotid, and the Left Subcla- 
 vian. 
 
 The Arleria Innominata is first in its origin : in ascending from 
 left to right in front of the trachea, and behind the transverse 
 vein, it crosses the trachea very obliquely ; is from an inch to 
 an inch and a half, and sometimes, though rarely, two inches 
 long, when it divides into the right subclavian and the right pri- 
 mitive carotid. The left primitive carotid arises from the aorta, 
 close upon the left border of the innominata ; frequently, indeed, 
 from a part of it. The left subclavian, though at its origin, near 
 the left carotid, generally leaves a distinct interval of one, two, 
 or three lines. The relative situation of these trunks is particu- 
 larly alluded to in the account of the superior mediastinum. The 
 two last are, of course, longer than the corresponding trunks of 
 the right side, by the whole length of the arteria innominata. 
 With the exceptions connected with their mode of origin, the ar- 
 terial trunks of the two sides are exactly alike, and have the 
 same mode of distribution. 
 
 The Common Carotid Artery (Carotis Primitiva) being a branch 
 of the innominata on the right side, and of the aorta on the left, 
 goes up the neck to terminate just below the cornu of the os hy- 
 oides. In the early part of its course, the right one is more in- 
 clined outwardly than the left, owing to its origin from the arte- 
 ria innominata in front of, and to the right side of the trachea; 
 whereas, the left ascends almost vertically. 
 
 At the lower part of the neck, just above the sternum and the 
 
 clavicle, the carotid is covered by the sterno-hyoid and thyroid 
 
 muscles, and by the sternal portion of the sterno-cleido-mastoid. 
 
 It is crossed obliquely on a line with the lower part of the thy- 
 
 VOL. II. 26' 
 
198 CIRCULATORY SYSTEM. 
 
 roid cartilage or of the larynx, by the omo-hyoid muscle. It lies 
 at the side of the thyroid gland, the trachea, the larynx, the oeso- 
 phagus, and pharynx, in front of the transverse processes of the 
 cervical vertebrae, and the longus colli muscle ; having on its 
 outer margin, but somewhat in front the internal jugular vein, 
 and the pneumogastric nerve enclosed in the same sheath, and 
 the sympathetic nerve behind. At the side of the larynx, the 
 carotid is very superficial, and, with the exception of being 
 crossed by the omo-hyoideus muscle, it is only covered by the 
 platysma myodes and the integuments. 
 
 The Carotid having got as high as the space between the os 
 hyoides and the thyroid cartilage, but varying slightly in differ- 
 ent subjects, there divides into two large trunks, the Internal 
 Carotid, which goes to the brain and to the eye, and the Exter- 
 nal Carotid, which is principally distributed upon the more su- 
 perficial parts of the head and neck. The first of these trunks 
 is placed behind the other, and bends outwardly at its root : it is 
 generally the largest in infancy, on account of the proportionate 1 
 volume of the brain atthat age ; it is also swollen at its root, so 
 as to form a sinus there, resembling an incipient aneurism. No 
 branch, except in the abnormous cases, is given off from the ca- 
 rotid between its origin and bifurcation. 
 
 SECT. II. OF THE CAROTIDS, AND THEIR BRANCHES. 
 
 The Internal Carotid, (Arteria Carotis Internet,} in the adult, is 
 smaller than the external, and extends from the larynx to the 
 sella turcica. It ascends between the external carotid and the 
 vertebrae of the neck, being in front of the internal jugular vein, 
 and having the pneumogastric nerve at its outer margin : as it 
 gets on a level with the base of the lower jaw, it is crossed ex- 
 ternally by the digastric and the stylo-hyoid muscles : it is im- 
 mediately afterwards concealed in the subsequent part of its 
 ascent by the ramus of the lower jaw. Having gone along the 
 most internal or deeply seated margin of the parotid gland and 
 the styloid process of the temporal bone, at the side of the supe- 
 
CAROTIDS, AND THEIR BRANCHES. 199 
 
 rior constrictor of the pharynx, it then penetrates into the crani- 
 um through the carotid canal of the temporal bone. 
 
 It is slightly flexed between its origin and the carotid canal : 
 just before it reaches the latter it curves upwards and forwards. 
 The first part of its course through the canal is vertical, after- 
 wards it goes horizontally forwards ; and to escape from the ca- 
 nal it has once more to ascend almost vertically, which brings 
 it to the posterior extremity of the Sella Turcica. On the side 
 of the Sella Turcica it again passes horizontally forwards through 
 the cavernous sinus ; and at the anterior clinoid process it once 
 more ascends, and having penetrated the dura mater, it reaches 
 the brain. 
 
 In this passage, through the carotid canal, it is attended by 
 the upper extremity of the sympathetic nerve, and gives one or 
 more small branches to the petrous bone ; it also gives a few 
 branches to the dura mater and to the nerves about the caver- 
 nous sinus. But for the full exposition of the distribution of the 
 internal carotid, see the articles Brain and Eye. 
 
 The External Carotid Artery (Carotis Externa] extends from 
 the termination of the primitive carotid, to the neck of the lower 
 jaw. In the early part of its course, where it is situated in front 
 of the internal carotid, and between the pharynx and the sterno- 
 mastoid muscle, it is comparatively superficial, being only enve- 
 loped by its sheath, and covered by the platysma myodes and 
 the skin. Just above this place it is crossed externally by the hy- 
 poglossal nerve, which detaches the descending branch along 
 the front of its sheath and of that of the primitive carotid. Some- 
 what above this nerve, it is also crossed externally by the digas- 
 tric and the stylo-hyoid muscle, and lies there on the side of the 
 superior constrictor muscle of the pharynx, near the tonsil gland. 
 About its middle, it is crossed internally by the stylo-glossus and 
 the stylo-pharyngeus muscle ; it then ascends through the sub- 
 stance of the parotid gland, between the ramus of the lower jaw 
 and the ear, to its termination. 
 
 Several very important branches are given off from the ex- 
 ternal carotid ; they are as follow : 
 
 The Superior Thyroid Artery (Art. fhyroidea Superior) arises 
 
200 CIRCULATORY SYSTEM. 
 
 from the external carotid, about a line above its root, and is dis- 
 tributed to the larynx and to the thyroid gland. It goes at first 
 inwards and forwards on the side of the larynx, being covered 
 by the omo-hyoideus muscle, and by the platysma myodes; it 
 then descends under the sterno-thyroideus to the upper margin 
 of the lobe of the thyroid gland. In this course, it performs 
 several flexuosities, of considerable variety in different indivi- 
 duals. 
 
 The Laryngeal Branch comes from it near the superior margin 
 of the thyroid cartilage; this branch glides in between the thyreo- 
 hyoid muscle and the middle membrane or ligament of the same 
 name; after a short course, it penetrates the latter, and is then 
 distributed in a great number of small twigs to the muscles and 
 to the lining membrane of the larynx. A small trunk, either 
 from the laryngeal branch, or from the thyroid artery itself, is 
 spent upon the crico-thyroid muscle, and traversing the front 
 surface of the middle crico-thyroid ligament, anatomoses with 
 its fellow: small twigs from this branch penetrate to the interior 
 of the larynx through the middle crico-thyroid ligament. Some- 
 times this crico-thyroid ramus is superior in size to the one 
 above, in which case, it principally supplies the interior of the 
 larynx. 
 
 The Thyroid Branch is the continuation of the principal trunk : 
 it penetrates into the substance of the thyroid gland, and divides 
 into two ramuscles, one of which goes along the posterior face 
 of the lobe of the gland, and anastomoses with the inferior thy- 
 roid; the other goes along the upper margin of the gland, and 
 anastomoses with its congener of the opposite side. The thy- 
 roidal artery is split up into a great many branches in the sub- 
 stance of the gland, it also sends small branches to the pharynx, 
 oesophagus, and the little muscles on the front of the neck. 
 
 The Lingual Artery (Art. Lingualis] comes from the external 
 carotid at the distance of from six to twelve lines above the su- 
 perior thyroid, and goes to the tgngue. It is concealed in the 
 early part of its course by the. digastric and the stylo-hyoid mus- 
 cles; it then penetrates the hyo-glossus muscle just above the 
 cornu of the os hyoides, or goes between it and the middle con- 
 strictor of the pharynx ; jt then ascends between the hyo-glossus 
 
CAROTIDS, AND THEIR BRANCHES. 201 
 
 and the genio-hyo-glossus muscle; advancing forwards, it is 
 placed between the latter and the sublingual gland, and, finally, 
 reaches the tip of the tongue. 
 
 The lingual artery sends off the following branches. At the 
 root of the tongue one or more trunks arise from it (Dorsales 
 Lingua) which go to the base of this organ, the tonsils, the palate, 
 and the epiglottis. A little farther on, this artery detaches an- 
 other branch, (Ramus Sublingualis,} which, advancing between 
 the mylo-hyoid and the genio-hyo-glossus muscles, and above 
 the sublingual gland, detaches a great many ramifications to 
 these parts and to the lining membrane of the mouth; it is some- 
 times a branch of the facial. The Ramus Raninus, is the con- 
 tinuation of the lingual ; it advances between the lingualis and 
 the genio-hyo-glossus muscle, to the tip of the tongue, distributing 
 continually its twigs on each margin, and ends there by anasto- 
 mosing with the corresponding artery of the other side. 
 
 The Facial Artery (Arteria Facialis, Maxillaris Externa) arises 
 from the external carotid two or three lines above the lingual, 
 and is spent principally on the side of the face below the eye. 
 It is of considerable size, and very tortuous ; its root is concealed 
 by the stylo-hyoid and the digastric muscles, and it is traversed 
 externally by the hypo-glossal nerve. It goes forward within 
 the angle of the lower jaw, and above the submaxillary gland, 
 but very much connected with it: it then mounts over the base 
 of the maxilla inferior, at the anterior margin of the masseter 
 muscle, and afterwards shapes its course, in a serpentine manner, 
 to the internal canthus of the eye, passing between the muscles 
 and the integuments of the face. In this course, the fascial 
 artery sends off the following branches. 
 
 As it passes by the submaxillary gland it sends several twigs 
 to it: previously it also sends several little branches to the con- 
 tiguous muscles, as the internal pterygoid, digastric, and so on ; 
 but they are too small to be of much consequence. 
 
 The Submental branch arises, then, on a level with the base 
 of the lower jaw ; it advances forwards under the origin of the 
 mylo-hyoides, and above the anterior belly of the digastricus. 
 It sends several ramuscles to these muscles, some of which 
 anastomose with the ranine artery ; behind the symphysis of the 
 
202 CIRCULATORY SYSTEM. 
 
 jaw it anastomoses with its fellow, it then mounts over the chin, 
 to which and to the lower lip it is distributed, anastomosing 
 there with the inferior coronary artery of the mouth, and with 
 the inferior maxillary which comes out from the anterior men- 
 tal foramen in the lower jaw. 
 
 When the fascial artery has got upon the face, it sends back- 
 wards a small branch to the lower part of the masseter muscle. 
 Somewhat above this it sends forwards a branch called the In- 
 ferior Labial, which is distributed upon the middle of the chin. 
 When it gets on a level with the corner of the mouth, but some- 
 times lower down, it sends forward, under the depressor anguli 
 oris, the Inferior Coronary Artery, to the lower lip, which fre- 
 quently supplies the place of the inferior labial entirely; but when 
 the latter is large, the coronary is small in proportion : a Tew 
 lines higher up the fascial sends forward a third branch, the 
 Superior Coronary, which goes to the upper lip. These coro- 
 nary arteries are very tortuous, and are distributed by many 
 branches in the substance of the lips : by anastomosing with 
 their congeners of the other side, they surround the mouth com- 
 pletely. The superior coronary artery, as it passes under the 
 nose, sends upwards one or more small branches to the integu- 
 ments of its orifice and septum.' 
 
 After this, the facial artery, in ascending towards the internal 
 canthus of the eye, sends a branch to the ala nasi, and another 
 to anastomose with the infra-orbitar artery. It, finally, termi- 
 nates at the internal canthus of the eye by anastomosing with 
 the branches of the ophthalmic, which come out there upon the 
 side of the root of the nose. Several ramuscles, which are too 
 small to merit special description, are given by the fascial to 
 the integuments and muscles of the face, and to the lower 
 eyelid. 
 
 The Inferior Pharyngeal Artery (Art. Pharyngea Inferior, as- 
 cendens) is one of the smallest of the original branches of the ex- 
 ternal carotid, and generally arises opposite to the lingual ; but 
 there is much variety in the latter respect, it being sometimes 
 higher up or lower down, and not unfrequently a branch of one 
 of the other arteries, instead of being an original trunk. It 
 ascends on the side of the pharynx, between the external and 
 
CAROTIDS, AND THEIR BRANCHES. 203 
 
 the internal carotid, and is covered by the stylo-pharyngeus 
 muscle. It is principally distributed on the constrictor muscles 
 of the pharynx, and upon their lining membrane. But one of its 
 branches, called the Posterior Meningeal Artery, ascends through 
 the posterior foramen lacerum of the cranium, between the jugu- 
 lar vein and the pneumo-gastric nerve, and is distributed on the 
 contiguous dura mater. 
 
 The Occipital Artery (Arteria Occipitalis) is a very considera- 
 ble trunk, which comes from the external carotid, generally op- 
 posite to the facial, and is spent upon the integuments, on the 
 back part of the head. 
 
 At its root, it is deeply situated in the side of the neck, below 
 the parotid gland, and has the internal jugular vein and the par 
 vagum on its inside. It goes obliquely backwards, in ascending 
 along the posterior belly of the digastricus between the trans- 
 verse process of the atlas and the mastoid portion of the tempo- 
 ral bone, being covered by the several muscles which are in- 
 serted into the latter, as the sterno-mastoid, the splenius, and the 
 trachelo-mastoid. It is covered, for some distance, by the in- 
 sertion of the splenius capitis, and becomes at length superficial 
 at the posterior margin of this muscle. The occipital artery is 
 distributed as follows : 
 
 Shortly after its origin, it sends branches to the digastric 
 muscle behind, to the upper part of the sterno-mastoid and to 
 the lymphatic glands of the upper part of the neck. While en- 
 closed by the muscles on the back of the neck, it also sends 
 branches to them, and anastomoses thereby with the vertebral 
 artery; occasionally, one of these branches is of considerable 
 magnitude, and has been found descending very low on the back, 
 between the splenius and the complexus muscles. ' It also sends 
 a small branch to the dura mater, through the mastoid foramen 
 generally, but sometimes through the posterior fprameri lacerum. 
 When the stylo-mastoid artery is wanting, it also detaches a 
 branch through the stylo-mastoid foramen to the internal parts 
 of the ear. 
 
 The occipital artery, having become superficial at the inter- 
 nal margin of the splenius on the occiput, ascends on the latter 
 bone towards the 'vertex in a tortuous manner, sending off, on 
 
204 CIRCULATORY SYSTEM. 
 
 each side, many small ramifications. It ends by anastomosing 
 with the posterior temporal artery. 
 
 The Posterior Auricular Artery (Art. Auricularis Posterior) 
 arises a little above the last, at the lower edge of the parotid 
 gland, from the external carotid, and is one of its smallest 
 branches. It ascends backwards enclosed by the parotid gland, 
 and afterwards between the meatus auditorius externus and the 
 mastoid bone : at the latter place, it sends a ramification to the 
 internal side of the external ear ; it then ascends and is distri- 
 buted, by small branches, on the contiguous integuments of the 
 side of the head. While still involved in the parotid gland, it 
 sends some small ramifications through the meatus externus to 
 its lining membrane and the membrana tympani. It then de- 
 taches a branch through the stylo-mastoid foramen, from which 
 the whole artery is also named Stylo-Mastoid ; but this branch, 
 as stated, sometimes comes from the occipital. The stylo-mas- 
 toid passes along the aqueduct of Fallopius, detaching its arte- 
 riole to the typanum and to the labyrinth. 
 
 The External Carotid having given off these trunks, pene- 
 trates vertically through the inner margin of the parotid gland, 
 and gives to it several small twigs. When it arrives on a line 
 with the neck of the lower jaw, it divides into two large trunks; 
 one of them, the Internal Maxillary, goes to the parts within the 
 ramus of the lower jaw ; the other, being smaller, is the Tern* 
 poral Artery. 
 
 The Temporal Artery (Arteria Temporalis) continues to as- 
 cend through the substance of the parotid, but becomes super- 
 ficial in front of the meatus externus, in mounting over the root 
 of the zygoma; it is then distributed to the integuments on the 
 side of the head. 
 
 It frequently sends off one or two ramifications, of but little 
 volume, to the masseter muscle. Just above its root, and while 
 surrounded by the parotid, a branch of some importance, the 
 Transverse Facial, (Transfer sails Faciei,) leaves it, and crosses, 
 horizontally, the masseter muscle, just below the parotid duct, 
 sometimes above it. This branch is distributed to the adjacent 
 integuments and muscles, and terminates in front by anasto- 
 mosing with the facial and the infra-orbitar artery. 
 
CAROTIDS, AND THEIR BRANCHES. 205 
 
 A little below the zygoma, the Middle Temporal Artery (Art. 
 Temp. Media) comes off from the Temporal, and, ascending with 
 the parent trunk, perforates the temporal fascia at the upper 
 margin of the zygoma, and is distributed to the temporal muscle 
 by many ramifications, which anastomose with the deep-seated 
 temporal arteries. After this, some small twigs, called Auri- 
 cular, go to the external ear from the trunk of the temporal 
 artery. , 
 
 The temporal artery, having ascended for an inch or so be- 
 tween the aponeurosis of the temporal muscle and the skin, it di- 
 vides into an Anterior and a Posterior Branch. The former as- 
 cends towards the side of the os frontis, and is distributed in 
 ramuscles to the orbicularis palpebrarum, the belly of the occi- 
 pito-frontalis, and the integuments of the front of the cranium, 
 anastomosing with the . frontal artery and the temporal of the 
 other side. The posterior branch is distributed on the integu- 
 ments of the middle of the side of the cranium, anastomosing 
 with the anterior branch, with its fellow of the other side, and 
 with the occipital artery. 
 
 The Internal Maxillary Artery (Jlrteria Maxillaris Inter- 
 no] winds around the neck of the lower jaw, and, passing be- 
 tween the pterygoid muscles, proceeds in a tortuous manner 
 to the deepest points of the zygomatic fossa. The first part of 
 its course is horizontally inwards; it then ascends in front of 
 the pterygoideus externus to the bottom of the temporal bone, 
 or the spinous process of the sphenoidal; it then passes for- 
 wards, within the temporal muscle, to the upper part of the 
 pterygo-maxillary fossa. 
 
 It sends off several branches, and commonly in the following 
 order: 
 
 1. The Arteria Tympanica, to the tympanum, through the 
 glenoid fissure. 
 
 2. The Arteria Meningea Parva, to the dura mater, through 
 the foramen ovale. It is most frequently a branch of the next. 
 
 3. The Arteria Meningea Magna, or Media, to the dura ma- 
 VOL. II. 27 
 
206 CIRCULATORY SYSTEM. 
 
 ter, through the foramen spinale. This branch having entered 
 the cranium, is distributed upon the dura mater in the manner 
 marked off by the furrows upon the internal face of the tempo- 
 ral, the parietal, and the frontal bones. One of its branches en- 
 ters the aqueduct of Fallopius, through the Vidian Foramen, 
 and is distributed upon the internal parts of the organ of hear- 
 ing, anastomosing with the stylo-mastoid artery. 
 
 4. The Arteria Maxillaris, or Dentalis Inferior, descends 
 along the internal face of the ramus of the lower jaw, and 
 having sent off some ramifications of small size to the contigu- 
 ous muscles and the lining membrane of the mouth, it enters 
 the posterior mental foramen with the inferior dental nerve. 
 Going along the canal in the substance of the lower jaw, it de- 
 taches successively from its superior margin ramifications to 
 the teeth. At the anterior mental foramen a trunk is sent for- 
 ward as far as the symphysis, which supplies in its course the 
 canine and incisor teeth; the remainder of the inferior maxilla- 
 ry artery comes out at the foramen, and supplies the chin, anas- 
 tomosing with the facial artery. 
 
 5. The Arteriae Temporales Profundae are two in number. 
 The first of them, called Posterior, arises next to the inferior 
 maxillary. It is concealed between the external pterygoid and 
 the temporal muscle for some distance; it then' ascends in the 
 posterior part of the temporal fossa, beneath the temporal mus- 
 cle, and is minutely distributed upon it. The anterior deep 
 temporal artery is separated from the posterior, in its origin 
 from the internal maxillary, by the pterygoid and the buccal 
 arteries. It arises near the pterygo-maxillary fossa; and, as- 
 cending between the temporal muscle and the fore part of the 
 corresponding fossa, it is minutely distributed u^on the former, 
 anastomosing with the posterior deep, and with the middle tem- 
 poral artery. 
 
 6. The Arteria3 Pterygoideae arise after the posterior deep 
 temporal. They vary considerably in regard to number, size, 
 and origin, and are distributed upon the pterygoid muscles, as 
 their name implies. One of their branches, which is sometimes 
 
CAROTIDS, AND THEIR BRANCHES. 207 
 
 an independent trunk from the internal maxillary, goes between 
 the posterior margin of the temporal muscle and of the neck of 
 the lower jaw, in front of the latter, to be distributed upon the 
 internal face of the masseter muscle. 
 
 7. The Arteria Buccalis, sometimes a branch of the internal 
 maxillary, but frequently coming from one of its trunks, either 
 the alveolar or the anterior temporal, passes along the external 
 face of the upper jaw, and distributes its branches to the bucci- 
 nator and zygomatic muscles, and to the lining membrane of 
 the mouth. 
 
 8. The Arteria Maxillaris Superior, or Alveolaris, proceeds 
 downwards and forwards in winding around the tuber of the 
 upper jaw bone. It first sends some ramifications through the 
 bone to the roots of the great and small molar teeth, and to the 
 lining membrane of the maxillary sinus; it then passes forwards 
 along the gums, near the buccinator, and gives ramifications to 
 them and to the contiguous muscles. 
 
 9. The Arteria Infra-orbitalis comes from the internal maxil- 
 lary, at the upper part of the pterygo-maxillary fossa; it sends 
 some inconsiderable ramifications to the fat and the periosteum 
 of the orbit, through the spheno-maxillary fissure. It then en- 
 ters the infra-orbitary canal, and passes through it with the in- 
 fra-orbitary nerve. On arriving near the anterior orifice of the 
 canal, it detaches downwards a branch which goes to the canine 
 and the incisor teeth, and to the lining membrane of the an- 
 trum. It then gets to the face below the origin of the levator 
 labii superioris muscle, and is distributed upon the muscles in 
 front of the upper maxilla, anastomosing with the facial and 
 with the ophthalmic artery. 
 
 10. The Arteria Palatina Superior descends through the pos- 
 terior palatine canal, and, having reached the mouth, leaves 
 some ramifications with the soft palate: it then advances be- 
 tween the bones and the lining membrane of the roof of the 
 mouth, and disperses itself in several small twigs; one of which 
 passes through the foramen incisivum into the nostril. 
 
208 CIRCULATORY SYSTEM. 
 
 11. The Arferia Pharyngea Superior is sometimes a branch 
 of the last, and is spent upon that portion of the pharynx bor- 
 dering on the pterygoid processes. 
 
 12. The Arteria Spheno-Palatina is the terminating trunk of 
 the internal maxillary; it enters the nose through the spheno- 
 palatine foramen, and divides into two branches, which are 
 minutely distributed over the Schneiderian membrane. One 
 of them descends along the septum narium; the other along the 
 external margin of the posterior naris, and divides into two 
 principal ra muscles, one of which is dispersed along the mid- 
 dle turbinated, and the other along the inferior turbinated bone. 
 
 SECt. III. OF THE SUBCLAVIAN ARTERY, AND ITS 
 
 BRANCHES. 
 
 The Subclavian Artery (Arteria Subclavia] of the right side 
 having arisen from the innominata, and that of the left from the 
 aorta, they each go over the first rib of their respective sides, 
 adhering closely to it, in the bottom of the interval between the 
 scalenus anticus and medius muscles. The right subclavian is 
 much shorter, and more superficial than the left, from its origin 
 to the scaleni muscles. Near the latter they are each covered 
 in front by the sternal end of the clavicle, by the sterno-hyoid 
 and thyroid muscles, and by the subclavian vein of the corre- 
 sponding side; behind they are separated from the vertebral co- 
 lumn by the longus colli muscle; below them is the pleura, the 
 left artery being in contact with it for its whole passage in the 
 thorax; and on their internal side is the primitive carotid. The 
 subclavian of the right side is crossed near the scalenus anticus 
 by the par vagum ; the phrenic nerve also goes in front of it, 
 but on the internal edge of the scalenus. The subclavian of the 
 left side having a course almost vertical from its origin to the 
 interval of the scaleni muscles, is nearly parallel with, and be- 
 hind, the primitive carotid of that side; the phrenic nerve has 
 the same relative position with it as on the right side; but the 
 par vagum goes parallel with, and in front of the subclavian ar- 
 tery, for some distance along the root of the latter. 
 
 At the inner margin of the Scaleni Muscles the Subclavian 
 
SUBCLAVIAN, AND ITS BRANCHES. 209 
 
 gives off a cluster of trunks; to wit, the Vertebral; the Inferior 
 Thyroidal; the Superior Intercostal; the Internal Mammary; 
 and the Cervical Artery. They sometimes arise distinctly, and 
 after the order mentioned; but there is too great a diversity in 
 subjects to establish any rule on these points. 
 
 1. The Vertebral Artery (JLrleria Vertebralis) is the most 
 voluminous of the branches of the Subclavian. Immediately af- 
 ter its origin it ascends on the side of the spine, and enters the 
 canal of the transverse processes of the neck at the sixth ver- 
 tebra. Pursuing this course, it gets into the cavity of the cra- 
 nium through the foramen magnum occipitis, and is distributed 
 to the brain in the manner mentioned in the description of that 
 organ. 
 
 While in the canal of the transverse processes, it sends off 
 several branches to the heads of the contiguous muscles, and to 
 the medulla spinalis of the neck. 
 
 2. The Inferior Thyroid Artery (Jlrteria Thyroidea Infe- 
 rior} arises from the upper face of the subclavian, and goes to the 
 thyroid gland. It ascends at first on the internal margin of the 
 scalenus medius muscle, and then turns suddenly inwards be- 
 tween the vertebra and the great vessels of the neck. 
 
 In this course several unimportant twigs are sent from it to 
 the contiguous parts. Near its root it detaches the Anterior, 
 or the Ascending Cervical Artery, which going up the neck is 
 spent upon^the heads of the muscles arising from the transverse 
 processes, as the scaleni, the longus colll, and so on. The infe- 
 rior thyroidal then gets to the thyroid glan<$^and is very mi- 
 nutely distributed to it, anastomosing with tiie other arteries 
 which supply the same organ. 
 
 \ 
 
 3. The Superior Intercostal Artery, (Jlrteria Intercostalis 
 
 Superior,) arising from the under surface of the subclavianjpp- 
 posite the inferior thyroid, descends across the neck of the first 
 rib, and divides into two branches, which supply the two upper 
 intercostal spaces: each of them also sends backwards near-tfee 
 vertebra a small trunk to the muscles of the back. 
 
210 CIRCULATORY SYSTEM. 
 
 4. The Internal Mammary Artery (Jirteria Mammctria In- 
 terna, Thoracica) descends at first along the internal margin of 
 the scalenus anticus; having then got fairly into the cavity of 
 the thorax, it continues to descend across the posterior face of 
 the costal cartilages, parallel with, and about nine lines from, 
 the outer edge of the sternum, between the triangularis sterni 
 and. the intercostal muscles. 
 
 In this course, besides some distinct twigs to the anterior me- 
 diastinum, it sends a branch (Phrenica Superior) which accom- 
 panying the phrenic nerve between the pleura and the pericar- 
 'dium, reaches finally the diaphragm, and is spent upon it. At 
 each intercostal space which it crosses, the internal mammary 
 sends outwards a branch^ which is spent upon the fore part of 
 the intercostal muscles, and anastomoses with the correspond- 
 ing intercostal artery: other branches also leave it at each space, 
 which getting forwards near the sternum, are distributed upon 
 the pectoralis major, and upon the contiguous muscles. The 
 last of these branches, according to M. H. Cloquet, goes trans- 
 versely over the ensiform cartilage, and, having anastomosed 
 with its fellow, descends between the peritoneum and the linea 
 alba to the suspensory ligament of the liver. 
 
 On a line generally with the anterior extremity of the fifth 
 rib, the internal mammary divides into two principal branches; 
 the most exterior of which, descending along the cartilaginous 
 margin of the thorax, is distributed in small twigs to the origin 
 there of the diaphragm and of the transverse muscle of the ab- 
 domen. The internal branch reaches the posterior face of the 
 rectus abdominis muscle, and is dispersed upon it: some of its 
 branches go as low as the umbilicus, to anastomose there with 
 the epigastric artery. 
 
 5 ; The posterior Cervical Artery (*Arteria Cervicalis Pos- 
 terior, Tr(tnsversa) is of a very unsettled origin, but comes 
 most frequently either from the subclavian itself, or from the 
 inferior thyroid. It is but small in some subjects, owing to 
 its place being supplied by branches from the adjoining arteries. 
 
 It crosses horizontally the root of the neck on the outer face 
 of the scaleni muscles above the subclavian artery. It gets 
 
SUBCL AVIAN, AND ITS BRANCHES. 211 
 
 under the anterior margin of the trapezius, and is there divided 
 into two principal branches; the ascending one is spent upon 
 the trapezius and the levator scapulae; the other descends along 
 the base of the scapula, and is spent in ramifications upon the 
 rhomboidei and the serratus magnus muscles. Several branches 
 of minor size and importance are sent off from the posterior 
 cervical artery to the muscles on the back of the neck -and 
 thorax. 
 
 The Subclavian Artery having sent off the preceding branches, 
 then escapes from the thorax between the scaleni muscles, and 
 gets to the arm-pit between the first rib and the subclavius 
 muscle. The trunk of it is then continued downwards through 
 the axilla, and at the inner side of the arm to the elbow joint. 
 
 From the scaleni muscles to the elbow its relative position is 
 as follows: When it first appears between the scaleni, it is 
 bounded above and behind by the collected fasciculi of the ax- 
 illary plexus of nerves. In front it is separated from the sub- 
 clavian vein by the insertion of the scalenus anticus. It is 
 placed at the bottom of the depression between the sterno-ma- 
 stoideus and the trapezius, _being covered by the skin, the pla- 
 tysma myodes, and some loose cellular substance below the 
 latter. It then descends between the first rib and the subcla- 
 vius; escaping from below the latter, it is covered in front by 
 the outer margin of the pectoralis major until it reaches the 
 lower part of the axilla; and in this course it has the following 
 relation to other parts: it passes under the shoulder joint, then 
 under the insertion of the pectoralis minor, then along the in- 
 ternal face of the coraco-brachialis muscle; it has the axillary 
 vein in front of it, and the axillary nerves plaited around it as 
 far down as the coracoid process, when they begin to disperse. 
 This artery in emerging from the axilla is placed upon the an- 
 terior face of the insertion of the latissimus dorsi: it then runs 
 out the length of the coraco-brachialis, and is afterwards 
 conducted along the inner margin of the biceps flexor cubiti 
 and its tendinous termination: it lies upon the anterior face 
 of the brachialis internus; and goes beneath the aponeurosis at 
 the bend of the arm, coming from the tendon of the biceps. 
 In the arm it is concealed only by the integuments and fascia, 
 
212 CIRCULATORY SYSTEM. 
 
 and is bordered internally by the brachial vein and the median 
 nerve. 
 
 This great trunk of the upper extremity loses the name of 
 subclavian, to be called Axillary Artery, (*3rt. flxillaris,) from 
 the subclavian muscle to the lower margin of the arm-pit: and 
 from the latter place to the elbow joint, it is named Brachial 
 Artery, (Jlrt. Brachialis.') It sends oft' many interesting 
 branches to the thorax, to the shoulder, and to the arm; and, 
 finally, terminates a little below or at the elbow joint by bifur- 
 cating. 
 
 Of the Branches of the Axillary Jlrtery. 
 
 1. The Superior Scapular Artery (*ff.rt. Dorsalis Superior 
 Scapula?) varies considerably in its origin. Sometimes it is a 
 branch of the subclavian, sometimes of the inferior thyroid, and 
 it frequently comes from the upper part of the axillary; so that 
 it cannot be_referred, with strict propriety, to any determined 
 origin. When it comes from the axillary, it is very tortuous, 
 and has to ascend to its destination, which removes it entirely 
 from any interference with the course of the subclavian over 
 the first rib, and over the upper head of the serratus magnus 
 muscle. But in the other cases, it goes transversely backwards 
 and outwards, somewhat below the posterior cervical, and along 
 the posterior inferior margin of the clavicle, being covered by 
 the sterno-mastoideus, the platysma myodes, and the trapezius; 
 consequently, it is just in the way of the incisions which are 
 made for 'reaching the subclavian artery, from above the clar 
 vicle. 
 
 It reaches the superior costa of the scapula near the root of 
 the coracoid process, and passing through the notch there, is 
 distributed, by one large branch, upon the supra-spinatus muscle; 
 and by another, which goes across the anterior margin of the 
 spine of the scapula, to the infra-spinatus muscle. In its course, 
 it sends oft* several small ramifications to contiguous parts. 
 
 2. The External Mammary Arteries (Art. Mammarm sen Tho- 
 
 Extern') arise from the axillary, between the subclavius 
 
SUBCLAVIAN, AND ITS BRANCHES. 213 
 
 and the pectoralis minor muscle. They are four principal 
 trunks, which go uniformly to certain parts, but vary considera- 
 bly in their origin ; for sometimes the latter is distinct in the 
 case of each artery, but frequently otherwise. Their distribu- 
 tion is as follows: 
 
 a. The Thoracica Superior is distributed to the upper part of 
 the pectoralis major muscle, and to the pectoralis minor. Some 
 of its branches reach the mamma in the female, and anastomose 
 with the internal mammary and with the intercostals. 
 
 b. The Thoracica Longa descends along the posterior face of 
 the pectoralis major, between it and the serratus magnus. It 
 gives many branches to the lower part of the pectoralis major, 
 to the integuments, and, in the female, to the mamma ; anasto- 
 mosing likewise with the internal mammary and with the inter- 
 costals. 
 
 c. The Thoracica Acromialis, immediately after its origin, 
 makes for the fissure between the deltoid and the great pectoral 
 muscle, and divides there into an ascending and a descending 
 branch. The former reaches the clavicle, and is partly distri- 
 buted superficially along it, partly to the contiguous muscles, 
 and to the shoulder articulation. The other branch follows the 
 cephalic vein along the interstice between the deltoides and pec- 
 toralis major, and is, finally, distributed to these muscles and to 
 the integuments. 
 
 d. The Thoracica Axillaris is irregular, both in regard to the 
 number of its branches and to their origin. Instead of a distinct 
 origin by one or more trunks from the axillary artery, the 
 branches belonging to the name of thoracica axillaris, are some- 
 times derived from the other thoracic arteries. They are ge- 
 nerally distributed only to the fat and the lymphatic glands in 
 the axilla. They occasionally exist primitively as a large trunk, 
 which runs on the scapular face of the serratus magnus the 
 whole length of the scapula, and is distributed to the adjacent 
 muscles, and to the fat and glands of the axilla. 
 
 3. The Scapular Artery (Arteria Scapularis communis, Sub- 
 scapularis] arises from the axillary below the shoulder joint, at 
 or near the anteriojr margin of the subscapularis muscle. Giving 
 VOL. II. 28 
 
214 CIRCULATORY SYSTEM. 
 
 off some inconsiderable branches to the lymphatic glands of the 
 arm-pit, it descends along the anterior margin of the subscapir 
 laris, and is distributed to it, to the latissimus dorsi, and to the 
 teres major and minor muscles. 
 
 A little below the neck of the scapula, it detaches a large 
 trunk, the Dorsalis Inferior Scapulae, which, winding around the 
 inferior costa of the bone over the anterior margin of the sub- 
 scapularis and the teres minor, reaches the fossa infra-spinatar 
 This trunk then divides into two branches : one of which is dis- 
 tributed superficially between the aponeurosis and the infra-spi- 
 natus, and the other more deeply near the dorsum of the bone: 
 one of the ramuscles of the latter ascends beneath the neck of 
 the .Acromion to anastomose with the Dorsalis Superior Sca- 
 pulas. 
 
 4. The Anterior Circumflex Artery (Art. Circumflexa Anterior? 
 Articularis Anterior) is about the size of a crow quill, and arises 
 from the axillary just above the tendon of the teres major and 
 of the latissimus dorsi. It adheres closely to, and surrounds the 
 front of the neck of the os humeri, passing between it, the cora- 
 co-brachialis, and the short head of the biceps. It then divides 
 into several branches, some of which go to the deltoides, and 
 anastomose therewith the posterior circumflex; others go imme- 
 diately to the articulation, and either terminate on it or ascend 
 to the muscles on the dorsum of the scapula, where they anasto- 
 mose with the scapular arteries. 
 
 The Posterior Circumflex Artery (Art, Circumflexa Posterior] is 
 much larger than the last, and arises from the axillary somewhat 
 below it. It surrounds the posterior face of the neck of the os hu- 
 meri, passing between it and the long head of the triceps muscle, 
 below the insertion of the teres minor. Many of its ramifica- 
 tions go to the capsular ligament of the articulation and to the 
 muscles adhering to it. But this artery is principally intended 
 for the deltoid muscle, to the internal face of which the most of 
 its branches go. It anastomoses with the anterior circumflex, 
 and with the scapular arteries. 
 
 In some cases, the posterior circumflex arises from the axil- 
 lary below, instead of above the tendinous insertion of the latis- 
 simus dorsi: when this happens, it commonly gives off the arte- 
 
SUBCLAVIAN, AND ITS BRANCHES, 215 
 
 Tia profunda major of the arm, and afterwards ascends on the 
 posterior face of the tendon to its appropriate destination. 
 
 Of the Branches of the Brachial Artery. 
 
 1. The Profound Artery (Arleria Profunda Major 4 Humeri, 
 Spiralis) arises from the brachial, a little below the tendinous 
 insertion of the latissimus dorsi; and having passed downwards, 
 for a short distance, it enters the interstice between the first and 
 the third head of the triceps muscle, and winds spirally down- 
 wards around the ps humeri in company with the radial nerve. 
 On the outer side of the arm, it becomes superficial between the 
 margins of the triceps and of the brachialis internus, and then 
 directs its course between the latter and the supinator longus to 
 the external condyle. 
 
 In this course, the artery sends several branches to the triceps 
 muscle, to which, indeed, it is principally destined. Near the 
 external condyle, it supplies the brachialis internus and the heads 
 of the extensor muscles of the fore arm, and anastomoses with 
 the recurrent branch of the radial artery. 
 
 2. The Small Profound Artery (Art. Profunda Minor] comes 
 from the brachial, two or three inches below the profunda ma- 
 jor, but frequently it is only a branch of the latter, and is gene- 
 rally much smaller. It is distributed superficially on the internal 
 face of the triceps at its lower part, and has its terminating 
 branches reaching as far as the internal condyle. 
 
 3. The Nutritious Artery (Art. Nutritia) is the next in order 
 from the brachial; and arises from it near the medullary fora- 
 men of the os humeri, through which it penetrates, and is distri- 
 buted to the lining membrane of the bone. It is not larger than 
 a knitting needle. 
 
 4. The Anastomotic Artery (Arteria Anaslomotica) arises from 
 the brachial below the last, and is larger than it. It lies upon 
 the lower internal part of the brachialis internus muscle, and 
 crosses the ridge leading to the internal condyle in order to 
 
216 CIRCULATORY SYSTEM. 
 
 reach the depression between the latter and the olecranon, 
 where it anastomoses with the ulnar recurrent artery. 
 
 The preceding is a common arrangement of the branches 
 proceeding from the brachial artery, yet deviations from it are 
 continually met with, in a deficiency or in a redundancy of these 
 collateral trunks, and in their mode of origin. An account of 
 all the varieties which are observed here would be almost end- 
 less, as every subject has some peculiarity. Several small ar- 
 teries are also sent from the brachial to the coraco-brachialis, 
 the biceps, the brachialis internus, and to the triceps muscles. 
 They, for the most part, are, simply, muscular branches, which 
 are too small and irregular to deserve specifying. 
 
 A division of the brachial artery into two trunks, the Radial 
 and the Ulnar, will be found in a majority of subjects in front 
 of the brachialis internus muscle on a line with the elbow joint : 
 sometimes it occurs nearer the root of the coronoid process, 
 It is, however, by no means rare to see this bifurcation much 
 above the elbow. Examples of it have been witnessed at every 
 point between the latter and the arm-pit ; in such cases, the 
 course of the radial artery down the fore arm is generally much 
 more superficial than usual, as it is placed immediately below* 
 the skin. 
 
 Of the Radial Artery. 
 
 The Radial Artery (Arteria Radialis) is smaller than the ulnar, 
 and extends from the elbow to the hand. In the upper half of 
 the fore arm it is placed at the bottom of the fissure between 
 the supinator radii longus and the pronator teres muscle. Having 
 crossed the insertion of the latter, it runs in front of the radius 
 between the tendon of the supinator and of the flexor carpi ra- 
 dialis. Below the styloid process of the radius it runs between 
 the outer end of the carpus and the extensor muscles of the 
 thumb ; it then penetrates to the palm of the hand between the 
 root of the metacarpal bone of the thumb and of the fore finger, 
 above the abductor indicis muscle. 
 
 The following branches are sent from the Radial Artery. 
 
SUBCLAVIAN, AND ITS BRANCHES. 217 
 
 1. The Recurrens Radialis arises at the neck of the radius. 
 It winds, externally, around the joint between the external con- 
 dyle and the muscles coming from it, and anastomoses with the 
 spiralis of the humeral artery, being distributed in many colla- 
 teral branches, to the joint and to the contiguous muscles. 
 
 2. Several small and irregular muscular branches arise from 
 the radial artery, in its progress to the wrist : they have no ap- 
 propriate names. 
 
 3. The Superficial Volae arises from the radial about the in- 
 ferior margin of the pronator quadratus muscle. It passes su- 
 perficially over the process of the trapezium to the muscles of 
 the ball of the thumb, and one of its terminating branches joins 
 the arc us sublimis. Sometimes the superficial volas is the prin- 
 cipal branch of the radial. 
 
 4. The Dorsalis Carpi arises from the radial at the carpus, 
 runs across the back of the latter below the extensor tendons, 
 and detaches the posterior interosseous arteries of the back of 
 the hand. They anastomose with branches from the ulnar and 
 interosseous arteries of the fore arm. 
 
 5. The Magna Pollicis, a terminating branch of the radial, 
 comes from it in the palm of the hand just at the root of the me- 
 tacarpal bone of the thumb. It runs beneath the abductor indi- 
 cis, and at the head of the metacarpal bone divides into two 
 branches which run along the sides of the thumb to its extremity, 
 where they anastomose and terminate. 
 
 6. The Radialis Indicis, arising at the same place with the 
 latter, runs along the metacarpal bone of the fore finger, and 
 along the radial side of the same finger to its extremity. 
 
 7. The Palmaris Profunda is the third terminating branch of 
 the radial artery. It arises near the same place with the two 
 last, crosses the hand between the metacarpal bones and the 
 flexor tendons; thus forming the Arcus Profundus, from which 
 branches proceed to the interossei muscles, and which ends on 
 
218 CIRCULATORY SYSTEM. 
 
 the ulnar side of the palm of the hand by a branch to the Arcus 
 Superficialis. 
 
 Of the Ulnar Artery. 
 
 The Ulnar Artery, (Arteria Ulnaris,) one of the forks of the 
 brachial at the elbow, passes more in a line with it than the ra- 
 dial artery does. It goes, immediately after its origin, under se- 
 veral of the muscles of the internal condyle, to wit : the pronator 
 teres, flexor radialis, flexor sublimis, and palmaris longus, and 
 between the flexor sublimis and profundus digitorum, being deep- 
 ly seated ; getting from beneath the flexor sublimis, it afterwards 
 runs parallel with the ulna, or nearly so, lying on the flexor pro- 
 fund as between the flexor ulnaris and the ulnar margin of the 
 flexor sublimis, and concealed two-thirds of the way down the 
 fore arm by the overlapping of these muscles. At the thin part 
 of the fore arm, commonly called the wrist, it is superficial, and 
 may be felt pulsating in the living body at the radial margin of 
 the tendon of the flexor ulnaris. 
 
 The ulnar artery, at the carpus, takes a very different course 
 from the radial, for it passes over the anterior annular ligament 
 of the carpus just at the radial side of the os pisiforme, to which 
 it is held by a small ligamentous noose ; it then proceeds to the 
 palm of the hand. Between the aponeurosis palmaris and the 
 flexor tendons it forms that curve from the ulnar to the radial 
 side of the hand called the Arcus Sublimis. This curve com- 
 monly begins a little beyond the anterior margin of the annular 
 ligament, and presenting its convexity forwards, terminates about 
 the middle of the ball of the thumb at its inner margin. 
 
 The branches sent from the ulnar artery are as follow: 
 
 1. The Recurrens Ulnaris arises from the ulnar about the 
 lower part of the tubercle of the radius, and, winding upwards, 
 
 . is distributed in small branches to the muscles of the internal 
 condyle. One of its ramuscles goes between the internal con- 
 dyle and the olecranon process to anastomose with the arteria 
 anastomotica of the humeral. 
 
 2. The Interossea arises from the ulnar, just below the other. 
 
SUBCLAVIAN, AND ITS BRANCHES. 219 
 
 It is a large trunk, and proceeds but a little distance when it di- 
 vides into two principal branches, called anterior and posterior 
 interosseal arteries. 
 
 a. The Interossea Anterior is much the larger; it runs in con- 
 tact with the interosseous ligament to the upper margin of the 
 pronator quadratus, giving off branches to the deep-seated mus- 
 cles of the fore arm in its course. Under the pronator it per- 
 forates the interosseous ligament, and distributes branches to the 
 back of the carpus and of the hand, which anastomose with 
 branches of the radial and posterior interosseal. 
 
 6. The Interossea Posterior is sometimes a separate trunk, 
 arising from the ulnar just above the former. In either case it 
 soon perforates the interosseous ligament to get to the back of 
 the fore arm. Here it sends backwards a Recurrent Branch 
 (Recurrens Interossea) to the back of the elbow, which anasto- 
 moses with the recurrens ulnaris and radialis. It then proceeds 
 downwards, being deeply seated and distributed to the different 
 muscles on the back of the fore arm. Some of its branches 
 reach the wrist, and anastomose with the carpal arteries. 
 
 3. The ulnar artery, in its descent on the fore arm, sends off 
 many small and irregular muscular branches, called by Pro- 
 fessor Chaussier, Cubito-muscularis: they do not require descrip- 
 tion. 
 
 4. The Dorsalis Manus leaves the ulnar at the lower end of 
 the fore arm, and passes under the tendon of the flexor ulnaris 
 to the back of the hand. It there meets ramuscles of the radial 
 and interosseous, and conjointly they supply with very small 
 branches the back of the wrist, of the metacarpus, and of the 
 fingers. 
 
 5. As the Arcus Sublimis is about beginning, the ulnar arte- 
 ry sends superficial but small branches to the integuments of the 
 palm; and a little farther on, a considerable branch, which dives 
 into the bottom of the palm, through thef muscles of the little 
 finger, and joins the ulnar extremity of the arcus profundus: this 
 is the Cubitalis Manus Profunda of Haller. 
 
220 CIRCULATORY SYSTEM. 
 
 6. The Arcus Sublimis then sends a hranch to the ulnar side 
 of the little finger. Afterwards in succession three digital 
 branches are sent off, which, arriving at the interstices between 
 the heads of the metacarpal bones, each divides into two 
 branches to supply the sides of the fingers which are opposite 
 to each other; one branch is called Digito-radial, the other Di- 
 gito-ulnar, according to the side of the finger on which the ar- 
 tery may be placed. 
 
 The digital arteries, before they divide, receive each a small 
 branch from the arcus profundus. The digito-radial, and the 
 digito-ulnar arteries, pass along the sides of the fingers in front 
 to their extremities: at the joints and extremities, anastomoses 
 between the arteries of the two sides of the same finger fre- 
 quently occur. 
 
 The arcus sublimis terminates on the radial side of the palm 
 by a branch which joins the inner branch of the Arteria Magna 
 Pollicis of the Radial. 
 
 The most frequent distribution of the arteries of the hand is 
 what has just been described: anatomists are, however, not all 
 agreed on this point. It would probably be more just to say, 
 that this occurs more frequently than any other single arrange- 
 ment. The varieties, in fact, are so great, that before a hand is 
 opened, it is not possible to know in what manner its arteries 
 will be distributed. Sometimes the Radial Artery furnishes 
 one half of the arcus sublimis, and the Ulnar the other half. 
 On other occasions, the interosseous artery or the superficialis 
 volae is continued as a large trunk over the ligament of the 
 wrist, and crosses the root of the thumb, to join the arcus sub- 
 limis. 
 
 SECT. IV. BRANCHES OF THE DESCENDING THORACIC 
 AORTA. 
 
 The Aorta, in its course from the lower part of its curvature 
 to the crura of the Diaphragm, gives off several branches to the 
 viscera and to the parietes of the thorax. 
 
 The Bronchial Arteries (<flrterias Bronchiales) are the nu- 
 
SUBCLAVIAN, AND ITS BRANCHES. 221 
 
 tritious vessels of the lungs. There is commonly one for each 
 lung, but sometimes two or more. The right arises frequently 
 from the superior aortic intercostal artery, instead of from the 
 aorta, while the left comes from the latter: occasionally they 
 have a common root. 
 
 On either side they follow the course of the bronchia into the 
 substance of the lung; and are distributed along with it, by ra- 
 mifications which become successively finer and finer, and 
 anastomose with the pulmonary artery; after the manner men- 
 tioned in the description of the lungs. Before they enter the 
 latter, they send some small ramifications to the posterior me- 
 diastinum, to the pericardium, and to the black bronchial glands. 
 
 The (Esophageal Arteries (Jlrterise GSsophagea) are gene- 
 rally five or six small twigs which come successively from the 
 descending thoracic aorta. They ramify minutely in the sub- 
 stance of the oesophagus, communicating freely with each other: 
 the lowest of them also anastomoses around the cardia with the 
 superior coronary artery of the stomach. 
 
 The Posterior Arteries of the Mediastinum, (Jlrterise Me* 
 diastinales Posteriores,) are numerous and small; they come 
 from the anterior face of the aorta, as well as from the branches 
 last mentioned; and are spent upon the posterior mediastinum, 
 and upon its contents. 
 
 The Intercostal Arteries (JlrtericR Intercostales Inferiores 
 *ftortic(R) of the aorta supply the ten lower intercostal spaces on 
 each side, as the two upper ones are supplied by the subclavian 
 artery. There is commonly an intercostal artery arising dis- 
 tinctly from the aorta for each space, but sometimes two of 
 them arise from a common trunk. Those for the right side 
 having to cross the spine behind the oesophagus and the vena 
 azygos, are, of course, longer than such as belong to the left. 
 The upper ones on either side have to ascend, in order to reach 
 their destination. 
 
 Each artery joins the rib near its tubercle, and goes along the 
 groove in its lower margin, between the external and the inter- 
 nal intercostal muscles, for two-thirds of the length of the rib. 
 VOL. II 29 
 
222 CIRCULATORY SYSTEM. 
 
 It then abandons the groove, and divides into several branches, 
 which go to the intercostal muscles and contiguous parts, and 
 anastomose in front with the internal mammary artery. 
 
 As each intercostal artery passes the head of the rib, it sends 
 a branch backwards, (ramus dorsalis,) between -the transverse 
 processes of the adjoining vertebrae, which penetrates to the 
 posterior face of the trunk, and is distributed to the muscles and 
 skin on the side of the spine. A ramification from this branch 
 enters the intervertebral foramen, and is spent upon the medulla 
 spinalis and its membranes. 
 
 Each intercostal artery also gives off, about the middle of the 
 rib, a branch, (ramus costalis inferior?) much smaller than the 
 trunk. This branch advances along the upper margin of the 
 rib below, and gives ramifications to its periosteum and to the 
 adjacent intercostal muscles. 
 
 The last intercostal artery is remarkable for its size. Its ori- 
 gin^is concealed by the small muscle of the diaphragm, to which 
 it gives some ramifications: it then passes, at the under margin 
 of the rib, behind the upper end of the quadratus lumborum 
 muscle, where it divides into three branches; one of which goes 
 transversely to the broad muscles of the abdomen; while the 
 other two descend between the oblique and transverse muscles 
 towards the crest of the ilium, where they anastomose with the 
 lumbar arteries, and with the circumflexa ilii. . 
 
 SECT. V. OF THE BRANCHES OF THE ABDOMINAL AORTA. 
 
 The Phrenic Arteries (Arteries, Phrenicce) are two in num- 
 ber, one for the right and the other for the left side of the dia- 
 phragm. They arise singly, but sometimes by a common trunk, 
 from the front of the aorta, immediately on the latter showing 
 itself in the abdomen, between the crura of the diaphragm; con- 
 sequently, just below the crossing of the muscular fibres, which 
 lakes place between the foramen for the aorta and that for the 
 O3sophagus. 
 
 The phrenic arteries ascend along the lesser muscle of the 
 diaphragm, and give some ramifications to it and to the capsulae 
 rcnalcs. They then divide each into two leading trunks, which 
 arc distributed over the diaphragm, principally on its concave 
 
BRANCHES OP THE ABDOMINAL AORTA. 223 
 
 surface. Some small ramifications from them go to the liver 
 and to the lower part of the oesophagus. 
 
 The two phrenic arteries anastomose with each other: also, 
 with the superior phrenics, coming from the internal mammary; 
 and with the intercostals. Sometimes one or both of them come 
 from the coeliac artery, or its branches. 
 
 The Coeliac Artery (Jlrteria Ccdiaca) is the next branch of 
 the abdominal aorta, and arises immediately below the phrenics, 
 between the pillars of the diaphragm, opposite the junction of 
 the last dorsal with the first lumbar vertebra. It is a very large 
 trunk, and goes off at right angles, being placed between the 
 left lobe of the liver and the superior margin of the pancreas. 
 When it is only half an inch long, it is split into three trunks, 
 the Gastric, the Hepatic and the Splenic; this division is the 
 Tripus Halleri. 
 
 The Gastric Artery (Jlrteria Gastrica, Coronaria Ventri- 
 culi) is the smallest of the three trunks, and frequently arises 
 from one of the others. It advances forwards and towards the 
 left, in order to reach the small curvature of the stomach, the 
 course of which it pursues to the pylorus, between the two lami- 
 nae of the little omentum. It gives off the following branches: 
 
 a. Ramifications to the oesophagus, some of which ascend 
 along it into the posterior mediastinum, and anastomose there 
 with the similar branches coming from the aorta; others go trans- 
 versely, so as to surround the cardia, reach the greater end of 
 
 .the stomach, and anastomose with the vasa brevia. 
 
 b. The ramifications to the stomach are abundant, but of an 
 indeterminate number, and arising along its lesser curvature, are 
 distributed in winding branches to the anterior and the posterior 
 surfaces of this viscus, between its membranes. 
 
 c. Not unfrequently the artery which supplies the left lobe 
 of the liver is a branch from the gastric, in which case the lat- 
 ter/is much larger than usual. 
 
 2. The Hepatic Artery (<flrteria Hepaticd) is generally con- 
 siderably larger than the gastric, and inclines towards the right 
 side, in order to reach the liver, which it does through the cap- 
 sule of Glisson. It send off the following branches: 
 
224 CIRCULATORY SYSTEM. 
 
 a. The Right Gastric or Gastro-Epiploic Artery (*Arteria 
 Gastrica Dextra] comes from it near the pylorus, and descend- 
 ing between the duodenum and pancreas, reaches the great- 
 er curvature of the stomach, to the right half of which, and to 
 the corresponding part of the great omentum, it is distributed. 
 In the early part of its course, the right gastric detaches some 
 small ramifications to the pylorus (arttrm pyloriccc;) also, to 
 the duodenum and to the pancreas (art. pancrealico duode- 
 nales.) The latter communicate, by very free anastomoses, with 
 the superior mesenteric artery. 
 
 After having sent off this branch, the hepatic artery advances 
 to the transverse fissure of the liver, in front of and to the left 
 of the vena portarum. It then divides into a right and a left 
 branch. The former sends off a ramification to the gall-bladder, 
 (art. Cystica,} which first reaches its neck, and is distributed, 
 by many arterioles, upon the parietes of this reservoir; the right 
 branch then penetrates deeply into the transverse fissure, and is 
 distributed, by many ramifications, throughout the right lobe of 
 the liver. The left branch of the hepatic artery is distributed, 
 in the same manner, throughout the left lobe of the liver. 
 
 3. The Splenic Artery (Jlrteria Splenicd) is larger in the 
 adult than either of the other two branches of the cceliac, and 
 goes to the spleen along the superior margin of the pancreas, 
 performing, in this course, several considerable flexuosities. It 
 gives off the following branches: 
 
 a. The Pancreatic Arteries (Art. PancreaticK Media et Sinis- 
 trce) come successively from its inferior margin, as it goes along 
 the pancreas. Their number and size are variable, but com- 
 monly they are not bigger than a knitting needle: they pene- 
 trate perpendicularly into the pancreas, and then subdivide mi- 
 nutely in furnishing its structure. 
 
 b. The Left Gastric Artery (*ftrt. Gastrica Sinistra, Gaslro- 
 epiploica Sinistra) comes from the left extremity of the splenic, 
 and is about the same size with the right gastric artery, but some- 
 times larger. It attaches itself to the left extremity of the sto- 
 mach, and goes along the left half of its greater curvature, ter- 
 minating by an. anastomosis with the right gastric artery. In 
 this course, it detaches ramifications to the front and to the back 
 of the stomach, and to the omentum majus. 
 
BRANCHES or THE ABDOMINAL AORTA. 225 
 
 . The Short Vessels ( Vasa Brevia, Jlrt. Gastricce Breves] 
 come from the splenic, immediately before it enters the spleen, 
 and after it has subdivided for that purpose. They are five or 
 six in number, and are distributed upon the greater extremity 
 of the stomach, between the cardia and the left gastric artery. 
 The anastomoses between the several arteries of the stomach 
 are so free, that a fine injection pushed into one, readily finds 
 its way into all the others. 
 
 The splenic artery, when it gets to the left end of the pan- 
 creas, is divided into a cluster of branches, and in that condition 
 enters the fissure of the spleen, throughout the interior of which 
 it is divided into an infinitude of ramifications. 
 
 The Superior Mesenteric Artery (Jlrteria Mesenterica Su- 
 perior) arises from the aorta, while the latter is still engaged, 
 between the crura of the diaphragm. It is about the same size 
 as the coeliac, and comes off half an inch below it. It is distri- 
 buted to all the small intestine and to the right side of the large 
 one after the following manner: it first passes behind the pan- 
 creas, and then in front of the duodenum, to reach the root of 
 the mesentery, between the two laminae of which it divides 
 and subdivides into several series of arches, one after another: 
 they become successively smaller and more numerous till they 
 reach the margin of the intestine, where they cease by sending 
 a great many small parallel branches. 
 
 The trunk of the superior mesenteric artery, in descending 
 between the laminae of the mesentery, describes a considerable 
 curvature, the convexity of which is to the left side and down- 
 wards, while its concavity is in a contrary direction. It is from 
 the convexity of this trunk, that from fifteen to twenty large 
 branches are sent off successively to form the roots of the first 
 row of arterial arches. These branches are shorter, and gene- 
 rally somewhat smaller, the lower down they arise; and their 
 origins very closely succeed each other. 
 
 Besides the preceding branches, the superior mesenteric ar- 
 tery send-off the following: 
 
 Near its root several small ramifications arise, which go to 
 the duodenum and to the pancreas, and anastomose there with 
 other arteries supplying the same organs. 
 
CIRCULATORY SYSTEM. 
 
 From about the middle of the concavity of the superior me- 
 senteric artery, arise the three Colic arteries called Ileo-colica, 
 Colica Dextra, and Colica Media: the first supplies a cluster of 
 branches to the lower part of the ileum and to the head of the 
 colon, anastomosing on the left with the last of the small in- 
 testinal arteries and on the right with the colica dextra: the 
 Colica Dextra is smaller than either of the other two branches, 
 and going between the laminae of the mesocolon, supplies the 
 ascending portion of the colon by dividing into two principal 
 branches, one of which anastomoses with the ileo-colic artery, 
 and the other with the colica media: the Colica Media, situated 
 between the laminae of the transverse mesocolon, and arising 
 higher up than the colica dextra, advances forwards and divides 
 Into two principal trunks; one of which supplies that part of 
 the colon in the right hypochondriac region, and the other the 
 remainder of its transverse portion, forming an anastomosis 
 with the colica superior of the inferior mesenteric artery. The 
 arteries which supply the colon differ from those supplying the 
 small intestines, in forming but one row of arches; which, in 
 fact, are produced by the anastomoses spoken of, and have, there- 
 fore, extremely large meshes. From the convexity of these 
 arches, many parallel branches run out to supply the colon, and 
 are very minutely distributed to it. 
 
 The Capsular Arteries, the Emulgents, and the Spermatics, 
 arise from the aorta, between the superior and the inferior me- 
 senteries. But they will be described after the inferior mesen- 
 teric, so as to keep together the account of the arteries of the 
 intestines. 
 
 The Inferior Mesenteric, Artery (Jlrt, Mesenterica Inferior) 
 generally arises about one inch above the division of the aorta 
 into the two primitive iliacs, and is much smaller than the su- 
 perior Mesenteric. It inclines downwards to the left side, and 
 gets between the lamina of the mesocolon; it then divides into 
 three branches, called the Left Colic Arteries, from their dis- 
 tribution to the left side of the colon. From their relative si- 
 tuation to each other, they are distinguished into the Superior, 
 the Middle, and the Inferior; sometimes, however, there are 
 but two of these trunks. 
 
BRANCHES OF THE ABDOMINAL AORTA. 227 
 
 The Superior Colic (Art. Colica Sinistra Superior) goes ho- 
 rizontally towards the colon in the left lumbar region; having 
 got near the intestine it divides into two branches, one of which 
 ascends to the transverse colon to form the anastomosis with 
 the Colica Media of the upper mesenteric, while the other, de- 
 scends to unite with the colica media sinistra. The middle 
 Colic Artery (Jlrt. Colica Sinistra Media] is sometimes a 
 branch of the superior, and is occasionally wanting; it goes to- 
 wards the upper part of the sigmoid flexure of the colon, and 
 then bifurcates; one branch ascends' to form by anastomosis an 
 arch with the superior colic, while the other branch descends 
 to join the lower colic artery. The Inferior Colic Artery (*flrt. 
 Colica Sinistra Inferior) goes towards the middle of the sig- 
 moid flexure of the colon, and there, like the preceding, divides 
 into two branches; one anastomoses with the artery above, while 
 the other joins with the arteries which go to the rectum from? 
 the inferior mesenteric. 
 
 The Superior Ifemorrhoidal Artery (Art. H&morrhoidea Supe- 
 rior, Intern a) is the lowest and the last branch of the inferior me- 
 senteric. It descends between the laminae of the mesorectum, 
 and is divided into two symmetrical trunks, which radiate by 
 dividing and subdividing on the side of the rectum, and are dis- 
 persed in very fine and numerous branches throughout its sub- 
 stance : and anastomose with the middle and the inferior hae.- 
 morrhoida! arteries, also with the lateral sacral. 
 
 The Capsular Arteries (Art. Capsulares) arise frequently from 
 the aorta just below the superior mesenteric ; but quite as often, 
 if not more so, from the emulgents. They are not larger than 
 a crow's quill, and vary from one to three on either side, gene- 
 rally, however, not exceeding one : when they do, they are pro- 
 portionably small. Passing horizontally outwards, they divide 
 into several small ramifications, which terminate in the capsule 
 renales. Some of their branches go to the lesser muscle of the 
 diaphragm. 
 
 The Emulgent Arteries (Art. Emulgentes, Renales) are two i 
 number, one for each kidney, but sometimes more. They are 
 large and short, arise from the side of the aorta immediately be- 
 
228 CIRCULATORY SYSTEM. 
 
 low the superior mesenteric, and pass outwardly in a horizontal 
 direction. The right one is longer than the left, somewhat lower 
 down, and passes behind the ascending cava. They are both, in 
 their course, from the aorta to the kidney, covered in front by 
 the emulgent vein, and have to pass through a mass of adipose 
 matter. 
 
 The emulgent sends off some fine ramifications to the adipose 
 matter, which surrounds it, and before it reaches the fissure of 
 the kidney divides into three or four branches, preparatory to its 
 introduction into this gland ; upon the structure of which it is ul- 
 timately distributed by .very fine branches. 
 
 The Spermatic Arteries (Arlerm Spermaticce, Seminales) arise 
 from the aorta somewhat below the emulgents, but in some 
 cases from the latter themselves. They are two in number, one 
 on each side, and are about the size of a crow quill in the male 
 subject, but smaller in the female. One comes off generally 
 higher up than the other ; they then descend on the sides of the 
 vertebral column before the psoae muscles, and cross in front of 
 the ureters, being in all this course behind the peritoneum. They 
 are tortuous, and shortly after their origin begin to adhere to the 
 spermatic veins, which adhesion is continued to the testicle. 
 
 The branches that the spermatic artery sends off in the abdo- 
 men are inconsiderable, consisting in very fine twigs to the adja- 
 cent adipose matter, to the lymphatic glands, to the ureter, and 
 to the peritoneum. In the male subject, it passes with the vas 
 deferens, through the abdominal canal, and reaching the testicle 
 divides into branches which supply the body of this gland and 
 the epididymis. In descending from the external ring to the tes- 
 tis, some small ramifications, to the adjacent parts leave it. In 
 the female, the spermatic artery does not leave the cavity of the 
 abdomen, but descending into the pelvis, gets between the lami- 
 nae of the broad ligament to the ovarium, and is spent principally 
 upon the latter. Some of its branches go to the Fallopian Tube, 
 to the Round Ligament of the uterus, and to the sides of the lat- 
 ter, where they anastomose with the uterine arteries. 
 
 The Lumbar Arteries (Arteries Lumbares) are commonly five 
 in number on either side, but seldom less than three, and, in their 
 course outwards, correspond with the intercostal arteries. They 
 
BRANCHES OF THE ABDOMINAL AORTA. 229 
 
 are much larger than the latter. They arise in pairs, from the 
 posterior external face of the aorta, at a point corresponding 
 with the middle of the bodies of the four upper lumbar vertebrae ; 
 and pass outwards between the fasciculi of the psoas magnus 
 muscle, to which, to the quadratus lumborum, and the bodies of 
 the vertebras, they distribute several branches. Sometimes each 
 pair arises by a common trunk from the posterior face of the 
 aorta. As the latter terminates at the fourth lumbar vertebra, 
 the fifth lumbar artery is a branch from the fourth in most in- 
 stances. At the base of the transverse process each artery di- 
 vides into two branches, a posterior or dorsal one, and an ante- 
 rior or lumbar. 
 
 The dorsal branch, which is smaller than the other, detaches 
 a ramification through the intervertebral foramen to the lower 
 part of the medulla spinalis and to the cauda equina : it then gets 
 to the back, where it is spent upon the muscles near the spine. 
 The anterior lumbar branch advances between the broad mus- 
 cles of the abdomen, to which it is distributed ; and runs for- 
 wards far enough to anastomose with the epigastric artery. 
 
 The first lumbar artery is small, and sometimes comes from 
 the last intercostal ; it goes a little below the inferior margin of 
 the last rib, and then descends almost vertically between the pe- 
 ritoneum and the transversus abdominis muscle. The lower lum- 
 bar arteries anastomose with the circumflexa ilii, and with the 
 superficial branches of the gluteal. 
 
 The Middle Sacral Artery (Arteria Sacra Media) is generally 
 not so large as a lumbar ; it arises from the centre of the bifur- 
 cation of the aorta into the two primitive iliacs, or else a line or 
 two above it, behind. It descends, in front of the middle line of 
 the fifth lumbar vertebra and of the sacrum, to the coccyx, 
 adhering to the surface of these bones, and performing some 
 flexuosities. 
 
 It sometimes happens that the last pair of lumbar arteries 
 come from it, or at least one, according to Meckel, more com- 
 monly the left : in which case the sacral is of unusual size. The 
 sacral afterwards sends off, to the right and left, a pair of 
 branches for each pair of sacral foramina. They run across the 
 sacrum, send branches to it, anastomose with the lateral, sacral 
 VOL. II. 30 
 
230 CIRCULATORY SYSTEM. 
 
 arteries, and then penetrate to the cauda equina. The middle 
 sacral artery is lost at the inferior end of the coccyx, in the fat 
 and cellular tissue of the part. 
 
 SECT. VI. OF THE PRIMITIVE ILIAC ARTERIES, AND THEIR BRANCHES. 
 
 The Primitive Iliac Arteries, (Art. Iliac Primitives, communes,) 
 one on each side, are, as mentioned, the terminating trunks of 
 the abdominal aorta. They extend from the lower part of the 
 fourth lumbar vertebra to the sacro-iliac junction, or near it, 
 where they divide into two trunks, the Internal and the External 
 Iliac. 
 
 The primitive iliac is bounded on the outer side by the psoas 
 magnus muscle, and behind by the primitive iliac vein; it is 
 crossed at its lower part by the ureter. No branches deserving 
 of especial notice are sent from it before it bifurcates ; such as 
 exist are very small, and go simply to the parts immediately con- 
 tiguous. The right artery crosses in front of the root of the left 
 iliac vein. 
 
 SECT. VII. OF THE INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 
 
 The Internal Iliac Artery (Art. Iliaca Internet, Hypogastrica) 
 descends from the front upper part of the sacro-iliac junction, to 
 the lower part of the same articulation. In this descent, it is 
 bounded behind by the sacral plexus of nerves, and gives off se- 
 veral arterial trunks ; but the manner by which the last is ac- 
 complished is much varied in different subjects. For the most 
 part, it is an inch or more long before any important branches 
 leave it ; it is, then frequently divided into two principal trunks, 
 an anterior and a posterior, from which proceed the several 
 branches that supply the internal and the external parts of the 
 pelvis. The rule of origin of the secondary trunks from these 
 two principal ones, even when the latter exist, is not fixed, for 
 sometimes they arise from one, sometimes from the other, and 
 then again from the trunk of the hypogastric itself. 
 
 The Ilio-Lumbar Artery (Art. llio-Lumb aris^is commonly the 
 
INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 231 
 
 first branch of the hypogastric, or of its posterior trunk. It as- 
 cends outwards and backwards behind the psoas magnus mus- 
 cle, and there divides into two branches, a superior and an in- 
 ferior. The former continues to ascend between the psoas 
 magnus and the iliacus interims muscles, to which, and to the 
 quadratus lumborum, it distributes branches: it also sends rami- 
 fications into the spinal cavity, and anastomoses with the lower 
 lumbar arteries; sometimes it supplies the place of the last lum- 
 bar entirely. The inferior branch, going outwardly, is divided 
 into two orders of ramifications which supply the iliacus inter- 
 ims muscle, on its surface and more deeply; also the os ilium by 
 a ramuscle which penetrates the nutritious foramen of the latter. 
 The inferior branch anastomoses with the circumflexa ilii of the 
 external iliac. 
 
 The Lateral Sacral Arteries (Arteries Sacrce Laterales) arise 
 next, either from the hypogastric or from its posterior trunk : 
 their number is commonly equal to that of the foramina on the 
 side of the sacrum in front, though they come from only one or 
 two roots. They cross the front of the sacrum, and divide into 
 branches, some of which anastomose with the middle, sacral 
 artery, while others enter the foramina of the sacrum, to be 
 spent on the lower part of the cauda equina. 
 
 The Obturator Artery (Arteria Obturatoria) comes commonly 
 from the hypogastric or from one of its principal trunks ; in some 
 cases it arises from the epigastric or from the external iliac, 
 near Poupart's ligament. In the first cases it passes forwards 
 parallel with the brim of the pelvis, and in the latter cases it de- 
 scends behind the superior rarnus of the pnbes. Whatever may 
 be the condition of its organ, it gets from the pelvis through the 
 upper part of the thyroid foramen over the superior margin of 
 the obturator internus muscle, having previously sent off some 
 inconsiderable ramifications to the periosteum and the contiguous 
 muscles. 
 
 It emerges from the pelvis on the upper margin of the obtu- 
 rator externus muscle, and then divides into two principal trunks. 
 The posterior despends along the external margin of the obtu- 
 rator externus muscle, to which it gives ramifications; it like- 
 
232 CIRCULATORY SYSTEM. 
 
 wise sends some branches to the heads of the muscles coming 
 from the tuber of the ischium, and thereby anastomoses with the 
 sciatic artery; other branches are spent upon the hip joint, one 
 of which gets into the cavity of the latter through the notch at 
 the lower part of the acetabulum, and is spent upon the adipose 
 matter in its bottom. The anterior branch goes to the heads of 
 the adductor muscles, to the pectineus, to the obturator externus, 
 and to the integuments of the upper internal part of the thigh. 
 Near its origin this branch sends a ramification along the inter- 
 nal margin of the thyroid foramen to anastomose with the pos- 
 terior branch, so that the foramen is surrounded by an arterial 
 
 circle. 
 
 i 
 
 The Middle Ifemorrhoidal Artery (Art. Hcemorrhoidea Media) 
 varies in its origin, being sometimes from the hypogastric itself, 
 and, on other occasions, from one of its branches, as the gluteal, 
 ischiatic, &c. It descends on the fore part of the rectum, op- 
 posite the lower fund us of the bladder in the male, and is distri- 
 buted by branches to the rectum, to the vesiculae seminales, and 
 to the prostate gland. In the female it dispenses branches to 
 the vagina. It is called middle, from its position between the 
 upper and the lower haemorrhoidal arteries. 
 
 In both sexes, the branches which it sends to other parts be- 
 sides the rectum, frequently arise from other arteries, and in a 
 manner which causes them to have distinct appellations, as va- 
 ginal, &c. 
 
 The Vesical Arteries (Arteries, Vesicales) consist in several ra- 
 mifications, coming from what was the umbilical artery of the 
 foetus, but which, in the adult, with the exception of a short space 
 near its origin, is converted into a ligamentous chord. These 
 branches ramify upon the parietes of the bladder ; one of them, 
 more voluminous than any other, and called, by M. Chaussier, 
 vesico-prostatic, gains the lower fundus of the bladder ; sends 
 branches to it, to the prostate, to the vesiculae seminales, and to 
 the commencement of the urethra. 
 
 The Uterine Artery (Arteria Uterina) arises from the hypogas- 
 tric, or one of its branches, near the vesical, sometimes before, 
 
INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 233 
 
 and on other occasions subsequent to them. Being peculiar to 
 the female sex, its size varies according to the individual, being 
 in a state of pregnancy or not : in the latter stages of gestation 
 it is as large as any other branch of the hypogastric. 
 
 It goes inwards towards the superior part of the vagina, to 
 which it gives some ramifications ; it then ascends between the 
 laminae of the broad ligament, in a tortuous manner along the 
 side of the uterus, and divides into many branches which are 
 distributed through the tissue of this organ. It anastomoses with 
 the corresponding arteries of the other side, and with the branches 
 of the spermatic artery which go to the Fallopian tube and to 
 the ovarium. 
 
 Besides the preceding, the hypogastric artery sends off two 
 large branches, the Gluteal and the Ischiatic, which terminate it. 
 In many subjects they are the direct continuation of the two pri- 
 mitive trunks, into which the hypogastric is frequently originally 
 divided. 
 
 The Gluteal Artery, (Arteria Glutea,) shortly after its origin, 
 issues from the pelvis above the pyriformis muscle, at the upper 
 part of the ischiatic foramen, where it adheres closely to the edge 
 of the bone. When it first gets to the dorsum of the ilium, it is 
 covered by the gluteus maximus muscle, and lies at the poste- 
 rior margin of the gluteus minimus, precisely under a line drawn 
 from the posterior superior spinous process to the top of the tro- 
 chanter major. It almost immediately afterwards divides into 
 two principal trunks. 
 
 One of these trunks, the more superficial, advances between 
 the gluteus medius and the maximus, and distributes branches to 
 them ; also, to the posterior margin of the maximus, where it 
 comes from the posterior sacro-sciatic ligament. The more 
 deeply-seated trunk goes forwards between the gluteus medius 
 and minimus, and subdivides into three orders of branches for 
 their supply. One set follows the superior margin of the gluteus 
 minimus towards the anterior superior spinous process ; another 
 set passes nearer the middle of the gluteus minimus ; and the 
 third set still lower down upon the dorsum of the ilium, above 
 the acetabulum ; some of the ramifications go to the capsular li- 
 
234 CIRCULATORY SYSTEM. 
 
 gament of the joint, where they anastomose with branches from 
 the femoral artery. 
 
 The Ischiatic Artery (Arteria Ischiadica) is somewhat smaller 
 than the gluteal, but looks rather more like the continuation of 
 the hypogastric. It descends between the rectum and the pyri- 
 formis muscle, and issues under the lower margin of the latter, 
 out of the pelvis, being there placed in front of the sciatic nerve. 
 It goes downwards on the back of the thigh, between the tro- 
 chanter major and the tuberosity of the ischium, being at the in- 
 ternal edge of the sciatic nerve, and on the posterior face of the 
 small rotator muscles of the thigh. It sends off in the pelvis the 
 Internal Pudic Artery, and also some inconstant branches, of 
 small size, to the viscera within the pelvis ; when it has emerged 
 from the latter, it detaches some considerable branches to the ori- 
 gin and to the inferior margin of the gluteus magnus muscle, and to 
 the small rotator muscles. The branch which may be consi- 
 dered as the continued trunk of the ischiatic, descending on the 
 f-posterior face of the thigh, along with the sciatic nerve, under 
 the hamstring muscles, is lost in ramifications to them, and by 
 anastomoses with the perforating arteries. 
 
 The< Internal Pudic Artery, (Arteria Pudica Internal) though a 
 branch of the ischiatic, is only in a slight degree smaller. It 
 arises a little above the spinous process of the ischium, in the 
 pelvis, in front of the sciatic plexus, and getting from the pelvis 
 between the anterior sacro-sciatic ligament and the inferior 
 margin of the pyriformis muscle, it passes over the posterior 
 face of the anterior sacro-sciatic ligament, at the spinous process 
 of the ischium. It immediately afterwards returns into the ca- 
 vity of the pelvis, between the two sacro-sciatic ligaments, at 
 the place where the obturator internus muscle winds over the 
 ischium ; it then winds along the internal face of the latter bone 
 and of its ascending ramus, at the inferior margin of the obtu- 
 rator internus muscle ; and continues on the internal face of the 
 ramus of the pubes, between the two laminae of the triangular 
 ligament, above the crus of the penis to the symphysis of the 
 pubes. 
 
INTERNAL ILIAC ARTERY, AND ITS BRANCHES. 235 
 
 In this course the Internal Pudic Artery detaches several im- 
 portant branches, in the following order : 
 
 a. A ramification along the inferior margin of the pyriformis, 
 to this muscle and to the parts on the posterior face of the neck 
 of the os femoris, where it anastomoses with the other arteries 
 of this region. 
 
 b. The Lower Haemorrhoidal Artery (Art. Hcemorrhoidea In- 
 ferior Externa) to the inferior part of the rectum, and to the 
 
 external sphincter ani muscle. This artery arises after the inter- 
 nal pudic has returned within the pelvis, and consists sometimes 
 in several branches. 
 
 c. The Perineal Artery (Art. Perinea, Transversa Perinei) has 
 its root near the origin of the transversus perinei muscle, and 
 advancing obliquely forwards is distributed in several ramifica- 
 tions to the muscles and integuments of the perineum, and to the 
 posterior part of the scrotum. It is unavoidably cut in the late- 
 ral operation for the stone. In the female it goes to the sphinc- 
 ter vaginae and to the labium externum. 
 
 d. When the internal pudic has got beyond the transversus 
 perinei muscle near the beginning of the crus penis, it detaches 
 to the bulb of the urethra, along the posterior margin of the tri- 
 angular ligament, a branch which penetrates to the corpus spon- 
 giosum, and is minutely distributed upon it, some of its ramifica- 
 tions reaching to the corpus cavernosum. This branch is called, 
 by M. Chaussier, Urethro-bulbar, and instead of being always 
 distinct, it on some occasions comes from the Perineal. 
 
 e. At the under part of the symphysis pubis, between it and 
 the back of the penis, the internal pudic sends forwards, on the 
 dorsum of the penis, a superficial branch, (Ramus Superficialis 
 Dorsi Pe?iis.) It advances to the end of the penis, under the 
 skin, being parallel with its fellow of the other side, and near to 
 it: sometimes the two unite after a short course. They are dis- 
 persed in branches to the integuments, and to the elastic liga- 
 ment of the penis. 
 
 /. The Cavernous Artery of the Penis (Art. Cavernosa Proftm- 
 da Pe?iis) may be considered as the terminating trunk of the in- 
 ternal pudic. It penetrates the corpus cavernosum, beneath the 
 symphysis of the pujbes, and quickly divides into many ramifica- 
 tions. The latter advance, and continue to subdivide upon the 
 
236 CIRCULATORY SYSTEM. 
 
 cells of the corpus cavernosum, to which they are principally 
 distributed : some of them reach the corpus spongiosum urethrae, 
 and others anastomose with the corresponding arteries of the 
 other side. 
 
 SECT. VIII. OF THE EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 
 
 The External Iliac Artery (Arteria lliaca Externa) extends 
 from the bifurcation of the primitive iliac to Poupart's ligament, 
 where it is continued to the lower extremity under the name of 
 the femoral artery. It looks like the continuation of the primi- 
 tive iliac, and descends at the superior strait of the pelvis along 
 the internal margin of the psoas magnus muscle. In the early 
 part of its course, it is anterior to the external iliac vein ; it then, 
 as it approaches Poupart's ligament, gets to its outer margin. 
 It is covered by the peritoneum in front. Where it passes be- 
 neath Poupart's ligament to the thigh, it is about half way be- 
 tween the anterior superior spinous process of the ilium and the 
 symphysis pubis, having the vein at its pubic margin and the 
 anterior crural nerve, half an inch from its iliac margin. No 
 branches of consequence arise before it reaches the crural arch ; 
 it then sends off two, the Epigastric and the Circumflex of the 
 ilium. 
 
 The Epigastric Artery (Arteria Epigastrica] arises somewhat 
 above the crural arch, at the line where the peritoneum is re- 
 flected from the fascia transversalis upon the iliac fascia. It at 
 first passes horizontally inwards, then rises obliquely upwards 
 and inwards, behind the spermatic chord, at the pubic margin 
 of the internal abdominal ring. Afterwards it reaches the ex- 
 ternal margin of the rectus abdominis muscle, two or three 
 inches above the pubes : ascending along it for a short distance, 
 it then passes to its posterior face, and continues ascending 
 above the umbilicus ; where being divided into several branches, 
 it terminates by anastomosing with the lower ramifications of 
 the internal mammary artery. 
 
 This artery is almost entirely spent upon the anterior parietes 
 of the abdomen, in ramifications, which anastomose with the 
 last intercostal and with the lumbar arteries. One of its small 
 
EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 237 
 
 twigs, following the course of the spermatic chord, or of the 
 round ligament, is distributed upon the cremaster, the tunica 
 vaginalis, and the scrotum of the male, and upon the mons ve- 
 neris of the female. In some cases it gives off the obturator 
 artery. 
 
 The Circumflex Iliac Artery (Arteria Circumfleoca llii) is of the 
 same size with the epigastric, and comes from the external iliac, 
 sometimes on a level with it, and on other occasions lower down, 
 even below the crural arch. It ascends outwardly towards the 
 anterior superior spinous process of the ilium, along the posterior 
 margin of the crural arch, and following afterwards the direc- 
 tion of the crista of the ilium, it anastomoses with the corre- 
 sponding branch of the ilio-lumbar artery. 
 
 The following branches come from it. In the early part of 
 its course some unimportant twigs are sent to the adjacent mus- 
 cles, as the sartorius, iliacus internus, and so on. At the ante- 
 rior superior spinous process, it divides into two branches, the 
 smaller ascends between the internal oblique and the transversa- 
 lis muscle, and is distributed upon them; the other branch, 
 which is the continuation of the main trunk along the crista of 
 the ilium at the margin of the iliacus internus muscle, sends ra- 
 mifications to the latter, and also to the posterior part of the 
 broad muscles of the abdomen, where it anastomoses with the 
 other arteries of this region. 
 
 Of the Femoral Artery. 
 
 The Femoral Artery (Arleria Femoralis, Cruralis] the continu- 
 ation of the external iliac, extends from the crural arch to the 
 perforation for its passage through the abductor magnus, which 
 is commonly one-third of the whole length of the os femoris, 
 above the knee joint. This great trunk, immediately below 
 Poupart's ligament is very superficial, and may be felt pulsating 
 where it passes over the pubes. It is there covered only by the 
 common integuments and the fascia femoris, which is thin ; it is 
 bounded internally by the femoral vein, externally by the crural 
 nerve, is half-way between the anterior superior spinous process 
 and the symphysis of the pubes, and lies upon the internal face 
 VOL. IL 31 
 
238 CIRCULATORY SYSTEM. 
 
 of the psoas magnus over the interstice between it and the pec- 
 tineus. In the upper third of its course the femoral artery is at 
 the inner edge of the rectus femoris, and at a short distance from 
 it ; it then inclines inwards, and occupies the angle formed by 
 the adhesion of the vastus internus to the adductor longus. The 
 sartorius, at first, is remote at its outside, but this muscle inclining 
 inwards in its descent gets to the exterior margin of the artery, 
 and afterwards covers it completely for the remainder of its 
 course. The femoral artery is in front of the femoral vein when 
 it has descended tliree or four inches below the crural arch : be- 
 hind the two is the arteria profunda. When the femoral artery 
 and vein reach the angle formed by the vastus internus and the 
 adductor longus, they are covered by a strong interlacement of 
 tendinous fibres from these muscles. 
 
 The femoral artery sends off these branches: 
 
 1. The Superficial Artery of the Abdomen (Art. ad Cutem Ab- 
 dominis) is small, and arises at the lower margin of Poupart's 
 ligament ; it goes upwards towards the umbilicus, lies beneath 
 the fascia superficialis abdominis, and is distributed to the in- 
 teguments of this region. One of its ramifications goes to the 
 inguinal glands. 
 
 2. The External Pudic Arteries (Art. Pudenda External) come 
 from the femoral at the same point, and are two or even three 
 in number ; they are of small size. One of them inclines inwards 
 along the groin, between the skin and the fascia femoris, and is 
 distributed to the integuments of the pubes to those of the 
 penis, and to the scrotum, or to the labium externum of the fe- 
 male. The second, and the third when it exists, are rather 
 lower down, and are dispersed upon very much the same parts. 
 The lymphatic glands of the groin also derive their supply of 
 blood from these external pudic arteries. 
 
 3. The Profound Artery, (Arteria Profunda Femoris,} the great 
 muscular artery of the thigh, is but slightly inferior in size to the 
 femoral itself, and comes from the latter at the distance of from 
 one to two inches below the crural arch. It lies behind the fe- 
 moral artery, and descends in that situation between the inser- 
 
EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 239 
 
 tion of the adductor brevis and the vastus interims muscle, to 
 the upper part of the insertion of the adductor longus. In this 
 course, its size is much diminished, by the origin from it of seve- 
 ral considerable trunks, as follows : 
 
 a. The External Circumflex, (Arteria Circumflexa External) 
 though most frequently a branch of the profunda, sometimes 
 comes from the femoral above or below it a short distance. It 
 goes immediately outwards between the rectus femoris muscle 
 and the cruralis, giving off some inconsiderable ramifications. 
 While between these muscles it divides into two branches, one 
 of which ascends, and the other descends; the former is distri- 
 buted to the anterior margins of the gluteus medius and minimus, 
 to the capsule of the joint, and the parts about the trochanter 
 major, anastomosing with the gluteal and the ischiatic. It is 
 said by Meckel, that these anastomoses have been found much 
 dilated where the external iliac artery has been taken up. The 
 descending branch is about the size of a crow quill, or even 
 larger ; it first passes obliquely downwards between the rectus 
 femoris and the cruralis, it then descends vertically under the 
 anterior margin of the vastus externus, between it and the cru- 
 ralis, to terminate at the knee, where it becomes superficial and 
 anastomoses with the articular arteries. It is, however, princi- 
 pally distributed to the vastus externus and to the cruralis. 
 
 6. The Internal Circumflex Artery (Arteria Circumflexa In- 
 terna) arises from the profunda, near the external circum- 
 flex, generally below it, but sometimes the reverse; in some 
 cases, it comes from the femoral artery itself, near the crural 
 arch. It passes transversely inwards, and dips into the inter- 
 stice between the pectineus and the psoas magnus, after having 
 given off some small twigs to the heads of the adjoining ad- 
 ductors. It then winds under the neck of the os femoris and 
 divides into two branches; the upper one goes to the capsular 
 ligament of the joint, to the obturator externus muscle, anasto- 
 moses with the obturator artery, and sends a branch behind the 
 adductor brevis to the upper part of the adductor magnus : the 
 inferior branch is larger than the other ; it descends behind the 
 adductor magnus and is distributed in branches to it, to the gra- 
 cilis, and to the hamstring muscles, sending upwards some rami- 
 fications (raini trochanterici] to the parts about the trochanter 
 
240 CIRCULATORY SYSTEM. 
 
 major, where they anastomose with the external circumflex ar- 
 tery. 
 
 c. Muscular branches of inconstant origin, and of inconsider- 
 able size, are sent from the profunda to supply the anterior face 
 of the adductor muscles. 
 
 d. The Perforating Arteries (Rami Profundi Perforantes) ob- 
 tain the name from their perforating the adductor magnus, which 
 they do near the linea aspera, so as to get to the back of the 
 thigh. They commonly are four in number, and as they come 
 off successively from the profunda, they are designated numeri- 
 cally. In some cases, however, they are reduced to one, by be- 
 ing concentrated in a common trunk, which, penetrating high up 
 the adductor magnus, and afterwards descending on its posterior 
 face, is dispersed upon the muscles on the back of the* thigh. 
 
 The First Perforating Artery arises somewhat below the tro- 
 chanter minor, and penetrates the adductor magnus a little be- 
 low its superior margin. One of its branches ascends towards 
 the trochanter major, where it anastomoses with the external 
 circumflex and with the gluteal, while another descending is 
 spent upon the heads of the flexor muscles of the leg. 
 
 The Second Perforating Artery gets to the back of the thigh, 
 at the lower margin of the insertion of the gluteus maximus into 
 the linea aspera, being distributed in that region, and to the cor- 
 responding portion of the long head of the biceps flexor cruris. 
 
 The Third Perforating Artery penetrates the Adductor mag- 
 nus somewhat below the commencement of the short head of 
 the biceps, and is dispersed upon the adductor and the adjacent 
 portion of the flexor muscles. 
 
 The Fourth Perforating Artery penetrates the insertion of the 
 adductor magnus an inch and a half above the opening in it, for 
 the femoral artery ; it, in the same way, supplies the posterior 
 face of the adductor and the adjacent muscles. 
 
 As a summary, it will be readily understood that the profunda 
 is, in this way, through the external and the internal circumflex, 
 and through the perforating arteries, distributed upon all the 
 large muscles of the thigh. 
 
 After the origin of the profunda, the Femoral Artery gives 
 
POPLITEAL ARTERY, AND ITS BRANCHES. 241 
 
 off, at different points of its course to the opening of the ad- 
 ductor magnus ; several twigs the size of a large knitting needle, 
 which go to the sartorius, the gracilis, the adductors, and the 
 extensors on the front of the thigh ; but they are too inconstant 
 to require more particular description. 
 
 The Anastomosing Artery (Arteria Anastomotica) is the last 
 branch of the femoral, and arises just before it perforates the 
 adductor magnus. It descends to the knee, in front of the ten- 
 don of the latter, concealed by the internal margins of the vastus 
 internus muscle. It sends off many small twigs to the adjacent 
 muscles, and terminates below by anastomosing with the inter- 
 nal articular arteries. It is about the size of a crow-quill. 
 
 The Popliteal Artery (Arteria Poplitcea) is the continuation of 
 the femoral, after the latter has passed through the tendinous 
 insertion of the adductor magnus, and extends from this point to 
 the opening in the interosseous ligament of the leg, just below 
 the head of the tibia. It, first of all, passes from the internal 
 margin of the os femoris, to the notch between the condyles; 
 being there placed in the middle between the internal and the 
 external hamstring muscles, and surrounded by a mass of adi- 
 pose matter which fills up the hollow of the ham. It is in con- 
 .tact, anteriorly, with the knee joint, and a little below the latter 
 with the popliteus muscle, descending there between the heads 
 of the gastrocnemius. It is covered, in the greater part of its 
 extent, posteriorly, by the popliteal vein, and by the sciatic nerve, 
 the latter being more superficial than the vein. 
 
 The popliteal artery sends off some small branches to the 
 hamstring muscles, and to the parts contained between the lat- 
 ter, which are too irregular and inconstant for description. The 
 following arteries, also, come from it: 
 
 1. The Superior Internal Articular Artery (Jlrt. JLrticularis 
 Superior Internet) arises at or above the internal condyle, and 
 frequently consists in two trunks. It passes through the ten- 
 don of the adductor magnus, just above the condyle; it then be- 
 gins to distribute itself in branches, some of which are spent 
 
242 CIRCULATORY SYSTEM. 
 
 upon the lower part of the vastus internus muscle, and others 
 upon the superior internal part of the knee joint. 
 
 2. The Superior External Articulating Artery (*ftrl. Articu- 
 laris Superior Externa] arises from the popliteal, somewhat 
 above the external condyle of the os femoris. It winds, hori- 
 zontally, above the external condyle, around the bone, between 
 it and the lower part of the biceps flexor cruris, and is then dis- 
 tributed, also, in two orders of branches, some of which supply 
 the lower part of the vastus externus muscle, and others the 
 superior external portion of the knee joint. 
 
 3. The Middle Articular Artery (*flrt. Articularis Media) 
 is smaller than either of the above, and sometimes comes from 
 one of them, but generally from the popliteal, on a line with 
 the articulation of the knee. It is distributed to the posterior 
 part of the capsular ligament, to the crucial ligaments, and to 
 the corresponding adipose matter. 
 
 4. The Inferior Internal Articular Artery (Art. Articularis In- 
 ferior Interna) arises on a line with the inferior part of the inter- 
 rial condyle, sometimes lower down. Its origin is very much 
 concealed by the internal head of the gastrocnemius; it passes 
 beneath the latter, and then between the internal lateral liga- 
 ment of the knee and the head of the tibia; consequently, it is 
 covered by the internal hamstring muscles. It afterwards as- 
 cends towards the patella, and is distributed in numerous 
 branches to the inferior internal part of the knee joint, and to 
 the adjacent portion of the tibia. 
 
 5. The Inferior External Articular Artery (Art. Articularis 
 Inferior Externa) arises near the last, below the external condyle, 
 being concealed by the belly of the plantaris. It passes, hori- 
 zontally, or nearly so, between the popliteus and the outer head 
 of the gastrocnemius, and afterwards beneath the tendon of the 
 biceps and the external lateral ligament of the joint, around the 
 external face of the head of the tibia. It gives small branches 
 to these several parts, and is then distributed, by two orders of 
 
EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 243 
 
 ramifications, to the superficial and to the more deeply seated 
 parts at the external inferior portion of the knee joint. 
 
 These several articular arteries anastomose freely with each 
 other, and are minutely ramified on the knee joint and the con- 
 tiguous structure. They also anastomose with the long de- 
 secnding branch of the external circumflex of the thigh, with 
 the ananstomotica of the femoral, and with the tibial recurrent. 
 
 6. The Gastrocnemial Arteries (Arterial Gemellce) are two in 
 number, one for each head of the gastrocnemius. They arise 
 commonly between the superior and the inferior articular arte- 
 ries, and are about the same size. They penetrate into the 
 muscle, and supply it with blood, terminating their course near 
 the lower part of its bellies. 
 
 Moreover, some small branches, which go to the contiguous 
 muscles, are frequently observed here; also, the nutritious ar- 
 tery of the tibia. But their number and condition are very in- 
 constant. Near the head of the fibula, branches go from the 
 popliteal artery to the upper end of the soleus muscle. 
 
 Generally, on a level with the aperture in the upper part of 
 the interosseous ligament, but sometimes an inch or two higher 
 up, the popliteal artery terminates by dividing into two large 
 trunks, the Anterior and the posterior Tibial. 
 
 The Anterior Tibial Artery (Art. Tibialis interior] passes 
 forwards through the foramen of the interosseous ligament, just 
 below the head of the fibula, and runs down the front of the leg 
 and foot, as far as the base of the metatarsal bone of the great 
 toe. In this course, its relative situation is as follows: It rests 
 upon the front of the interosseous ligament of the leg, on a line 
 drawn from the middle anterior part of the head of the fibula 
 to the middle of the ankle joint. Superiorly, it is bounded on 
 the tibial side by the tibialis anticus muscle, and on the other 
 by the extensor longus digitorum: lower down on the leg, the 
 place of the latter is supplied by the extensor pollicis pedis. 
 Somewhat above the ankle joint the artery, leaving the inter- 
 osseous ligament, rests upon the front of the tibia, and then gets 
 to the top of the foot, between the joint and the annular liga- 
 
244 CIRCULATORY SYSTEM. 
 
 ment. Under the ligament it is crossed by the tendon of the 
 extensor pollicis, which gets to its inner side, and afterwards 
 continues so. The anterior tibial nerve adheres to it, in its 
 whole length. 
 
 The following branches come from the anterior tibial ar- 
 tery: 
 
 1. The Recurrent Tibial (<flrt. Tibialis Recurrens) ascends 
 through the upper extremity of the tibialis anticus muscle, having 
 come off from the anterior tibial immediately upon the latter 
 getting to the front of the leg. Several small ramifications pass 
 from it to the heads of the contiguous muscles on the tibia, and 
 to the lower part of the knee joint, where it anastomoses with 
 the lower articular arteries of the knee. 
 
 2. Several small arterial twigs are afterwards sent to the 
 muscles and to the periosteum of the leg, as the anterior tibial 
 descends, but they are too inconstant in size and position to re- 
 quire description. 
 
 3. The Internal Malleolar Artery (Art. Malleolaris Internet) 
 arises from the anterior tibial, an inch or two above the ankle 
 joint. It descends, inwardly, between the tibia and the tendon 
 of the tibialis anticus, and, having gained the internal malleolus, 
 is distributed by branches upon it and upon the adjacent portion 
 of the articulation. 
 
 4. The External Malleolar Artery (Art. Malleolaris Externa) 
 consists most commonly in two arterial twigs of small size, but 
 frequently in one only. It arises in front of the ankle joint, 
 and going outwardly between it and the tendons of the extensor 
 digitorum longus, is spent upon the external face of the articu- 
 lation, where it inosculates with the peroneal artery. 
 
 This artery is sometimes of considerable size, in which case 
 it also supplies the outer part of the tarsus, and is a substitute 
 for the next. 
 
 5* The Tarsal Artery (Arteria Tarsea) arises from the anterior 
 tibial, somewhat below the ankle joint near the scaphoides, and, 
 
EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 245 
 
 going outwardly beneath the extensor brevis digitorum muscle, 
 it is distributed in branches near the external ankle, and upon 
 the outer upper surface of the tarsus. It anastomoses with the 
 external malleolar, with the external plantar, and with the me- 
 tatarsal artery. 
 
 Some'small branches also pass from the anterior tibial at this 
 point to the upper internal face of the tarsus. 
 
 6. The Metatarsal Artery (*2rt. Metatarsea) arises just be- 
 low the last. It is directed forwards and outwards beneath the 
 extensor brevis muscle, and forms a sort of arch at the roots of 
 the metatarsal bones. It furnishes several ramifications to the 
 upper surface of the tarsus and the contiguous parts; amongst 
 them is an interosseal artery for each of the three outer interos- 
 seal spaces. These arteries communicate, by small anastomoses, 
 with the arteries of the sole of the foot, both at the bases and at 
 the ends of the metatarsal bones, and terminate in front by sup- 
 plying the backs of the small toes. 
 
 This artery is sometimes a branch of the tarsal. 
 
 7. The Dorsal Artery of the Great Toe (Art. Dorsalis Hal- 
 lucis) arises from the anterior tibial at the root of the first me- 
 tatarsal bone. It runs along the superior face of the first me- 
 tatarsal interval, and, having reached the anterior end of it, di- 
 vides into two branches, one of which goes to the back of the 
 great toe and the other to the tibial margin of the next toe. 
 
 The Anterior Tibial, in its course from the ankle joint to the 
 base of the first metatarsal bone, is sometimes called Pedal (#r- 
 teria Pedicea;} at the posterior end of the first metatarsal inter- 
 val, being still of considerable size, it sinks down to the sole 
 of the foot, and joins itself to the external plantar artery at this 
 point. 
 
 It frequently happens that the anterior tibial being small in 
 its course down the leg, is joined by the continued trunk of the 
 peroneal, which perforates the interosseous ligament somewhat 
 above the ankle joint. Afterwards the trunk formed by this 
 union, being of considerable size, follows the course and has the 
 distribution mentioned. 
 VOL. II. 32 
 
246 CIRCULATORY SYSTEM. 
 
 The Posterior Tibial Artery (Arteria Tibialis Posticti) is 
 sometimes called, at its commencement, till it gives off the pe- 
 roneal, tibio-peroneal; it extends from the head of the tibia to 
 the sinuosity of the os calcis, in a line from the middle of the 
 ham to the internal ankle. It is at the tibial side of the back of 
 the leg, on the posterior face of the flexor longus digitorum mus- 
 cle; and covered by the fascia of the latter. In the two supe- 
 rior thirds of its course, it is concealed behind by the gastroc- 
 nemius and the solaeus muscle: in the inferior third, it is at the 
 internal margin of the tendo-achillis. At the ankle joint, be- 
 fore it passes into the sinuosity of the os calcis, it is between 
 the tendon of the tibialis posticus and that of the flexor lon- 
 gus pollicis pedis, being covered by the laciniated ligament. It 
 is accompanied, at its external margin, by the posterior tibial 
 nerve. 
 
 The posterior tibial artery is distributed after the following 
 manner: 
 
 1. The Peroneal Artery (Jlrteria Peronea] is its first branch 
 of any importance, and is but little smaller than the continued 
 trunk. It arises an inch or two below the origin of the ante- 
 rior tibial, and extends, on the posterior face of the leg, to the 
 external ankle. It is, in some measure, concealed by the pos- 
 terior side of the fibula, being placed there between the origin 
 of the flexor longus pollicis muscle and the external edge of the 
 tibialis posticus. It is covered behind by the flexor longus pol- 
 licis, by the soleus, and by the gastrocnemius; it is, therefore, 
 deep and of extremely difficult access in the living body. 
 
 In this course, it sends small branches to the gastrocnemius, 
 to the soleus, and to the other contiguous muscles on the back 
 of the leg. After having descended two-thirds of the length of 
 the fibula, it divides into an anterior and a posterior branch. 
 The former traverses the interosseous ligament, and, descend- 
 ing in front of it, covered by the muscles which arise from the 
 lower part of the fibula, is distributed upon the upper external 
 part of the foot near the ankle joint. The posterior branch con- 
 tinues in the primitive course of the peroneal artery at the in- 
 ternal posterior margin of the fibula, and descending behind the 
 tibio-peroneal articulation, reaches the external face of the os 
 
EXTERNAL ILIAC ARTERY, AND ITS BRANCHES. 247 
 
 calcis; it detaches several small ramifications to the contiguous 
 muscles; and, upon the os calcis, is divided into twigs which 
 supply the adjacent parts and the integuments below the exter- 
 nal ankle. 
 
 2. In the descent of the posterior tibial artery to the hollow 
 of the os calcis, it detaches several small muscular branches, 
 principally to the tibialis posticus, and to the flexors of the toes. 
 One twig, which is the nutritious artery of the tibia, comes from 
 its upper part when not furnished from the popliteal artery, and 
 enters the foramen on the posterior surface of the bone. 
 
 While the posterior tibial is in the hollow of the os calcis, 
 between it and the abductor muscle of the great toe, it furnishes 
 some small twigs to the contiguous muscles, and to the integu- 
 ments of the sole of the foot; it then divides into two branches, 
 the Internal and the External Plantar Artery. 
 
 The Internal Plantar Artery (Jlrt. Plantaris Interna) is 
 much smaller than the other. It advances between the abductor 
 pollicis pedis and the internal inferior margin of the sole of the 
 foot, and terminates at the anterior end of the first metatarsal 
 bone, by joining the internal digital artery of the great toe. In 
 this course, it sends, continually, small ramifications to the mus- 
 cles of the great toe and to the flexor brevis digitorum pedis. 
 One of the largest of these ramifications comes off near the os 
 scaphoides, and cruises along the internal margin of the abduc- 
 tor pollicis to its anterior end; another becomes superficial on 
 the sole of the foot, between the abductor pollicis and the flexor 
 brevis, and goes forward as far as the other. 
 
 The External Plantar Artery (Jlrt. Plantaris Externa] is 
 the continuation of the posterior tibial, and diverges from the 
 internal plantar towards the outer margin of the sole of the foot, 
 between the flexor brevis digitorum pedis and the flexor acces- 
 sorius. Having reached the internal margin of the abductor 
 minimi digiti, it advances along the latter to the base of the me- 
 tatarsal bone of the fourth toe; it then makes a curvature for- 
 wards and inwards, across the metatarsal bones, between the ten- 
 
248 CIRCULATORY SYSTEM. 
 
 dons of the flexor longus and the inter osseous muscles, to the first 
 metatarsal interval, where it is joined by the anterior tibial ar- 
 tery from above. This curvature is the Arc us Plantaris, of 
 which the concavity is behind and inwards. 
 
 The external plantar artery is distributed as follows : 
 Shortly after its origin, it detaches a branch which goes back- 
 wards and outwards, and which, keeping close to the os calcis 
 in front of its tuberosity, is distributed to the heads of the mus- 
 cles arising from it, and to the outer surface of the heel ; it "also 
 sends an arteriole along the external edge of the abductor mini- 
 mi digiti. 
 
 At the base of the fourth metatarsal bone, arises a branch 
 called the External Digital Artery of the Little Toe. It goes at 
 first deeply along the internal margin of the muscles situated on 
 the fifth metatarsal bone, and, afterwards, at the head of the lat- 
 ter, it gets between them and the bone, and is distributed along 
 the external margin of the little toe. 
 
 The four Digital Arteries of the foot arise next successively 
 from the arcus plantaris, at or near the metatarsal intervals. 
 They run along the inferior surface of the interosseous muscles, 
 getting to the bases of the first phalanges above the transversalis 
 pedis. Each artery there bifurcates, so as to supply the opposed 
 surfaces of the adjacent toes, in the same way that the digital 
 arteries of the hand are distributed. 
 
 The digital artery of the first metatarsal interval which comes 
 from the internal extremity of the arcus plantaris, where the an- 
 terior tibial artery joins the latter, goes forwards concealed by 
 the flexor brevis of the great toe : just behind the sesamoid bones, 
 it sends a branch which supplies the internal side of the great 
 toe, being its internal digital artery, and anastomoses with the 
 internal plantar artery. What remains of it, is still a trunk of 
 considerable magnitude, which advancing to the space between 
 the first phalanx of the great toe and of the toe next to it, there 
 bifurcates, as mentioned, so as to supply the opposite sides of 
 these two toes. 
 
 The Perforating Arteries, as they are called, are of two kinds, 
 
OF THE VEINS. 249 
 
 the anterior and the posterior. The former arise from the con- 
 vexity of the plantar arch, and being destined principally to the 
 interosseous muscles, anastomose at the anterior end of the lat- 
 ter with the branches from the metatarsal artery, which supply 
 their superior surface. The posterior perforating arteries come 
 also from the plantar arch, and penetrating the posterior end of 
 the interosseous spaces, anastomose also with the metatarsal ar- 
 teries on the dorsum of the foot. 
 
 The preceding trunks of the internal and of the external plan- 
 tar arteries are the principal ones which are found in the bottom 
 of the foot, but from them there arise an immense number of ar- 
 terioles ; which, descending vertically between the interstices of 
 the muscles and of the aponeurosis plantaris, supply the adipose 
 matter and the skin of the sole of the foot, so as to render them 
 extremely vascular. 
 
 CHAPTER III. 
 
 OF THE VEINS. 
 
 THE veins of the body, assembling from different points, unite 
 successively into the ascending and into the descending vena 
 cava, which discharge their blood into the right auricle of the 
 heart. The veins of the head, of the upper extremities, and of 
 the thorax, run into the descending cava, while the veins of the 
 abdomen and of the lower extremities concur to form the 
 ascending cava. 
 
 SECT. I. OF THE VEINS OF THE HEAD AND NECK, 
 
 Many of these veins are described elsewhere with the en- 
 cephalon and with the eye, to which account the reader is re- 
 ferred. The others are more superficial, and arise as follows: 
 
 ^ The Facial Vein* ( Vena Facialis) observes the course of the 
 
250 CIRCULATORY SYSTEM, 
 
 facial artery, being placed behind the latter. It arises upon the 
 forehead by a considerable number of roots, which unite into a 
 single trunk called the frontal vein. This vein descends from 
 the forehead, over the root of the nose, along the internal can- 
 thus of the orbit. It there receives re-enforcements from the 
 eyelids, and anastomoses with the ophthalmic veins ; descending 
 afterwards, in the same way with the facial artery, and taking 
 the name of facial vein, it receives successively the veins from 
 the nose, from the outer side of the orbicularis palpebrarum, from 
 the upper and lower lips, and from the muscles and the inte- 
 guments of the face. It descends to the neck at the anterior 
 margin of the masseter muscle, and is then augmented by the 
 ranine, the submental, and the inferior palatine veins, and im- 
 mediately afterwards goes into the internal or the external ju- 
 gular vein. 
 
 The Ranine Vein ( Vena Ranina) arises at the point of the 
 tongue, and then goes along its under surface, where it can 
 be readily seen by turning up the end of the tongue. It joins 
 the facial near the posterior margin of the mylo-hyoideus mus- 
 cle. 
 
 The Submental Vein ( Vena Submentalis) arises by ramuscles 
 from the sublingual and submaxillary glands, and from the con- 
 tiguous muscles. It joins the facial vein a little below the last : 
 sometimes it runs into the superior thyroidal vein. 
 
 The Inferior Palatine Vein (Vena Palatina Inferior] arises 
 principally from the soft palate and from the tonsil gland, but 
 receives a few twigs from the contiguous parts. It corresponds 
 with the inferior palatine artery, a branch of the lingual ; and 
 descends the pharynx alongside of it, and terminates in the 
 trunk of the facial near the last. 
 
 The Lingual Vein (Vena Lingualis] has its origin from a 
 plexus of veins situated on the root of the tongue under its lining 
 merribrane, between the epiglottis and the foramen caecum: 
 branches are also sent to it from the muscular structure of the 
 tongue, from the sublingual gland and from the adjacent mus- 
 
VEINS OF THE HEAD AND NECK. 251 
 
 cles. and it anastomoses with the vena ranina. It goes back- 
 wards between the hyo-glossus and the mylo-hyoideus muscle, 
 along the superior margin of the os hyoideus, and then dis- 
 charges into the internal jugular vein near the facial. 
 
 The Pharyngeal Vein ( Vena Pharynged) arises from a plexus 
 of veins belonging to the pharynx, and discharges either into 
 the lingual or into the internal jugular near it. 
 
 The Superior Thyroid Vein (Vena Thyroidea Superior] cor- 
 responds with the distribution of the superior thyroid artery, 
 in the origin of its primitive roots. Having collected the lat- 
 ter into one or more trunks, it passes upwards and backwards 
 beneath the sterno-hyoid and thyroid muscles, and discharges 
 itself into the upper part of the internal jugular, or into one of 
 the large branches of the external jugular. 
 
 The Occipital Vein (Vena Occipitalis) arises from the branches 
 of the occipital artery, and following the course of the latter, 
 beneath the muscles connected with the mastoid process of the 
 temporal bone, it is discharged into the upper part of the inter- 
 nal jugular or of the external; more rarely into the latter. 
 
 The Diploic Veins (Vena Diploicce) have been described in 
 the account of the bones of the cranium as situated between the 
 two tables in the diploic structure, and commence by very fine 
 capillary tubes from its lining membrane. The one in the fron- 
 tal bone discharges itself into the frontal vein, that in the occi- 
 pital bone into the occipital vein, and the two in the parietal 
 bone into the deep temporal veins. They do not open each by 
 one orifice, but by several, which makes their termination not 
 very distinct or abrupt: besides which, they communicate free- 
 ly by a crowd of raniuscles, with the veins of the scalp on the 
 outside, and with those of the dura mater internally. 
 
 i 
 
 dii 
 
 The Superficial Temporal Vein (Vena Temporalis Superfi- 
 cialis) corresponds with the temporal artery, and takes its rise 
 from the terminating ramifications of the latter. It is imme- 
 diately below the skin. Its branches communicate freely with 
 
252 CIRCULATORY SYSTEM. 
 
 each other, and with the branches of the frontal and of the occi- 
 pital vein: at the zygoma it receives the trunk of the Middle 
 Temporal Vein, which, collecting the blood from the temporal 
 muscle and other parts within the zygoma, perforates the tem- 
 poral fascia to discharge itself into the superficial temporal vein. 
 
 / The Temporal Vein, (Vena Temporalis^ which is formed 
 by the junction of the Middle and the Superficial Temporal, 
 descends over the root of the zygoma, in company with the ar- 
 tery, and penetrates, like the latter, through the substance of the 
 parotid gland. It is joined, near the neck of the lower jaw, by 
 the internal maxillary vein. It is also joined, in its descent 
 through the parotid gland, by the anterior auricular veins, by 
 the parotid veins, and" by the transverse facial, all of which cor- 
 respond with the arteries of the same name. The temporal vein, 
 on issuing from the parotid gland, immediately afterwards be- 
 comes the External jugular; but, occasionally, it ends wholly or 
 in part in the internal jugular. 
 
 The Internal Maxillary Vein (Vena Maxillaris Internd] is 
 derived from the terminating ramifications of all the arteries 
 into which the internal maxillary is divided; it is, therefore, 
 composed of the spheno-palatine vein, which brings the blood 
 from the nose, of the infra-orbital, of the pterygoids, inferior 
 maxillary, deep-seated temporal, and so forth, with the excep- 
 tion of the vein, which might belong to the middle artery of 
 dura mater, but which does not exist according to Portal and to 
 Hippolytus Cloquet. But, by the aid of the spheno-palatine 
 vein, the internal maxillary communicates with the sinuses in 
 the bottom of the cranium, by branches, called the Emissary 
 Veins of Santorini,* which pass through the foramen ovale, ro- 
 tundum, and spinale. It also communicates with the plexus of 
 veins on the side of the pharynx. 
 
 The External Jugular Vein (Vena Jugularis Externa) is the 
 continuation of the temporal. It descends on the neck almost 
 vertically, between the platysma myodes and the sterno-mas- 
 
 * Obs. Anat. chap. iii. p. 74. 
 
VEINS OF THE HEAD AND NECK. 253 
 
 loideus,in the direction of the fibres first, and crossing those of the 
 latter obliquely. Just behind the clavicle, at the external mar- 
 gin of the sterno-mastoideus, it opens into the subclavian vein, 
 in front of the scalenus anticus muscle. Sometimes, instead of 
 one trunk only, there are two or three, which unite at a varia- 
 ble distance above the subclavian. This vein varies also in its 
 size, and in the branches from which it is made up: sometimes 
 it receives the facial vein, and on other occasions the latter runs, 
 as stated, into the internal jugular. The condition and arrange- 
 ment of the internal and external jugulars are, indeed, so incon- 
 stant, in regard to the trunks that compose them, that it is 
 scarcely possible to give more than a very general description 
 of them with tolerable accuracy. 
 
 The external jugular, in going down the neck, anastomoses 
 more or less with the internal jugular, either directly or by its 
 branches: one of these anastomoses is found near the angle of 
 the lower jaw, about the trunk of the facial vein, and is so large 
 as to explain the difference of opinion among anatomists in re- 
 gard to the latter's termination. Sometimes the occipital vein, 
 or a large trunk from it, joins the external jugular. At the 
 lower part of the neck, the external jugular is augmented by 
 the superficial cervical veins. Some of these come from the 
 lower part of the neck, near the shoulder, and join the jugular 
 just above the clavicle; others are placed on the lower front 
 part of the neck, above the sternum, and there form with each 
 other a remarkable and an irregular plexus, consisting in nu- 
 merous meshes. It frequently happens that the external jugu- 
 lars of the two sides, just before they terminate, anastomose 
 with each other by a large horizontal trunk, which runs just 
 above the end of the sternum, in front of the sterno-mastoid, 
 sterno-hyoid, and the thyroid muscles: this trunk, on other oc- 
 casions, goes more deeply, and behind these muscles, from one 
 subclavian vein to another, or to a jugular; its mode of attach- 
 ment is, indeed, much varied: when it exists, however, it fre- 
 quently receives several of the superficial veins of the neck, and 
 the inferior thyroidal. 
 
 The Internal Jugular Vein (Vena Jugularis Inferno) extends 
 from the basis of the cranium to the internal margin of the first 
 VOL. II. 33 
 
254 CIRCULATORY SYSTEM. 
 
 rib, at'the insertion of the scalenus anticus muscle. The lateral 
 sinuses of the dura mater, receiving ultimately all the blood of 
 the brain, of the eye, and a portion of that of the nose, convey 
 it from the cranium through the posterior foramina lacera, 
 where they are joined to the upper end of the internal jugular 
 veins, the lining membrane of each sinus being continuous with 
 that of its respective veins. Each vein is somewhat enlarged 
 at its commencement, which is therefore called its Gulf or Sinus; 
 the right vein is frequently larger than the left. , The internal 
 jugular then descends in front of the transverse processes of the 
 vertebrae of J-he neck, on the outer side of the internal end of 
 the primitive cais^tid artery, and of the pneumogastric nerve. 
 It is concealed above by the styloid process of the temporal 
 bone, and the muscles belonging to it; it is crossed, half way 
 down the neck, by the omo-hyoideus muscle; and, in the great- 
 er part of its course, is beneath, and nearly parallel with the 
 anterior edge of the sterno-mastoideus. Having got behind the 
 sternal end of the clavicle, it is joined at the internal edge of 
 the scalenus anticus by the subclavian vein, and the union of 
 the two forms the vena innominata. 
 
 The internal jugular receives frequently a large anastomotic 
 branch, just alluded to, from the external jugular, at the under 
 margin of the parotid gland, between the digastric muscle and 
 the lower jaw, and it is in this vicinage that it is generally re- 
 enforced by the Occipital; the Lingual; the Facial; the Pha- 
 ryngeal; and the Superior Thyroidal Veins, that have been 
 described. 
 
 The Vena Innominata, or Brachio Cephalic Vein, is the trunk 
 formed on either side by the junction of the subclavian with the 
 internal jugular. On the right side it looks like the continua- 
 tion of the internal jugular, and descends in contact with the 
 right pleura, behind the right side of the sternum, for the dis- 
 tance of an inch or thereabouts. On the left side it crosses be- 
 hind the superior end of the sternum, descending obliquely in 
 this course, from left to right, until it joins the trunk on the 
 right side. It lies in front of the great vessels proceeding from 
 the arch of the aorta; and is much longer than the trunk of the 
 other side. 
 
VEINS OP THE HEAD AND NECK. 255 
 
 The Vena Cava Superior, or Descendens, arise from the 
 junction of the two venae innominate. It begins between the 
 cartilage of the first rib on the right side, and the arch of the 
 aorta, and descends to the superior posterior part of the right 
 auricle, into which it empties itself. Its course is not entirely 
 vertical, but inclining somewhat to the left side and forward. 
 It is about three inches long. The superior third of it is free, 
 and is in contact on the right with the pleura, and on the left 
 with the arteria innominata; the remaining portion of it is in- 
 vested by the pericardium, and has the aorta on its left anterior 
 face.* 
 
 k sr" 
 
 The following venous trunks discharge into the venae inno- 
 minatie, or into the descending cava. The Inferior Thyroidal; 
 the Vertebral; the Superior Intercostal; the Internal Mammary; 
 the Vena Azygos, and some others of smaller size. 
 
 1. The Inferior Thyroid Vein (Vena Thyroidea Inferior) 
 arises from the inferior part of the thyroid gland, by many 
 small roots, which anastomose with those of the opposite side. 
 It descends in front of the trachea, involved in the loose cellu- 
 lar and fatty matter lying upon it, and empties itself into the 
 left brachio-cephalic vein. 
 
 There is occasionally another thyroid vein, called the mid- 
 dle, which discharges itself into the lower part of the internal 
 jugular. 
 
 2. The Vertebral Vein ( Vena Vert ebr alls] is placed in the 
 same canal with the vertebral artery. At its upper extremity 
 it anastomoses with the occipital sinus, by a branch lodged in 
 the posterior condyloid foramen., In its descent of the canal of 
 the transverse processes, it communicates at each intervertebral 
 foramen with the vertebral sinuses, and also receives a branch 
 from the muscles of the neck. It issues at the sixth transverse 
 process, and going on the right side behind the subclavian ar- 
 tery, but on the left, in front of it, it is, finally, emptied into the 
 commencement of the vena innominata. 
 
 * In some very rare -cases there have been two descending venae cavse, one 
 for the right side and the other for the left. J. F. Meckel. 
 
256 CIRCULATORY SYSTEM. 
 
 3. The Superior Intercostal Vein ( Vena Inter cost alis Supe- 
 rior} is on the right side an inconsiderable trunk, sometimes 
 deficient, which commences by branches belonging to the two 
 first intercostal spaces, and empties into the vena innominata 
 just below the vertebral. On the left side it is much larger, 
 and arises from the six or eight superior intercostal spaces. It 
 lies on the left side of the bodies of the upper dorsal vertebrae, 
 and at each intercostal space, as it ascends, receives its contri- 
 bution of an intercostal vein, corresponding with the intercostal 
 artery; it also receives branches from the oesophagus, and about 
 the third dorsal vertebra the left bronchial vein is discharged 
 into it. Issuing from the thorax above, it discharges into the 
 left vena innominata near its commencement. 
 
 4. The Internal Mammary Vein ( Vena Mammaria Interna) 
 arises from the terminating branches of the internal mammary 
 artery, and in its .situation and course corresponds with the lat- 
 ter. It is re-enforced by small branches from the diaphragm, 
 the pericardium, and the thymus gland. Each internal mam- 
 mary vein discharges itself on its respective side into the vena 
 innominata near the superior intercostal. 
 
 5. The Vena Azygos is placed in the posterior mediastinum, 
 on the right anterior margin of the Dorsal Vertebrae, and dis- 
 charges itself in making an arch forwards over the root of the 
 right lung, into the descending cava, just above the introduction 
 of the latter into the pericardium. Its orifice there is supplied 
 with a membranous duplicature or valve, which prevents the 
 blood once discharged from the re-entering it. The valve is 
 sometimes double, and also somewhat removed from the orifice. 
 It was the observation of these valves, first of all, which called 
 the attention of Sylvius and of Charles Etienne to their existence 
 in other veins. 
 
 This vein begins in the abdomen, either by an anastomosis 
 with the ascending cava, or with the upper lumbar vein; it 
 then ascends into the thorax through the aortic orifice of the 
 diaphragm, and continuing to mount upwards beneath the pleura, 
 it lies on the right side of the thoracic duct, and crosses in front 
 of the intercostal arteries of the right side. In this course, it 
 
VEINS OF THE HEAD AND NECK. 257 
 
 receives from the ten inferior intercostal spaces of the right side, 
 their respective intercostal veins corresponding in their origin 
 and course with the intercostal arteries. About the sixth ver- 
 tebra of the back, it receives a trunk ( Vena Hemiazygos] which 
 is formed from the four or six lower intercostal veins of the left 
 side, and commences in the abdomen, also, by anastomosis with 
 the left emulgent vein or the left superior lumbar, and which 
 gets into the thorax either through the aortic orifice of the dia- 
 phragm, or through a special opening to the left of it. The 
 vena azygos also receives some small ramifications from the 
 oesophagus, and near the fourth dorsal vertebra, the right bron- 
 chial vein is discharged into it. Other small ramifications join 
 it from the parietes of the descending cava of the aorta, and of 
 the right pulmonary artery. Branches also proceed to it, or to 
 the intercostal veins, from the interior of the vertebral canal at 
 each intervertebral foramen. 
 
 This vein is commonly spoken of by anatomists, as forming 
 a great anastomosis between the ascending and the descending 
 cava. The tendency to establish this anastomosis is strikingly 
 confirmed by a preparation made by myself, when I was a stu- 
 in this institution, in 1813, and now in the Anatomical Cabinet, 
 where the ascending cava, instead of emptying, as usual, into 
 the lower part of the right auricle, ascended on the right side 
 of the dorsal vertebrae, and supplanting in situation and office 
 the vena azygos, discharged itself into the descending cava, in 
 a manner corresponding with the vena azygos, by making a 
 curvature forwards over the root of the right lung. 
 
 The Sinuses of the Vertebral Column* (Sinus Columnae 
 Vertebralis) are situated in the vertebral cavity, on the pos- 
 terior face of the bodies of the vertebras, and in front of the 
 dura matter of the spinal marrow. They are two long veins, 
 one at each margin of the posterior vertebral ligament, and ex- 
 tend from the foramen magnum occipitis to the inferior end of 
 the sacrum. They are maintained in their places by a loose 
 cellular tissue between the bones and the dura mater, and, there- 
 fore, unlike the sinuses of the brain, are entirely independent 
 of the dura mater. 
 
 * G. Breschet, Essai sur les Veines du rachis. Paris, 1819. 
 
258 CIRCULATORY SYSTEM. 
 
 These sinuses are small where they begin in the sacrum, and 
 are there merely two cylindrical veins surrounded by the loose 
 cellular matter, and which have an anastomosis between them. 
 In ascending the spine they enlarge, but not continually, as 
 they are somewhat smaller in the cervical than in the dorsal 
 vertebrae. On the body of each vertebra they are rather larger 
 than on the intervertebral substance: this giv r es them a knotted 
 appearance, which is especially distinct in the loins. 
 
 At the middle of each vertebra they are joined to one an- 
 other by transverse branches, which pass beneath the posterior 
 vertebral ligament, and receive the veins belonging to the can- 
 cellous structure of the bone. Externally, they communicate 
 with thfc vertebral veins in the transverse processes of the neck, 
 with the intercostal, and with the lumbar veins, as an opening 
 occurs between the adjacent vertebrae. They also receive many 
 delicate veins from the dura mater of the spine. These two 
 trunks terminate at their upper end by an anastomosis, through 
 the anterior condyloid foramen, with the internal jugular: they 
 also terminate by anastomosis with the anterior occipitaUsinus 
 and with the vertebral veins. 
 
 From the arrangement of these sinuses, it appears that each 
 bone of the spine has its own venous system or circle; which 
 also is the case in regard to the corresponding section of me- 
 dulla spinalis in early life, when it occupies the whole length 
 of the spine. Each of these circles, by the freedom of their 
 anastomoses, therefore, forms a link in a long chain of venous 
 circles belonging to the structure of the spine. 
 
 SECT. II. OP THE VEINS OP THE TIPPER EXTREMITIES. 
 
 The veins of the upper extremities are superficial and deep- 
 seated, and arise from the distribution of the axillary artery. 
 
 The Deep-seated Veins are found in company with each ar- 
 terial ramification, there being two veins to one artery gene- 
 rally. We thus have them observing the course of the arteries 
 of the hand, of the fore arm, of the arm, and of the shoulder. 
 At the bend of the arm, the two radial and the two ulnar veins 
 
VEINS OF THE UPPER EXTREMITIES. 259 
 
 coalesce into the two brachial veins, which attend the brachial 
 artery, one on each of its sides, and at intervals thrbw anasto- 
 motic branches across it. Sometimes, but one of these trunks 
 exists, with the exception of the lower part of the arm, where 
 there are most commonly two. The trunk (or trunks, as the 
 case may be,) is joined by the basilic vein, at a point varying 
 from the middle of the arm to the axilla. These venae comites, 
 or satellites, are invariably called after the arteries which they 
 attend, and having no difference from the latter in relative si- 
 tuation, a farther description of them may be dispensed with. 
 
 The Superficial Veins lie between the skin and the brachial 
 aponeurosis, and are considerably larger than the preceding. 
 Their earliest roots are seen on the back of the fingers; they 
 then appear on the back of the hand, on the posterior face of 
 the lower end of each interosseous space. There are commonly 
 six trunks in all: the one on the ulnar side of the hand, and 
 the three next to it, converge towards the middle of the back 
 of the carpus into a single trunk; the two others, one of which 
 comes from the thumb and the other from the back of the fore- 
 finger, converge to the outer end of the carpus, and there form 
 a single trunk also. Between these several trunks, there are 
 frequent anastomoses, and they, finally, assemble into two prin- 
 cipal branches called the Cephalic and the Basilic Vein. 
 
 The Cephalic Vein (Vena Cephalica, Radialis Cutanea] is 
 the trunk which comes from the thumb and from the fore fin- 
 ger, and has at first the name of Cephalica Pollicis. It ranges 
 along the anterior and radial margin of the fore arm, and re- 
 ceives, continually, an augmentation from small collateral 
 branches on the back of the fore arm. Having 'reached the 
 bend of the arm, it then* ascends along the external margin of 
 the biceps flexor cubiti till it reaches the lower margin of the 
 pectoralis major muscle; it then rises superficially along the in- 
 terstice between this muscle and the deltoid, to within eight or 
 ten lines of the clavicle, where it dips down to join the axillary 
 vein. Along the arm, it receives some small secondary cuta- 
 neous branches. 
 
260 CIRCULATORY SYSTEM. 
 
 The Basilic Vein (Vena Basilica, Cubitalis Cutanea] is 
 larger than the cephalic, and begins by the trunk which comes 
 from the ulnar side of the back of the hand, and is first called 
 the Vena Salvatella. On the fore arm, the basilic frequently 
 consists in two long trunks, the anterior and the posterior: in 
 this case, the posterior is the principal one, and runs along the 
 internal posterior edge of the ulna until it comes to the bend of 
 the arm; it then mounts over the latter, rising obliquely in front 
 of the internal condyle. The anterior branch begins near the 
 palm of the hand, runs up in front of the ulnar side of the fore 
 arm, and discharges itself into the median basilic vein over the 
 brachial artery in front of the bend of the arm. These two 
 trunks, or one as the case may be, receive the cutaneous veins 
 belonging to the ulnar side of the fore arm. 
 
 Above the elbow joint, the basilic gets below the fascia of 
 the arm at the inner edge of the biceps, and about the middle 
 of the arm becomes, by its junction with the venae satellites, 
 the Brachial Vein; but sometimes, as mentioned, this junction 
 occurs much higher up. 
 
 s ' The Median Vein ( Vena Mediana] arises, by branches, from 
 the wrist, from the palm of the hand, and from the middle of 
 the front of the fore arm. It forms a trunk which ascends in 
 front of the fore arm, and which, a few inches below the bend 
 of the arm, divides into two. One branch runs outwardly, in 
 ascending for an inch or two, and joins, at the outer side of the 
 bend of the arm, the cephalic vein; it is called, therefore, the 
 Median Cephalic. The other branch continues to ascend, and, 
 crossing obliquely the direction of the brachial artery, it re- 
 ceives, near the latter, the anterior trunk of the basilic vein, 
 and somewhat above the bend of the arm, runs into the proper 
 basilic vein: it is called the Median Basilic. 
 
 There is frequently a departure ^rom the preceding arrange- 
 ment of the median vein; the most common is where a trunk 
 begins from the cephalic, below the bend of the arm, and runs 
 obliquely in front of the latter to join the main trunk of the 
 basilic above the elbow joint. This oblique trunk stands in the 
 place of median cephalic and median basilic, and receives sue- 
 
VEINS OP THE UPPER EXTREMITIES. 261 
 
 cessively the median, the anterior, and the posterior basilic. It 
 is frequently the median itself, and has a short anastomosis, in 
 such case, with the cephalic vein. 
 
 The Superficial Veins anastomose frequently with each other, 
 so that, when they are all fully injected, a plexus of veins is 
 found immediately beneath the skin of the upper extremity 
 from one end to the other. The Venae Satellites also anasto- 
 mose frequently by branches which cross the artery to which 
 they belong. At the bend of the arm, at the wrist, and in dif- 
 ferent places, there are also anastomoses between the deep-seat* 
 ed and the superficial veins. 
 
 
 The Axillary Vein ( Vena Axillaris) results from the union 
 of the basilic with the brachial vein. It is below and in front 
 of the axillary artery, being included in the same sheath with 
 it, and also involved with the axillary plexus of nerves. It re- 
 tains its name from the lower margin of the arm pit to the un- 
 der surface of the clavicle, where, like the artery, it is then 
 called subclavian. In this course it is joined near the points 
 where the corresponding arteries are given off, by the Anterior 
 and the Posterior Circumflex Veins; by the Scapular; and by 
 the External Thoracic. 
 
 ' The Subclavian Vein (Vena Subclavia) extends from the 
 termination of the axillary to the vena innominata, where the 
 latter is constituted by the junction of the internal jugular with 
 the subclavian. In its course it goes under the subclavian mus- 
 cle, and is in front of the subclavian artery from the beginning, 
 but near it: afterwards it is separated from the artery by the 
 latter going between the anterior and the middle scalenus mus- 
 cle; whereas the vein runs over the anterior end of the first 
 rib, in front of the insertion of the scalenus anticus. 
 
 The Subclavian Vein is joined by some branches coming 
 from the shoulder and from the lower part of the neck, and, at 
 the outer margin of the origin of the sterno-mastoid muscle: it 
 is augmented by the addition to it of the external jugular. It 
 terminates at the internal margin of the scalenus anticus, as 
 mentioned in the vena innominata. 
 VOL. II. 34 
 
262 CIRCULATORY SYSTEM. 
 
 "SECT. III. VEINS OF THE LOWER EXTREMITIES. 
 
 The veins of the lower extremities, like those of the upper, are 
 deep-seated and superficial. The former follow the course of 
 the arteries, and are the venae satellites; there being, for the 
 most part, two veins for every artery as far up as the ham, and 
 also as regards the muscular branches of the thigh. These venae 
 satellites adhere closely to the artery, and are separated from 
 each other by the latter. They also have frequent anastomoses 
 with each other across the artery. 
 
 The Popliteal Vein ( Vena Poplitea) is a single trunk formed 
 fey the union of the anterior tibial, the posterior tibial, and the 
 peroneal veins. It begins on the posterior part of the head of 
 the tibia, and extends upwards through the ham to the perfora- 
 tion in the adductor magnus muscle, which transmits the femo- 
 ral artery. It is situated on the posterior face of the popliteal 
 artery, to which it closely adheres; and behind it is the popliteal 
 nerve, the continuation of the great sciatic. 
 
 The Femoral Vein (Vena Femoralis) is the continuation 
 upwards of the popliteal: it at first is placed behind the artery, 
 but in a short space it gets to its interior face, and continues to 
 adhere to it, in that situation, up to Poupart's ligament, where 
 it becomes the external iliac vein. At the usual distance below 
 the groin, where the arteria profunda is given off, the femoral 
 vein receives the vena cruralis profunda, which is derived from 
 the branches of this artery, and is rather more superficial than 
 it; the two, however, adhere closely together. Just below 
 Poupart's ligament the femoral vein receives several small 
 branches of vein-s corresponding with the external pudic arte- 
 ries. 
 
 j 
 
 The Small Saphena ( Vena Saphena Minor Externa) com- 
 mences by several small branches near the external side of the 
 top of the foot, and the external ankle; a trunk is formed by 
 behind c the latter, which ascends along the tendo-achillis 
 the posterior face of the gastrocnemius muscle, collecting 
 
VEINS OF THE LOWER EXTREMITIES. 263 
 
 several small veins from the back of the leg in its course. This 
 vein is superficial in its whole course, being placed immediate- 
 ly beneath the skin. In the ham, it goes fora short distance 
 along the internal face of the popliteal nerve, and then makes a 
 dip through the adipose matter there to empty into the popli- 
 teal vein. 
 
 It is said, by Portal, that the branches of this vein become 
 very apparent in persons who suffer from podagra, and from en- 
 largements of the lymphatic glands in the ham. In such case 
 their distention has been relieved by the application of leeches 
 along them. 
 
 / The Great Saphena ( Vena Saphena Magna Internet) is also- 
 superficial, has its primitive roots coming from the internal up- 
 per part of the foot, and from the sole of the latter. These 
 branches are assembled into a trunk which passes upwards in 
 front of the internal ankle, then ascends along the internal face 
 of the leg, in a line corresponding with the posterior margin of 
 the tibia. The great saphena continues its ascent over the in- 
 ternal condyle near its posterior part, and then mounts up the 
 internal face of the thigh, in a line corresponding nearly with 
 the internal margin of the sartorius muscle. It finally termi- 
 nates in the femoral vein about twelve or eighteen lines below 
 Poupart's ligament, an opening being left in the fascia femoris 
 for this purpose. 
 
 In the whole of this course the great saphena is situated be- 
 tween the skin and the fascia of the lower extremity ; it is, con- 
 sequently, so superficial, that in persons of moderate corpulency 
 it is very visible, and by slight pressure above, along with the 
 erect position, it becomes so much swollen, that it is easily 
 opened with the lancet where it passes over the internal ankle. 
 It receives, in its ascent, small branches from the anterior and 
 posterior part of the leg, from the corresponding surfaces of the 
 thigh, and near its termination it gets a few of the external pu- 
 dendal veins. 
 
 When the great and the small saphena veins are successfully 
 injected, their branches are seen to form a considerable num- 
 ber of anastomoses, which thereby produce a remarkable venous 
 
264 CIRCULATORY SYSTEM. 
 
 net-work, just beneath the skin of the whole inferior extre- 
 mity. 
 
 SECT. IV. VEINS OP THE ABDOMEN. 
 
 The External Iliac Vein, (Vena Iliaca Externa,} being the 
 continuation of the femoral vein, passes into the abdomen, un- 
 der Poupart's ligament, and in contact with the internal margin 
 of the external iliac artery. It there receives the epigastric, 
 and the circumflex iliac veins, corresponding with the arteries 
 of the same name; it also receives a vein of some size, which 
 enters by the abdominal canal in adhering to the spermatic 
 chord, and which comes from the coats of the testicle.* It 
 keeps then along the internal side of the artery, somewhat be- 
 hind it, at the superior margin of the- pelvis, and joins the hy- 
 pogastric vein opposite to the sacro-iliac junction, and thereby 
 forms the common iliac vein. 
 
 The Hypogastric Vein (Vena Hypogastrica, Iliaca Interna) 
 comes from the inferior part of the pelvis in front of the sacro- 
 iliac junction, and in company with the hypogastric artery. It 
 arises by branches corresponding with the distribution of the 
 latter to the viscera of the pelvis, and to its external parts; these 
 branches are so numerous at particular points, and 'have such 
 frequent anastomoses, that they are often named Plexus. Thus, 
 there is a hemorrhoidal plexus for the lower part of the rectum, 
 a vesicle for the bladder, a sacral for the sacrum, a pudendal for 
 the parts of generation in the male, a vaginal for the vagina, 
 and a uterine for the uterus of the female. 
 
 The Plexus Hemorrhoidalis, besides being connected with 
 the hypogastric, also anastomoses with the branches of the vena 
 portarum. 
 
 The Plexus Vesicalis is different in the two sexes. In man 
 it commences at the extremity of the penis by several branches, 
 which unite into two trunks of considerable size, the Venae 
 Dorsales Penis. The latter go along the upper face of the pe- 
 nis, near or at its middle, to the symphysis of the pubes, con- 
 
 II. Cloquet, Traite D'Anat. 
 
VEINS OP THE ABDOMEN. 265 
 
 tinually receiving in this course small trunks from the integu- 
 ments of the penis and from the scrotum. They then get into 
 the pelvis, between the root of the penis and the symphysis pu- 
 bis, and continue horizontally backwards on the side of the pro- 
 state gland, of the vesiculae seminales, and of the lower fundus 
 of the bladder. They receive many branches from these parts, 
 which, with the frequency of the anastomoses about here, con- 
 stitute the vesical plexus. The latter, finally, discharges into 
 the lower part of the hypogastric vein by two or more branches. 
 In the female the vesical plexus begins on the"dorsum of the 
 clitoris, by several branches coming from it and from the vul- 
 va; they get into the pelvis under the symphysis pubis, and on 
 the sides of the urethra and of the vagina, forming upon the 
 lower part of the bladder, and on the side of the vagina, with 
 the assistance of branches from these viscera, a remarkable 
 plexus, which also empties into the internal iliac vein. 
 
 The Plexus Sacralis consists in an order of veins, anastomosing 
 freely with each other, and corresponding with the middle and 
 the lateral sacral veins. They communicate with the inferior 
 end of the vertebral sinuses through the anterior sacral forami- 
 na; they also communicate with the hemorrhoidal and with the 
 vesical veins. They terminate in the venous trunks, nearest 
 the origin of the arteries from which they are derived. 
 
 The Plexus Pudendalis is derived from the branches of the 
 internal pudic vein which go to the perineum, to the posterior 
 part of the scrotum, and to the integuments of the under part 
 of the penis. The trunk formed by the assembling of these 
 several ramifications, follows the course of the artery to which 
 it belongs, and gets into the pelvis at the lower part of the 
 sciatic foramen, where it contributes to the formation of the hy- 
 pogastric vein. 
 
 The Plexus Uterinus consists in a considerable number of 
 veins, which are distributed upon the surface, and in the texture 
 of the uterus; they are also found in abundance in the broad li- 
 gaments, where they anastomose with the ovarian veins. 
 
 The Plexus Vaginalis comes from the anterior parts of the 
 organs of generation constituting the vulva, as the labia majora, 
 minora, and so on. It also arises from the whole surface of the 
 
266 CIRCULATORY SYSTEM. 
 
 vagina, surrounds it completely, and anastomoses with the ute- 
 rine veins. 
 
 The Gluteal, the Obturator, and the Ilio-Lumbar Veins, also 
 contribute to the Hypogastric; their description conforms so 
 nearly to that of the corresponding arteries, that it is unneces- 
 sary to detail it. 
 
 The Primitive Iliac Vein, ( Vena Iliaca Primitiva, Commu- 
 ntSy) formed by the junction of the External and of the Internal 
 Iliacs, extends from the sacro-iliac symphysis to the lower mar- 
 gin of the fourth lumbar vertebra on its right side, where it joins 
 the corresponding trunk of the opposite side of the body, to 
 form the commencement of the ascending vena cava. In this 
 course the left one passes obliquely across the body of the fifth 
 lumbar vertebra, and beneath the right primitive iliac artery. 
 
 The Vena Cava Inferior is situated on the front of the spinal 
 column, to its right side, and extends from the lower part of 
 the fourth lumbar vertebra; or, in other words, from the junc- 
 tion of the primitive iliac veins to the under end of the right 
 auricle of the heart, into which it empties. It is larger than 
 the Descending Cava. 
 
 In its ascent it inclines very gradually to the right side of the 
 spine, so as to reach the opening in the tendinous centre of the 
 diaphragm, through which it passes just before it terminates in 
 the auricle. It is bounded on the left side by the aortaf and 
 above the latter it is in front of the left pillar of the diaphragm. 
 Its lower extremity is crossed in front by the root of the pri- 
 mitive iliac artery; it is also crossed in its ascent by the duode- 
 num and the pancreas. Its upper extremity is behind the liver, 
 and frequently passes through the substance of this viscus. 
 
 It receives the middle sacral, the lumbar, the spermatic, the 
 .emulgent, the capsular, the hepatic, and the phrenic veins. 
 
 The Middle Sacral Vein ( Vena Sacra Media) forms, as has 
 been just mentioned in the account of the branches of the hy- 
 pogastric vein, a part of the sacral plexus. Its trunk follows 
 
VEINS OF THE ABDOMEN. 267 
 
 4he course of the middle sacral artery on the front of the sacrum, 
 and discharges into the commencement of the vena cava, in the 
 fork formed by the origin of the primitive iliacs. 
 
 The Lumbar Veins ( Vense, Lumbales) correspond with the 
 lumbar arteries, and are commonly four or five in number on 
 each side. Their primitive roots anastomose with the epigas- 
 tric, the last intercostal, and the circumflex iliac veins; the 
 dorsal branches of them also anastomose with the vertebral 
 sinuses, through the intervertebral foramina. Their trunks 
 pass along with the arteries, between the bodies of the vertebra 
 and the psoas magnus muscle, or through the fasciculi of the 
 latter: those on the left side pass behind the aorta, in order to 
 reach the vena cava, and are, consequently, longer than such as 
 -are on the right. 
 
 * The Spermatic Veins ( Vense Spermaticse.} The right one 
 extends from the testicle to the ascending cava, just below the 
 emulgent veins; while the one on the left empties into the left 
 emulgent vein. They are larger than the corresponding arte- 
 ries, and present some peculiarities in the two sexes. 
 
 In the male, the extremities of these veins begin in the testi- 
 cle, and issue from it through the tunica albuginea; some of them 
 also arise from the epididymis. They anastomose with the su- 
 perficial veins of the penis and of the scrotum, and disengaging 
 themselves from the tunica vaginalis, at its back part, are assem- 
 bled into four or five anastomosing trunks; which envelop the 
 vas deferens and the spermatic artery, and compose a principal 
 part of the bulk of the chord. Having passed through the 
 abdominal canal, they are reduced on each side to one trunk, 
 which creeps along the spermatic artery, on the front of the 
 psoas magnus muscle, and in company with the ureter. Some- 
 what below the kidney, the spermatic vein is again resolved 
 into a sort of plexus, having frequent additions from the veins 
 in the adipose substance of the kidney, and also some from the 
 branches of the vena portarum in the mesentery, and in the 
 mesocolon. It then is reduced once more into a single trunk, 
 which terminates as mentioned. The term Corpus Pampini- 
 forme (vine-like) is 5 by some anatomists, limited to the last 
 
268 CIRCULATORY SYSTEM. 
 
 plexus formed by each spermatic vein, but it is also frequently 
 extended to both.* 
 
 In the female, the spermatic vein is not so large as in the 
 male; it "comes from the ovarium and from the side of the 
 uterus, and is joined by'some small branches from the round 
 ligament of the uterus, and from the Fallopian tube. Passing 
 outwardly between the laminae of the broad ligament of the 
 uterus, it crosses the external iliac artery, and in the subse- 
 quent part of its course is disposed of as in the male. 
 
 The Emulgent Veins (Venss Emulgentes, Renales} are 
 commonly two in pumber, one on each side, and extend ho- 
 rizontally from the fissure of the kidneys to the ascending 
 cava. They are of a considerable size, and owing to the 
 position of the vena cava, the left is much longer than the 
 right, and crosses in front of the aorta. They open on their 
 respective sides of the cava opposite to each other. The 
 branches of which the emulgent vein is composed, coming 
 From the ramifications of the corresponding artery in the 
 kidney, assemble into the single trunk near the fissure of the 
 kidney; this trunk is joined by some small veins from the 
 adjacent adipose matter and from the capsulae renales, and 
 on the left side, as mentioned, it is also joined by the sper- 
 matic vein. 
 
 The Capsular Veins (Venae Capsulares) arise from the 
 arteries spent upon the capsule renales; and are two in num- 
 ber, one on each side. That on the right discharges into the 
 vena cava, while the one on the left empties into the left 
 emulgent frequently. 
 
 Hepatic Veins (Vena Hepaticce) take their rise in 
 the liver, and collect into three principal trunks, which con- 
 verging towards the ascending cava, discharge themselves 
 into it, where it adheres to the posterior margin of the liver, 
 immediately below the diaphragm. Two of these trunks 
 <come from the right lobe, and one from the left, moreover, 
 
 * H. Ctoquet, Trait. D'Anat. 
 
OP THE VENA PORTARUM. 269 
 
 there are" several small hepatic veins which discharge them- 
 selves into the cava, and come principally from the Lobulus 
 Spigelii. 
 
 The Inferior Phrenic Veins ( Fence Phrenicce Inferiores) come 
 from the diaphragm, from the corresponding arteries. They are 
 two in number, and discharge into the ascending cava just above 
 the hepatic veins. 
 
 SECT. V. OF THE VENA PORTARUM. * 
 
 The Vena Portarum is derived from the viscera of the abdo- 
 men, and presents the singularity of a vein ramifying through a 
 gland, the liver, before its blood is returned to the general circu- 
 lation. The arteries from which it draws its supply of blood are 
 the superior and the inferior mesenteric, and the coeliac with the 
 exception of its hepatic branch. The viscera of the abdomen, 
 which contribute to it are the spleen, the gall-bladder, the pan- 
 creas, the stomach, the small and large intestines, and the large 
 and the small omentum. 
 
 a. The Splenic Vein (Vena Splenica) is formed by several 
 branches, which coming out distinctly from the fissure of the 
 spleen, unite after a short course into a single trunk. This trunk 
 runs in company with the splenic artery below it, along the su- 
 perior margin of the pancreas, is. not quite so tortuous as the* ar- 
 tery itself, and proceeding from left to right, is joined to the su- 
 perior mesenteric vein in front of the vertebral column. 
 
 In this course, the splenic receives the small veins,* (Fence 
 Breves,) corresponding with the vasa brevia of the great end of 
 the stomach, and then, successively, several branches from the 
 pancreas. It likewise receives the gastric, or the superior coro- 
 nary vein of the stomach, the right gastro-epiploic, and the left 
 gastro-epiploic of the same viscus, all of which correspond with 
 the arteries distributed to the latter. 
 
 b. The Inferior Mesenteric Vein ( Vena Meseraica Inferior) cor- 
 
 M. Bauer discovered, in 1824, valves in these vessels, contrary to the gene- 
 ral analogy of the system of the Vena Portarum. His observations have been 
 confirmed by H. Cloquet. 
 
 VOL. II. 35 
 
270 CIRCULATORY SYSTEM. 
 
 responds with the inferior mesenferic artery, and, consequently, 
 derives its primitive branches from the rectum by the upper he- 
 morrhoidal veins, which anastomose with the lower; from the 
 sigmoid flexure of the colon, and from the left descending por- 
 tion of the latter. The trunk formed by these branches, ascends 
 behind the peritoneum, between the ureter and the aorta ; and 
 going up behind the pancreas, is discharged into the splenic vein 
 an inch or two from its termination. But, like the veins belong- 
 ing to the lesser curvature, and the right side of the stomach, 
 it sometimes empties directly into the vena portarum, or into the 
 upper end of the superior mesenteric. 
 
 c. The Superior Mesenteric Vein ( Vena Meseraica Superior) is 
 the largest of the trunks which contribute to form the vena por- 
 tarum. It is derived from the ramifications of the superior me- 
 senteric artery upon the small intestines, the ileo-colic valve, the 
 right ascending and the transverse colon. Its branches consti- 
 tute in the mesentery and the mesocolon a vascular intertexture, 
 forming arches and meshes adhering to the corresponding ones 
 of the arteries. In the transverse mesocolon, it, like the artery, 
 anastomoses with the inferior mesenteric vein. Its trunk being 
 formed by the union of these several branches, ascends the me- 
 sentery, and goes in front of the duodenum, where the latter 
 crosses the spine ; immediately afterwards it gets behind the pan- 
 creas, and near its right end is joined by the splenic vein. It 
 here, also, receives small branches from the duodenum, from the 
 pylorus, and from the gall-bladder. 
 
 / The trunk of the Vena Portarum being formed behind the pan- 
 creas by the union of the superior mesenteric with the splenic 
 vein, extends from this point to the transverse fissure of the liver, 
 and is about four inches in length. It ascends obliquely from left 
 to right, behind the second curvature of the duodenum, being 
 bounded on the right side by the biliary ducts, and on the left 
 by the hepatic artery, where it is surrounded by a great many 
 nervous filaments and lymphatic vessels, with aU of which it is 
 united by a common envelope of cellular substance, and of peri- 
 toneum, called the capsule of Glisson. Having reached the 
 transverse fissure of the liver, it divides into two branches, which 
 
PECULIARITIES OF THE FCETUS. 271 
 
 are each at a right angle to it, but in line with one another: they 
 constitute the Sinus Portarum, of which the right branch being 
 spent upon the great lobe, and the left upon the small lobe of the 
 liver, are ramified almost to infinity through the structure of the 
 latter. The terminating branches of the vena portarum empty 
 into the venae hepaticae. 
 
 Several cases are recorded in the annals of anatomy in which 
 the vena portarum, instead of going into the liver, discharged 
 immediately into the ascending cava.* In such instances the 
 hepatic artery is much larger than usual. According to J. F. 
 Meckel, notwithstanding they are anomalies, yet, as in most other 
 cases of deviation from the general type of the human family, a 
 striking analogy may be found between them and what occurs 
 in some of the lower orders of animals. Here the analogy ex- 
 ists with the invertebrated animals. 
 
 CHAPTER IV. 
 
 OF THE PECULIARITIES IN THE CIRCULATORY SYSTEM OF THE 
 
 FOZTUS. 
 
 OWING to the want of respiration in the foetus, its circulation 
 is conducted in a manner very different from that of the adult. 
 Moreover, its parasitical life requires an alliance, through the 
 organs of circulation, with the mother. Its peculiarities, there- 
 fore, may be studied under two heads : those which arise from 
 the want of respiration, and those which are required for its 
 nourishment. The peculiarities of the first order are situated in 
 the thorax, and those of the second in the abdomen. 
 
 * Lieutaud, Hist. Anat. Med. Huber, Obs. Anat. p. 34. Abernethy, Ph. Tr. 
 1793, pai't i. Lawrence, Med. Ch. Trans, vol. v. 
 
272 CIRCULATORY SYSTEM. 
 
 SECT. I. OF THE PECULIARITIES OF THE FffiTUS, ARISING FROM THE 
 
 WANT OF RESPIRATION. 
 
 The Heart, at a very short period after conception, so early 
 as about the end of the first month, is sufficiently developed to 
 be in a state of great activity. The first indication of its exist- 
 ence, and, indeed, of the life of the new animal, is a small tre- 
 mulous point, called the Punctum Saliens, from its incessant mo- 
 tion. The muscular structure of it is soon evolved, and in a 
 few weeks becomes very manifest. At the earliest visible pe- 
 riod of the heart in the incubated egg, which affords a satisfac- 
 tory analogy, it consists of two vesicles united by a canal, (Ca- 
 nalis Auricularis of Haller.) One of the vesicles is the right 
 auricle ; the other is the left ventricle, and is probably the first 
 to pulsate. The aorta is also visible, as well as the venae cavae. 
 The circulation, at this period, is very simple: the blood, start- 
 ing from the left ventricle, is propelled into the aorta ; it is col- 
 lected from the ramifications of the last into the two venae cavas, 
 and thereby brought to the right auricle; it is then propelled by 
 the right auricle through the canalis auricularis into the left 
 ventricle, whereby its round is completed, and it then starts 
 again. This is the most simple kind of circulation, and is found, 
 in fact, during the whole lives of such animals as do not breathe 
 by lungs ; for example, fish. As the gills in them take the place 
 of lungs, a branch from the aorta, spent upon the gills, is suffi- 
 cient for their purposes of respiration. 
 
 The terms right auricle and left ventricle have been used, be- 
 cause the cavities alluded to perform the functions of the adult 
 state; but in the progress of the development of the heart, a par- 
 tition begins to show itself which ultimately divides each of them 
 into two distinct compartments, whereby we have a right auricle 
 and a left one, a left ventricle and a right one. And the canalis 
 auricularis is reduced from a canal into a short orifice, called 
 Ostium Venosum, communicating from the auricles to the ven- 
 tricles, and which is afterwards divided into two, one for either 
 side of the heart. The partition between the ventricles is com- 
 pleted about the end of the second month of gestation, at a period 
 when the aorta, from having been simple originally, is converted 
 
PECULIARITIES OF THE FffiTUS. 273 
 
 into two canals, one of which becomes the pulmonary artery. 
 The partition between the auricles is not completed till birth. 
 In cases of monstrosity, it is interesting to see how much the 
 heart, at the end of uterine life, has still preserved this origi- 
 nal type of simplicity. I have lately dissected a double foetus, 
 where, from the parasitical character of one, no effort had been 
 made for the development of the lungs of the latter. The con- 
 sequence of which was, the parasite's heart consisted only of the 
 right auricle and of the left ventricle, and the pulmonary artery 
 had not been formed at all, there being but the single tube, the 
 aorta, which led from the left ventricle, and had a sort of arrange- 
 ment in its branches depending upon the tendency to form pul- 
 monary arteries.* 
 
 At birth, the auricular septum has advanced so far that the 
 communication between the two cavities is kept up only by a 
 deficiency, called the Foramen Ovale. This foramen, marked 
 by a depression on the right side, admits a small quill, when con- 
 ducted obliquely through it, and is protected on the left side by 
 a valve, the edge of which is upwards, and which, when applied, 
 is just large enough to cover the whole foramen. The moment 
 that the blood ceases to pass through the foramen ovale, which 
 occurs at the first act of inspiration, the valve is applied, and 
 the aperture grows up by the adhesion of its edge. The me- 
 chanism of this process is sufficiently simple. So long as the 
 principal current of blood was into the right auricle, the valve 
 was pushed off from the side of the septum ; but as breathing 
 establishes, through the lungs, pulmonary veins, and left auricle, 
 a current of circulation equivalent, both in quantity and force, to 
 that through the two venae cavae and right auricle, a perfect 
 equilibrium between the auricles is established, and the valve re- 
 tains its place against the septum. Notwithstanding the inces- 
 sant action of the auricles, during all the subsequent periods of 
 life, this equilibrium, in the force and time of their contraction, 
 remains uniform: a circumstance proved, conclusively, by the 
 health and strength of adults in whom the valve has never ad- 
 hered to the day of their death; an observation made by many 
 
 * For a detail of this.case, see North American Medical and Surgical Journal, 
 Philad. Oct. 1826. 
 
274 CIRCULATORY SYSTEM. 
 
 anatomists, and of which I have witnessed several examples. In 
 one of them I passed two fingers readily from one auricle into 
 the other, owing to the unusual size of the aperture. 
 
 The valve which closes the foramen ovale is, first of all, 
 scarcely perceptible ; but as the foetus advances in age, it also ad- 
 vances in size, and is, indeed, large enough to close the foramen 
 some weeks before birth. It is formed from the lining mem- 
 brane of the two auricles, with some intermediate substance. 
 
 The Valve of Eustachius, which exists also in the adult heart, 
 is placed at the anterior semi-circumference of the orifice of the 
 ascending vena cava in the right auricle, one of its ends ad- 
 hering to the anterior margin of the foramen ovale. This valve, 
 contrary to the one in the foramen ovale, is larger in proportion 
 as the foetus is younger, and, when first observed, covers the 
 whole orifice of the vena cava ascendens ; its opening, however, 
 is in the direction of the current of blood in the latter. It also is 
 formed by a duplicature of the lining membrane of the auricle ; 
 and, from its disposition, determines the blood of the ascending 
 cava to flow through the foramen ovale into the left auricle, ei- 
 ther wholly or in part, according to the period of gestation. Its 
 obliquity also gives a direction to the blood of the descending 
 cava, into the right ventricle from the right auricle. These 
 uses of the Eustachian valve were pointed out by the celebrated 
 Sabatier :* their value will be illustrated hereafter. 
 
 The Ventricles of the Heart, at birth, have the same structure 
 and internal arrangement as afterwards ; they are remarkable, 
 however, for being of equal thickness, or nearly so, an observa- 
 tion of Mr. John Hunter.t This fact is connected with the cir- 
 cumstance of their both contributing to the aortic circulation till 
 respiration begins, owing to the pulmonary artery entering, 
 during foetal life, by its largest branch, into the aorta. 
 
 The Ductus Arteriosus constitutes this branch of the pulmo- 
 nary artery, and is, in fact, the continuation of the trunk of the 
 latter into the aorta, immediately behind the origin of the left 
 
 * Traite d'Anat. vol. ii, p. 296. 
 f Animal (Economy. 
 
PECULIARITIES OF THE FffiTUS. 275 
 
 subclavian artery. The right and the left pulmonary arteries, 
 at this period, are but inconsiderable trunks, incapable by any 
 means of carrying off all the blood of the right ventricle ; the 
 greater part of it, therefore, is conveyed by the ductus arteriosus 
 into the descending aorta. As the contraction of the ventricles, 
 like that of the auricles, is synchronous, it is evident that the 
 column of blood in the descending aorta, is acted upon by both 
 ventricles at the same moment. 
 
 The ductus arteriosus, preserves the principle of a single cir- 
 culation in the foetus ; which was first of all manifested by the 
 two ventricles, constituting but one cavity ; and by the aorta 
 and pulmonary artery being but one trunk. At the first act of 
 inspiration the lungs, which were before solid, and the thorax, 
 which was compressed, are greatly augmented in volume by 
 the introduction of air. The dilatation of the thorax, besides 
 introducing air through the trachea, causes an increased flow of 
 blood through the right and left pulmonary arteries, in order to 
 fill the vacuum in the lungs. The pulmonary arteries become 
 in that way permanently dilated, and the circulation is finally 
 drawn off entirely from the ductus arteriosus, though this takes 
 several weeks or months before it is completely accomplished. 
 The ductus arteriosus in this time is continually contracting, and 
 is at length converted into a ligamentous chord, like other ar- 
 teries, whose circulation has been arrested. 
 
 These are the several peculiarities which distinguish the foetal 
 circulation, owing to the privation of respiration ; and it is clear, 
 that the collective result is that of a circulation quite as simple 
 as if the heart consisted of but two cavities ; while, at the same 
 time, it keeps this organ in a state of preparation for carrying 
 on two distinct circulations, one pulmonary and the other aortic, 
 from the moment that respiration begins; so that the whole 
 mass of blood is, in subsequent life, brought successively under 
 the influence of respiration, by having to pass unavoidably 
 through the lungs. 
 
276 CIRCULATORY SYSTEM. 
 
 SECT. II. OF THE PECULIARITIES OF THE CIRCULATION OF THE 
 FCETUS CONNECTED WITH ITS NOURISHMENT. 
 
 The Umbilical Vein, one of the constituents of the umbilical 
 chord, .brings the blood from the placenta to the foetus. This 
 vessel is from three to four lines in diameter, and enters at the 
 navel ; thence it goes along the loose margin of the suspensory 
 ligament of the liver, and traverses the anterior half of the um- 
 bilical fissure, to terminate in the left branch of the sinus of 
 the vena portarum. In this course through the liver, the umbi- 
 lical vein sends off to the right and left lobes, several small 
 branches. As the intestinal circulation of the foetus is too small 
 to send much blood through the vena portarum, it would be suf- 
 ficiently correct to consider the sinus venag portarum as the bi- 
 furcation of the umbilical vein ; but, as this might introduce a 
 confusion into the description, it will be better to retain the adult 
 nomenclature. 
 
 The Ductus Venosus is a vein which occupies the posterior 
 half of the umbilical fissure, and is about a line and a half in 
 diameter. It arises from the left branch of the sinus portarum, 
 opposite to the place where the umbilical vein entered or termi- 
 nated, and is consequently in the same line with the latter. 
 Traversing the posterior part of the umbilical -fissure, it termi- 
 nates in the left vena cava hepatica, as this vein is about joining 
 the ascending cava, just below the tendinous centre of the dia- 
 phragm. Through this route much of the blood of the umbili- 
 cal vein is carried directly to the right auricle of the heart, and 
 then passed through the foramen ovale into the left auricle by 
 the mechanism of the Eustachian valve. 
 
 From these considerations, it is evident that the umbilical 
 vein really performs the office of a vein till it reaches the liver, 
 but that there much of its blood is spent through the portal cir- 
 culation, upon the nourishment of this viscus, and that what re- 
 mains is carried through the ductus venosus to the heart. Like 
 other veins, it is furnished with valves, of which there are two: 
 one at its termination in the sinus portarum, and the other at the 
 
PECULIARITIES OF THE IXETUS. 277 
 
 cardiac extremity of the ductus venosus.* The establishment 
 of respiration, by putting the circulation into other channels, 
 likewise causes its obliteration and final conversion into a liga- 
 mentous chord. The valve, at the sinus portarum, prevents the 
 blood from taking a retrograde course, and thereby keeping the 
 umbilical vein open ; the valve of the ductus venosus has the 
 same effect upon the duct to which it belongs, and is aided by 
 the current of blood in the left branch of the sinus portarum, 
 setting across the mouth of the ductus venosus instead of 
 plunging into it from the umbilical vein, as in foetal life. 
 
 It is worthy of remark, that the left branch of the sinus por- 
 tarum is bounded, on its right extremity, by the end of the vena 
 portarum, and receives, about its middle, the umbilical vein. In 
 the space, then, between the umbilical vein and the portal, the 
 circulation, from the predominance of umbilical blood in foetal 
 life, is conducted from left to right, but afterwards from right 
 to left, as the portal circulation is established and the other is 
 arrested. 
 
 The Umbilical Arteries discharge the important office of con- 
 ducting the effete blood of the foetus to the placenta. They are 
 the continuations of the internal iliacs, and are two in number, 
 one on either side ; they conduct off so much of the blood of the 
 primitive iliac:, as to leave the external iliacs of a very small 
 size. During the early months of uterine life, they are rather, 
 indeed, the continued trunks of the primitive iliacs, the branches 
 from the latter being then so little developed as to appear quite 
 subordinate to the chief function of carrying the blood out of 
 the foetus to the placenta. But as the inferior extremities and 
 the buttocks grow, these subordinate branches are more and 
 more evolved. 
 
 At birth, the umbilical arteries, after dipping very superficially 
 into the pelvis, rise up at the sides of the bladder and converge 
 towards the navel. They emerge at the latter, cling together 
 and traverse the umbilical chord by twisting spirally around the 
 umbilical vein, like two small strings wound in this way upon a 
 
 * Bichat, Anat, Descrip. vol. v. p. 419. 
 VOL. II. 36 
 
278 CIRCULATORY SYSTEM. 
 
 larger one. Their diameter is from a line to a line and a half. 
 They anastomose as they join the placenta, but not previously. 
 
 Like the circulation between arteries and veins in other parts 
 of the body, the capillaries of the umbilical arteries terminate in 
 those of the umbilical vein in the placenta. From the observa- 
 tions of Wrisberg, Osiander, and the highly distinguished Pro- 
 fessor Chapman of the University of Pennsylvania, it seems that 
 there is no direct vascular communication between the mother 
 and the foetus. 
 
 This opinion is founded upon the leading facts, that the finest 
 injections do not pass from one to the other; that foetuses, after 
 the death of the mother from haemorrhage, still live and retain 
 their usual quantity of blood ; that if the foetus be expelled entire 
 with the placenta, and membranes unhurt, the circulation still 
 continues. One example of which was witnessed nine minutes 
 by Wrisberg;* another fifteen by Osiander ;f some from ten to 
 twenty minutes by Professor Chapman ;J another for an hour 
 by Professor Channing of Boston, and Dr. Selby of Tennessee, 
 where a bath of tepid water was used to resuscitate the foetus. 
 Also, from the observations of Breschet, it seems that the glo- 
 bules of the blood of the foetus, when inspected by the micro- 
 scope, are different in appearance from those of the mother. || 
 
 Mascagni says that he has made several most minute injec- 
 tions of the pregnant uterus, so as* to cover with small vessels 
 its whole internal surface, and to return the injection by the ute- 
 rine veins : and yet he has never succeeded in injecting, in that 
 way, the secundines.lf 
 
 I have, myself, repeatedly tried by minute injection to pass 
 articles from the fnetal into the maternal vessels, and the re- 
 verse, but always without success ; in two instances, the experi- 
 ment was upon human subjects, and, in the others, on the cow. 
 In one of the latter, I perceived that some of the injecting mat- 
 ter thrown into the foetal vessels had got into the uterine veins ; 
 but as the observation was in opposition to all my others, and 
 solitary, I have felt no disposition to array it against them, at 
 
 * Meckel, Man. D'Anat. vol. iii. p. 1G3. f Id. 
 
 t Chapman's Mcd. and Phys. Journal, vol. i. p. 6. . Id. 
 
 || Am. Mcd. Jour. vol. 5. p. 193. 
 ^ Prodromo, vol. i. p. 127. 
 
PECULIARITIES OF THE FffiTUS. 279 
 
 least, until farther and more decided experience. My second ex- 
 periment on the human subject was made in April, 1833, under 
 the following circumstances : A white female, aged 24, died at 
 the Alms House, suddenly, and in the ninth month of pregnancy, 
 the foetus was still in utero, but the membranes were ruptured. 
 In the presence of several of the physicians and students, and 
 with the assistance of my young friend, Dr. Goddard, to whose 
 suggestions and manipulations I am indebted for the chemical 
 compounds resorted to. I injected through the aorta one gallon 
 of the saturated solution of Prussiate of potash, and followed it 
 with an equal quantity of a saturated solution of sulphate of iron. 
 The injection penetrated very minutely, as might be expected, 
 and the precipitate of Prussian blue coloured deeply many*parts 
 of the skin. On dissecting the uterus, the uterine arteries were 
 found well injected, but the injection did not reach the umbilical 
 vein or arteries, as was proved both by simple inspection and by 
 chemical test. 
 
 Having cut out the uterus and taken it to the University, the 
 experiment was continued the next day in the presence of a large 
 concourse of students and several physicians. The umbilical 
 vessels were first of all injected with a saturated solution of bi- 
 chromate of potash, and then with a saturated solution of sugar 
 of lead, the result was a strong yellow precipitate, the bichro- 
 mate of lead. The injection passed reciprocally from the arte- 
 ries into the vein, or from the vein into the arteries, conforma- 
 bly to the direction in which it was thrown for the time. The 
 sinuses of the uterus were then injected with similar materials 
 to those of the uterine arteries ; to wit, a solution of Prussiate of 
 potash, followed by one of sulphate of iron. 
 
 The umbilical vessels were then all filled with liquid plaster of 
 Paris coloured yellow ; and the uterine sinuses with liquid plas- 
 ter of Paris coloured blue, of which they readily received eigh- 
 teen ounces. A short time having been allowed for the setting 
 of the injection, I cut into the substance of the uterus and of the 
 placenta. No yellow injection was found in the vessels of the 
 uterus, nor was there any blue injection found in the umbilical 
 vessels of the placenta ; there was, therefore, a deficiency of evi- 
 dence of direct vascular communication between the fcetus and 
 the mother. The placenta was infiltrated with Prussiate of iron, 
 
280 CIRCULATORY SYSTEM. 
 
 and considerable quantities of blue plaster were found in the ca- 
 vity of the uterus. 
 
 In the progress of the injection with the Prussiate of iron, into 
 the uterine sinuses, the membranes were raised from the uterus 
 in vesications. 
 
 The parts having been distended and put aside to dry, at the 
 end of a fortnight they were examined again by incisions, and 
 the same evidence of the want of direct vascular communication 
 was renewed. But the placenta was found to be infiltrated ac- 
 cording to certain rules seeming to depend on its organization. 
 The blue colouring matter on the part of the uterus, and the 
 yellow on the part of the fetus, determined in it two parts, one 
 uteriie and the other fetal, closely and alternately interlocked, 
 like a dove-tailing : the uterine processes passed to within a short 
 distance of the free surface of the placenta, while the foetal pro- 
 cesses went almost to the base of the placenta. The confines of 
 the two colours were defined well by this abrupt termination, the 
 borders of these dove-tails. The appearance would, perhaps, be 
 better designated by the terms uterine lobes, and fetal lobes, 
 alternately penetrating, so as to constitute the whole mass of the 
 placenta. No distinct vessel of a blue colour could, however, be 
 seen in the uterine lobes, but a few very sparse yellow ones were 
 visible. On raising up these uterine divisions, the orifices of the 
 uterine sinuses were seen at their base. 
 
 The inference from this experiment is, that though there is no 
 direct connexion of blood vessels between the mother and the 
 foetus, yet there is a part of the placenta which seems to bold a 
 special connexion with the uterine sinuses, and which may pos- 
 sibly, therefore, by interstitial circulation, establish a connexion 
 with the fetus. The facts are at any rate presented as they 
 occurred. 
 
 The effete blood of the umbUical arteries becomes regenerated 
 in the placenta, assumes a brighter hue, and is returned to the 
 foetus by the umbilical vein. According to the theory of Saba- 
 tier concerning the use of the Eustachian valve, if the latter 
 diti. not exist, the fresh blood brought to the heart by the 
 ductus venosus, instead of being diverted into the left auricle 
 through the foramen ovale, would be received by the right 
 auricle, and transmitted, either wholly or in a great degree, into 
 
ANATOMY OF THE ABSORBENT SYSTEM. 281 
 
 the right ventricle. It would then be passed from the latter 
 through the pulmonary artery and ductus arteriosus into the de- 
 scending aorta, so that no part of the system, above the junction 
 of the duct with the aorta, could receive the benefit of it: this 
 would leave the head and upper extremities unsupplied with 
 fresh blood. Moreover, much of the latter would be fruitlessly 
 introduced, for it would depart almost immediately through the 
 umbilical arteries. But the Eustachian valve determining the 
 flow of blood of the ascending cava into the left auricle, its pas- 
 sage into the left ventricle is a matter of course : thence it be- 
 gins the aortic circulation fairly, so that every part of the sys- 
 tem participates in its benefits. 
 
 The celebrated Wistar* has also happily suggested, that with- 
 out this arrangement the blood of the coronary arteries of the 
 heart itself, the purity of which is so essential to the vigour of 
 circulation, would otherwise have been effete, and, consequently, 
 unfit for its object of refreshing the heart. 
 
 The umbilical arteries become the round ligaments of the 
 bladder, after the circulation through them has ceased, with the 
 exception of their pelvic extremities, which subsequently consti- 
 tute the trunks of the Internal Iliac Arteries. 
 
 CHAPTER V. 
 
 OF THE GENERAL ANATOMY OF THE ABSORBENT SYSTEM. 
 
 THE absorbent system is one of the most interesting of those 
 which compose the human body, both on account of its very 
 general diffusion, and of the office of interstitial absorption that 
 it incessantly carries on, thereby removing the effete parts of 
 the body and making room for the deposite of new ones. It is 
 also called the lymphatic system, owing to the transparent co- 
 lour of the fluid which it conducts. 
 
 * System of Anat. vol. ii. p, 76, 3d edition^ 
 
282 CIRCULATORY SYSTEM. 
 
 With the exception of an imperfect observation of some of 
 these vessels in the mesentery of a goat, by Herophilus and 
 Erasistratus, 280 years before Christ, during the reigns of the 
 Ptolemies in Egypt, what is known of them is entirely a modern 
 acquisition in anatomy. In 1564, Eustachius discovered the tho- 
 racic duct of a horse, which, in the ignorance of its use, he 
 called vena alba thoracis. This fact remained insulated and 
 almost forgotten for seventy years. In 1622, Asellius disco- 
 vered the absorbents of the mesentery, and in the discussions 
 consequent thereto, the original observation of Herophilus and 
 Erasistratus was raised from an oblivion of nineteen centuries, 
 to be again brought to light and admired. Asellius seems to 
 have understood that the absorbents of the mesentery collect the 
 chyle from the intestines, but his knowledge ceased there, for he 
 thought that they discharged into the vena portarum.* In 1634, 
 Weslingius saw the thoracic duct again; and in 1649, ascer- 
 tained that the chyliferous vessels of Asellius terminated in it. 
 In 1650, Olaus Rudbeck, a young man pursuing his anatomical 
 studies in Leyden, saw first the lymphatic vessels of the liver, 
 and in a few months afterwards injected similar ones in the 
 loins, in the thorax, in the groins, and in the arm-pits. Thomas 
 Bartholine, a teacher of great reputation in those days, in a dis- 
 sertation, dated in 1652, claimed for himself the priority of these 
 observations, and from the obscurity of Rudbeck, enjoyed for 
 some time the merit of them. In 1654, Rudbeck published and 
 set forth his own pretensions with such force, that he finally 
 triumphed over his antagonist, but not until the whole world of 
 anatomy had been set in commotion ; one party being for the 
 professor, and the other for the pupil; and many bloody strifes 
 having arisen between the students of the respective sides. In 
 1653, Jolyff, a celebrated anatomist, of London, proclaimed his 
 own rights to this warmly contested honour; but the period be- 
 ing rather late, his name is scarcely associated with the history 
 of these feuds. Almost a century then passed before there were 
 many important additions to the knowledge of those times. After 
 
 * It is somewhat remarkable, that the celebrated Harvey, who had himself so 
 much to complain of, in the obstinacy with which his cotemporaries adhered to 
 ancient errors, for thirty years resisted the discovery of Asellius, and died, final- 
 ly, protesting against it. 
 
ANATOMY OF THE ABSORBENT SYSTEM. 283 
 
 which great contributions were made by Dr. A. Munro,* Dr. W. 
 Hunter,f Hewson,f Cruikshank, but chiefly by the celebrated 
 Mascagni,|| who, having imagined finely pointed instruments of 
 glass for executing his injections of these vessels, succeeded in 
 demonstrating them in almost every part of the body, excepting 
 the spinal marrow, the brain, the ball of the eye, and the placen- 
 ta. In some of these parts, however, he says he has seen them, 
 and he speaks confidently of their existence, without exception 
 every where, even in the enamel of the teeth.1F 
 
 The Lymphatic Vessels are small, pellucid, transparent, cy- 
 lindrical tubes, generally of about a line or less in diameter, 
 whose trunks have been traced to all the external and internal 
 surfaces of the body, and to the depth of all the organs, with 
 the exceptions stated. It is only very lately, however, that their 
 existence on the external surface of the skin has been put be- 
 yond doubt, by the observations and injections of M. Lauth.** 
 Their origin is so attenuated, that anatomists have come to no 
 satisfactory conclusion in regard to its manner. The earlier 
 cultivators of this branch of study, not knowing their absorbent 
 properties, conceived them to be continuations of the arteries 
 applied to the reconducting of the serous part of the blood to 
 the heart; and considered the opinion substantiated by the cir- 
 cumstance of their being occasionally filled by fine injections 
 thrown into the arteries. More improved views of their uses 
 caused the abandonment of this theory, and the substitution of 
 their absorbing powers ; in which case the minds of anatomists 
 became divided between the ampulla-like mouth, or wide patu- 
 lous origin of Lieberkuhn, and the small orifices of Hewson. 
 It is, perhaps, not possible to solve the question in regard to the 
 mode of origin of the lymphatics, at least, in most parts of the 
 body. Meckel, about the middle of the last century, asserted 
 
 * De Venis Lymph. Valv. Berlin, 1757-70. 
 
 f Med. Comment. London, 1762-77. 
 
 t Experimental Inquiries, London, 1774-77. 
 
 Anat. of the Lymphatics, London, 1774-90. 
 
 II Vasor Lymph. Corp. Hum. Historia et Ichnographia, Sienne, 1787. 
 
 11 Prodrome della Grande Anatomia, vol. i. p. 1. 
 
 ** Essai sur les Vaisseaux Lymph. Strasburg, 1824. 
 
284 CIRCULATORY SYSTEM. 
 
 their continuity with the veins. Mr. Ribes has seen matter in- 
 jected into the vena portarum find its way into the lymphatics 
 of the liver. 
 
 On this subject, M. Chaussier says,* that, ignorant of the man- 
 ner in which the arteries, veins, .nerves, and lymphatics, arrange 
 themselves collectively into a glandular structure, or, in other 
 words, into a capillary system, we cannot "avoid ignorance of 
 the part acted by the lymphatics alone ; we only know that the 
 minute lymphatics form a portion of the elements of each viscus 
 and structure of the body, and that they only become visihje in 
 becoming larger trunks. 
 
 The absorbents, in proceeding from their origins, in general 
 become larger and less numerous, and form frequent anastomoses 
 with one another. The proportionate increase of magnitude from 
 the successive junction of trunks is, however, by no means equal 
 to what occurs in the veins. The larger superficial absorbent 
 trunks of the extremities have not so much disposition to run 
 into one another, whence they retain a size almost uniform from 
 one end of the limb to the other. When fully distended, the ap- 
 pearance of absorbents is not regularly cylindrical, but knotted, 
 owing to the frequent valvular interruptions to their cavities. 
 The absorbents, from all parts of the body, are finally united 
 into two trunks ; one on the left, and the other on the right side 
 of the trunk of the body, and which discharge their contents into 
 the venous system, each on its respective side, at the junction of 
 the internal jugular and subclavian vein. The trunk on the right 
 side receives the lymphatics of the right side of the head and 
 neck, of the right lung, and right superior extremity; while the 
 trunk on the left, called the thoracic duct, receives all the chyli- 
 ferous vessels and the lymphatics of the remaining part of the 
 body. It would appear, from the observations of the younger 
 Lauth,t that there are also other terminations of the lymphatics 
 in the veins; to wit, such as in the yet capillary state end in the 
 veins of the minute structure of organs, and such as empty into 
 them in the interior of the lymphatic glands. Previously to 
 Lauth, this sentiment of communication with the veins was strong- 
 
 * Diet, des Sciences Med. Art, Lymphatiques. - 
 
 f Loc. cit. 
 
ANATOMY OF THE ABSORBENT SYSTEM. 285 
 
 ly advocated by several anatomists and physiologists, for the fol- 
 lowing reasons: 1. That the known roots, of the lymphatic sys- 
 tem have an area much superior to that of the trunks in which 
 they terminate. 2. That substances introduced into certain 
 lymphatics by absorption or injection, have been found in the 
 contiguous veins. 3. That a ligature upon the thoracic duct 
 produced death only after ten or fifteen days, and then the ar- 
 ticles which had been absorbed by the intestines, were found in 
 the blood. 4. And that injections had proved this communica- 
 tion. 
 
 Notwithstanding the well known fact of injections, under cer- 
 tain circumstances, passing from the arteries into the lymphatics, 
 some anatomists of modern date have hesitated in admitting a 
 direct communication. M. Meckel has, indeed, rejected the no- 
 tion entirely, on the ground that the fluid contained in the trunks 
 of the absorbents is always the same as one finds at their com- 
 mencement. For example, the lymphatics coming from the 
 liver contain a fluid like bile ; those which come from the mammaB 
 contain a fluid like milk; those which come from parts suffering 
 from an extravasation of blood contain a sanguineous fluid; the 
 bronchial glands are coloured by the black pigment brought to 
 them from the lungs; poisonous matter, as that of the small-pox 
 or venereal, irritates and inflames the lymphatics that lie in the 
 course of its introduction into the system. For these reasons it 
 would appear to him, that the arteries do not continue themselves 
 into the lymphatics as they do into the veins. The observations 
 of M. Lauth seem to have proved the point, that some of the 
 lymphatics take their origin from the internal surface of the ar- 
 teries ; and it may be through them that injections have been 
 forced from one system into the other. 
 
 The coats of the lymphatics generally are too thin and trans- 
 parent for an investigation of their structure ; but as those of the 
 thoracic duct are sufficiently large for the purpose, one may 
 estimate the structure of other trunks by it. It is thus ascertained 
 that they consist of two coats, an internal and an external one. 
 
 The external coat is somewhat irregular in its surface, from 
 its connexion with the adjacent cellular substance; and has a 
 filamentous appearance more deeply, which has been considered 
 .as fibrous, or muscular, by some anatomists, owing to its con- 
 
 VOL. II. 37 
 
286 CIRCULATORY SYSTEM. 
 
 traction upon the application of certain stimulants. The inter- 
 nal membrane is extremely fine and perfectly transparent, and 
 is remarkable for its frequent duplications, whereby a system 
 of valves is produced resembling those of the veins. These 
 valves are generally of a semi-lunar or parabolic shape, and are 
 arranged in pairs, though, according to Lauth,* some of them are 
 circular, and do not close the canal entirely. The pairs are not 
 placed at stated distances from one another, but vary in differ- 
 ent parts of the body; in some places there are several in the 
 course of an inch, and in others not one pair. As a general 
 rule, they are less frequent as the trunk increases in magni- 
 tude; hence, the thoracic duct has but very few of them. The 
 yalves, by having their semi-circumference fixed, while the dia- 
 meter is loose and inclined in the course of the circulation, pre- 
 vent the retrograde movement of the contained fluid. The en- 
 largement of the trunk at their outer face into sinuses, resem- 
 bling those at the valves of the veins, gives also to the lympha- 
 tic trunk the knotted condition when it is fullyMnjected. 
 
 The coats of the lymphatic vessels, though very thin, are yet 
 dense and extremely strong, much more in proportion than 
 those of any other tubes. They are both extensible and elastic, 
 possess striking powers of spontaneous contraction in the living 
 body, and also in the dead, but to a less extent. They are fur- 
 nished with arteries and veins, and probably with nerves also, 
 from their sensibility in a state of inflammation. And, as they 
 stand in need of a similar organization with other canals, their 
 parietes are said also to have lymphatics. 
 
 The absorbent vessels are, by some, divided into lacteals and 
 lymphatics,! the first term expressing those which convey the 
 chyle from the intestines, and the second such as are found in 
 other parts of the system. As the difference is more in the 
 fluid conducted than in. the structure of the vessels themselves, 
 
 * Loc. cit. 
 
 j- This division has been handed down from the time of Bartholine, who, not sus- 
 pecting the absorbing powers of the lymphatics, held them only as organs of circu- 
 lation for restoring to the heart the serum of the blood. The sagacious mind of 
 the late Dr. W. Hunter first imagined their absorbing powers, and established 
 the theory of their identity of function, in this respect, with the lacteals. The 
 priority of the theory was warmly contested for Dr. Monroe, of Edinburgh. 
 
ANATOMY OP THE ABSORBENT SYSTEM. 287 
 
 the division is rather superfluous. There is also a distinction of 
 the lymphatics, arising from their situation, as in the veins; some 
 of them are called superficial, and the others deep-seated. The 
 arrangement upon which this nomenclature depends, is found 
 in the head, trunk, extremities, and in the most of the vis- 
 cera. The deep-seated trunks are the largest, but the least 
 numerous. 
 
 Of the Lymphatic Glands. 
 
 The Lymphatic or Absorbent Glands or Ganglions, some- 
 times called waxen kernels in common language, are an appen- 
 dage of a very important description to the absorbent system. 
 They are flattened ovoidal bodies, of a reddish ash colour, in- 
 durated so as to afford a strong resistance to pressure, and of a 
 variable volume, from a line to twelve lines in their long dia- 
 meter. They are found principally in clusters or chains, and 
 more abundant in the neck, in the groin, in the arm-pit, in the 
 mesentery, and about the bifurcation of the trachea. 
 
 The lymphatic vessels, in their course towards the thoracic 
 duct, have to pass through one or more of these glands. This 
 rule is almost universal; some exceptions, however, to it, in the 
 case of the lower extremity, have been stated byJVIr. Hewson, 
 and in the case of the back, by Mr. Cruikshank:* the latter be- 
 lieves Mr. H. to have been under a misapprehension in this 
 statement concerning the extremities, as it had not been verified 
 by the result of his own investigations. The vessels that enter 
 into the glands are called vasa inferentia, while those that de- 
 part from them are the vasa efferentia. As, owing to the jux- 
 taposition of many of these glands, the vessels between them 
 are very short, this distinction would likewise seem almost su- 
 perfluous, because there is scarcely space to apply the term ef- 
 ferentia, before the same vessels enter the consecutive gland, 
 thereby becoming inferentia. For the most part, the vasa in- 
 ferentia are more numerous and somewhat smaller than the ef- 
 ferentia. The former, as they enter the gland, radiate into 
 
 * Anat. of Absorb, Vessels, second edit. p. 79. London, 1790. 
 
288 CIRCULATORY SYSTEM. 
 
 smaller branches, while the latter are formed from the junction 
 of smaller branches. 
 
 Each lymphatic gland is surrounded by a capsule, resembling 
 condensed cellular substance, which adheres very closely to the 
 gland, and from which cause many anatomists are disposed to 
 deny its existence, at least as a distinct membrane. They are 
 also abundantly furnished with arteries and with veins destitute 
 of valves; but though they are penetrated by nervous filaments, 
 it is not yet satisfactorily ascertained that any remain with them ; 
 it is, however, more probable than otherwise. Their connexion 
 with the surrounding cellular substance is sufficiently loose to 
 permit them, in certain parts, to be slid moderately backwards 
 and forwards. When this motion is arrested, it is from inflam- 
 mation about them. 
 
 The capsule of the lymphatic gland, like that of other glands, 
 sends processes within to keep its parts together, and to con- 
 duct the blood vessels. It also contains a peculiar fluid called, 
 by Haller, succus proprius, which is principally found in young 
 animals, diminishes as they advance in age, and finally disap- 
 pears. It is of various colours, but more frequently white; it 
 appears to have globular particles in it, which- the late Mr. 
 Hewson, for divers reasons, thought to become afterwards the 
 red globules of blood. 
 
 When a lymphatic gland is injected with quicksilver, it ap- 
 pears to be made up by the minute branching of the vasa infe- 
 rentia, and the roots of the vasa efferentia, the former being con- 
 tinued into the latter. There is also some appearance of small 
 cells intermediate to these two orders of vessels. All anato- 
 mists admit the former opinion; but many reject the latter, un- 
 der a presumption that the appearance is delusive. The argu- 
 ments, however, seem to be in favour of their existence. Mr. 
 Cruikshank,* whose address in these matters was certainly of 
 the first order, declares that he never failed to perceive them, 
 and particularly well, just as the mercury was entering the 
 gland. This arrangement is still more readily made out in 
 animals,, as the horse, ass, mule. It also seems, from his ob- 
 servations, that when there are more than one vas inferens and 
 
 * Loc. cit. p. 85, pi. iii. 
 
ANATOMY OF THE ABSORBENT SYSTEM. 289 
 
 eflerens, there are cells for each set, which are kept distinct 
 from the cells of the others, though they communicate freely 
 with their cognates. Mr. Abernethy's investigations, on the 
 mesenteric glands of whales, coincide with the views of Mr. 
 Cruikshank: he states, indeed, the cells as being large spherical 
 bags, into which the lacteals plainly open. The celebrated 
 Mascagni also acknowledges, and, indeed, describes the cellu- 
 lar structure of these glands,* which he had ascertained both by 
 quicksilver and by wax injections. The improved notions of 
 modern anatomy, upon what is called the erectile tissue, that is, 
 the cells intermediate to arteries and veins, as in the penis and 
 other places, now considered rather as the dilated extremities 
 of vessels, would also assist in warranting the opinion advo- 
 cated. The celebrated Ruysch thought that he had discovered 
 acini in the lymphatic glands, and sent his injected preparation 
 illustrative of them to Boerhaave. Some idea of the enthusiasm 
 of the old anatomists may be conceived by his saying, " Quan- 
 do jam clarius et perfectius videbam haec omnia, pra3 gaudio ex- 
 siliebam." 
 
 When the absorbing powers of the lymphatics had been 
 established by Dr. W. Hunter, they were for a long time con- 
 sidered as the exclusive functionaries in this operation; and the 
 opinions previously entertained had sunk into such disrepute, 
 from some experiments of Mr. John Hunter,t that they were 
 considered rather as food for literary research and curiosity, 
 than for deliberate adoption. In the year 1809, M. Magendie 
 reported his experiments on absorption, which seemed to fa- 
 vour the notion that the veins also assisted in this office, a the- 
 ory as ancient as Galen. The more recent observations of 
 Fohman, in 1821, and Lauth, in 1824, on the communications 
 of the lymphatics with the veins, in the midst of the tissues of 
 organs, and in the lymphatic glands, seem now to explain away 
 again the theories of the absorbing powers of the veins, and to 
 
 * Vasor. Lymph. Hist. 
 f Med. Commentaries. 
 
290 CIRCULATORY SYSTEM. 
 
 reinstate the lymphatics in their reputed exclusive functions. 
 It is also stated that an anatomist of Florence, M. Lippi, has 
 still more lately found several large lymphatic trunks entering 
 into the ascending cava. The connexion of the lymphatic sys- 
 tem with the vena cava ascendens, and also with the external 
 iliac veins has been farther demonstrated by certain preparations, 
 exhibited by M. Amussat to the Academic Royale.* M. Fo- 
 dera has, however, again brought the subject under discussion, 
 by multiplying the active agents of this function, and says, that 
 his experiments prove that all organized tissues enjoy it, and 
 not certain parts only, as has been heretofore supposed;! from 
 which it results that most of the rules in regard to the applica- 
 tion of local remedies are inexact, and that we should have 
 more regard to the thickness and density of tissues, to the 
 quantity and rapidity of their circulation, than to simple lo- 
 cality 4 
 
 CHAPTER VI. 
 
 OF THE SPECIAL ANATOMY OF THE ABSORBENT SYSTEM. 
 SECT. I. OP THE ABSORBENTS OF THE HEAD AND NECK. 
 
 THE Superficial Absorbents of the head are found in company 
 with the several branches of the temporal, the occipital, the 
 frontal, and the facial arteries, and, in order to get into the 
 lymphatic trunks leading to the thoracic duct, follow or rather 
 reverse the course of their respective arteries. There are at 
 least two absorbent trunks for one arterial, and frequently 
 
 * Am. Med. Jour. vol. i. p. 422. 
 
 -} Recherches Experimentales sur 1' Absorption et 1'Exhalation. Paris, 1824. 
 
 * For a most interesting and instructive series of experiments on the laws and 
 phenomena of absorption, see Philadelphia Journal of the Medical and Physical 
 Sciences. Nos. 6 and 10. The experiments were executed by Drs. Lawrence, 
 Coates, and Harlan, of this city. 
 
ABSORBENTS OF THE HEAD AND NECK. 291 
 
 more: those on the face are more abundant than such as are on 
 the side of the cranium, owing to the excess of cellular substance 
 on the former. The absorbents of these two regions anasto- 
 mose freely beneath the external ear, between the skin and the 
 parotid gland. 
 
 The Deep-Seated Absorbents of the head have been followed 
 to the membranes of the brain, but not farther. Ruysch ob- 
 served them between the tunica arachnoidea and pia mater, in- 
 flated with air, and called them vasa pseudo-lymphatica. Lan- 
 cisius, Pacchioni, and others, assert their having found them in 
 the pia mater. Doubts, however, are cast upon these several 
 observations, owing to such vessels not having been injected 
 with quicksilver, and from the want of a valvular appearance 
 in them; also from the want of lymphatic glands in the brain. 
 Their existence, however, would seem to be sufficiently proved, 
 both from general analogy, and from affections of the brain 
 producing swellings in the glands of the neck. On the dura 
 mater they have been traced along the course of its arteries. 
 They descend from the interior of the cranium into the 
 neck, along the carotid and vertebral arteries. The absence 
 of lymphatic glands in the cranium may be accounted for from 
 the fact, that the ready tendency of these organs to swell upon 
 slight causes of irritation, would have rendered the individual 
 liable to death, from compression of the brain, by their tume- 
 faction. Mr. Cruikshank has found lymphatic glands in the 
 carotid canal. 
 
 The Deep Lymphatics of the'face, as those from the interior 
 of the nose, of the orbit, of the tongue and mouth, attend the 
 arteries which respectively supply those parts. 
 
 These several absorbents, from the surface and from the in- 
 terior of the head, descend to the base of the cranium, and then 
 begin to pass through the chain of lymphatic glands situated 
 along the course of the great blood vessels of the neck. They 
 lie, for the most part, under the ster no-mas to id muscle, and, 
 when successfully injected, are thought to form the most bril- 
 liant plexus of absorbents in the whole frame. On each side 
 of the neck, one or more common trunks are, at length, formed; 
 
292 CIRCULATORY SYSTEM. 
 
 that on the left side joins the Left Thoracic Duct near its ter- 
 mination, while the one on the right assists in forming the duct 
 peculiar to that side, the Right Thoracic Duct, or, more pro- 
 perly called, Brachio Cephalic. 
 
 The lymphatic vessels of the muscles of the neck, and those 
 of the thyroid gland, enter into the trunks of the neck. Ac- 
 cording to Mr. Cruikshank, those of the thyroid gland may be 
 readily injected by plunging a lancet at random into its sub- 
 stance, and then introducing air or quicksilver. 
 
 Of the Absorbent Glands of the Head and Neck. 
 
 The only claim of lymphatic glands to an existence in the 
 cavity of the cranium, is founded upon the supposition that the 
 Pineal, the Pituitary, and Pacchioni's Glands are of this cha- 
 racter; but it is far from being established, and there seems in- 
 deed to be some dolibt whether the glands found in the carotid 
 canal, by Mr. Cruikshank, are not the carotid ganglion of the 
 Sympathetic, lately noticed by Laumonier. 
 
 On the external surface of the cranium, over the insertion of 
 the sterno-mastoid muscle, there are from four to six of a small 
 volume; on the face there is one or more small ones, below the 
 zygoma, and from two to four on the external surface of the pa- 
 rotid; there is one or more small ones situated in the substance 
 of the parotid gland, which, according to Burns, are generally 
 the seat of tumours falsely attributed to the parotid itself. There 
 are also some small glands along the facial artery as it ascends 
 from the base of the jaw to the corner of the mouth. 
 
 On the neck there are two or more small glands, immediate- 
 ly under the skin of the symphysis of the jaw, and eight or nine 
 around the submaxillary gland. The most numerous congeries 
 of glands on the neck is, however, along its great blood vessels, 
 and covered more or less by the sterno-mastoid muscle, being 
 principally between its posterior margin and the anterior of the 
 trapezius. Along the latter line there are about twenty, in ad- 
 dition to six just above the superior margin of the clavicle. On 
 the trachea, just above the sternum, there are four, forming the 
 upper end of a series which descends along the esophagus and 
 trachea to the root of the lungs. 
 
ABSORBENTS OF THE UPPER EXTREMITIES. 293 
 
 SECT. II. OF THE ABSORBENTS OF THE UPPER EXTREMITIES, AND OF 
 
 THE CONTIGUOUS PARTS OF THE TRUNK OF THE BODY. 
 
 The superficial absorbents of the upper extremity are very nu- 
 merous, and lie between its skin and aponeurosis. They begin 
 at the ends of the fingers and thumb; there being two or more 
 branches for each, both before and behind. The posterior 
 branches pass to the back of the hand and of the fore arm: some 
 of them, more especially those from about the thumb, run up 
 along the radial side of the fore arm to the bend of the arm; but 
 by far the greater part of them incline very gradually in a semi- 
 spiral manner towards the ulna, and then to the front of the fore 
 arm. 
 
 Such of the superficial vessels as come from the front of the 
 fingers and hand, continue to ascend straight up the fore arm to 
 its bend. These vessels of the fore arm are so numerous that 
 for every few lines there is an ascending trunk on its circum- 
 ference: some of them coalesce, others form plexuses, and their 
 number is much reduced at the elbow. 
 
 From the elbow the superficial lymphatics ascend to the ax- 
 illa in fifteen or twenty parallel trunks, along the internal mar- 
 gin and the front surface of the biceps flexor cubiti. The outer 
 side of the arm has comparatively but few absorbent trunks 
 upon it, but some follow the course of the cephalic vein, pene- 
 trate with it into the axilla, and then join the inferior lympha- 
 tics of the neck. 
 
 The Deep Absorbents of the upper extremity attend the ar- 
 teries, and are at least two for each principal artery. They 
 anastomose with the superficial ones at intervals, and at last ter- 
 minate in the axillary glands. As they follow strictly the 
 course of the arteries, a farther specification is needless. 
 
 The Superficial Absorbents of the contiguous portions of the 
 
 trunk of the body are not by any means so numerous as those 
 
 of the upper extremity; they consequently are more distant 
 
 from one another, and they also go along in a more serpentine 
 
 VOL. II. 38 
 
294 CIRCULATORY SYSTEM. 
 
 manner. From the nape of the neck to the lower part of the 
 loins they all converge to the arm-pit. The absorbents which 
 are situated on the front of the pectoralis major muscle, and 
 those on the side of the body from the arm-pit to the hip, also 
 converge to the axilla. In regard to the two latter places, how- 
 ever, some of their absorbents, by penetrating the parietes of the 
 thorax or abdomen, respectively join the internal absorbent 
 trunks of these cavities. 
 
 These several lymphatics from the upper extremity and from 
 the trunk, traverse the axillary glands, and are successively re- 
 duced in number to four or five voluminous trunks, which sur- 
 round the subclavian artery. While in the axilla they are re- 
 enforced by the deep lymphatics from beneath the pectoralis 
 major, the latissimus dorsi, and the shoulder. Their number 
 being again reduced, they go along the subclavian vein over the 
 first rib; those of the left side open either into the thoracic duct 
 at its termination, or into the subclavian vein near it; but those 
 on the right are finally assembled into the single large trunk, 
 brachio-cephalic, which discharges into the angle of junction of 
 the right internal jugular and subclavian vein. 
 
 Msorbent Glands of the Upper Extremity. 
 
 These glands are rarely found on the fore arm, but when they 
 do exist, it is in the course of the deep absorbents, and they are 
 very small, and but few. From one to four are found scattered 
 on the front of the elbow and internal condyle. From four 
 to seven exist along the sheath of the humeral vessels and 
 nerves. 
 
 The axillary glands are very numerous, and of different sizes; 
 they are dispersed throughout the cellular substance of the ax- 
 illa, reposing on the serratus major anticus, between the pecto- 
 ral muscles and those of the shoulder, and being, for the most 
 part, below the axillary vessels and nerves, but some reposing 
 immediately upon them, and forming a chain from the lower 
 part of the axilla to the clavicle. Their number is from fifteen 
 to thirty-five or forty. All the absorbents which observe the 
 
ABSORBENTS OF THE UPPER EXTREMITIES. 295 
 
 route of the axilla to reach the thoracic duct have to pass through 
 these glands. 
 
 SECT. III. ABSORBENTS OF THE INFERIOR EXTREMITIES, AND OF THE 
 CONTIGUOUS PARTS OF THE TRUNK OF THE BODY. 
 
 The superficial absorbents, like those of the upper extremity, 
 are placed between the skin and the aponeurosis, in the cellular 
 tissue that contains the subcutaneous veins. They are also very 
 abundant, and are found every few lines on the circumference 
 of the limb; they are, however, more numerous internally than 
 externally, and, for the most part, run upwards. 
 
 Those on the inner or anterior side of the limb, are first per- 
 ceived on the back of the toes and foot. They incline over the 
 front of the ankle, and its internal face to the inner side of the 
 leg; they then ascend over the inner side of the knee, and along 
 the same side of the thigh to the groin. The superficial absor- 
 bents of the back of the lower extremity are first perceived on 
 the sole of the foot. They ascend along the back of the outer 
 ankle and of the leg above the knee; they then incline semi- 
 spirally inwards, so as to bring themselves to the front of the 
 thigh. These several absorbents, though there are but few on 
 the foot, augment continually in number by new accessions in 
 their ascent. All those on the posterior internal face of the 
 thigh wind over its internal side, while such as are on its pos* 
 terior external face wind over the outer side, to reach the ingui- 
 nal glands. 
 
 The Deep Absorbents adhere to the arteries, being at least 
 two to each, and adopting the same distribution and nomencla- 
 ture. The anterior tibial begins in the sole of the foot, and 
 arises to its back between the two first metatarsal bones; ano- 
 ther branch begins on the dorsum of the foot. The first pur- 
 sues the course of the anterior tibial artery through the inter- 
 osseal ligament to the ham, the second frequently join the 
 peroneal absorbents about half way up the leg. The posterior 
 tibial and the peroneal absorbents, as they cruise along their 
 respective arteries, do not require any farther comment. There 
 
296 CIRCULATORY SYSTEM. 
 
 is a fourth set of these deep absorbents, amounting to two Of 
 three in number, which attend the external saphena vein, and 
 come from the external side of the foot. Getting between 
 the heads of the gastrocnemii muscles, th'ey are re-enforced by 
 other trunks , from this muscle; some of the branches then asso- 
 ciate themselves with the superficial lymphatics, and others pe- 
 netrate the ham so as to join the deep trunks there. 
 
 The deep absorbents of the leg coalesce partially in the ham 
 and ascend along the popliteal artery. On the thigh, there are 
 from four to eight of these trunks attending the femoral artery, 
 and receiving additions as the latter detaches branches. 
 
 There are two or three lymphatic vessels on each side of the 
 penis, which begin at its glans and prepuce, and traversing the 
 length of this organ, wind above the external abdominal ring to 
 join the nearest inguinal gland. There are several from the 
 side of the scrotum and perineum, which ascend along the chord 
 and thigh to join also the nearest inguinal gland. In the fe- 
 male, those of the labia externa and clitoris correspond with 
 those of the scrotum and penis. 
 
 The superficial absorbent trunks, from the lower front of the 
 abdomen, are not numerous: they descend and converge also to 
 the inguinal glands. Some of those from the loins, such as do 
 hot ascend to the axilla, advance to the inguinal glands. Those 
 of the buttocks do the same. 
 
 Msorbent Glands of the Lower Extremities. 
 
 Absorbent Glands, below the knee, are not abundant, or, in- 
 'deed, very common; yet one or two exist sometimes in the 
 course of the anterior tibial artery in the. upper part of the 
 leg. The popliteal glands are three or four; they are small 
 and scattered at wide intervals in the fat of the ham around its 
 Vessels. From the latter to the groin, they are not usually 
 found at all. 
 
 The Inguinal Glands are amongst the largest in the system; 
 they repose along the anterior margin of Poupart's ligament and 
 'a little below, and are readily felt beneath the skin. The su- 
 
DEEP ABSORBENTS OF THE PELVIS. 297 
 
 perficial vary in number, in different individuals, From seven to 
 twenty, being more numerous as they are smaller, and are 
 placed between the laminae of the fascia superficialis. They 
 receive, first of all, the superficial lymphatics of all the parts 
 mentioned. The deep-seated are smaller, are a little lower 
 down on the thigh, and lie along the course of the femoral arte- 
 ry, beneath the aponeurosis of the thigh; they are from three 
 to seven in number, but are much less constant than the super- 
 ficial. 
 
 SECT. IV. DEEP ABSORBENTS OF THE PELVIS. 
 
 The Deep Absorbents of the parietes of the pelvis, as in other 
 cases, attend the arteries of the part and have the same names. 
 The obturators come from the heads of the adductor muscles, 
 and, passing through the obturator foramen, end in the hypo- 
 gastric glands. The ischiatics come from the small muscles on 
 the back of the hip joint, and getting into the pelvis along with 
 the sciatic artery, they also terminate in the hypogastric glands. 
 The gluteals come from the three gluteal muscles, and entering 
 the pelvis along with the artery at the superior margin of the 
 sciatic notch, they likewise terminate in the hypogastric glands 
 along with some vessels from the anus and the perineum. The 
 ilio-lumbar, the sacral, and the circumflex iliac absorbents, also 
 follow their respective arteries and terminate in the nearest 
 glands. 
 
 The absorbents of the Testicle are numerous and large: ao 
 cording to Dr. W. Hunter,* they can sometimes be very com- 
 pletely injected by a pipe thrust into the substance of the testi* 
 cle, and, according to Cruikshank, very advantageously from 
 the vas deferens.-)- They form two layers, one superficial coming 
 from the txmiea vaginalis testis, and the other from the substance 
 of the gland. They, finally, unite into some six or eight trunks, 
 whichj ascend with the chord through the abdominal canal. Oc- 
 casionally, one or more of them is as large as a crow-quill. By 
 following the course of the spermatic artery, they at last termi- 
 nate in the lumbar glands. 
 
 * Loc, cit. f Loc, cit, p, 155, t Mascagni, loc. cit, 
 
293 CIRCULATORY SYSTEM. 
 
 The deep absorbents of the Penis accompany the arteries, 
 and, therefore, either get into the pelvis beneath the symphysis 
 of the pubes, or along the crura and the tuberosities of the is- 
 chia; hence, a chancre on the prepuce causes bubo, while one 
 on the glans very rarely does, and yet the constitution will be 
 equally affected.* These absorbents terminate in the hypogas- 
 tric glands. 
 
 The deep absorbents of the Clitoris follow, in the same way, 
 the internal pudic artery. 
 
 The absorbents of the Urinary Bladder are also numerous, 
 and pass in several trunks from its sides to the hypogastric 
 glands. Those of the prostate gland and vesiculse seminales 
 are associated with them. 
 
 The absorbents of the lower part of the vagina accompany 
 the round ligament of the uterus through the abdominal canal, 
 and, finally, anastomose with those of the uterus. Those of the 
 upper portion of the vagina are immediately associated with 
 such as belong tq the uterus. 
 
 The absorbents of the uterus are not so well seen in the un- 
 impregnated state, but in impregnation they are so prodigious- 
 ly numerous, that when injected with quicksilver, one is al- 
 most tempted to suppose that the uterus consists entirely of 
 them. Mascagni's plate on this subject is an exquisite speci- 
 men.! As they all terminate in the hypogastric trunks, the 
 latter are in such case as large as goose-quills.J 
 
 The hypogastric plexus, from these several accessions from 
 the parietes and viscera of the pelvis, becomes very numerous, 
 and follows the course of the hypogastric artery in ascending 
 into the loins. 
 
 There are likewise some spermatic absorbents in the female, 
 called so from attending the vessels of the same name. They 
 come from theovarium, the Fallopian tube, and the round liga- 
 ment, to terminate in the lumbar glands; they anastomose be- 
 low with those of the uterus. 
 
 * Cruikshank, loc. cit. f Loc, cit. * Cruikshank, loc. cit. 
 
ABSORBENTS OF THE ORGANS OF DIGESTION. 299 
 
 Of the Glands of the Pelvis. 
 
 Some few glands lie beneath the glutens maximus muscle, 
 but the majority are within the pelvis. Those which are called 
 the External Iliac are at least six, frequently more, and extend 
 from Poupart's Ligament to the lower part of the loins, being 
 planted along the external iliac artery, both above and belov.'. 
 The Hypogastric or Internal Iliac Glands are rather more nu- 
 merous than the others, and form a chain along the hypogastric 
 artery. The latter are much disposed to form large indurated 
 masses from diseases of the rectum, uterus, and bladder.* 
 
 SECT. V. ABSORBENTS OF THE ORGANS OF DIGESTION. 
 
 The Absorbents of the Stomach are very numerous, and lie in 
 two planes; one is superficial, being immediately beneath the 
 peritoneal coat, and the other is profound, being placed be- 
 tween the muscular and the mucous coat. They are, finally, 
 assembled into three divisions, which follow the course of the 
 principal blood vessels of this organ. 
 
 One division, coming from the anterior and the posterior 
 faces of the stomach, converges to its lesser curvature, and 
 passes through some six or eight small glands in the adjacent 
 portion of the lesser omentum. Inclining to the right of the 
 cardiac orifice, they then pass through some glands common to 
 them and to the deep lymphatics of the liver. Their numbers 
 being reduced, they then descend behind the pancreas, and ter- 
 minate in the thoracic duct near the creliac artery. 
 
 The second division comes from the left inferior portion of 
 the stomach, and from its greater extremity, and, blending with 
 the absorbents of the spleen and pancreas, goes with them inta 
 the thoracic duct. 
 
 The third division comes from the right inferior portion of 
 the stomach, and, assembling towards the pylorus, are subse- 
 
 * Cruikshank, loc. cit. 
 
300 CIRCULATORY SYSTEM. 
 
 quently mixed with some of the absorbents of the liver and of 
 the small intestines, and go along with them into the thoracic 
 duct. 
 
 The Absorbents of the Great Omentum join those of the 
 stomach and of the colon, at the points most convenient to 
 them. 
 
 . The Absorbents of the Small Intestines, like those of the 
 stomach, are both superficial and deep, and from the function of 
 conveying chyle, have been called lacteals, or chyliferous ves- 
 sels. As the chyle, however, can only be absorbed by the deep 
 ones; and, as they and th superficial have common trunks, as 
 they also absorb, from the intestines, fluids not converted into 
 chyle, there seems to be no necessity for distinguishing them 
 by a particular epithet. The deep are in the cellular coat of the 
 intestine, and follow the ramifications of the arteries, being dou- 
 ble their number. The superficial, being immediately beneath 
 the peritoneal coat, run for some distance, longitudinally, on the 
 gut, and then turn off to the mesentery at right angles. 
 
 On the mesentery these absorbents are not rigidly bound to 
 the course of the blood vessels; they converge in a slightly tor- 
 tuous manner from its circumference to its root. They anasto- 
 mose with one another, by which their number is reduced; 
 and they also have to pass through the series of mesenteric 
 glands. The lacteals of the duodenum and jejunum are larger 
 and more numerous than those of the ileum, in the proportion 
 of the greater extent of the internal surface of the former intes- 
 tines, from the number of their valvulae conniventes. The ves- 
 sels of the mesentery, after having cleared the series of glands, 
 and held some intercourse with the lymphatics of the spleen, 
 liver, stomach, and pancreas, are reduced at last into one or more 
 large trunks, which, observing the course of the superior me- 
 senteric artery, empty near the root of the latter, but some- 
 times lower down, into the thoracic duct. 
 
 The absorbents of the Large Intestines are much less nume- 
 rous than those of the small. They are also superficial and deep, 
 
ABSORBENTS OF THE ORGANS OF DIGESTION. 301 
 
 and observe the course of the felood vessels. Those from the 
 right portion and middle of the colon join the lacteals of the me- 
 sentery, while such as belong to the sigmoid flexure follow the 
 inferior mesenteric artery up to the lumbar glands. Those of 
 the rectum go partly into the lumbar and partly into the hypo- 
 gastric glands, and as its blood vessels are more numerous than 
 those of other portions of the large intestines, its absorbents are 
 in the same proportion.* 
 
 The Absorbents of the Liver are exceedingly numerous, and 
 are also injected with unusual ease from the larger into the 
 smaller trunks, from the imperfection of the valvular arrange- 
 ments. They are also superficial and deep. 
 
 The Superficial Absorbents of the upper surface of the liver 
 run in several divisions, the number of which is unsettled. Those 
 near the middle front of the liver assemble into six or more trunks, 
 which ascend the suspensory ligament, and enter the thorax be- 
 tween the diaphragm and the sternum. They are joined by se- 
 veral trunks from the diaphragm, and, continuing to ascend up 
 the anterior mediastinum between its laminae behind the sternum, 
 they are re-enforced by contributions from the pericardium, from 
 the thymus gland, and from the anterior parietes of the thorax. 
 The division then crosses the upper end of the descending cava, 
 and those from the two sides assembling, they go in one or more 
 large trunks along the left vena innominata, and finally empty 
 into the left thoracic duct near its termination. Sometimes they 
 enter into the right thoracic duct. It occasionally happens that 
 a detachment of this division, instead of ascending through the 
 mediastinum, is directed towards the coronary ligament of the 
 liver; and being there joined by other vessels, it enters imme- 
 diately into the thoracic duct at the upper part of the abdominal 
 cavity, or at the lower part of the thorax. 
 
 Another division comes from the upper surface of the right 
 lobe, and gaining the right lateral ligament, penetrates into the 
 thorax through the diaphragm, and advancing along the costal 
 
 * Cruik shank, loc. cit. 
 VOL. II. 39 
 
302 CIRCULATORY SYSTEM. 
 
 margin of this muscle, terminates in the first division under the 
 sternum. Sometimes one of its branches, thrice as large as a 
 crow-quill, runs backward to the spine, and is inserted into the 
 thoracic duct behind the oesophagus, without passing through 
 any gland; there are also, occasionally, several other arrange- 
 ments of the trunks of this division.* 
 
 Another division comes from the upper surface of the left lobe 
 of the liver, and its trunks, advancing to the left lateral ligament, 
 get into the thorax through the diaphragm. Some of the trunks 
 then run forward on the convexity of this muscle, to terminate 
 in the trunks Under the sternum, while others retire backward 
 to end in the glands around the oesophagus, immediately above 
 the diaphragm. 
 
 There are various departures from this general arrangement 
 of the absorbents on the upper surface of the liver; as their 
 trunks invariably reach the thoracic duct, ultimately, the par- 
 ticular routes do not seem to be rigidly fixed. 
 
 The Superficial Absorbents of the under surface of the liver 
 present, also, diversities, but they are seldom arranged into so 
 many divisions as those of the upper surface. They communicate 
 freely with the latter, and also with the profound, and, finally, 
 assembling in the transverse fissure, they descend along the cap- 
 sule of Glisson to join and anastomose with the contiguous 
 trunks from the alimentary canal, from the pancreas, and the 
 spleen. 
 
 The Deep Absorbents of the liver follow the branching of the 
 vena portarum, and, emerging at the transverse fissure, pass 
 through the glands in the capsule of Glisson, associating them- 
 selves at the same time with the superficial trunks, and having a 
 common termination with them. By putting a ligature around 
 the vena portarum of a living animal, many of them are in- 
 cluded in it ; they then become exceedingly turgid, and are seen 
 to diverge through the liver like the pori biliarii. 
 
 The liver is said to be more abundantly furnished with ab- 
 sorbents than any other vise us. 
 
 * Cruikshank, loc. cit. 
 
ABSORBENTS OF THE ORGANS OF DIGESTION. ^ 303 
 
 The Absorbents of the spleen are also superficial and deep- 
 seated. The former are between the peritoneal and the proper 
 coat, and are injected with some difficulty in the human subject, 
 but are very demonstrable and numerous in the calf. The latter 
 emerge at the fissure of the spleen, and, traversing the glands 
 tha/ lie along the course of the splenic artery, receive successively 
 the absorbents from the pancreas. They,, finally, end in the tho- 
 racic duct, after reciprocal junctions, and anastomose with the 
 vessels from the stomach and liver. 
 
 The Absorbents of the Pancreas are also numerous, and may 
 be injected, contrary to their circulation, from those of the liver. 
 They arise from the substance of the pancreas, like its vessels, 
 by short trunks, which join those of the Splenic Plexus at right 
 angles. 
 
 The Absorbents of the Kidneys are superficial and deep ; the 
 former, though numerous, are too small in the healthy state of 
 these organs to be well seen, but they become very distinct from 
 disease, and converge from its periphery to its fissure. The deep 
 absorbents accompany the vessels, and, emerging with them at 
 the fissure, are joined with the superficial; they all then run 
 along the emulgent vessels, and have frequent anastomoses with 
 those of the testicles or ovaries, and with those of the capsulae 
 renales. These absorbents may be filled by putting a pipe into 
 the excretory duct of the kidney. 
 
 The absorbents of the Capsulae Renales unite to those from 
 the kidneys, and, therefore, terminate with them in the lumbar 
 glands. 
 
 Of the Absorbent Glands of the Abdomen. 
 
 The cavity of the abdomen contains many more glands than 
 any other region of the body, on account of the very great ex- 
 tension of the serous system in it, of the functions exercised by 
 its viscera, and of its being traversed by the absorbents of the 
 lower extremities. Many of these bodies have already been de- 
 scribed under the denomination of hypogastric, and external 
 
304 CIRCULATORY SYSTEM. 
 
 iliac ; in addition to which there are a few between the laminae 
 of the mesorectum in front of the sacrum. 
 
 The Mesenteric Glands are exceedingly numerous, and amount 
 to between one and two hundred ; they begin at an inch or two 
 from the small intestines, and may be traced to the root of the 
 mesentery, being placed between its layers, on the convex side 
 of the upper mesenteric artery. As the intestinal canal is longer 
 in some individuals than in others, they are proportionately more 
 numerous. Their largest size seldom exceeds that of an almond : 
 those belonging to the jejunum are rather more developed than 
 such as belong to the ilium, and they all augment in size as they 
 approach the root of the mesentery. 
 
 The Glands of the Mesocolon are placed between the laminae 
 of this membrane, near the intestine ; they receive the absorbents 
 from the large intestines, are much smaller than those of the me- 
 sentery, and their number seldom exceeds fifty. Some few of 
 them are situated near the root of the mesocolon. They are by 
 no mea'ns so disposed to tumefaction from scrofulous affections 
 as those of the Mesentery. It is stated by Winslow, that he de- 
 monstrated to the Academy of Sciences at Paris, chyle in the 
 absorbents of the Mesocolon ; this fact will assist us in account- 
 ing for the effects of nutritive glysters. 
 
 The Gastro-Epiploic Glands are situated between the lami- 
 nae of the omenta, where they join the curvatures of the stomach. 
 Their number seldom exceeds four or five for each curvature, 
 and they receive the lympathics of the stomach and omenta. 
 
 The Caeliac Glands are those which belong to the liver, the 
 spleen, and the pancreas ; they follow the course of the blood 
 vessels of these organs, and are traversed by their absorbents. 
 The trunk of the vena portarum is surrounded by them, and Mr. 
 Cruik shank says, that he has seen the biliary and pancreatic 
 ducts in a state of compression from their tumefaction. 
 
 The Lumbar Glands are very numerous and large; they are 
 scattered over the whole region from the base of the sacrum to 
 
ABSORBENTS OF THE VISCERA OF THE THORAX. 305 
 
 the pillars of the diaphragm, lying on each side of the bodies of 
 the lumbar vertebrae, and in front of the abdominal aorta and 
 vena cava, being concealed by the root of the mesentery and of 
 the mesocolon. They may be considered as continuations of 
 all the preceding congeries of glands in the abdomen, and, there- 
 fore, when they, along with the vessels leading to them, are suc- 
 cessfully injected, they form so thick a plexus of absorbents, 
 reaching from the pelvis to the concavity of the diaphragm, that 
 the great blood vessels can scarcely be seen for them. Many 
 of the vessels reaching from one to another, are as large as a 
 crow-quill. 
 
 SECT. VI. ABSORBENTS OF THE VISCERA OF THE THORAX. 
 
 The Absorbents of the Lungs are thought to be next in abun- 
 dance after those of the liver, and are likewise divided into two 
 sets, the superficial and the deep-seated. The former are be- 
 neath the pleura pulmonalis. Mr. Cruikshank* says, that they 
 are not always to be found, though commonly he has readily 
 shown them covering with their meshes the whole external sur- 
 face of the lung. The larger meshes follow the interstices of 
 the lobules, and within them are others of extreme delicacy. 
 The same author states, that one of the easiest methods of find- 
 ing them, is to inflate the lungs of a still-born child, from the 
 trachea, and the air passing from its proper cells, will get into 
 the absorbents; a puncture being then made into one of the lat- 
 ter, quicksilver may be very readily introduced. Some of their 
 trunks penetrate to the bottom of the fissures of the lungs, and 
 pass through the glands there, while others continue more super- 
 ficial along the internal face of the lung, and so reach the bron- 
 chial glands. 
 
 The deep absorbents of the lungs observe the course of the 
 pulmonary vessels and of the bronchise. They arise from the 
 substance of the lung, anastomose very freely with the superfi- 
 cial vessels, and, in parting from the lung, pass through the 
 bronchial glands, where they are joined by the superficial. 
 
 By the junction of the branches from the left lung, three con- ' 
 
 * Loc. cit. p. 194. 
 
306 CIRCULATORY SYSTEM. 
 
 siderable trunks are formed; one, which is sometimes the size 
 of a goose-quill, is inserted into the thoracic duct, immediately 
 behind the bifurcation of the trachea ; another ascends between 
 the trachea and the oesophagus, to join the thoracic duct near 
 its termination, and the third joins the glands belonging to the 
 absorbents of the heart.* 
 
 The absorbents of the right lung also coalesce into three prin- 
 cipal trunks at the root of the lung : one of them ascends across 
 the front of the superior cava, making, in its course, many ele- 
 gant convolutions, and at length terminates in the second trunk 
 on the left side.t The other trunks, ascending on the side of 
 the trachea, and having traversed their glands, discharge into 
 the right thoracic or brachio-cephalic trunk, or else near it into 
 the right internal jugular, or into the right subclavian vein. 
 There are, in these respects, diversities in different subjects. 
 
 The trunks of the Absorbents of the Heart follow the course 
 of the coronary vessels, and distribute themselves by branches 
 over its whole surface. They are, without previous manage- 
 ment, easily discovered; but if the heart be macerated in water 
 for several days, so as to become somewhat putrid, the absor- 
 bents are filled and distended by the gazeous exhalation: on the 
 puncture of one of these vessels and the introduction of a pipe, 
 they may all be readily filled. 
 
 There are three principal trunks of these absorbents; one fol- 
 lows the right coronary artery to the root of the aorta, and then 
 ascends over the front surface of the latter to the top of its arch, 
 where it enters a gland. The other two trunks follow the two 
 principal branches of the left coronary artery, and, coalescing 
 near its origin, they ascend to the bifurcation of the pulmonary 
 artery, and from that along the posterior face of the arch of the 
 aorta, to enter a gland between it and the trachea. These se- 
 veral vessels subsequently traverse the lymphatic glands about 
 the trachea, common to the heart and to the lungs; and ulti- 
 mately terminate under varied circumstances, either directly or 
 indirectly, in the left thoracic duct, the left internal jugular, or 
 the subclavian vein. Mr. Cruikshank says, that the right coro- 
 
 * Cruikshank, loc. cit. f Cruikshank, loc. cit. 
 
ABSORBENTS OF THE PARIETES OF THE TRUNK. 307 
 
 nary trunk empties into the lymphatic trunks of the right side 
 of the neck, which shows that there is no fixed arrangement. 
 
 The Absorbents of the Pericardium may also be found; they 
 terminate, like the others of the heart, in the bronchial glands, 
 and are particularly associated with those of the thymus gland. 
 
 The Absorbents of the CEsophagus are so numerous as to 
 form a plexus from one end to the other of it. They run into 
 the bronchial glands, and, therefore, have a common termina- 
 tion with the absorbents of the heart and lungs. Mr. Cruikshank 
 says, that he has reason to believe that he has seen life sustained 
 through them alone and the absorbents of the mouth, in a case 
 where stricture prevailed for some months just above the cardia, 
 and where the food, after remaining for three or five minutes 
 in the oesophagus, was vomited up.* 
 
 The Absorbents of the Thymus Gland are very abundant in 
 the infant, but diminish with the rest of the structure in the 
 adult: they terminate in the bronchial glands also. 
 
 SECT. VII. THE ABSORBENTS OF THE PARIETES OF THE TRUNK. 
 
 t 
 
 In addition to the absorbents mentioned as belonging to the 
 internal and external parietes of the pelvis, there are some 
 others belonging to this cavity, as the ilio lumbar, the sacral, 
 and the circumflex. 
 
 The Ilio Lumbar Lymphatics come from the parts to which 
 the artery of the same name is distributed, and, assembling into 
 two or more large trunks which pass beneath the psoas magnus 
 muscle, one of them joins the lumbar glands, and another the 
 hypogastric. 
 
 The Sacral Lymphatics arise from the cellular tissue in front 
 of the sacrum and from the spinal canal in the latter. Emerging 
 
 * A case somewhat similar has occurred in the practice of Dr. Physick. 
 
308 CIRCULATORY SYSTEM. 
 
 through its foramina in front, they terminate in the lower part 
 of the lumbar and in the hypogastric plexus. 
 
 The Circumflex Iliac Lymphatics attending the artery of the 
 same name, arise from the lateral inferior parietes of the abdo- 
 men> in the thickness of its broad muscles, the several branches 
 assemble into a few trunks, which descend along the posterior 
 margin of Poupart's ligament to terminate in the external iliac 
 plexus. 
 
 The Epigastric Absorbents are derived from the inferior an- 
 terior parietes of the abdomen, along the region of distribution 
 of the epigastric artery. Their trunks coalesce into larger ones, 
 and descend along this artery to end in the external iliac plexus, 
 near the crural arch. 
 
 The Lumbar Absorbents arise from the muscles of the loins, 
 from the posterior part of those of the abdomen, and from the 
 spinal cavity. Their trunks correspond with the lumbar arte- 
 ries, and passing beneath the psoas magnus muscle towards the 
 spine, they terminate in the lumbar glands. 
 
 The Intercostal Absorbents take their origin from the parietes 
 of the thorax, and following the course of their respective inter- 
 costal arteries, pass through some small glands occasionally 
 found between the external intercostal muscles near the heads 
 of the ribs. They are there joined by trunks from the spinal 
 cavity and from the muscles of the back, and afterwards passing 
 through some small glands on the front of the vertebral column, 
 they anastomose more or less with one another, and finally ter- 
 minate in the left thoracic duct. The absorbents of the pleura 
 costalis and of the posterior part of the pericardium terminate 
 in the intercostals. 
 
 The Internal Mammary Absorbents have their roots in the 
 anterior region of the parietes of the abdomen, above the umbi- 
 licus, where they anastomose with the epigastric. They ascend, 
 along with the internal mammary arteries, behind the sternal 
 
ABSORBENTS OF THE PARIETES OF THE TRUNK. 309 
 
 Cartilages, pass through some small glands, and receive contri- 
 butions from the anterior extremities of the intercostal spaces. 
 Those of the left side, assembling into one or two trunks, cross 
 in front of the left subclavian vein, traverse the inferior cervical 
 glands, descend afterwards from this point, and terminate in the 
 left thoracic duct, or in one of the contiguous trunks of the ve- 
 nous system. Those on the right execute the same movements, 
 but terminate in the right thoracic duct, or in one of the conti- 
 guous venous trunks of that side. 
 
 The Absorbents of the Diaphragm are exceedingly numerous, 
 and very much connected with those of the liver. The anterior 
 ones join the internal mammary absorbents, while the posterior 
 follow the phrenic arteries, or go to contiguous trunks belonging 
 to the intercostals. The front ones on the right side, then ter- 
 minate in the right thoracic duct, while the remainder go in the 
 various routes of the absorbents, with which they are connected, 
 into the left thoracic duct. They are principally seen on its 
 upper surface. Mr. Cruikshank * says, that he once saw them 
 to the amount of three hundred or more, filled with chyle from 
 the mesentery that had passed through the substance of the liver. 
 Asellius was, therefore, probably justified by an accident of this 
 kind, in asserting that the lacteals went to the liver. 
 
 The Absorbents of the Female Mamma?, like their arteries 
 and veins, are superficial and deep ; the former attend the exter- 
 nal thoracic blood vessels, and the latter the internal mammary. 
 The superficial arise from the circumference of the nipple, from 
 the skin and cellular membrane, and according to the injections 
 of Mr. Cruikshank, communicate freely with the vesicles of the 
 tubuli lactiferi. They run towards the axilla, having sometimes 
 to pass through some glands which are situated half way ; they 
 then enter the first series of glands of the axilla in their direc- 
 tion, and afterwards others successively, until they terminate in 
 the lymphatic trunks of the upper extremity, high up in the arm- 
 pit Some few of these superficial vessels ascend over the pec- 
 toralis major to some glands in the neck, just above the clavicle. 
 
 * Loc. cit. p. 90. 
 VOL. II.-40 
 
CIRCULATORY SYSTEM. 
 
 The deep absorbents of the mammae arise from their thoracic 
 face, and penetrating the intercostal spaces, join the absorbents 
 that attend the internal mammary artery. 
 
 \ 
 
 Of the Absorbent Glands in the Thorax. 
 
 There, are, as mentioned, a few small glands in the intercos- 
 tal spaces near the heads of the ribs between the internal and ex- 
 ternal intercostal muscles, intended to receive the lymphatics 
 of these spaces. There are also several small ones situated on 
 the front of the dorsal vertebrae, along the aorta and the oeso- 
 phagus, in the posterior mediastinum. There are also from six 
 to ten along the internal mammary artery; and some others in 
 the anterior mediastinum, along the sternal face of the pericar- 
 dium. They are said to be very rarely affected by disease. 
 
 The most considerable and striking glands in the thorax are 
 those called Bronchial or Pulmonary, which receive the absor- 
 bents of the lungs. They cluster about the bifurcation of the 
 trachea, and follow the bronchise for some distance into the sub- 
 stance of the lungs. They are from ten to twenty in number, 
 and vary in size from an inch to a few lines in diameter. Till 
 puberty tlfey have a reddish colour, -but afterwards they be- 
 come gray, and finally black, following in these respects the 
 change of colour in the lungs. According to Mr. Pearson, 
 their complexion depends upon the deposite of pure carbon. 
 
 In pulmonary consumption these glands are always enlarged, 
 and look scrofulous. 
 
 SECT. Yin. o~ OF THE THORACIC DUCTS. 
 
 The Left Thoracic Duct (Ductus Thoracicus Sinister] is the 
 main stream of the absorbent system, to which almost all the 
 others are but tributary, and by divers routes ultimately find 
 their way into it. It begins about the second or third lumbar 
 vertebra, in front o^ its body. Shortly after its commencement, 
 while still in the abdomen, it suffers a dilatation more or less 
 considerable, and varying in its shape in different subjects. 
 This is called the Reservoir of Pecquet, or the Receptaculum 
 'Chyli; the dilatation, however, is frequently absent, and does 
 
THORACIC DUCTS. 311 
 
 not seem to be an essential part of the structure: in bur pre- 
 parations at the University some have it, and others Jiave it 
 not. 
 
 The thoracic duct enters the thorax between the crura of the 
 diaphragm, to the right of, and behind the aorta: it then ascends 
 on the front of the dorsal vertebrae, between the aorta and the 
 vena azygos, in front of the right intercostal arteries, and behind 
 the oasophagus. At the fourth dorsal vertebra it begins to in- 
 cline in its ascent to the left side, and then ascends into the 
 neck near the head of the first rib; it rises commonly as high 
 up as the upper margin of the seventh cervical vertebra; it then 
 turns downwards and forwards, over the left subclavian artery 
 within the scaleni muscles, and finally discharges into the angle 
 of junction of the left subclavian and internal jugular veins. 
 
 The preceding is the most simple, and perhaps the most com- 
 mon form, under which the thoracic duct is presented, but va- 
 rieties are continually occurring in its place and mode of origin, 
 in its trunk, and its manner and place of termination. It com- 
 monly begins by the union of three absorbent trunks; one for 
 each side of the pelvis, along with the corresponding lower ex- 
 tremity; and a middle one for the chyliferous vessels, which 
 unites with the common trunk of the other two, a few lines 
 above its point of formation; on other occasions, the chyliferous 
 trunks join 'it in a confused manner by nine or ten distinct 
 channels. Sometimes an intricate plexus of several large trunks, 
 derived from the lumbar and mesenteric glands; by the gradual 
 reduction of the number of meshes from the successive joining 
 of trunks; begins to assume, at the crura of the diaphragm, the 
 form of a solitary trunk, which is the thoracic duct. The trunk 
 of the duct is also disposed to keep up the anastomosing plan, 
 even in the thorax; we hence see it sometimes dividing itself 
 into two or three channels of equal sizes, which unite again af- 
 ter a shorter or longer distance, and perhaps in a little space 
 repeat the same arrangement: sometimes a small arm is sent 
 off, which runs alone for an inch or two, and joins into the pa- 
 rent stream; sometimes spiral turns are adopted by the thoracic 
 duct, sometimes nodosities, or small pouches, are formed on its 
 sides; sometimes it-is dilated at intervals in its whole circumfe- 
 
312 CIRCULATORY SYSTEM. 
 
 rence. Sometimes it splits into several channels at its termina- 
 tion; one channel terminating in one vein and another in a con- 
 tiguous one, of the several trunks forming the vena innominata; 
 on other occasions, instead of entering into a venous trunk 
 of the left side, it goes into the corresponding one of the right. 
 
 Commonly, it is about the size of a large crow-quill, but some- 
 times as large as a goose-quill, or even still more voluminous, 
 seeming to be in a varicose state, of which Mr. Cruikshank men- 
 tions an example where it was half an inch in diameter, and 
 took two pounds of mercury to fill it. There is generally a pair 
 of valves at the termination of the thoracic duct, or if it be di- 
 vided into several streams there is a pair at the embouchure of 
 each, to keep the venous blood out of it. There are also valves 
 in its length, but they are not numerous, and vary in different 
 subjects. 
 
 The thoracic duct is the grand outlet for the lymphatics of the 
 left side of the head and neck, of the left superior extremity, of 
 the intercostals, of the left side of the thorax, of the viscera of 
 the abdomen, and of the inferior extremities. Though those of 
 the viscera of the abdomen and of the lower extremities have 
 this route, yet, from the observations of Mr. Lippi, of Florence, 
 as mentioned, they have also some more direct means of getting 
 into the general circulation. For example, he has found several 
 large lymphatic trunks emptying into the ascending cava, one of 
 them opposite the third lumbar vertebra; another into the primi- 
 tive iliac vein : he has also found some of the lympathics of the 
 liver discharging into the vena portarum. 
 
 
 
 The Uight Thoracic Duct, (Ductus Thvracicus Dexter,) as it 
 is called, W more properly the Right Brachio-cephalic, after the 
 name given by M. Chaussier to the vein, is not more than an inch 
 long, and descends to empty itself, as mentioned, into the junc- 
 tion of the right internal jugular with the right subclavian vein. 
 It is derived from the lymphatic trunks of the right side of the 
 head and neck, from the right upper extremity, the superficial 
 lymphatics of the right side of the thorax, the lymphatics of the 
 right lung, of the right side of the diaphragm, and some of those 
 of the right side of the liver, the courses of all of which have 
 been detailed. 
 
THORACIC DUCTS. 313 
 
 Though the single trunk is formed from these several tributary- 
 streams, yet the latter have sometimes several embouchures into 
 the venous system at or near the point mentioned, and, as on 
 the other side of the body, there is a proper security, by valves, 
 from the introduction of blood into them. 
 
 There is always an ample system of anastomosis, not only be- 
 tween the branches which concur to form the right and left tho- 
 racic ducts, but even between the ducts themselves,* so that if 
 one be occluded or impeded, its circulation can be turned into 
 the other, as in the case of veins. 
 
 * Meckel, Man. D'Anat. torn. ii. p. 581. 
 
BOOK IX. 
 
 PART I. 
 
 Of the General Anatomy of the Nervous System. 
 NERVOUS SYSTEM. 
 
 THE nervous system in man, and other vertebrated animals, 
 consists in two portions of dissimilar forms : one is spheroidal, 
 elongated at its base into a cylindrical process, and is contained 
 in the cranium and in the spinal canal; the other is an assem- 
 blage of arborescent rays, which proceed from different points of 
 the first portion, to every part of the body. The first portion is 
 the Central or Internal part of the nervous system, composed of 
 the Brain and Spinal Marrow, while the radiating portion is 
 called the External or Peripheral, and consists in the Nerves of 
 the brain and spinal marrow. 
 
 The nervous system is remarkable for its symmetry ; as it is 
 universally double, it very seldom happens that any striking dif- 
 ference of it on the two sides of the body is manifested, particu- 
 larly as regards its Central portion; it is said, however, that 
 aberrations, in this respect, are more common in man than in 
 other mammiferous animals. 
 
 The Central Portion of the Nervous System is composed of 
 two kinds of substance, distinguished by their colour and rela- 
 tive situation : one is improperly enough called Medullary, (Sub- 
 stantia MedullarisJ but as the name is now sanctioned by uni- 
 
316 NERVOUS SYSTEM. 
 
 versal usage, it is impossible to dispense with it. The other is 
 called Cineritious, (Substantia Cinerea,) with, perhaps, sufficient 
 propriety, from its colour. They are both of a soft pulpy con- 
 sistence, and constitute the chief mass of the brain and spinal 
 marrow: some anatomists have desired to add, from some slight 
 distinction of colour, two other substances, a yellow and a black, 
 but that seems unnecessary, and has not been acknowledged. 
 These substances differ from one another in regard to their 
 quantity, the medullary being more abundant than the cineri- 
 tious ; it is also harder, and receives fewer vessels. But the 
 atoms of both have the same elementary form, that of globules 
 united by a semi-fluid substance ; the shape of these globules, as 
 well as their size and degree of solidity, are not yet ascer- 
 tained.* 
 
 The Medullary Matter, when quite fresh and scraped in par- 
 ticular directions, has a fibrous appearance, which may be ren- 
 dered still more distinct by hardening it in alcohol, in boiling oil, 
 in a solution of the neutral salts, or in diluted mineral acids. If 
 an attempt be then made to tear it, it will be immediately per- 
 ceived that the fibres separate in a fixed direction, and in no 
 other. These fibres, when viewed with a microscope, seem to 
 consist of fibrillae too fine to admit of any rigid conclusions in 
 regard to their size ; and which are, in some instances, parallel, 
 in others, concentric, and in others, diverging or converging.! 
 
 The two substances are variously placed in different parts of 
 the nervous system : the surface of the cerebrum and of the ce- 
 rebellum is formed by the cineritious matter, and the interior 
 principally of medullary ; while the surface of the pons, of the 
 crura, and of the spinal marrow, is medullary, and their interior 
 cineritious. Again, in other points, they are intermixed. The 
 medullary matter is always so arranged that it is never inter- 
 rupted, but forms a continuous whole ; while the cineritious is in 
 detached masses, and is found wherever the central extremities 
 of the nerves are implanted, or where there is an increase of 
 
 * Sir Everard Home, and M. Bauer, Phil. Transactions. London, An. 1821. 
 Milne Edwards, Thesis on the Elementary Tissues of Animals. Paris, 1823. 
 
 f See Lessons on Practical Anatomy, by W. E. Homer, for description of 
 Brain according to Gall and Spurzheim. 
 
GENERAL ANATOMY OF THE NERVOUS SYSTEM. 317 
 
 medullary fibres. Some anatomists have even supposed that it 
 existed at the peripheral extremities of the nerves, and particu- 
 larly in the rete mucosum of the skin. 
 
 The fibrillae of the medullary tissue are united by a very fine 
 and thin cellular substance, which may be seen by tearing them 
 apart. This cellular substance is more condensed near the sur- 
 face of the brain, where it is formed into a highly vascular mem- 
 brane, the pia mater, and is continued along the nerves as a neu- 
 rileme, or covering to them. 
 
 The central nervous system is abundantly supplied with 
 blood vessels, but lymphatic trunks have not yet been injected 
 in it. 
 
 The Peripheral Portion of the Nervous System or the Nerves, 
 are formed by parallel anastomosing fasciculi of fibres, percep- 
 tible to simple inspection, which may be reduced into fibrillae, 
 and then again into filaments as small as the thread of a silk 
 worm. The finest filament is enclosed in its appropriate sheath, 
 so that the latter is a tube filled with nervous matter. The ner- 
 vous matter is soluble in an alkali, and in that way may be re- 
 moved; the canals may then be filled with quicksilver or air, 
 and their existence demonstrated. On the other hand, nitric 
 or muriatic acid dissolves the sheath, but hardens the nervous 
 matter, and renders it more distinct, so that the finest filaments 
 are made obvious.* In either case it is evident that the shape 
 of the nerve is preserved. These filaments are supposed to be 
 precisely the same with the fibres of the brain, excepting that 
 their sheaths keep them more distinct from one another. 
 
 The Sheath of the nerves, or the Neurileme (Neurilemma) 
 forms a general envelope to the nervous fasciculi, as well as a 
 particular one to each fibre, and is continuous, at its central ex- 
 tremity, with the pia mater. Its canals branch off and unite 
 again at intervals, forming a species of reciprocal anastomosis, 
 sufficiently represented by the plan of the large nervous plex- 
 uses, -as they occur in various parts of the body. It is the ge- 
 neral envelope which is obviously continuous with the pia ma~ 
 
 * Reil, de Struct. Nerv. 
 VOL. II. 41 
 
318 NERVOUS SYSTEM. 
 
 ter, but the particular sheaths of the finer fibres are lost insen- 
 sibly, so that these fibres appear naked in the centre of the 
 nerve, at its central extremity. The same destitution of neu- 
 rilematic covering is observable at the peripheral extremities of 
 the nerves, wherever the latter can be traced. The interior of 
 these canals is traversed by processes, which cross the nervous 
 matter and sustain it. From the increase in size, the additional 
 solidity, and the close adhesion of the nerves to the dura ma- 
 ter, where they pass out of their several foramina in the spine 
 and cranium, there is no doubt that the dura mater contributes 
 to the neurileme, though its structure is altered and made much 
 less dense. The best evidence of this is the sheath of the optic 
 nerve, and of the spinal nerves. This opinion, advanced by the 
 ancients, has been strongly contested by Haller,* and by Zinn.t 
 The tunica arachnoidea is too fine to admit of any positive opi- 
 nion about the extent to which it follows the nerves. 
 
 The neurileme has but little contractility, is solid and diffi- 
 cult to tear, and is supposed to be the secretory organ of the 
 medullary substance. 
 
 The nervous fasciculi are, moreover, held together by cellu- 
 lar substance, which has in the progress of life, a tendency to 
 the deposite of fat. This cellular substance, in neuralgic affec- 
 tions, is subject to infiltrations and redness, whereby it becomes 
 hard. This circumstance has induced pathologists to consider 
 the pain as depending upon its inflammation.^ 
 
 The optic nerve, owing to the size of its canals, furnishes the 
 best example of structure, and the nerves of the muscles are 
 next. There are, however, some peculiarities in different nerves; 
 as the observations of Sir Everard Home have ascertained that 
 the medullary filaments of the optic nerve augment in numbers 
 and diminish in volume, from its origin towards its termina- 
 tion. The principal light thrown upon these minute and inte- 
 resting points of nervous organization, has been derived from 
 the researches of Reil. 
 
 In addition to the preceding structure, the nerves present a 
 satin-like undulated surface, with small bands that pass some- 
 
 * Prim. Lin. [ Memoires de Berlin, 1753. 
 
 * Beclard, Anat. Gen. p. 665. 
 
 Reil, de Structure Nervorum. Halx Saxonum, 1796. 
 
GENERAL ANATOMY OP THE NERVOUS SYSTEM. 319 
 
 what spirally and in a zigzag direction. The latter appearance 
 is illusory, and depends upon the contraction or shortening of 
 the nerve when not stretched; its seat is in the neurileme, and 
 it accordingly disappears upon extension. 
 
 The nerves abound in blood vessels; when a vascular trunk 
 reaches them, one of its branches ascends and another descends, 
 and if successfully injected, the neurileme is covered by its ca- 
 pillary ramifications. As in the brain, the lymphatics have not 
 yet been injected. 
 
 There are three modes by which the nervous fasciculi unite 
 with one another; anastomosis, plexus, and ganglion. Anasto- 
 mosis is the junction of the filaments, either of the same nerve 
 or of different nerves, and the examples of it are very abun- 
 dant. Plexus is an anastomosis on a larger scale, and occurs 
 between the larger fasciculi of the same nerve, or of different 
 nerves, whereby a very complete intertexture of their fibres 
 occurs. 
 
 Ganglions are knots which occur in the course of nerves 
 whereby they have, for the time, a great augmentation of vo- 
 lume. The ganglions have a great variety of form and size; 
 they are parabolic, circular, crescentic and so on; and, in their 
 general appearance, hardness, and colour, resemble somewhat 
 lymphatic glands. Their structure is intricate, and as yet ra- 
 ther unsettled. When submitted to maceration, they are re- 
 solved into two kinds of substance; one is filamentous and 
 continuous with the nerves adhering to the ganglion, and the 
 other is gelatinous and of a reddish ash colour. The filaments, 
 in penetrating the ganglions are deprived of their neurileme, 
 which is continued into a sort of capsule that surrounds the gan- 
 glions. They pass uninterruptedly through the ganglion, and, 
 therefore, continue the several nervous cords into one another; 
 but in a complicated way. The nature of the gelatinous sub- 
 stance is not fully ascertained; by some, and Scarpa among 
 others, it is thought to be fat. The ganglions, like other parts 
 of the nervous system, are very vascular. 
 
 The Ganglions are said to be simple and compound; the first 
 
320 NERVOUS SYSTEM. 
 
 is where a single nerve produces the ganglion, and the second 
 where the filaments of two or more nerves concur to form 
 it. The simple ganglions are invariable in their form and si- 
 tuation, and belong to the spinal marrow, being formed upon 
 the posterior fasciculi alone: this fact was first pointed out by 
 Haase,* and has been subsequently confirmed by the obser- 
 vations of Scarpa and of Prochaska and by the admission of 
 anatomists generally. The exterior envelope is continuous 
 with the dura mater, and the internal with the pia mater, from 
 whence they have more firmness than other ganglions. The 
 composite ganglions are found at divers stations about the 
 body. 
 
 The Nervous system is the seat of intelligence, and also 
 extends its physical influence to every part of the body. Both 
 the one and the other qualities reside in its central portion; 
 the first in the brain, and the second in the spinal marrow. 
 When the communication between the brain and the spinal 
 marrow is interrupted by an accident, or in an experiment, 
 the difference between the influence of the two is strongly 
 marked:! the influence of the brain seeming to be entirely in- 
 tellectual, so that an animal will even bear its removal with- 
 out immediate death; while the influence of the spinal mar- 
 row is so indispensable to life, that its destruction is followed 
 by instantaneous and perfect death.J Under common health- 
 ful circumstances, however, the two seem to exercise a mixed 
 influence on all parts of the body; as, for example, upon the 
 reception of distressing intelligence, the stomach ejects its con- 
 tents, or refuses to receive more; alarming intelligence causes 
 the heart to flutter and to palpitate, and both the bladder and 
 the intestines to evacuate their contents. On the contrary, a 
 proper degree of corporeal exertion strengthens the intellec- 
 tual operations, while its excess debilitates them. That these 
 several nervous influences are seated in the central part of the 
 
 * De Gangliis Nervorum. Leipsick, 1772. 
 -j- Legallois on the Principle of Life. 
 
 $ Observ. and Exper. on the Nervous System, by W. E. Hofner. See Chap- 
 man's Med. and Phys. Journal, vol. i. p. 285, 
 
GENERAL ANATOMY OF THE NERVOUS SYSTEM. 321 
 
 nervous system, seems proved by the fact, that where there 
 has been a congenital deficiency of all the limbs, or an ac- 
 cidental one, which, of course, removes a very considerable 
 portion of the peripheral part of the nervous system, animal 
 life and the intellectual operations have still gone on vigo- 
 rously. 
 
 The following are some of the physical functions over which 
 the nervous system seems to preside. 
 
 Digestion; the whole alimentary canal, from the mouth to the 
 anus, is under this influence : first of all in mastication, then in 
 swallowing, afterwards in digestion and the absorption of chvle, 
 and, finally, in the passing of the effete matter out of the body. 
 It has been sufficiently proved, by the experiments of several 
 physiologists, that the section of the par vagum destroys the 
 faculty of digestion. 
 
 Respiration ; the mechanical act of this process, that by which 
 the cavity of the thorax is enlarged so as to admit of the intro- 
 duction of air, evidently depends upon the phrenic and the in- 
 tercostal nerves. If the nerves which supply the structure of 
 the lungs be alone intercepted, as the par vagum, either by liga- 
 ture or section, the changes on the blood produced by respiration 
 cease, and the animal dies. 
 
 Secretion, exhalation, absorption, and animal heat, seem also 
 to be dependent upon the integrity an'd the activity of nervous 
 influence. The action of the heart, sensation and voluntary mo- 
 tion, are in the same predicament. 
 
 The manner in which these several kinds of innervation is 
 produced, is unintelligible. One has supposed it to consist in a 
 vibration of the elementary fibres' of the nerves ; another in an 
 agitation of its elastic globules ; another in the transmission of an 
 imponderable fluid, as ether, magnetism, electricity, and Galva- 
 nism. Reil has proposed, on this subject, what has been termed 
 a chemico-vital hypothesis: according to him, the general action 
 of parts depends upon their form and composition ; consequently, 
 when the two latter vary, the first does also. M. Beclard* in- 
 clines to the opinion, that " the nervous system is the elaborator 
 and conductor of an imponderable agent ; and, like electricity 
 
 * Anat. Gen. 
 
322 NERVOUS SYSTEM. 
 
 or magnetism, that by it we can explain all the phenomena of 
 innervation: The relation between the benumbing influence of 
 electric fish and Galvanic phenomena on one part, and ordinary 
 nervous action on the other; The practicability of causing 
 Galvanic phenomena by the nerves and muscles alone; The 
 possibility of producing muscular contraction, the chymifiant ac- 
 tion of the stomach, the respiratory action of the lung, &c., in 
 substituting a Galvanic for a nervous influence ; The existence 
 of a nervous atmosphere, acting at a distance around the nerves 
 and muscles, and between the ends of divided nerves; The 
 wrinkling of muscular fibres in contraction, and the relation of 
 the finest transverse nervous fibres with those wrinkles, are phe- 
 nomena of innervation which nearly approach certain electro- 
 magnetical ones." 
 
 This subtile fluid, according to M. Be clard, seems to be formed 
 every where, but principally in places where there is much vas- 
 cularity along with the ash-coloured substance. It impregnates 
 all the humours and organs. The blood seems to be especially 
 endowed with it, and owes to it the properties which distinguish 
 it during life. In consequence of which, life is essentially con- 
 nected to the reciprocal action of the blood upon the nervous 
 substance, and of the nervous substance upon the blood.* 
 
 Mr. Charles Bell, of London, has lately presented, in a very in- 
 teresting light, certain functions of the nervous system:! by his 
 researches it appears, that besides the nerves of vision, smell, 
 and hearing, there are four other systems, having different func- 
 tions, and extended through the whole frame. Those of Sensa- 
 tion ; of Voluntary Motion ; of Respiratory Motion ; and nerves, 
 which give unity to the body in harmonizing the functions of 
 nutrition, growth, and decay, or whatever else is indispensable 
 to animal existence. 
 
 * M. Rolando (Saggio sulla vera struttura del cervello, e sopra le funzioni del 
 sistema nervoso, 1809, Beclard, p. 622,) has been so much taken with the Gal- 
 vanic manifestations of the nervous system, that in the laminated arrangement of 
 the cerebellum, he has only seen a modification of the Voltaic pile'. In the con- 
 volutions of the cerebrum, he, no doubt, would have recognised an acquaintance 
 with that powerful instrument, the Spiral Calorimotor of Professor Hare of this 
 University. 
 
 f Exposition of the Natural System of the Nerves of the Human 9ody. Philad. 
 1825. 
 
GENERAL ANATOMY OF THE NERVOUS SYSTEM. 323 
 
 According to this theory, the several filaments of a nerve 
 exercise one or the other function, but only tfie one ; these dis- 
 similar filaments being bound up in the same fasciculus, con- 
 stitute a nerve or fascis, and they never exchange power with 
 one another: their anatomical differences, however, are such, as 
 not to make obvious one kind of filaments from the others. Se- 
 veral columns of nervous matter form the spinal marrow, six in 
 all, three on each side ; the anterior for voluntary motion, the 
 posterior for sensation, and the middle for respiration; and it is 
 probable that still more may be found out. The first and the 
 third ascend into the brain, and the middle stops short in the 
 medulla oblongata; hence, the function of respiration goes on so 
 long as the medulla oblongata remains entire. These few prin- 
 ciples, supported by several experiments, have enabled Mr. Bell 
 to bring forward a system of no small importance on the anatomy 
 and physiology of the nervous system.* 
 
 The development of the nervous system is amongst the earliest 
 processes in the distinct evolution of the foetal organs.! At the 
 end of the first month, when the head is a mere swelling of one 
 end of the small maggot-like being, the brain and the spinal 
 marrow are not by any means distinct, but the parts being trans- 
 parent, a limped fluid holds their place. About the fifth or sixth 
 week, the embryo having acquired a length of five or six lines, 
 the rudiments of the brain appear as vesicles containing a whitish 
 and almost diaphanous fluid, while the spinal marrow represents 
 a long canal containing the same, and communicating with the 
 cerebral vesicles. 
 
 In the early part of the third month, the brain and spinal mar- 
 row show very distinctly the rudiments of the several cavities, 
 elevations, and fasciculi, which mark their subsequent mechanical 
 arrangement of surface ; and from this period it is no longer dif- 
 ficult to trace the successive development of each part to the 
 degree of perfection which it has at the time of birth. 
 
 * The same subject has been taken up, in an inaugural thesis, by a zealous and 
 intelligent graduate of the University; and, by a series of ingenious experiments, 
 seems to have been generally proved and illustrated. Chapman's Med. and 
 Phys. Journal, 1823, vol. vi. p. 240. Remarks on some of the Nervous Func- 
 tions, by J. P. Hopkinson, M. D. 
 
 f Anat. du Cerveau, par F.Tiedemann, traduit par Jourdan, Paris, 1823, Anat. 
 Comp. du Cerveau, par E. R. A, Serres, Paris, 1824. 
 
324 NERVOUS SYSTEM. 
 
 From the many observations made by Tiedemann on these 
 points, he has deduced the conclusion, that the brain is produced 
 by the superior part of the spinal marrow; that is to say, by the 
 medulla oblongata, which grows and is developed for the pur- 
 pose. That this is proved, in the extension upwards and for- 
 wards of the two principal fasciculi of the spinal marrow, and 
 by a canal which is found in the spinal marrow of the foetus, 
 being extended to the fourth, and even to the third ventricle; 
 also, by the cerebellum proceeding evidently from the medulla 
 spinalis, since its two crura may be traced growing from it, and 
 subsequently uniting over the fourth ventricle, so as to form the 
 especial structure of the cerebellum; also, by the tubercula 
 quadrigemina being derived from the corpora olivaria of the me- 
 dulla oblongata, and by the thalami and the corpora striata pro- 
 ceeding from the corpora pyramidalia, and, finally, forming the 
 hemispheres of the cerebrum. 
 
 In addition to the preceding proofs, comparative anatomy fur- 
 nishes other illustrations. The brain becomes more and more 
 complex as one ascends from fish to reptiles, from the latter to 
 birds, and then to jnammiferous animals. The spinal marrow 
 is very voluminous in the inferior animals, while the brain only 
 forms an appendix to it ; whereas, if the spinal marrow were an 
 appendix to the brain, we ought to find the last of a prior forma- 
 tion in fetuses, and also in a perfect state in the lower animals, 
 before a medulla spinalis could be found.* 
 
 * Tiedemann, loc. cit p. 157. 
 
BOOK IX. 
 
 PART II. 
 
 On the Special Anatomy of the Central portion of the Nervous System. 
 
 CHAPTER I. 
 
 OF THE SPINAL MARROW AND ITS MEMBRANES. 
 
 THE Spinal Marrow, (Medulla Spinalis) though commonly 
 described after the brain, as a continuation or appendage of it, 
 has precedence, as seen, both in the period of its formation in 
 the embryo, and in its importance to the functions of the ani- 
 mal system; it will, consequently, be useful to give it that prio- 
 rity in description to which its natural rank entitles it. 
 
 SECT. I. OF THE SPINAL MARROW. 
 
 It is placed within the vertebral cavity, and extends from the 
 first vertebra of the neck to the first or second vertebra of the 
 loins, inclusively. It is surrounded by three membranes, of 
 which the Dura Mater is external, the Pia Mater internal, and 
 the Tunica Arachnoidea, between the other two. Its general 
 form is cylindrical, yet it has slightly the appearance of being 
 flattened both behind and before. It departs also from the strict 
 cylindrical shape, by being enlarged or swollen at particular 
 points. One of these enlargements occurs in the neck, where 
 the canal is formed by the five lower cervical vertebras, and the 
 axillary plexus of nerves is given off. The enlargement is i 
 VOL. IL 42 
 
326 NERVOUS SYSTEM. 
 
 the transverse direction or axis of the spinal marrow, but not 
 so much in its thickness, and terminates gradually both above 
 and below. The medulla spinalis afterwards continues small, 
 with very slight undulations or nodosities, until within three or 
 four inches of its lower extremity, when it again enlarges. 
 The enlargement here, though sufficiently obvious, is not equal 
 in actual magnitude to that in the neck, and is the place from 
 which all the lumbar nerves and the three superior sacral pro- 
 ceed. It is then brought gradually to a point somewhat blunt- 
 ed, which most commonly does not descend below the first lum- 
 bar vertebra. The point is, in some rare cases, bifurcated, and 
 by a transverse fissure converted into a tubercle. 
 
 The spinal marrow, besides terminating so much above the 
 lower end of the spinal canal, is much smaller in its diameter, 
 even with the addition of its membranes, than the canal. This 
 circumstance prevails, especially in the neck, and in the loins, 
 where much motion is experienced; and, consequently, a provi- 
 sion is thus made against any injury to it from pressure. 
 
 
 
 The Medulla Spinalis is marked off, longitudinally, into two 
 symmetrical parts, by one fissure in front and another behind, 
 both of which extend its whole length, and are placed exactly 
 in its middle. The contiguous edges or surfaces of each of these 
 fissures adhere so, that it requires a slight maceration or dissec- 
 tion to render them evident. The posterior fissure is decidedly 
 deeper, especially at its upper part, than the anterior; but the 
 latter, in return, is somewhat broader. The difference in depth, 
 however, is unimportant, as subjects are frequently met with in 
 which it is not appreciable. 
 
 Moreover, on each side of the medulla spinalis there is a la- 
 teral fissure. It is not precisely in the middle, but somewhat 
 posterior, and penetrates inwards and forwards. In many in- 
 stances it is merely a simple superficial depression, much less 
 deep than either of the former. It does not run the whole length 
 of the medulla spinalis, but terminates somewhere in the upper 
 part of its thoracic portion by joining with its fellow after having 
 converged regularly towards it.* The different opinions of ana- 
 
 * Meckel, Manuel D'Anatomie. 
 
SPINAL MARROW. 32? 
 
 tomists on the existence of this fissure may be accounted for 
 by its being readily found in early life, while it is obliterated 
 or very indistinct in old age. This lateral fissure should be care- 
 fully distinguished from two others, one before and the other 
 behind it, which extend the whole length of the medulla spina- 
 lis, and consist in a series of little depressions, running into 
 each other and transmitting the filaments which form the roots 
 of the spinal nerves. The posterior, of the last named lateral 
 fissures, is deeper than the anterior, and penetrates in the same 
 direction with the lateral fissures first mentioned; it also, in like 
 manner, joins its fellow, but only after having proceeded to 
 within a few lines of the inferior end of the medulla spinalis. 
 
 The substance of the spinal marrow being of two kinds, ci- 
 neritious and medullary, the order of their position is reversed 
 from what occurs in the brain; for the cineritious is included or 
 enveloped by the other. On making a transverse section the 
 cineritious will be found much less abundant than the other, 
 and consisting of a thin transverse part in or near the centre of 
 the medulla. This part is joined at either end to a portion 
 somewhat crescentic, whose concavity is outwards, and the con- 
 vexity inwards. The transverse part does not run into the 
 middle of the crescent, but somewhat anterior to the middle, so 
 that the anterior horn is shorter than the other, and is also 
 thicker and obviously more obtuse. The cineritious or grayish 
 substance is more abundant at the lower part of the medulla 
 spinalis than it is above. In the foetus, at the end of gestation, 
 it predominates below, occasionally, to the entire exclusion of 
 the other. The medullary or white substance is more abundant 
 laterally than elsewhere, and has its two symmetrical sides 
 joined together by a thin lamina at the bottom of the anterior 
 and of the posterior fissure. 
 
 Each half or symmetrical side of the medulla spinalis is itself 
 divided into two chords, marked off from each other by the pos- 
 terior horn of the cineritious crescent, and by the first described 
 lateral fissure. Of these chords the anterior is, consequently, 
 much the larger; it is also longer and forms the inferior extre- 
 mity or the point of the medulla spinalis. The posterior chord, 
 though so much smaller and narrower than the anterior, is it- 
 
S28 NERVOUS SYSTEM. 
 
 self subdivided into two, by a slight but well marked split; of 
 the two last chords, the one next to the posterior middle fissure 
 of the medulla is smaller than the other. These arrangements, 
 according to Meckel, are much more obvious in the early life 
 of the human subject, than afterwards, and are particularly con- 
 spicuous in the brute creation. 
 
 The thin white laminae by which the two sides of the spi- 
 nal marrow adhere to each other at the bottom of the middle 
 fissures, are called, by modern anatomists, Anterior and Poste- 
 rior Commissures. Their precise arrangement is not yet fully 
 ascertained, but it is stated by Gall and Spurzheim,* that the 
 Anterior Commissure is formed by transverse fibres or filaments, 
 which adhere to one another from the opposite sides like a su- 
 ture, or after a serrated fashion; whereas, the Posterior Com- 
 missure is formed by a band of longitudinal fibres. There is 
 also another Commissure, called Middle or Cortical, from its 
 position, and from its being formed out of the transverse part of 
 the grayish or cineritious substance. 
 
 The chords which form each half of the medulla are different- 
 ly disposed: the posterior continues on the side to which it 
 specially belongs, while the anterior having got within the cir- 
 cumference of the first cervical vertebra, crosses over to the op- 
 posite side by decussating with its fellow. This decussation 
 occupies the space of four or five lines, and interrupts, for that 
 distance, the middle fissure in front of the medulla. It is not 
 effected by the chords passing in mass from one side to the 
 other, but each chord sends off four or five fasciculi, which are 
 interwoven with their congeners, like the fingers of the two 
 hands when interlocked obliquely. It is to be observed that 
 the whole mass of the anterior chords is not subjected to such 
 distribution; for the fasciculi just described come from their an- 
 terior and from their posterior faces, while the intermediate 
 part is permitted to pursue its course straight upwards. This 
 decussation, upon which so much interesting physiological spe- 
 culation depends, though known for the last century, and spoken 
 of by Mistichelli and Petit, has been strangely overlooked by 
 many anatomists, and is even positively denied by some. There 
 
 * Rechercbes sur le Syst. Nerv, et sur celui du Cerveau. Paris, 1809. 
 
SPINAL MARROW. 329 
 
 are other places where the fasciculi of the spinal marrow seem 
 to cross from one side to the other, but the fact is not yet veri- 
 fied sufficiently. 
 
 The existence of canals in the spinal marrow has been from 
 time to time announced ;* though authors differ much in the ac- 
 counts of their position and extent. When such an appearance 
 is presented, it is supposed, by some, to be either the result of 
 disease or of accident, with the exception of a small one of eight 
 or nine lines long, which communicates at one end with the 
 fourth ventricle, and is shut up at the other, f 
 
 The Spinal Marrow sends out from its sides thirty pairs of 
 nerves, which, like the vertebrae, are arranged into cervical, dor- 
 sal or thoracic, lumbar, and sacral. Of these there are eight 
 cervical, one of which, from its escaping between the occiput 
 and the first vertebra, is most usually designated as sub-occipital, 
 and, therefore, the number of the cervical nerves is reduced to 
 the same with that of the vertebras, to wit, seven. There are 
 twelve pairs of dorsal nerves, five of lumbar, and five of sacral. 
 Occasionally, there is a sixth sacral nerve on each side, which 
 augments the number of spinal nerves to thirty-one pairs. 
 
 Every spinal nerve is formed from two roots on the same 
 level, one before and the other behind, and each root consists in 
 several fasciculi of nervous matter. The front root arises from 
 the anterior chord of the medulla spinalis, and the other from 
 the posterior chord. The posterior root is larger than the ante- 
 rior, but has fewer fasciculi in its composition, and is not so fila- 
 mentous. The two roots are kept asunder by the Ligamentum 
 Denticulatum. The fasciculi of each are slightly connected by 
 a loose delicate cellular substance, and as they are about pene- 
 trating the dura mater, each fasciculus collects into a single 
 chord, which passes the dura mater through its appropriate fo- 
 ramen. In this way the anterior and posterior roots are kept 
 distinct till they have got to the outside of the membrane men- 
 tioned; but the foramina, through which they pass, border close- 
 ly upon one another. The posterior root, then forms a ganglion 
 
 * Gall, Portal, Morgagni. 
 
 f Meckel, p. 605, vol. ii. Bichat, vol. Hi. p. 128. 
 
330 NT3RVOITS SYSTEM. 
 
 of a round or oval shape; from whose external extremity there 
 proceeds a single nervous trunk, which is joined immediately at 
 its commencement by the anterior root. 
 
 With the exception of the ganglions of the sacrum, which 
 are in the spinal cavity of that bone, these bodies are placed in 
 the intervertebral foramina. The size of the ganglion is not 
 proportionate to that of the nerve from which it proceeds; for 
 some of the dorsal ganglions are the largest, while those of the 
 sacrum are smaller than any others. 
 
 The two nerves of the same pair, though generally symme- 
 trical, or precisely resembling, are not invariably so ; sometimes 
 one is placed higher than another, and the number of the fasci- 
 culi may be greater or smaller. The roots of the nerves are 
 much nearer, or cluster more at the extremities of the spinal 
 marrow, than in its middle. The lumbar and sacral nerves are, 
 indeed, so close together and so much in a bunch, that the ar- 
 rangement is designated by the term Cauda Equina. 
 
 The Cervical Pairs of Nerves are nearly horizontal in their 
 course from the medulla spinalis to the foramina in the dura 
 mater. The first one, of the sub-occipital, is strictly so ; the 
 others incline very gradually more and more downwards. They 
 have, therefore, but a very short passage before they reach the 
 intervertebral foramina. Their roots are so pyramidal, that the 
 bases nearly touch each other, and, for the most part, are con- 
 nected by an anastomosing filament, which goes from the upper 
 margin of the root below to the lower margin of the root above. 
 These anastomoses are found connecting the upper with the 
 lower fasciculi, both on the anterior and posterior chords of the 
 medulla, but more uniformly as regards the latter. Modifica- 
 tions of this arrangement, which it is unnecessary to specify, 
 are met with in different subjects. 
 
 The Dorsal, or Thoracic Pairs, are much inferior in size to 
 any other nerves, except the inferior sacral. Anastomosing 
 filaments do not generally prevail, yet they are found occasion- 
 ally, as in the neck, upon the two or three upper pairs. The 
 first one has the broad pyramidal or triangular root of a cervi- 
 
MEMBRANES OF THE SPINAL MARROW. 331 
 
 cal nerve, and resembles it also in volume. The second is the 
 smallest of any; they then go on increasing in size to the low- 
 est, but not in an uniform gradation. They are successively 
 more oblique, and consequently longer from their bases to their 
 passage through the dura mater. 
 
 The Lumbar and the Sacral Pairs arise closely upon each 
 other, indeed in absolute contact successively, from the lower 
 end of the medulla spinalis. As their place of origin is within 
 the precincts of the first lumbar vertebra and the two or three 
 last dorsal, they all observe a very oblique course in their de- 
 scent to the vertebral foramina, and the lower ones are almost 
 vertical. Notwithstanding they are in contact, and adhere by 
 a loose cellular substance, yet there are no anastomosing fila- 
 ments between the adjacent roots. From the sacral gangli- 
 ons presenting the peculiarity of being situated in the spinal 
 cavity of the sacrum, instead of in the foramina, the single nerve 
 formed from the ganglion and the anterior fasciculus, has to 
 proceed a distance more or less considerable in the spinal cavi- 
 ty before it can escape from it. 
 
 SECT. II. MEMBRANES OF THE SPINAL MARROW. 
 
 Of the, Dura Mater of the Medulla Spinalis. 
 
 This membrane, forming the exterior envelope of the spinal 
 marrow, extends from one end of the spinal canal to the other, 
 being continuous above with the dura mater of the brain, and 
 terminating below in a cul-de-sac, or closed extremity. It does 
 not adhere to the surface of the spinal canal, but lies loosely at- 
 tached to it, with the exception of the first cervical vertebra, to 
 which it is closely fastened. Between it, and the ligaments and 
 periosteum on this surface of the bones of the spine, is a long, 
 loose, and spare cellular substance, generally somewhat watery, 
 and containing in the lumbar and sacral regions, a reddish adi- 
 pose matter. 
 
 This membrane is so much larger than the medulla, that it 
 invests it very loosely and always presents a collapsed appear- 
 ance. Where the nerves penetrate, it furnishes to each one, a 
 
332 NERVOUS SYSTEM* 
 
 sheath as far as the inter vertebral foramen. Those sheaths are 
 longer for the cauda equina than elsewhere, and, of course, ob- 
 serve the same successive obliquity with the nerves to which 
 they belong. Having reached the intervertebral foramina, they 
 enlarge so as to enclose the ganglions, adhere by cellular sub- 
 stance to the contiguous periosteum, and are then insensibly 
 lost in the tunics of the nervous trunks. The internal surface 
 of the dura mater is smooth and shining, which is probably 
 owing to the tunica arachnoidea being reflected over it. This 
 membrane has a fibrous texture, and, with inconsiderable ex- 
 ceptions, is like that of the brain. 
 
 Of the. Tunica Arachnoidea of the Medulla Spinalis. 
 
 This membrane is next to the dura mater, and is easily dis- 
 tinguished by its extreme delicacy, thinness, and almost perfect 
 transparency. It is destitute of red blood vessels. It forms, 
 also, a complete envelope for the medulla spinalis, and adheres 
 to it only very loosely by means of long, slender, and scattered 
 filaments of cellular substance. If the dura mater be slit up its 
 whole length before and behind, and a blow-pipe be introduced 
 at one end of the medulla, between the pia mater and the arach- 
 noidea; inflation will cause the latter to rise, and to present 
 itself as a long capacious tube, detaching on each side processes- 
 which surround the roots of the nerves. These processes having 
 reached the points where the nerves penetrate the dura mater, 
 are then reflected upon its internal face, and are supposed to 
 give it the glistening appearance. The processes enclosing the 
 fasciculi of the spinal nerves, are particularly conspicuous about 
 the Cauda Equina. 
 
 Of the Pia Mater of the Medulla Spinalis. 
 
 This third envelope of the spinal marrow forms also a com- 
 plete investment of the latter, and adheres very closely to it. 
 Its external face is smooth, and is in contact with the arachnoi- 
 dea, from which it may be readily separated by inflating the 
 latter. But from the middle of its internal face both anteriorly 
 and posteriorly, a process or partition penetrates into the middle 
 
MEMBRANES OF THE SPINAL MARROW. 333 
 
 fissures of the medulla spinal is, and reaches to their bottoms. 
 From these partitions there propeed a great number of small 
 vascular canals, that pass in various directions through the me- 
 dulla, and anastomose freely with each other. This arrangement 
 is rendered sufficiently obvious by injecting and then destroying 
 the medulla in an alkaline solution; or if the medulla be hardened 
 by neutral salts or acids, it splits into longitudinal radiated la- 
 minae, divisible into chords, whereby the arrangement is made 
 equally manifest. A fact of some consequence is thus estab- 
 lished, to wit, the similitude between the structure of a nerve 
 and of the medulla spinalis. 
 
 At the inferior end of the medulla the pia mater becomes a 
 single chord, which is continued among the cluster of nerves 
 to the lower end of the tube formed by the dura mater, and 
 there it joins with the latter. As a membrane, the pia mater is 
 much more complete than the corresponding one of the brain, 
 has more strength, but is not so vascular. Its thickness in- 
 creases in its descent. It is of a yellowish-white colour. It 
 seems to hold the medulla somewhat in a state of compression, 
 for when a puncture is made through it, the medullary substance 
 protrudes like a hernia. It. goes from the medulla to the fasci- 
 culi of nerves and forms their neurileme or sheath. 
 
 Of the Ligamenta Denticula. 
 
 These bodies are narrow semi-transparent bands, and very 
 thin, which are placed one on either side of the medulla spina- 
 lis, between the pia mater and the tunica arachnoidea. They 
 commence at the occipital foramen, and descending between 
 the anterior and the posterior fasciculi of nerves, terminate 
 somewhat above the inferior extremity of the medulla. 
 
 Each one is, at its commencement, in front of the accessory 
 nerve, and in descending is rather nearer to the posterior than 
 to the anterior fasciculi. By its internal margin it adheres 
 with uniformity to the pia mater, but the external margin has 
 a very different arrangement; for it sends off at intervals from 
 twelve to twenty-four serrated or denticulated processes, which 
 for the most part are placed between the fasciculi of cervical 
 and of dorsal nerves. The extremities of these teeth are small, 
 VOL. IL 43 
 
334 NERVOUS SYSTEM. 
 
 rounded, and strong, are surrounded by the arachnoidea, and 
 adhere very firmly to the dura mater, being pointed down- 
 wards. The position and connexions of each ligamentum den- 
 tic ulatum are such, as to make it serve as a fastening; which use 
 is additionally indicated by its fibrous texture, and by the ne- 
 cessity that the medulla has for such fastening, in consideration 
 of its being so deficient in filling up the vertebral canal. 
 
 It is taught by many anatomists, that the ligamenta denticu- 
 kta, from the opposite sides, join at the lower end of the spinal 
 marrow to form the single cylindrical chord, just mentioned, 
 that passes thence to the lower end of the spinal cavity, and has 
 been described as an emanation from the pia mater. I am, 
 however, induced to think with Meckel and others, that gene- 
 ral analogy is in favour of the latter. 
 
 SECT. III. OF THE BLOOD VESSELS OF THE MEDULLA SPINALIS. 
 
 The Arteries of the Spinal Marrow are derived from the 
 VertebralSj Intercostals, Lumbar, and Sacral Arteries. 
 
 1. The Posterior Spinal Artery (Jlrteria Spinalis Posterior) 
 is the lowest branch of the vertebral, given off in the cavity of 
 the cranium. It reaches, soon after its origin, the posterior face 
 of the Medulla Spinalis, and runs to the lower extremity of the 
 latter, on the side of its posterior fissure. Its course is parallel 
 with its fellow, and very serpentine. In its descent it is con- 
 tinually re-enforced by the small branches which get into the 
 spinal cavity through each of the intervertebral foramina. 
 
 2. The Anterior Spinal Artery (jlrleria Spinalis interior) 
 arises above the last from the vertebral. Shortly after its ori- 
 gin it unites with its fellow into a common trunk, which de- 
 scends along the anterior fissure of the medulla spinalis, but is 
 subject to interruptions. It also is re-enforced by twigs from 
 the arteries that pass into the spinal cavity through the inter- 
 vertebral foramina. In its whole course it sends off branches 
 from each side to the medulla spinalis. 
 
 The Cauda Equina is supplied by arteries from the Lumbar 
 
THE ENCEPHALON. 335 
 
 and from the Sacral Arteries, which reach it through the fora- 
 mina, between the vertebrae and in the sacrum. 
 
 The Veins of the Spinal Marrow are very abundant. A large 
 one, called the Sinus Columnar Vertebralis, is situated in the 
 spinal cavity, on the posterior face of the bodies of the vertebrae, 
 between their ligamentous covering and the dura mater. One 
 of these veins exists on each side of the middle line. They 
 detach a considerable number of branches, which run trans- 
 versely, and anastomose with one another on the body of each 
 vertebra, so that each vertebra has its little system of anasto- 
 mosing branches, called Circelli Venosi. These anastomoses 
 communicate with the intercostal veins, and* indeed, with all 
 such as are on the outside of the spinal column, by means of 
 small branches that get out by the intervertebral foramina. 
 They receive the veins from the bodies of the vertebrae, and 
 from the dura mater of the spine. 
 
 The two sinuses may be traced as low down as the inferior 
 end of the sacrum, where they arise by small trunks from the 
 fatty matter which surrounds the lower end of the cauda equina. 
 When their size is somewhat augmented by their ascent, they 
 communicate by a large transverse branch. The superior end 
 of each sinus terminates by several anastomoses with the verte- 
 bral vein, and with the anterior occipital sinus; through the 
 latter of which its blood is, finally, carried into the lateral sinus. 
 For a farther account, see Sinus Vertebrales. 
 
 CHAPTER II. 
 
 OF THE ENCBPHALON, OR BRAIN. 
 
 BY this term is designated that section of the central portion 
 of the nervous system, which is contained within the bones of 
 the cranium. In jts general configuration it differs materially 
 from the medulla spinalis in being spheroidal or oval. It is 
 
336 NERVOUS SYSTEM. 
 
 surrounded by the same membranes; to wit, the Dura Mater, 
 externally, the Tunica Arachnoidea next, and the Pia Mater, 
 internally. 
 
 The Encephalon is formed by cineritious and medullary 
 matter, and, as a mass, consists of four distinct portions. The 
 Medulla Oblongata, which is a continuation of the spinal mar- 
 row, or its superior part; the Protuberantia Annularis, or Pons 
 Varolii, which is placed at the upper extremity of the Medulla 
 Oblongata; the Cerebrum, which occupies six or seven-eighths 
 of the cavity of the cranium; and the Cerebellum, which lies 
 upon the posterior fossae of the base of the cranium. As the 
 brain is a double organ, each of these parts is symmetrical, or 
 consists in right and left halves perfectly alike. 
 
 SECT. I. OP THE MEMBRANES OP THE BRAIN, OR ENCEPHALON. 
 
 Of the Dura Mater. 
 
 This membrane, the most exterior of the three belonging to 
 the encephalon, lines the whole internal face of the cavity of. 
 the cranium, and is attached with great tenacity to it, particu- 
 larly in early life, from which cause it is also considered as 
 an internal periosteum. 
 
 Its external surface has a rough and unequal appearance, and 
 adheres much more strongly where the sutures exist than else- 
 where, owing to its detaching many large filaments, which pe- 
 netrate into the sutures and reach to the pericranium. The 
 adhesion to the surface generally of the bones is accomplished 
 by fine filaments of fibres, and by very numerous and small 
 blood vessels which become evident from the dots of blood 
 collected upon its surface, when the bones are torn up, as in 
 the usual manner of examining the head. To the base of the 
 cranium, its adhesion is still stronger, owing to the abundance, 
 of the foramina and fissures there; \g the margin of each one of 
 which it is fixed with extreme compactness, and may be con- 
 sidered as continuous with the adjacent pericranium. 
 
 The external surface is marked by the arteries and veins 
 which creep and ramify through it, and make, as mentioned 
 elsewhere, corresponding furrows in the bones. 
 
MEMBRANES OP THE BRAIN. 337 
 
 The Dura Mater consists of two laminae, one within the 
 other; they, however, are attached so closely in the greater part 
 of their extent, that it requires the knife, or strong artificial 
 force, to separate them. Sometimes, in tearing off the skull- 
 cap of a middle-aged person, the external lamina is brought 
 away with the bone. 
 
 Several processes arise by a duplicature of the internal la- 
 mina of the dura mater, and extend from the circumference to- 
 wards the centre of the cavity of the cranium. They are as 
 follow: 
 
 The Falx Cerebri separates the hemispheres of the brain, and 
 is, consequently, precisely under the middle line of the head. 
 Its shape is well indicated by its name. It commences by a 
 small point from the middle of the body of the sphenoid bone, 
 and continues to arise along the crista galli, the spine, and 
 middle line of the frontal bone, the sagittal suture and the up- 
 per limb of the occipital cross, till it reaches the internal occi- 
 pital protuberance. It is about an inch broad in front, where 
 it begins, but it increases continually, though gradually, in 
 breadth till its termination, where it is two or two and a half 
 inches wide. It is strongly fastened along the crista galli, and 
 *-at the foramen coecum, and being also fastened behind to the 
 tentorium, (with which it is continuous,) as well as along the 
 intermediate points of bone, it is kejit in a state of strict tension, 
 which does not admit of its wavering to one side or to the other. 
 Its inferior margin is very concave, and goes to within a small 
 distance of the corpus callosum. There are sometimes conside- 
 rable apertures in it, through which the flat surfaces of the he- 
 mispheres come in contact. 
 
 The Tentorium Cerebelli, another process of the dura mater, 
 is placed transversely across the posterior part of the cranium, 
 and separates the cerebellum from the posterior lobes of the 
 cerebrum. It is continuous with the posterior end of the falx 
 major, whereby these two processes exercise a mutual tension. 
 The tentorium is, therefore, kept convex above and concave 
 below. 
 
338 NERVOUS SYSTEM. 
 
 Its form is crescentic; its outer circumference is extended 
 along the horizontal limbs of the occipital cross, and along the 
 superior corner or margin of the petrous bones to the posterior 
 clinoid process. The internal circumference is much smaller 
 and unattached, and being placed immediately behind the sella 
 turcica, it leaves an opening (the Foramen Ovale) which is near- 
 ly of the same size with, and occupied by the tuber annulare, 
 and the crura cerebri. The anterior extremities of the crescent 
 are continued from the posterior clinoid process to the anterior 
 on each side, so that a deep depression is formed for lodging 
 the pituitary gland. 
 
 The Falx Cerebelli is a small triangular process of the dura 
 mater, which extends in the middle line from the under surface 
 of the tentorium to the posterior margin of the occipital fora- 
 men. Its base is above, and its point below: the latter termi- 
 nates by a small bifurcation. It adheres by its posterior mar- 
 gin to the middle inferior limb of the occipital cross; the ante- 
 rior margin is free, and serves to separate the two hemispheres 
 of the cerebellum." 
 
 The Dura Mater is essentially fibrous, as is sufficiently evi- 
 dent at whatever point it may be examined. These fibres have 
 no settled course, but cross each other in every direction. It 
 is white, sufficiently transparent for the vessels of the pia ma- 
 ter to be imperfectly seen through it, and almost inelastic. Its 
 internal face is smooth and polished, and is covered or lined by 
 the tunica arachnoidea, the halitus from which gives it a slip- 
 pery feel. It is insensible to common excitants, such as cutting, 
 or even cauterizing it; from which circumstance, together with 
 the common inability of anatomists to trace nerves into its struc- 
 ture, it is supposed, by many, to be entirely destitute of them. 
 The venerable Chaussier, however, takes a different position in 
 regard to these points, and says, that it has sensibility, and that 
 though none of the cerebral nerves can be traced into it, yet, 
 by attentive examination, it is found, that filaments from the 
 sympathetic nerve follow the ramifications of its middle or great 
 artery.* 
 
 * Exposition de L'Encephale, p. 29. 
 
MEMBRANES OF THE BRAIN. 339 
 
 It is well supplied with blood vessels, both arteries and veins. 
 The former are derived principally from the branches of the in- 
 ternal maxillary of either side, which get into the cranium 
 through the foramen spinale and ovale. There are branches 
 also from the aethmoidal, the inferior pharyngeal, and the ver- 
 tebral. The branch of the internal maxillary called meningea 
 magna, divides into two, of which the anterior being the more 
 considerable, gains the anterior and inferior angle of the parie- 
 tal bone; but the other is directed backwards to the squamous 
 portion of the temporal. Each of these branches is subdivided 
 into a considerable number of smaller ones, which for the most 
 part incline backwards. Their capillary terminations are sup- 
 posed by Bichat to be in small number comparatively, and to be 
 limited principally to those of nutrition. 
 
 Some of the veins accompany the arteries, as in other parts 
 of the body, and empty into the sinuses about the base of the 
 cranium. In the case of both arteries and veins, there is, how- 
 ever, a very considerable anastomosis with the blood vessels of 
 the diploic structure of the cranium, and with those of the in- 
 teguments. 
 
 Of the Sinuses of the Dura Mater. The sinuses are large 
 cavities placed between the two laminae of the dura mater, and 
 receive the blood from the veins of the pia mater. They are 
 formed by the separation of these laminae, and are 'lined by a 
 membrane corresponding with the internal coat of the veins. 
 
 -1. The Sinus Longitudinalis Superior extends along the whole 
 base of the falx cerebri, from the ethmoid bone to the tentori- 
 um, where it terminates in the lateral sinuses. It begins at the 
 foramen coecum in a small pointed manner, and, according to 
 some anatomists, by a small vein, which passes from the nose 
 through this foramen; it is successively increased in size frorni 
 before backwards, and is of a prismatic shape. One side of the 
 prism is upwards, and, of course, is formed by the external la- 
 mina of the dura mater; while the other two parietes are late- 
 ral, and are formed by the duplicature of the internal lamina. 
 Its cavity presents.a number of small cords, round or flattened, 
 
340 NERVOUS SYSTEM. 
 
 passing from one side to the other; they are called Chordae Wil- 
 lisii or Trabeculae, and prevail principally at its back part. 
 
 The longitudinal sinus receives on each side from ten to twelve 
 large veins, which bring the blood from the pia mater. Those 
 from the convex surface of the brain are joined just before enter- 
 ing the sinus by such as belong to the flat side of the hemispheres. 
 These veins enter the sinus, for the most part, obliquely forwards, 
 or in a manner opposed to its circulation. The most posterior 
 ones previously glide eight or ten lines between the laminae of 
 the dura mater, and are. somewhat tortuous; they are also 
 furnished with valves, which circumstance, besides their oblique 
 entrance into the sinus, is a provision against their being filled by 
 the regurgitating blood. This sinus also receives several veins 
 from the bones, and some from the scalp, which traverse the 
 bones at different places : among the largest of them are those 
 that come through the parietal foramina. The dura mater itself 
 sends some of its veins into this sinus. 
 
 In the longitudinal sinus, towards its posterior part, are found 
 a considerable but variable number of small granular bodies; 
 some in clusters, others insulated; and from the size of a pin's 
 head to a line or more in diameter. They are the Glandular 
 Pacchioni; they have no excretory ducts that have been dis- 
 covered, and it is entirely uncertain whether any specific fluid 
 is secreted from them. These bodies are also to be found on 
 the surface of the dura mater near this sinus ; some of them, in- 
 deed, make foramina through the dura mater, and corresponding 
 depressions in the skull. One on each side, larger than usual, 
 and near the parietal foramen, is remarkable for this. 
 
 2. The Sinus Laterales, one on each side, are situated in the 
 base of the tentorium, and follow its course along the grooves of 
 the occipital and parietal bones. They then leave the tentorium 
 and go along the groove in the mastoid portion of the temporal 
 bone to reach the posterior foramen lacerum, where they ter- 
 minate in the internal jugular veins. Their shape is ovoidal, 
 instead of prismatic, as the longitudinal sinus is; they are also 
 larger than it. 
 
 The sinus of the right side is very frequently larger than that 
 of the left, and seems to be more a continuation of the superior 
 
MEMBRANES OF THE BRAIN. 34 1 
 
 longitudinal sinus. In some rare cases one of these sinuses is 
 deficient. The lateral and inferior veins of the cerebrum, and 
 the inferior veins of the cerebellum run into the lateral sinuses. 
 
 3. The Sinus Longitudinalis Inferior is situated in the falx 
 cerebri just above its concave edge. It is much smaller than 
 the superior, and terminates behind in the sinus quartus. It re- 
 ceives the veins of the falx, and sometimes a few from the cor- 
 responding parts of the hemispheres. 
 
 4. The Sinus Quartus, or Rectus, is situated in the tentorium, 
 where the latter is joined by the falx major or cerebri. It is 
 triangular or prismatic, and runs from the anterior margin of 
 the tentorium to the posterior, where it terminates in the extre- 
 mity of the longitudinal sinus. The general union which is there 
 found between the longitudinal, the fourth, and the lateral sinuses, 
 constitutes the Torcular Hierophili. 
 
 The anterior extremity of the fourth sinus, besides receiving 
 the inferior longitudinal, is joined by the Vena Galeni, a single 
 trunk, formed by the junction of the two veins of the middle of 
 the velum interpositum, and extending from the posterior margin 
 of the fornix to the beginning of the fourth sinus. The latter, in 
 its course, also receives the superior veins of the cerebellum, 
 with the exception of the most anterior ones, which terminate in 
 the Vena Galeni. 
 
 5. The Sinus Petrosi are small cylindrical cavities, and are 
 so called from being situated on the petrous bone. There are 
 two on each side ; one above and the other below. The former 
 is the Superior, and runs from the cavernous sinus along the su- 
 perior margin of the petrous bone to join the lateral sinus, where 
 the latter quits the tentorium to descend towards the base of 
 the cranium. The other Petrous Sinus is the Inferior. It is 
 larger than the superior, and arises, also, from the cavernous 
 sinus by its posterior margin. It then runs along the fissure be- 
 tween the occipital and the petrous bone, leaving its mark on 
 the margin of these bones, but principally on the former, and 
 then terminates in the lateral sinus just above the posterior fora- 
 men lacerum. 
 
 VOL. II. 44 
 
NERVOUS SYSTEM. 
 
 6. The Sinus Cavcrnosi, one on each side, are also formed by 
 a separation of the two laminae of the dura mater, though their 
 'shape is so different from that of the others. They are situated 
 at the sides of the sella turcica, and on the body of the sphenoid 
 bone. Their cavity is very irregular, and is furnished with a 
 number of filaments, which cross in every direction, and give it 
 a cellular arrangement. Hie internal carotid artery and the 
 sixth nerve traverse it, but are protected by its lining membrane 
 being reflected over them. 
 
 The cavernous sinus anastomoses in front with the circular 
 sinus, and behind with the two petrous sinuses and the anterior 
 -occipital. It receives, in front, the ophthalmic veins ; froma bove, 
 the anterior and inferior cerebral veins; and on the sides, some 
 veins from the dura mater. 
 
 7. The Sinus Circularis is placed in the sella turcica, and sur- 
 rounds the pituitary gland. It is a small cavity which receives 
 the veins of this gland, and, ^as just mentioned, communicates 
 with the cavernous sinus. 
 
 8. In the posterior part of the base of the cranium, there are 
 also some other sinuses, called, from their position, Occipital. 
 One of these is upon the basilar process of the os occipitis, and 
 extends itself directly across the bone, from the hind part of one 
 cavernous sinus to the corresponding point of the other ; and is, 
 therefore, a means of communication between these two cavities. 
 Another of these sinuses extends from the region of the torcular 
 hierophili, or the upper extremity of the lateral sinuses, along 
 the base of the falx cerebelli, to the posterior margin of the oc- 
 cipital foramen, where it bifurcates, and then goes along the 
 margin of this foramen to discharge itself into the lateral sinus 
 at the posterior foramen lacerum. 
 
 The smaller sinuses about the base of the cranium, besides 
 the outlets mentioned, have collateral ones, which pass at dif- 
 ferent places through the base of the cranium, and run into the 
 branches of the internal jugular vein. These communications, 
 as mentioned in the account of the veins, were known to San- 
 torini, and are called his Emissaries. 
 
MEMBRANES OF THE BRAIN* 343 
 
 Of the Tunica AracJmoidca. 
 
 This membrane is the second of the envelopes of the brain, and 
 is spread over the surface of the pia mater, adhering to it close- 
 ly in the greater part of its extent. It is so diaphanous and thin 
 as its name implies, that it is distinguished with some difficulty, 
 wherever it adheres to the pia mater; which it does all over, 
 with the exception of some few places on the basis of the brain, 
 as, for example, just in front of the tuber annulare, and behind 
 the medulla oblongata. There this membrane may be seen 
 stretched from one prominence to another, and separated con- 
 siderably from the pia mater. It does not follow the anfrac- 
 tuosities of the brain, but goes directly across them, from the 
 ridge of one convolution to that of the adjacent, so that it is en- 
 tirely smooth and uniform in its distribution. Notwithstanding 
 the general closeness of its connexion with the pia mater, it 
 may yet be separated from it by careful dissection, by slight 
 maceration, or by the use of the blow-pipe; dropsical effusions 
 frequently make out the distinction between the two membranes ; 
 also the deposite of coagulating lymph. 
 
 Considering this membrane as a single layer, we have to 
 speak of the dura mater, as lying loosely upon it. But the au- 
 thority of Bichat, sanctioned by the testimony of many other 
 anatomists, has assigned to it a much more considerable extent. 
 For it seems to be well ascertained, both by analogy and by ob- 
 servation, that it is a sac; which, besides covering the external 
 surface of the pia mater, is reflected over the internal surface 
 of the dura mater, and gives to the latter its smooth shining 
 appearance. This lining is on the same principle that the se- 
 rous lamina of the pericardium lines its fibrous lamina, or that 
 the synovial membrane lines the ligamentous attachments of 
 an articulation. In the early periods of life, it may be sepa- 
 rated from the dura? mater, by dissection. Vicq. D'Azyr has 
 related a case in which it was detached by a collection of pus. 
 Its places of reflection to the dura mater are on the basis of the 
 cranium, where the blood vessels and nerves pass into the 
 sheaths formed by'the dura mater, and along the blood vessels 
 
344 NERVOUS SYSTEM, 
 
 entering into the sinuses. This membrane is continuous with 
 the tunica arachnoidea of the medulla spinalis. 
 
 The tunica arachnoidea passes into the ventricles of the brain 
 by the same apertures that the pia mater does, but it is much 
 less manifest there than elsewhere. 
 
 The texture of this membrane is exceedingly delicate and 
 fine. It is always found, in health, in a transparent state, and 
 is furnished with neither red blood vessels nor nerves. It se- 
 cretes a sort of halitus, or synovia, which facilitates the motions 
 of the brain, and prevents it from adhering. Occasionally, 
 this secretion is so much augmented as to constitute a genuine 
 dropsy. 
 
 Of the, Pia Mater, 
 
 The Pia Mater, or Tunica Cerebri Vasculosa, is in contact 
 with the substance of the brain. It also is extremely delicate, 
 but, unlike the last, is furnished with an immense number of 
 blood vessels which go to or return from the brain, and are, 
 in most subjects, so abundant that they give a florid appearance, 
 at a little distance, to the whole membrane. Its external face 
 appears entirely smooth, owing to its being covered, and its 
 processes cemented together by the tunica arachnoidea; but its 
 internal face exhibits these processes as following precisely 
 the anfractuosities of the brain; consequently, it is very un- 
 equal. 
 
 The pia mater presents, along the course of the longitudinal 
 sinus, an abundance of those small graniform bodies, existing 
 also in this sinus, and called Glandulae Pacchioni. They beset 
 the veins as they enter into the longitudinal sinus, and even 
 follow them there, so that there is a chain of them from the 
 surface of the pia mater, into the sinus. They are frequently 
 so abundant an the superior part of the hemispheres, near the 
 great fissure, that they cause the dura and pia mater to adhere, 
 as if from inflammation. It is the larger of this kind which 
 frequently produce an absorption of the dura mater, and of the 
 internal table of the skull. These bodies are also found, along 
 with the pia mater, in the ventricles of the brain, as at the ex- 
 
MEMBRANES OP THE BRAIN. 345 
 
 ternal margin of the plexus choroides, around the pineal gland, 
 and at the bottom of the fourth ventricle. 
 
 The Glandule Pacchioni, wherever found, present a similar 
 appearance and structure, varying, much in size: they are ge- 
 nerally in clusters, which repose on common bases. Anato- 
 mists differ much in their opinion concerning them. Bichat 
 acknowledges his complete ignorance on the subject; Portal 
 says that they are only congeries of vessels or of cellular bo- 
 dies filled with fat. Meckel states, that as they are found es- 
 pecially in the latter periods of life, and never before birth; as 
 they never exist in very great abundance, except in persons 
 who have often experienced diseases of the head; and are not 
 observed in any animal: that we are forced to consider them 
 as morbific productions, and not, as Pacchioni conceived, glands 
 whose excretory ducts opened into the ventricles of the brain. 
 
 The Pia Mater covers the upper surface of the cerebrum with 
 such uniformity as not to require a detailed description of it; 
 where it sinks into the great fissure of the hemispheres, it ad- 
 heres from the two sides just above the corpus callosum. On the 
 basis of the brain, it penetrates deeply into the anterior fissure, 
 or the Fissura Sylvii; is reflected over the inequalities, but never 
 in such a way as to leave them ; and closes up the bottom of the 
 third and of the fourth ventricle. 
 
 The distribution of the pia mater, over the ventricles of the 
 brain, is more complicated than that over its periphery, and it 
 may be remarked, that this portion is called, by some anato- 
 mists, the Internal Pia Mater; that its texture is much more de- 
 licate, and net-like, and that it adheres more closely to the sub- 
 jacent parts. Being extended from the superior surface of the 
 cerebellum and of the tuber annulare, it enters into the third 
 ventricle, under the posterior margin of the fornix, by the large 
 transverse fissure between the latter and the tubercula quadrige- 
 minat By its course between the fornix and thalami, it consti- 
 tutes the Velum Interpositum, or the Tela Choroidea of Vicq. 
 D'Azyr. The pia mater is also introduced into the inferior cor- 
 nu of the lateral ventricles along the internal margin of the hip- 
 pocampus major,' at the side of the pons varolii; and into the 
 fourth ventricle from its bottom part. 
 
346 NERVOUS SYSTEM. 
 
 The several plexuses of vessels found in the ventricles of 
 the brain have for their basis the pia mater; which is there ar- 
 ranged into a great number of folds, some of them being lon- 
 gitudinal and others crossed. Their formation, according to the 
 new views which have been taken of the development and 
 growth of the brain, by Tiedemann, depends upon the internal 
 membrane of the brain contracting itself as it finishes the depo- 
 site of medullary matter called Centrum Ovale. The vessels of 
 the plexuses are the arteries, which are spent upon the surface 
 of the ventricles, and the veins derived from the same; the lat- 
 ter are much more numerous than the first. 
 
 Of the, Structure of the Pia Mater. The pia mater is com- 
 monly spoken of as a complete membrane, yet its structure is 
 different from that of membranes generally, inasmuch as it is a 
 net-work, the meshes of which are formed by arteries and veins, 
 and the interstices filled up by a loose, weak cellular substance. 
 Bichat has very justly observed, that the union with the tunica 
 arachnoidea is solely on the part of this cellular substance; 
 whereas, the union with the cerebrum is confined to the ves- 
 sels, which are extremely numerous and very small before they 
 penetrate it, and appear as bloody points when we cut into the 
 substance of the brain. The principal arterial trunks of the 
 pia mater are at the basis of the brain; these trunks divide into 
 smaller branches, in the anfractuosities and fissures. The pri- 
 mary divisions again divide and subdivide into tubes not much 
 exceeding the size of the capillary vessels. In this last state 
 they enter the brain and may be seen very readily, either by a 
 fine injection or by tearing up the pia mater. 
 
 SECT. II. OF THE MEDULLA OBLONGATA. 
 
 According to the usage of the best authorities of the present 
 day, who follow in the description of the central parts of the 
 nervous system, the order of their development in the human 
 subject, and also of their appearance in animals, I shall describe 
 the encephalon from below upwards instead of from above down- 
 wards. The preference thus shown is, perhaps, principally ser- 
 viceable in fixing upon the mind the order of growth and ap- 
 
THE MEDULLA OBLONGATA. 347 
 
 pearance, which, according to well established experiments, are 1 
 exactly in the order of importance to life. 
 
 The Medulla Oblongata, also called Bulbus Rachidicus, ex- 
 lends from the superior margin of the first cervical vertebra to 
 the middle of the basilar. process of the os occipitis.* It becomes 
 gradually larger as it ascends, and is about an inch in length, 
 and eight lines wide at its base. It is by no means so cylin- 
 droid as the medulla spinalis, but presents several risings and 
 depressions on its surface. 
 
 The under surface of the Medulla Oblongata is divided lon- 
 gitudinally by the middle fissure, a continuation of that on the 
 front of the Medulla Spinalis. The fissure is two or three lines 
 deep, which is rendered manifest by removing the pia mater. 
 The Corpora Pyramidalia are placed one on either side of it, 
 and are oblong bodies; being a continuation of the chords that 
 decussate from the opposite sides of the spinal marrow. These 
 bodies occupy the whole length of the Medulla Oblongata, in- 
 crease in breadth as well as in elevation during their ascent, 
 and are, lastly, somewhat constricted or diminished abruptly, 
 where they join the Protuberantia Annularis or Cerebralis. 
 Precisely at the latter point, between their bases, is a deep tri- 
 angular pit, into which penetrates the pia mater. J. F. Meckel 
 says, that they are united at their lower extremities by a small 
 transverse medullary Commissure of a line and a half in breadth. 
 This junction is above the decussation of the chords from which 
 the Corpora Pyramidalia arise. 
 
 The Eminentiae Olivares are two bodies; one on either side, 
 at the external margin of the corpus pyramidale. They are about 
 seven lines long: two and a half wide, and are elevated to the 
 height of one line. The elevation ceases somewhat ^hort of the 
 annular protuberance, but their interior structure is continued 
 into the latter, and may be traced into the thalamus nervi 
 optici. 
 
 Like the pyramidalia, those bodies are medullary externally; 
 but within, there is a nucleus of cineritious matter, called, from 
 the irregularities of its margin, Corpus Fimbriatum', and which 
 encloses some medullary matter. The corpus fimbriatum is 
 
348 NERVOUS 
 
 open at the inner circumference, and has the medullary matter 
 which it contains, continuous there with the substance of the 
 corpus pyramid ale. Below, its circumference is continuous 
 with the cineritious matter of -the medulla spinalis. In the 
 slight depression between the corpus pyramidale and the emi- 
 nentia olivaris, are the roots of the hypoglossal nerve. 
 
 The Corpora Restiformia, also one on either side, are placed 
 at the lateral posterior margins of the medulla oblongata, just 
 posterior to the olivares; and are readily brought into view by 
 elevating the contiguous parts of the cerebellum. They are el- 
 liptical risings of an inch in length; their lower extremities are 
 in contact, and project where they begin to arise from the bor- 
 ders of the posterior fissure of the medulla oblongata; they then 
 diverge, and advance forwards and upwards to terminate above 
 in the cerebellum. 
 
 The corpus restiforme is formed of medullary matter, and is 
 a continuation of the posterior cord of the medulla spinalis. 
 From its superior posterior margin a thin medullary lamina of 
 about three lines square arises, and being sustained by the pia 
 mater, advances to meet its fellow, but does not absolutely touch 
 it.* From the anterior margin of each corpus restiforme there 
 departs a second process of medullary matter, larger and more 
 thick than the preceding, and being covered by the roots of the 
 pneumogastric and glosso-pharyngeal nerves, adheres to the 
 plexus Choroides of the fourth ventricle. 
 
 The superior face of the medulla oblongata is excavated be- 
 tween the corpora restiformia, in such a way as to present the 
 outline of a writing pen, and is, therefore, called Calamus 
 Scriptorius; which forms a considerable part of the floor of the 
 fourth ventricle of the Brain, or the sinus rhomboideus. The 
 fissure, in its middle, corresponds with the slit of a pen, the 
 nib being downwards; and the fissure extends from the poste- 
 rior fissure of the medulla spinalis the whole length of the me- 
 dulla oblongata. 
 
 The calamus scriptorius is marked by several streaks of medul- 
 lary matter, which extend themselves transversely with a very 
 
 * Called Pons Sinus Rhomboidei by J. F. Meckel. 
 
THE MEDULLA OBLONGATA. 349 
 
 slight degree of obliquity upwards, and reach the external mar- 
 gin of the corpus restiforme of the corresponding side. These 
 medullary strias present some varieties in regard to their vo- 
 lume, number, and arrangement Sometimes they are slightly 
 elevated narrow lines, which are perfectly distinct from each 
 other, and from one to fourteen in number. On other occa- 
 sions their volume is greater, but they are not so numerous. 
 They generally extend, either one or all, from the middle fis- 
 sure to the commencement of the auditory nerve, and are 
 thereby a part of its origin. Sometimes the anterior ones are 
 directed towards the origin of the trigeminus nerve, but their 
 union with it is not yet ascertained ; the posterior ones are some- 
 times blended with the radical filaments of the pneumogastric 
 nerve. The striae themselves, are sometimes interwoven or 
 blended, and pass the boundary of the middle fissure to join 
 with those of the other side. Their roots may be traced occa- 
 sionally along the middle fissure, almost to the front or under 
 surface of the medulla oblongata. Meckel, whose observations 
 on this subject are highly interesting, is disposed to consider 
 the stria3 not only as forming the roots of the auditory nerve, 
 but as also related closely to the trigeminus and to the pneu- 
 mogastric. 
 
 On this surface, also, of the fourth ventricle, or sinus rhom- 
 boideus, but in advance of the preceding striae, there is another, 
 on each side, still larger, which may be distinguished by its al- 
 ways beginning at some distance from the middle fissure. Its 
 direction is transverse, and it passes just abov r e the anterior ex- 
 tremity of the corpus restiforme, to run into, or to assist in 
 forming, the root of the auditory nerve. Its existence is much 
 more constant than that of the others. It is considered as an 
 assistant ganglion to the auditory nerve, and in cases of deaf- 
 ness has been deficient. Being principally cineritious, it is 
 called Fasciola Cinerea. f 
 
 In tracing the continuation of the structure of the medulla 
 spinalis, into that of the medulla oblongata, we find that each 
 of the anterior cords of the medulla spinalis, besides crossing 
 with some of its fasciculi at the place mentioned, to wit, at the 
 decussation of Mistichelli, and continuing its course upwards 
 
 VOL. II. 45 
 
350 NERVOUS SYSTEM. 
 
 to form the corpus pyramidale, sends off a larger fasciculus, 
 which ascends behind the eminentia olivaris, and forms the floor 
 of the sinus rhomboideus. There is a third fasciculus of white 
 matter between the other two, into which the anterior column 
 of the medulla spinalis is divided. It is described by Rosen- 
 thai, who says, that it touches the eminentia olivaris, surrounds 
 it, and, after having traversed the annular protuberance, termi- 
 nates in the tubercula quadrigemina. 
 
 The posterior cords of the Spinal marrow, being continued 
 into the corpora restiformia, become still more evidently di- 
 vided into two fasciculi, from an increase of their volume, than 
 they were in the vertebral canal. The internal of these fasci- 
 culi stops, by a pointed termination, near the borders of the 
 sinus rhomboideus; while the external is continued on through 
 the annular protuberance to the cerebellum. 
 
 SECT. III. PROTUBERANTIA ANNULARIS. 
 
 The Annular Protuberance (Protuberantia Annular is, No- 
 dus Cerebri, Pons Varolii) is the large projecting body, placed 
 near the centre of the base of the encephalon, at the top of 
 the medulla oblongata, and upon the junction of the body of 
 the sphenoid bone with the basilar process of the os occipitis. 
 It is convex, and about an inch in diameter, its -transverse mea- 
 surement being a line or two larger than the other. It is di- 
 vided by a superficial fossa into two symmetrical halves, right 
 and left. 
 
 When the pia mater is removed from the Protuberantia An- 
 nularis, the under surface of the latter is seen to be formed by 
 transverse medullary fibres which come from the crura cere- 
 belli. When these, which are commonly one or two lines in 
 depth, are removed by scraping or cutting, a cineritious matter 
 is exposecf, which is traversed by numerous layers of medullary 
 matter, also going in a transverse direction. About two lines 
 deep from the surface of the protuberance, near the middle of 
 each of its halves, are found some longitudinal medullary fibres 
 connected with cineritious matter, and which may be fairly 
 traced as a continuation of the filamentous structure of the py- 
 
THE CEREBELLUM. 351 
 
 ramids. These fasciculi, or filaments, passing on through the 
 protuberance, are continued so as to form the under surface of 
 the crura of the cerehrum. 
 
 Lying still deeper than the medullary fibres alluded to, there 
 is an accumulation of cineritious matter, intermixed with per- 
 pendicular medullary layers situated one behind the other. Be- 
 hind (or above when we stand erect) this intertexture, a small 
 fasciculus (the cord described by Rosenthal) of medullary mat- 
 ter exists, which is a continuation of the intermediate fascicu- 
 lus of the anterior medullary cord of the medulla oblongata, and 
 may be traced afterwards to the superior face of the crus cere- 
 bri, where it terminates, as alleged by Rosenthal, in the Tuber- 
 cula Quadrigemina. 
 
 SECT. IV. OF THE CEREBELLUM. 
 
 The Cerebellum, being placed in the posterior fossse of the 
 cranium, is separated by the tentorium from the posterior 
 lobes of the cerebrum, beneath which it lies. It is connected 
 with the Pons Varolii by a trunk of medullary matter on 
 each side, called the crus of the cerebellum; which is a root 
 of the medullary matter entering into the composition of the 
 latter. 
 
 It is of a rounded form, and well fitted to the cavity in which 
 it reposes. It is convex above and below; measures about four 
 inches in its transverse diameter, two and a half in thickness, 
 and about the same from before backwards. The upper sur- 
 face is divided into two equal parts or halves, by a middle 
 ridge, while the lower surface is divided in the same way by a 
 fossa. These halves are called hemispheres; their surface is 
 marked by many horizontal fissures, the edges of which are 
 kept closed by the adhesion of the pia mater. 
 
 The fissures are interposed between the laminae or convolu- 
 tions of the cerebellum, which, for the most part, are concen- 
 tric; the larger are behind, while the shortest are in front, near 
 the annular protuberance. The pia mater penetrates to the bot- 
 tom of these fissures, some of which, when exposed fully by its 
 removal, are found to extend to the depth of an inch or more. 
 
352 NERVOUS SYSTEM. 
 
 One of these fissures, which exists on the superior surface of 
 the cerebellum, half an inch distant from the posterior and ex- 
 ternal margin of the latter, has a circular course, and is so well 
 marked by its size and depth, that it is called the Sulcus Supe- 
 rior Cerebelli. Another, situated under similar circumstances 
 on the inferior surface of the cerebellum, is called the Sulcus 
 Inferior Cerebelli. On the latter surface, also, there are two or 
 three more of a middle size, situated between the sulcas infe- 
 rior and the tuber annulare. These larger sulci have given oc- 
 casion to anatomists to multiply most unreasonably the number 
 of lobes of which the cerebellum consists. Bichat's mode of 
 description is preferable: he says, that by cutting (vertically) 
 through one of the hemispheres of the cerebellum, so as to ex- 
 pose the thickest part of its medullary matter, that six or seven 
 principal fissures will be seen, which, by penetrating to a con- 
 siderable depth, divide the cineritious portion into as many con- 
 verging parts. In the interior of these fissures there are much 
 smaller ones, which pass at right angles to them. On the sur- 
 face or periphery of the cerebellum, in the intervals of the 
 larger fissures, there are many small ones, which, though near- 
 ly horizontal, terminate in each other by acute angles. 
 
 The superior middle ridge of the cerebellum, from its shape 
 and position, is called, by Vicq. D'Azyr, Vermis Superior; the 
 anterior extremity of which, from its elevation, is the Monti- 
 culus Cerebelli. 
 
 The middle inferior part of the cerebellum, which presents 
 the deep sulcus running longitudinally and forming the divi- 
 sion into hemispheres, has a long ridge occupying the sulcus. 
 This ridge is the Vermis Inferior of Vicq. D'Azyr, and is so 
 concealed by the adjacent portions of the hemispheres, that a 
 good view of it can be got only by removing the pia mater and 
 pushing the hemispheres aside. The transverse fissures which 
 penetrate it, and its general irregularity of surface, will then be 
 sufficiently distinct. The pia mater passes from the fore part 
 of this body to the medulla oblongata, and thus assists in form- 
 ing the floor of the fourth ventricle; which, without this reflec- 
 tion, would be exposed. The central part of the cerebellum as 
 formed by the vermis superior and by the vermis inferior, is 
 the Fundamental Portion of Gall and Spurzheim. 
 
THE CEREBELLUM. 353 
 
 The Valve of Vieussens (Velum Medullare, Valvula Cerebri) 
 arises from the cerebellum, just under the anterior part of the 
 base of the monticulus, and runs obliquely upwards to terminate 
 in the testes. Sometimes it is marked, in its middle, by a lon- 
 gitudinal line or slight fissure, from either side of which proceed 
 small lateral ones. It is principally medullary, and has a small 
 quantity of cineritious matter at its extremities. It is thinner in 
 the middle than at either of its margins. 
 
 At the root of the crus cerebelli are two small protuberances ; 
 the one below it, in the erect position, is the Lobulus Amygda- 
 loides, and the other the Lobulus Nervi Pneumogastrici. 
 
 The substance of the cerebellum is formed of cineritious mat- 
 ter externally, and of medullary matter internally. When a 
 vertical section of it is made through the middle of one of its 
 hemispheres, the medullary matter puts on the appearance of 
 the thuya or arbor vitas, the roots and ramifications of whose 
 limbs, even to their smallest extremities, are surrounded by ci- 
 neritious matter. In this view, there appears to be more cineri- 
 tious than white matter; but when a horizontal cut is made 
 from the periphery to the centre, parallel with one of the deep 
 concentric fissures, the proportion of medullary matter seems to 
 to be much more considerable; and the arbor vitae arrange- 
 ment is proved to depend upon the laminae of medullary matter 
 radiating from the centre, or, in other words, from the massive 
 medullary trunk in the interior of the hemisphere of the cerebel- 
 lum. Each of these radiations commences by a root of consi- 
 derable size, which divides and subdivides into branches. Each 
 primitive radiation, as well as its branches, is covered by its own 
 layer of cineritious matter about one line in thickness, and is 
 kept perfectly distinct from the contiguous ones by the fissures 
 which extend internally from the periphery of the cerebellum. 
 
 In the middle of the trunk of the arbor vitas, exists the Corpus 
 Rhomboideurn, or Dentatum. It is an oblong rounded body, 
 and jagged and cineritious in its circumference, but medullary 
 within. Its configuration resembles that of the corresponding 
 body in the eminentia olivaris, with the addition of its being larger, 
 and having its outline better marked. It is the ganglion of the 
 cerebellum of Gall and Spurzheim. 
 
354 NERVOUS SYSTEM. 
 
 The Central or Fundamental Portion of the Cerebellum ex- 
 hibits also very clearly the arborescent arrangement, and is fur- 
 nished with about seven primitive radiations, coming from a 
 medullary trunk. The proportion of medullary matter to corti- 
 cal, is less in it than in the hemispheres of the cerebellum. 
 Each of the primitive radiations may be traced to some particu- 
 lar point or prominence on the surface of the fundamental* por- 
 tion, thus forming its basis ; but this study is more curious than 
 useful, though several anatomists have pursued it. 
 
 Three medullary fasciculi, on each side, have now been traced 
 to the cerebellum ; one of these is the continuation of the corpus 
 restiforme of the medulla oblongata ; a second is the valvula 
 cerebri ; and the third, the Crus Cerebelli, which joins the annu- 
 lar protuberance. The two first fasciculi belong to the middle 
 or fundamental portion of the cerebellum; they are, consequent- 
 ly, situated more internally, and are partially concealed by the 
 crus cerebelli, and have interposed between them and the latter, 
 the Corpus Rhomboideum, or Dentatum. 
 
 SECT. V. OF THE CEREBRUM. 
 
 The Cerebrum weighs about three pounds, and is seven times 
 as heavy as the cerebellum. It is ovoidal, and measures about 
 six inches in its antero-posterior diameter, five inches in its great- 
 est breadth, which is behind, and four or five in depth. It is 
 separated above by a deep fissure, (Fissura Longitudinalis,} into 
 two equal parts, called Hemispheres. At the bottom of this fis- 
 sure, by separating the contiguous surfaces of it, is to be seen a 
 broad lamina of medullary matter, passing from side to side, 
 and called the Corpus Callosum, which connects the two .hemi- 
 spheres together. The under surface of each hemisphere is 
 subdivided into three lobes ; Anterior, Middle, and Posterior. 
 
 The anterior lobes are placed upon the anterior fossae of the 
 base of the cranium; the Middle, upon the middle fossae of the 
 same; and the Posterior Lobes rest upon the tentorium. The 
 two anterior lobes are completely separated by the Fissura 
 Longitudinalis, which extends between them to the base of the 
 
THE CEREBRUM. 355 
 
 cranium; the same is the case with the posterior lobes; the 
 middle lobes have interposed between them the annular protu- 
 berance and the crura cerebri. When the pia mater is removed, 
 the anterior lobe is seen to be marked off from the middle lobe 
 by a deep sulcus, the fissure of Sylvius, in the under surface of 
 the cerebrum, corresponding, in its position, with the posterior 
 margin of the Lesser Sphenoidal Wing. The boundary between 
 the middle and the posterior lobe is, by no means, well defined 
 on the basis of the brain, but it is agreed to consider as posterior 
 lobe, all that part of the hemisphere which rests upon the tento- 
 rium. 
 
 The periphery of the cerebrum is formed into convolutions, 
 (Gi/ri,) which give it an unequal tortuous surface, resembling 
 the intestines of a small child. These convolutions are sepa- 
 rated by fissures (Sulci) of depths varying from an inch to two 
 inches or more. The convolutions proceed in diversified and 
 complicated courses, which never correspond in different indi- 
 viduals, and seldom on the two hemispheres of the same brain. 
 Though their summit is generally convex, yet some of them 
 have it depressed slightly, which is considered a proof of each 
 convolution being divisible into two halves or layers, placed side 
 by side. Some of the convolutions are short, others long; they 
 present numerous varieties in the manner of joining each other. 
 Owing to the narrowness of the fissures between them, they are 
 closely packed together, so that the lateral surfaces of each one 
 are suited to such as are contiguous: occasionally, there is a 
 departure from this rule. 
 
 The surface of the convolution, by which we mean not only 
 the most exterior periphery of the cerebrum, but also the surface 
 formed by the fissures to their very bottom, is covered by cine- 
 ritious matter of about one line in thickness. 
 
 Within the periphery of the cerebrum, the mass of medullary 
 matter is very considerable, and is of an ovoidal shape. This 
 ovoid is called the Centrum Ovale of Vieussens, and is brought 
 fairly into view by making a horizontal cut through the hemi- 
 spheres, two inches below their summit. 
 
 In proceeding with the anatomy of the cerebrum from its 
 base upwards, the following is the order or succession of parts 
 
356 NERVOUS SYSTEM. 
 
 in its structure : In advance of the pons varolii, and springing 
 from it, there are two divergent medullary trunks, one on each 
 side, which run forwards, and are lost in the medullary sub- 
 stance of the cerebrum. These trunks are the crura cerebri, 
 upon the upper surface of which are two protuberances : the pos- 
 terior is the thalamus nervi optici, and the anterior is the corpus 
 striatum. Each crus cerebri, having penetrated into the sub- 
 stance of its respective hemisphere, expands by a multiplication 
 of the filaments composing it, so as to constitute the principal 
 bulk of the hemisphere. These filaments may, indeed, be traced 
 very satisfactorily in almost every direction towards the peri- 
 phery of the cerebrum, where they terminate in the convolu- 
 tions, their extremities being covered by the cineritious matter 
 there. The arrangement is best seen by scraping with a knife 
 along the base of the brain, especially when the latter has been 
 hardened in spirits of wine, and it is constituted by what are 
 called, by MM. Gall and Spurzheim, the diverging fibres of the 
 brain. 
 
 The point is not, indeed, entirely settled that the diverging 
 filaments end in the convolutions, or do not rather afterwards 
 inflect or double on themselves, and pass inwards again to the 
 middle line of the brain, forming, by their convergence, the cor- 
 pus callosum. At all events, the fact is quite demonstrable, that 
 as the under and lateral portions of the hemisphere consist in 
 diverging filaments, arising in and from the crus cerebri, so the 
 upper portion and the corpus callosum, consist in filaments which 
 arise in the adjoining convolutions, and collect towards the mid- 
 dle line of the corpus callosum, where they adhere to the con- 
 generic filaments of the other side. 
 
 The arrangement, in the most simple conception and illustra- 
 tion of it, would be exemplified by folding a strip of cloth double 
 on itself, so as to convert it into a loop ; the under part of the 
 loop would then represent the diverging fibres of the cerebrum 
 and the upper part the converging fibres, or corpus callosum ; 
 it being at the same time borne in mind that the continuation of 
 the two orders of fibres into one another in the brain is not so 
 fully ascertained as it would be represented by this model. 
 
 Between the two orders of fibres there is a horizontal cleft or 
 interval. This interval is the lateral ventricle of the hemisphere, 
 
TIJE CEREBRUM. 35? 
 
 which may be got into under the posterior margin of the corpus 
 callosum, from its being open there, or rather only closed by an 
 adhesion of the membranes, which is easily lacerated. 
 
 The preceding is intended as a mere outline upon which to 
 form the base of the descriptive anatomy of the cerebrum. 
 The following, therefore, may be considered as the detailed 
 account : 
 
 The Crura Cerebri are rounded below ; are about eight lines 
 long, and increase in their transverse diameter as they advance; 
 their vertical diameter is about ten lines. They mutually di- 
 verge, beginning from their roots, and are separated by a deep 
 fissure, considered as a continuation of that on the front of the 
 medulla oblongata. This fissure is the third ventricle of the 
 brain. Their surface is marked by superficial furrows, running 
 longitudinally ; and about two lines before the tuber annulare, 
 by a transverse fasciculus of medullary matter, very slightly 
 elevated: the optic nerves also cross them obliquely at their fore 
 part. 
 
 In regard to texture, the crus cerebri presents, on its under 
 surface, a medullary layer of two lines in thickness ; to this suc- 
 ceeds a parcel of cineritiaus matter, which, on being removed, 
 is followed by a mixture of both cineritious and white matter, 
 more abundant than either of the preceding. 
 
 The Eminentiae Mammillares, or Corpora Albicantia, are two 
 small bodies, one on each side, about the size of a French pea. 
 They are situated near the anterior extremities of the crura ce- 
 rebri, on their internal faces, and almost in contact with each 
 other. Their texture is medullary without, and cortical within. 
 
 The Infundibulum is placed immediately before the eminen- 
 tiae mammillares. It is a flattened conoidal body, half an inch 
 long, with its base upwards, and its apex going downwards and 
 forwards. It is formed of cineritious matter. Most generally 
 its base is hollow, and opens into the third ventricle, but its point 
 is closed. J. F. Meckel, however, asserts that a communication 
 exists entirely through it, from the pituitary gland to the third 
 ventricle, and that lie has (frequently proved it by passing air or 
 VOL. II. 46 
 
NERVOUS SYSTEM. 
 
 liquids from this gland, though the experiment does not succeed 
 When he attempts the injection from the third ventricle. 
 
 The Pituitary Gland (Glandula Piluitaria) is situated in the 
 Sella Turcica, and is covered so completely by the dura mater, ' 
 that only a small aperture is left for the point of the infundibu- 
 lum to pass through and to adhere to it. It is an ovoidal body, 
 the greatest diameter of which is transverse, and amounts to 
 ^six lines. It is partially divided, so as to give the appearance 
 'of two lobes, of which the anterior is much the larger. It is 
 hard and cineritious, with a small quantity of medullary matter 
 Within. In either side of it there is a depression from w T hich 
 leads a small canal towards the place where the infundibulum 
 joins it : the two canals are, in the latter place, united into one. 
 5n sortie very rare Cases, gritty matter has been found in h% 
 as there is in the pineal gland. It is also surrounded by pia 
 mater. 
 
 The Tuber Cinereum, or Pons Tarini, is a portion of the un- 
 der surface of the crura cerebri, at the floor of the third ventri- 
 'cle. It is continuous in front with the anterior margin of the 
 corpus callosum. In front of the infundibuhfm the optic nerves 
 unite, after having crossed obliquely the crura cerebri from 
 without inwards and forwards. In this passage, where they reach 
 "the middle of the crura, and at the internal border of the same-, 
 they come in contact with the tuber cinereum, from which they 
 get a few filaments; but of this, more hereafter. 
 
 The Thalami Optici, called, by Gall, the Posterior Ganglions 
 t)f the brain, (Ganglia Postiva,) are amongst the most conspi- 
 cuous parts of the internal stracture of the cerebrum, and are 
 two in number, one for either side. They are situated on the 
 superior face of the crura cerebri, are about an inch and a half 
 long from behind forwards, and abotit eight or ten lines broad 
 ">and deep. 
 
 The thalami are convex above and internally. At the junc- 
 tion of these two surfaces is observed a medullary line, de- 
 scribed under the name of peduncle of the pineal gland. Their 
 .posterior extremity is likewise convex, and is divided into three 
 
THE CEREBRUM; 359 
 
 rounded prominences; one is above the other two-, and is the 
 Tuberculum Posterius Superius; the second is below and with- 
 in, (Corpus Geniculatum Inter num,) and the third is below 
 and external, (Corpus Geniculatum Externum.} There is a 
 fourth tubercle (Tuberculum JJnterius) which is situated on 
 the upper convex surface of the thakimus; it is produced by the 
 fan-like termination of a large medullary fasciculus which comes 
 from the eminentia mammillaris. 
 
 The thalami are somewhat flattened on the middle of their 
 convex internal surface, and adhere there to each other by a 
 layer of cineritiou^ substance, called Commissura Mollis. When 
 the brain is very slightly advanced in putrefaction, or has been 
 made soft by dropsy, this junction scarcely seems to exist at all. 
 
 The thalami are medullary on the surface presented to the 
 ventricles of the brain, but within they are a mixture of cin>eri- 
 tious with medullary matter. The fibres of the medullary are 
 very intimately blended with the crura cerebri, and radiate from 
 within towards the circumference of the brain: some of them 
 are placed in layers, and are connected with the tubercula quad-* 
 rigemina. 
 
 The Corpora Striata, or the Ganglia Cerebri Antica, also two 
 in number, one for each side or hemisphere of the brain, are 
 situated before the thalami optici, at the bottom of the lateral 
 ventricles. They are about two and a half inches long, convex 
 on their upper surface, and eight line* broad at their front part, 
 but taper very gradually to a point behind. They are about four 
 lines apart in front, and are separated there by the septum lu- 
 cidum, but their posterior extremities diverge from each other, 
 so as to admit the thalami optici between them. 
 
 The surface of the corpus striatum is cineritious, but within 
 it consists of cineritious and of medullary matter, placed in lay- 
 ers which alternate with each other. These layers are arranged 
 in a crescentic manner, so as to present the convexity upwards 
 and the concavity downwards. The medullary substance is a 
 continuation of that of the crus cerebri and of the optic thala- 
 mus. It enters at the posterior inferior part of the corpus stri- 
 atum, and immediately divides into three layers, placed one 
 above the other, and of which the two inferior are more narrow 
 
360 NERVOUS SYSTEM. 
 
 
 
 and short than the superior. The upper layer, in its progress 
 forwards, is interrupted by a body of cineritious substance, which 
 occasions it to divide into a multitude of distinct radiated fibres. 
 The same circumstance attends the other layers, but in a more 
 limited degree. The medullary matter of the corpus striatum 
 may then be traced, in all directions, into the hemisphere of the 
 brain. The cineritious substance of the corpus striatum is abun- 
 dant, and is divided by some anatomists into two kinds, one of 
 a light gray, and another of a darker colour. The first forms 
 the middle and inferior part of the corpus striatum; the second 
 is in greater quantity, and is found principally above and be- 
 tween the two upper layers. Such is the general plan of the 
 structure of the corpus striatum; but, it should also be under- 
 stood, that a close intertexture exists between its medullary and 
 cineritious matter. 
 
 The most satisfactory way of unravelling the structure of the 
 corpus striatum, is to scrape away its under surface, in tracing 
 its medullary matter from the crus of the brain, and through 
 the optie thalamus. It will then be seen, that the medullary 
 substance of the crus reaches the posterior inferior part of the 
 corpus striatum, and is immediately invested in the greater 
 part of its circumference with cineritious matter, it then begins 
 to expand after the manner of a fan into filaments. These fila- 
 ments or fasciculi penetrate the cineritious matter in various 
 directions, besides those just detailed. A particular exposition 
 of them is given by GalPand Spurzheim, in their anatomy of 
 the brain. 
 
 The Taenia Striata is placed in the angle formed between 
 the internal margin of tfie Corpus Striatum, and the external 
 one of the Thalamus Opticus, where these two bodies are in 
 contact and continuous with one another. It is a small medul- 
 lary band, not a line in breadth, commencing near the anterior 
 crus of the fornix, with which it is connected frequently by fila- 
 ments; and observing the curved course of the fissure in which 
 it is placed, it goes to the posterior end of the corpus striatum, 
 and even beyond it in most cases, by uniting itself to the top of 
 the Cornu Ammonis. 
 
 The Corpus Callosum. When the fissure between the he- 
 
THE CEREBRUM. 361 
 
 mispheres of the cerebrum is widely separated, or when the su- 
 perior part of the hemisphere is cut away on a level with the 
 bottom of the fissure, the Corpus Callosum, a medullary layer, 
 is brought fully into view. This body unites the medullary 
 mass of the two hemispheres, and is a large commissure. It 
 occupies about two-fifths of the long diameter of the brain, be- 
 ing nearer to its anterior than to its posterior end, and is about 
 eight lines broad: increasing, however, somewhat in breadth 
 posteriorly. The lateral half of it, on either side, is concealed 
 by the hemisphere overlapping it, but is prevented from ad- 
 hering by a horizontal fissure which extends from one end to the 
 other. It has an arched form, being convex above and concave 
 below. Its thickness is uniformly about three lines, with the 
 exception of its anterior and its posterior margins, which are 
 more. 
 
 The middle line of its upper surface is marked out from one 
 end to the other by a very slight depression, the Raphe; on 
 each side of which there is a very small linear elevation of the 
 same extent, but slightly curved inwards towards its fellow. 
 From these longitudinal lines there proceed outwardly trans- 
 verse ones, having a fibrous appearance. At the anterior and 
 posterior ends of the corpus callosum, the latter are somewhat 
 curved and radiated towards the periphery of the brain. Other 
 longitudinal lines also exist on the surface of the corpus callo- 
 sum, but they are not seen with equal facility. The anterior 
 extremity of the corpus callosum is rounded off, and bent down- 
 wards towards the basis of the brain, in such a manner as to 
 present backwards its concavity; which thus embraces the fore 
 part of the corpora striata, and closes the lateral ventricles at 
 this point. The posterior end of the corpus callosum is rounded, 
 also, and continuous with the fornix and with the cornu ammonis. 
 By examining the Corpus Callosum from below, or by look- 
 ing at its relative situation and shape on a hemisphere which is 
 accurately separated from its fellow in the middle line, it will 
 be seen that its lower surface is very concave, being highly 
 arched from before backwards; that it forms the roof of the la- 
 teral ventricles, and that this surface of it is about two inches 
 in its transverse diameter, and, therefore, more than twice as 
 broad as the upper surface. 
 
362 NERVOUS SYSTEM. 
 
 The Fornix (Trigone Cerebral, of the French) is placed im- 
 mediately below the corpus callosum. It is a triangular body 
 of the medullary matter, the base of which is behind and the 
 apex in front. It is about an inch and a half long in its body, 
 and one inch wide at its base. It is the latter part, which, ly- 
 ing immediately beneath the posterior end of the corpus callo- 
 sum, is continuous with it, and causes the fornix to be consi- 
 dered as a part of the same structure with the corpus callosum. 
 These two bodies, which may be compared to a sheet of me- 
 dullary matter doubled on itself, have their surfaces in contact 
 for a short distance behind, the fornix afterwards, by advancing 
 and keeping itself in close contact with the thalami nervorum 
 opticorum, which are just below it, diverges more and more 
 from the under surface of the corpus callosum. It conceals all 
 the upper surface of the thalami except their external margins, 
 and, having reached their anterior extremities, its apex de- 
 scends towards the basis of the brain. 
 
 The body of the fornix is about a line thick, but, at its ante- 
 rior extremity, it becomes somewhat cylindrical, and is divided 
 into two columns, called Crura Fornicis Anteriora. Each of 
 these crura, in descending adheres to the anterior extremity of 
 the thalamus of that side, and, getting finally below it into the 
 floor of the third ventricle, it, after a course slightly curved, 
 joins the cortical substance of the Eminentiae Mammillares. 
 Santorini, aware of this junction, considered the emineyntiae 
 as a part of the fornix, and, therefore, called them Bulbi For- 
 nicis. 
 
 The fornix has other attachments of a more complex descrip- 
 tion, which the anatomist should attend to, as they serve to 
 indicate the modes of intercourse between the several parts of 
 the cerebrum. Its fibres having reached, and probably formed, 
 the eminentiae mammillares: one fasciculus of them ascends 
 from thence along the internal face of the optic thalamus, in- 
 vested by the cineritious matter of the latter, and spreads it- 
 self above like a fan, and forms the tuberculum anterius: a se- 
 cond fasciculus from the same point, having divided into two, 
 after going a short distance, sends one division backwards 
 along the upper internal face of the optic thalamus, to join 
 
THE CEREBRUM. 363 
 
 the peduncle of the pineal gland, and the other division, which 
 is more anterior, runs to join the taenia striata; a third fasci- 
 culus from the eminentia mammillaris, being covered by the 
 optic nerve, goes outwards and backwards to terminate in the 
 thalamus. 
 
 'The posterior margin, or the base of the fornix, besides run- 
 ning into the Corpus callosum, has the angle on each side elon- 
 gated so as to rest upon and to join the upper end of the cornu 
 ammonis. The angle, being continued, then follows the wind- 
 ing course of the latter, adhering to its posterior margin, but 
 hanging loosely over the anterior. This loose edge or continu- 
 ation of the external margin of the fornix is the Tsenia. Hippo- 
 campi, or Corpus Fimbriatum of the Lateral Ventricle. The 
 elongations of the posterior angles are called Crura Posteriora 
 Fornicis. In the brains of individuals who have suffered from 
 general dropsy, one frequently finds the fornix narrower than 
 usual, and in its middle a fissure which separates almost com- 
 pletely its two halves. 
 
 As the fornix is fitted to the upper surface of the optic tha- 
 lami, it is of course concave below and convex above, or resem- 
 bles a triangular arch resting upon its three points or angles. 
 Owing to some misunderstanding of the original Greek word 
 ***<&$, which, according to the interpretation of Sabatier, 
 means a vault, and thereby expresses the whole body, anato* 
 mists, with the exception of him, have generally supposed the 
 striated under surface of the fornix to be meant by it, and 
 have called the surface Lyra, in which mistake one has followed 
 another. / 
 
 The Septum Lucidnm is a partition placed vertically in the 
 middle line of the brain, and extends from the corpus callosum 
 above to the fornix below. It is of a triangular shape, but ir- 
 regularly so, being much broader before than it is behind, and 
 having its edges so incurvated as to fit the bodies against which 
 it is applied. 
 
 The septum lucidum is formed by two lamina placed side to 
 but not adhering to each other, and leaving, therefore, an 
 interval between them, called the Ventriculus Septi, or the fifth 
 ventricle. Each of these laminae consists of two layers; the 
 
364 NERVOUS SYSTfcM. 
 
 internal is medullary substance, continuous with that of the cor* 
 pus callosum and of the fornix; and the external is a layer of 
 cineritious substance. The cavity is about an inch and a half 
 long by a line wide, and is narrower in the middle than at either 
 extremity. It is lined by a delicate serous membrane, which 
 becomes manifest when the halitus that naturally covers its sur- 
 face is accumulated into a body of water. It is generally sup- 
 posed to be insulated or completely shut up, yet occasionally it 
 has been found elongated in front, towards the space between 
 the anterior commissure and the anterior crura fornicis, and to 
 communicate there with the third ventricle.* 
 
 The Pineal Gland (Glandula PineaZis, Conttrium) is placed 
 beneath the posterior margin of the fornix, upon the superior of 
 the tubercula quadrigemina, or the nates. It is an oblong conoi- 
 dal body, the long diameter of which is transverse, and amounts 
 to three or four lines, while the short diameter is about three 
 lines. These diameters are, however, sometimes reversed. The 
 substance of the pineal gland is cineritious, and of a reddish co- 
 lour. At its inferior part there is a small cavity, sometimes 
 lined with medullary matter, and the orifice of which looks to- 
 wards the third ventricle. 
 
 This body is connected to the adjacent parts by several cords. 
 From its bottom there proceeds, on each side, the long medul- 
 lary filament, called its peduncle, which runs along the upper 
 internal face of the thalamtis opticus, and, as observed, joins, or 
 is continuous with, one of the filamentous processes from the 
 Eminentia Mammillaris. From its base there proceeds a trans- 
 verse lamina of medullary matter, called the Posterior Commis- 
 sure of the brain, which first advances forwards, and then re- 
 cedes, so as to be in some measure doubled on itself. This la- 
 mina, at either end, is united to the upper posterior part of the 
 corresponding optic thalamus, and by its lower margin runs into 
 the superior edge of the tubercula quadrigemina. 
 
 Frequently, within the pineal gland, and sometimes on its 
 surface, there is an accumulation of calcarious matter, the Acer- 
 vulus Cerebri, that appears about the sixth year of life, and con- 
 
 * J. F. Meckel. 
 
THE CEREBRUM. 365 
 
 tinues for ever afterwards. It is variable both in quantity and 
 in its mode of concretion, for sometimes there are only a few 
 atoms of grit, scarcely distinguishable by the feel; while, on 
 other occasions, it is collected into a body of irregular shape, 
 and more than a line in diameter. The pieces of which the 
 acervulus consists are sometimes united by cellular substance, 
 and enclosed in a sac. The chemical analysis presents phos- 
 phate of lime in large proportion, carbonate of lime, and ani- 
 mal matter. 
 
 A reflection of pia mater, called the Velum Interpositum, se- 
 parates the pineal gland from the fornix, and the fornix from the 
 thalami nervorum opticorum. 
 
 The Tubercula Quadrigemina (or the Nates et Testes) are 
 situated on the superior face of the crura cerebri, and just be- 
 hind the thalami nervorum opticorum. A very complete view 
 of them is obtained by separating the posterior lobes of the ce- 
 rebrum, and by paring off the vermis superior cerebelli. Though 
 the name implies four distinct prominences, yet they are formed 
 from a common mass of nine or ten lines square, on the poste- 
 rior surface of which these prominences arise. They are in 
 pairs, and are separated from one another by a crucial depres- 
 sion. The largest, or upper pair, is the Nates, the lower pair 
 the Testes. The external surface of these bodies is medullary, 
 and within they are cineritious. From the Nates there pro- 
 ceeds a considerable medullary fasciculus, which runs forward 
 to join the Corpus Geniculatum Internum on the internal pos- 
 terior face of the thalamus nervi optici; there proceeds also 
 from them a second fasciculus, which either joins the optic 
 nerve itself, or the contiguous part of its thalamus. The Testes 
 receive, at their lower end, the valve of the brain; and there 
 also proceeds from them a large fasciculus of medullary matter, 
 which joins the Corpus Geniculatum Externum of the optic 
 thalamus. 
 
 VOL. II. 47 
 
366 NERVOUS SYSTEM. 
 
 Of the Ventricles of the Brain. 
 
 These cavities are four in number: two, called lateral, are 
 placed one in either hemisphere of the cerebrum, a third is be- 
 tween the two thalami, and the fourth under the cerebellum. 
 They have all been alluded to, but only incidentally. 
 
 The two Lateral Ventricles ( Ventriculi Laterales] are horizon- 
 tal cavities, or fissures, of an extremely irregular shape, in the 
 very centre of the hemispheres, being the interval between the 
 diverging and converging filaments of the cerebrum. They are 
 separated from each other only by the septum lucidum ; are co- 
 vered over by the corpus callosum, and have the fornix, thalami 
 optici, and corpora striata for a floor. Each one consists in a 
 body or principal cavity, and three processes, called cornua. 
 The body has been sufficiently described in speaking of the parts 
 which constitute its parietes; but the processes are yet to be 
 considered. 
 
 The Cornua, from their position, are named Anterior, Poste- 
 rior, and Lateral or Inferior. The Anterior is a very small 
 space between the anterior extremity of the corpus striatum and 
 the opposite surface of the hemisphere, and has nothing in it 
 particularly deserving of notice. The Posterior Cornu extends 
 from the base of the fornix to the distance of an inch or more in 
 the substance of the posterior lobe of the cerebrum. Its cavity 
 is conoidal, somewhat curved, with its convexity outwards, and 
 of six or seven lines in diameter at its base. Its internal side is 
 furnished with an oblong eminence called Hippocampus Minor, 
 or Ergot, from its resemblance to a cock's spur, but its size and 
 form are somewhat variable. When this eminence is cut through 
 transversely, it is easy to see that it is formed by a convolution 
 of the posterior lobe projecting into the posterior cornu. The 
 convolution is covered by medullary matter on the side of the 
 ventricle, and of course by cineritious on the side of the peri- 
 phery of the brain, and is the bottom of an anfractuosity. 
 
 The Inferior, Middle, or Lateral Cornu, of the Lateral ven- 
 tricles is situated in the middle lobe of the cerebrum. It com- 
 
THE CEREBRUM. 367 
 
 mences at the posterior angle of the fornix, and winds down- 
 wards and forwards in a semicircle towards the fissure of 
 Sylvius, presenting its convexity outwards, and its- concavity 
 within. Its floor is furnished in its whole length with an ele- 
 vated ridge, the surface of which is semi-cylindrical. This ridge 
 is the Cornu Ammonis, or Hippocampus Major, and increases 
 somewhat, both in breadth and elevation, as it winds down the 
 process of the ventricle. Its lower or anterior extremity is ter- 
 minated by two or three small tubercles, and is the Pes Hip- 
 pocampi. Occasionally the Hippocampus Major is marked off 
 by a middle longitudinal fissure into two elevations, of which the 
 external is the smaller. On its concave side there is the thin 
 edge of medullary matter, continuous with the external margin 
 of the fornix. The extremity of a knife handle may be insinuated 
 for a short distance between this edge arid the Hippocampus ; it 
 ceases about half way down the latter, and in the natural state 
 of the parts is concealed by the plexus choroides. This edge is, 
 as mentioned in the account of the fornix, the Taenia Hippocampi 
 or Corpus Fimbriatum. Beneath the latter, and partially covered 
 by it, there is another body, which presents itself in the form 
 of a small chord of cineritious matter, is not quite so long as the 
 Taenia, and is called Fascia Dentata, from being divided into 
 several sections by transverse ^fissures, which give it an undu- 
 lating appearance. 
 
 A transverse incision of the Hippocampus Major shows that 
 it is a body of cineritious matter, covered on its surface by a 
 thin layer of medullary substance. 
 
 The Third Ventricle, ( Ventriculus Tertius.) When the fornix 
 is separated from its anterior crura and turned over backwards, 
 the process of pia mater, called Velum Interpositum, is found 
 between it and the optic thalami. This process is of a triangu- 
 lar shape, resembling the fornix, and is about the same size ; it 
 is insinuated into this place from the surface of the brain, under 
 the posterior margin of the corpus callosum. Its lateral margins, 
 which project beyond the corresponding ones of the fornix, are 
 formed by a congeries of convoluted vessels, constituting the 
 plexus choroides. The plexus, indeed, may be traced from the 
 Hippocampi along the corpus fimbriatum to its position on the 
 
368 NERVOUS SYSTEM. 
 
 margin of the velum interpositum ; and insinuates itself from 
 the bottom of the cerebrum between the pons varolii and 
 the convolution forming the Hippocampus Major; but when 
 it reaches the anterior end of the fornix its convoluted 
 character ceases, and it terminates, on each side, in a single 
 vein, (Vena Galeni,) which runs from before backwards, in a 
 straight line, near the middle of the velum interpositum. The 
 vein, finally, unites with its fellow to form a single trunk, which 
 runs into the fourth sinus of the dura mater. 
 
 The Velum Interpositum, or Tela Choroidea, adheres very 
 strongly to the fornix, by means of small vessels : it may be 
 raised with less difficulty from the thalami, though it serves to 
 keep the third ventricle closed above, with the exception of the 
 part just behind the crura of the fornix, where the third and the 
 lateral ventricle communicate by the foramen of Monro. The 
 pineal gland is entangled in its posterior part, being placed be- 
 low it, and js generally torn from its peduncles when the tela is 
 raised up. It is at this point that the tunica arachnoidea may 
 be traced into the cavity of the lateral ventricles, according to 
 Bichat* 
 
 The Plexus Choroides, which was stated to bound the tela 
 choroidea on each side, and to descend along the Hippocampus 
 Major to the fissure of Sylvius, or rather to ascend from this 
 point, and to terminate in the vein on the side of the middle line 
 of the tela, is narrow at its termination, but increases continually 
 in breadth as it is traced towards its commencement. The 
 middle part, however, where it makes its turn, is an exception 
 to this rule, for there it is larger in every way than elsewhere: 
 its vessels being more capacious and more tortuous. Precisely 
 at this point a vesicle or more is very frequently found, consi- 
 dered by some as a hydatid of the brain; in some cases it is 
 filled with calcarious matter instead of with water. The Glan- 
 dulae Pacchioni, as stated, also prevail at this margin. 
 
 On the under surface of the tela choroidea, adhering to it, 
 there is on each side a small venous plexus which goes from be- 
 
 * Some doubts may be reasonably raised on this point of anatomy, as the evi- 
 dence is seldom or never satisfactoiy to the full extent, and as such an arrange- 
 ment would be contradictory to that of the tunica arachnoidea on the surface of 
 the brain, as it never dips into fissures. 
 
THE CEREBRUM. 369 
 
 fore backwards, and terminates in the vena galeni, near its junc- 
 tion with its fellow. It receives the blood of the third and of 
 the fourth ventricle.* 
 
 There is also the same sort of plexus in the fourth ventricle. 
 
 Upon the removal of the Velum Interpositum, or its elevation, 
 the whole upper surface of the thalami optici is exposed. The 
 third ventricle is also brought into view, being placed imme- 
 diately between the thalami optici. It is a narrow oblong cavi- 
 ty, bounded below by the pons tarini, crura cerebri and the 
 eminentiae mammillares, and above by the velum interposi- 
 tum, and the fornix. The anterior crura of the fornix are at its 
 fore part, and just before them is the anterior commissure (Com- 
 missura Anterior.} This body is a transverse fasciculus of 
 medullary matter, which passes from one hemisphere to the 
 other through the anterior margins of the thalami optici. Its 
 middle part is rounded and free, but its extremities penetrate 
 into the substance of the anterior inferior portion of the corpus 
 striatum, and spreading out gradually, describe a curve with its 
 convexity forwards, which terminates on each side in the Taenia 
 Hippocampi of the inferior cornu of the lateral ventricle. This 
 fasciculus, in penetrating the corpus striatum, does not mix with 
 its substance, but, in the early part of its course, goes in a canal 
 formed in the latter. In order to see this arrangement, a part 
 of the corpus striatum must be removed. The anterior commis- 
 sure resembles a nerve in its structure, as it is surrounded by a 
 very delicate sheath, and is divided into fasciculi of fibres. It 
 will now be understood that three commissures are found in the 
 third ventricle, the anterior Commissure the posterior, which is 
 just in front of the Pineal Gland,t and soft Commissure, being a 
 cineritious adhesion of the Thalami. J 
 
 Just behind and below the anterior commissure, the base of 
 the infundibulum opens into the third ventricle ; this place is the 
 Iter ad Infundibulum. At the posterior extremity of the third 
 ventricle, just below the posterior commissure, which has been 
 described as a process of the pineal gland, the communication 
 exists with the fourth ventricle. This passage is the Aqueduct 
 
 * Meckel, Manuel D'Anutomie. 
 
 f See Pineal Gland. * See Thalami. 
 
370 NERVOUS SYSTEM. 
 
 of Sylvius, and leads obliquely downwards and backwards under 
 the valve of the brain. 
 
 The third ventricle communicates freely with the lateral ven- 
 tricle through the aperture called the Foramen of Monro, which 
 is situated precisely at the place where the plexus choroides ter- 
 minates; that is to say, under the anterior crus of the fornix. 
 Doubts have, from time to time, been suggested in regard to the 
 natural existence of this communication ; it only requires a mo- 
 derate degree of accurate observation to dispel them : they have 
 arisen, probably, from the aperture being shut up by the occa- 
 sional adhesion of the plexus choroides to the contiguous surface 
 of the brain. 
 
 The Fourth Ventricle (Ventriculus Quartus, Cerebelli) has 
 been, in a great degree, described in the account of the neigh- 
 bouring parts; it will, therefore, be very readily understood on 
 the present occasion. It is an irregular triangular cavity, the 
 base of which is downwards. It is bounded in front by the tuber 
 annulare, and the medulla oblongata, behind by the fundamental 
 portion of the cerebellum, and above by the valve of the brain 
 and the tubercula quadrigemina ; it is under the latter that the 
 communication between it and the third ventricle is found. Its 
 lateral parietes are formed by the medullary prolongations from 
 the cerebellum to the tubercula quadrigemina. This cavity, as 
 stated, is open below, when that portion of pia mater is removed, 
 which passes from the cerebellum to the medulla oblongata. 
 
 From what has now been said of the connexion of the pia 
 mater with the ventricles, it will be understood that as their sur- 
 faces are covered by pia mater, and the removal of it exposes 
 their cavities, they are, in fact, continuations of the external sur- 
 face of the brain. 
 
 SECT. VI. OF THE NERVES OF THE ENCEPHALON.* 
 
 These nerves are designated numerically, from before back- 
 wards, and, also, by some peculiarity of distribution or function. 
 
 * The more improved observations of modern anatomists having 1 pointed out 
 the fallacy of considering the brain as the source of the spinal marrow, instead of 
 
NERVES OF THE ENCEPHALON. S71 
 
 The Olfactory Nerve or First Part (Nervus Olfactorius, Par 
 Primum,) is situated on the under surface of the anterior lobes 
 of the brain, near the fissure that separates the hemispheres. It 
 goes forwards from its root, and also converges gradually to- 
 wards its fellow, so as to reach the cribriform plate of the 
 ethmoid bone, through the perforations of which it passes out. 
 In its course, it is lodged in a small furrow, by which pressure 
 upon it is prevented. 
 
 This nerve arises by three medullary fasciculi, or roots, from 
 the basis of the brain at the corpus striatum, in the fissure of 
 Sylvius, where the anterior and middle lobes join each other : 
 these roots are from eight to twelve lines on the outer side of 
 the infundibulum. The roots are placed, in regard to each other, 
 diverging; one is within, another in the middle, and the third 
 external. The external root is the longest, and arises from the 
 extreme poslerior margin of the anterior lobe by its last convo- 
 lution. It has a curved course from without inwards, the con- 
 cavity of which is forwards, and the convexity backwards. The 
 internal root is concealed by the chiasm of the optic nerves, and 
 arises from the adjacent surface of the anterior lobe. The middle 
 root comes from the posterior margin of the anterior lobe by the 
 cribriform surface, which is between the other two roots. These 
 origins unite to form a single prismatic cord, which increases in 
 size as it advances forwards, and consists of medullary and ci- 
 neritious longitudinal fibres mixed together. 
 
 The. anterior extremity of the olfactory nerve is swollen 
 out into what is called the Bulb, (Bulbus,) and sends from its 
 under surface filaments, which, surrounding themselves with a 
 tunic from the dura mater, penetrate into the nose, and spread 
 themselves on the Schneiderian membrane. In its whole 
 length it is exceedingly soft and pulpy, till it gets out of the 
 cranium. 
 
 The Optic Nerve or Second Pair (Nervus Oplicus, Par Se- 
 
 the reverse; it follows, that the proper order of describing the nerves of the en- 
 cephalon, is successively from the spinal marrow. I had adopted this plan, for- 
 merly, but certain considerations of facility in study, have induced me to abandon 
 it after some years of experience. 
 
372 NERVOUS SYSTEM. 
 
 cundum) is about the same size with the trigeminus. It arises 
 by a broad flattened root, one portion of which comes from the 
 posterior end of the thalamus opticus, and another from the 
 testis through the means of a medullary band that passes from 
 the latter towards the thalamus of the same side. From this 
 point the optic nerve winds forwards under the cms cerebri, 
 adhering to it, and inclining inwards towards its fellow. Its 
 adhesion to the crus is considered by many anatomists as an- 
 other of its origins. 
 
 The Optic Nerve, having reached the under anterior part 
 of the third ventricle, adheres so closely to its fellow that the 
 two seem fused together, in such a way that there is no line of 
 separation between them. This junction receives, above, from 
 the third ventricle, some medullary filaments, which Meckel 
 feels authorized to consider as another origin. The junction 
 presents the form of the letter X, and is called the chiasm or 
 crossing of the optic nerves. The most distinguished anato- 
 mists, however, have laboured in vain to settle the question of 
 the mode of junction; some believing that there was only a la- 
 teral union, others that the nerve of one side crossed over to 
 the other side, and others, again, that the decussation occurred 
 only with some of the fibres, but not all. Observations, in 
 comparative anatomy, on blindness, and indeed on every con- 
 ceived mode of elucidation, have been resorted to without 
 producing a solution of the problem; but the discussion of 
 their merits would require too much space for the present 
 work. 
 
 The Optic Nerves as they approach their chiasm become 
 more cylindrical, and, continuing so afterwards, penetrate into 
 the orbits through the foramina optica. It is only in front of 
 their junction that they are invested by a neurileme; which, 
 having considerable firmness, penetrates into their interior, and 
 divides them into distinct canals. 
 
 The Nervus Motor Oculi, or Third Pair (Par Tertium,) 
 arises from the internal face of the crus cerebri, about two lines 
 in advance of the anterior margin of the tuber annulare. Its 
 roots come, in great part, from the cineritious matter which is 
 found on the surface of the crus, and may be traced for some 
 
NERVES OF THE ENCEPHALON. 373 
 
 Distance upwards and backwards along the parietes of the third 
 ventricle. The nerves of the opposite sides are in contact for 
 some distance by the internal faces of their roots, but do not 
 adhere. 
 
 The Nervus Motor Oculi proceeds from its origin towards 
 the external margin of the cavernous sinus, and, penetrating into 
 the orbit through the sphenoidal foramen, it is distributed to 
 most of the muscles of the eye-ball. 
 
 The Pathetic Nerve, or Fourth Pair (Nervus Palheticus, 
 Par Cerebrale Quartum,) is the smallest which comes from 
 the encephalon, and is not larger than a sewing thread. It 
 arises by two filaments, or roots, from the upper anterior face 
 of the valve of the brain, just below the testes. This origin is 
 soft, and easily broken, from the want of a neurileme; but the 
 latter is soon afterwards furnished. 
 
 The Nervus Patheticus appears on the base of the brain, be- 
 tween the cerebellum and the posterior lobes of the cerebrum, at 
 the external margin of the ''tuber annulare. It then goes for 
 some distance along the margin of the tentorium till it comes 
 near the posterior clinoid process : it then penetrates into a ca- 
 nal of the dura mater, and reaches the orbit of the eye through 
 the sphenoidal foramen, to be distributed on the superior oblique 
 muscle. 
 
 The Nervus Trigeminus, or Fifth Pair, also called Trifacial, 
 (Par Quintum) is one of the largest among those that proceed 
 from the basis of the brain, and emerges from the side of the 
 pons varolii, just where it is continuous with the crus cerebelli. 
 It is composed of three roots : an anterior, a posterior, and a mid- 
 dle ;* of which the latter is much the largest. 
 
 The middle root is about a line and a half in breadth, and has 
 ti passage made for it by the very obvious splitting of the super- 
 ficial fibres of the pons varolii. It is composed of thirty or forty 
 fasciculi, which are divisible into a hundred or more fibres. 
 These fasciculi may be traced into the substance of the tuber 
 
 * Santorini, Observ. Anat. Venitia, 1724. Soemmering 1 , de Corp. Hum. Fab- 
 fcica, torn. iv. Gall and Spurzhelra, Anat. du Cerv. 
 
 VOL. II. 48 
 
374 NERVOUS SYSTEM. 
 
 annulare, (but intersected by the transverse fibres of the latter,) 
 in the direction of the fourth ventricle. When they have come 
 near the latter, they may be traced thence into the medulla ob- 
 longata, towards the fissure that exists between the corpus oli- 
 vare and restiforme. It is at this point, that the greater num- 
 ber of the fibres arise ; some from the corpus olivare, and others 
 from the fissure. 
 
 The commencement of this root is pulpy and destitute of fibres, 
 and is surrounded by grayish substance; but when it has ad- 
 vanced into the polls, it is surrounded by a fine membrane, and 
 is very evidently fibrous. There is a successive increase in its 
 size, from its commencement till it -is ready to emerge from the 
 pons, when it becomes somewhat contracted, and immediately 
 afterwards increases again considerably in size. It then enters 
 a canal of the dura mater at the fore part of the petrous por- 
 tion of the temporal bone, and just behind the cavernous sinus. 
 This canal sets but loosely about it at first, but afterwards it ad- 
 heres to the surface of the nerve. 
 
 The middle root of the nervus trigeminus, in the upper part 
 of the canal of the dura mater, preserves its fasciculated ap- 
 pearance, and many small filaments are interchanged between 
 the fasciculi, so as to make a complex net-work. But, at the 
 lower part of this canal, it is converted into a ganglion of a 
 semi-lunar shape, with its concavity upwards, being about six 
 or eight lines in length, and one and a half in breadth. This 
 body, called the Ganglion of Gasser, (Ganglion Semi-lunare, 
 Plexus Gangliformis,} is compact, and has its fibres very much 
 matted above, but below they assemble into larger and more 
 distinct fasciculi, which are afterwards arranged into three prin- 
 cipal trunks, departing from the cranium through different fora- 
 mina ; to wit, through the sphenoidal foramen, the foramen ro- 
 tundum, and the foramen ovale. 
 
 J. F. Meckel asserts that the filaments of the plexus above the 
 ganglion, for the most part terminate in a gutter formed in the 
 superior margin of the ganglion, and that there are but very few 
 of them which can be traced into the trunks below. The trunks 
 below, consequently, arise from the circumference of the gan- 
 glion. 
 
 The two smaller roots of the nervus trigeminus proceed out 
 
NERVES OF THE ENCEPHALON. 375 
 
 of the tuber annulare at different points, from that of the large 
 root, and each one has its appropriate fissure for that purpose. 
 One, from its situation, is called Anterior, and the other Poste- 
 rior. Each may be traced into the posterior cord of the me- 
 dulla oblongata, but not so far as the large middle root, and is 
 formed by several fasciculi of medullary fibres. The anterior 
 and the posterior roots, after going separately for six or eight 
 lines, unite to form a single cord. This cord does not merge it- 
 self in the semi-lunar ganglion, but continues distinct from, it,* 
 with the exception of sending off to it a few fasciculi; it after- 
 wards gets from the cranium through the foramen rotundum, 
 and is distributed to some of the muscles of mastication, as the 
 the temporal and buccinator. 
 
 The general distribution of the fifth pair of nerves, or the tri- 
 geminus, is to the orbit, to the face, and to the tongue. 
 
 The Motor Oculi Exiernm, or Sixth Pair of Nerves (Par Sex- 
 turn) is found four or five lines distant from the facial nerve, and 
 at its internal side* It arises from the base or upper extremity 
 of the corpus pyramidale, under the posterior margin of the tuber 
 annulare: when the latter is broader than usual, some of the 
 fibres seem to come from it; but the appearance is deceptious, 
 as they only penetrate it. The fibres are assembled into two 
 roots, of which the internal is three or four times as large as the 
 other. 
 
 These roots, before they penetrate the dura mater, most com- 
 monly unite into a single trunk, which goes almost directly for- 
 wards, and is enveloped in a neurileme. Passing through the 
 cavernous sinus, it gets into the orbit by the sphenoidal foramen, 
 and is spent upon the abductor oculi muscle. 
 
 The Seventh Pair of Nerves is composed of the Facial and 
 the Auditory. 
 
 The Facial Nerve (Nervus Facialis, Portio Dura, Septimi, 
 Par Septimum) is placed in front of and above the auditory nerve. 
 It arises by two branches, which are perfectly distinct from 
 
 * In this respect the fifth pair resembles one of the spinal nerves. 
 
376 NERVOUS SYSTEM. 
 
 each other, and differ much in their size. The larger onc> 
 which is placed within and above the other, arises from the me- 
 dulla oblongata at the most superior part of the corpus resti- 
 forme, where the latter joins the tuber annulare. The* origin of 
 the- nerve is sometimes overlapped by the latter, so that some 
 few of its fibres appear to come from the annular protuberance, 
 while they only pass through it, in their course from the medul- 
 la oblongata. The second branch, which is much smaller than 
 the other, arises, 4>y three or four filaments, from that portion of 
 the medulla oblongata which is placed between the first branch 
 and the auditory nerve. 
 
 The two branches of the facial nerve are kept distinct for the 
 distance of several lines before they unite. Proceeding outwards 
 and backwards, they reach the meatus auditorius interims, and 
 then proceed, as a single cylindrical trunk, through the aqueduct 
 of Fallopius, to emerge at the stylo-mastoid foramen, for the 
 purpose, of being distributed upon the muscles and skin of the 
 head. 
 
 The Auditory Nerve (Nervus Auditorius^ Acusticus, Portio Mol- 
 lis Septimi) arises, in part, from the medullary striae on the sur- 
 face of the calamus scriptorius, and partly from the corpus res- 
 tiforme, between the glosso-pharyngeal nerve and the tuber 
 annulare. At its. origin it is so extremely soft as not to bear 
 handling, and is too pulpy to present the appearance of fibres ; 
 but, becoming more distant from the medulla oblongata, it is 
 harder and more fibrous. 
 
 This nerve is impressed on its internal face by a longitudinal 
 furrow for the reception of the facial nerve. It passes obliquely 
 forwards and outwards beneath the crus cerebelli, and penetrates 
 into the meatus auditorius internus. It adheres somewhat near 
 its root to the under anterior margin of the cerebellum, just be- 
 hind the crus of the latter : the circumstance is considered by J. 
 F. Meckel, as a proof of its having there another origin, where- 
 by an analogy is established between it and the two other nerves 
 of the senses; to wit, the optic and the olfactory. 
 
 The distribution of this nerve is confined to the labyrinth of 
 the ear. 
 
NERVES OF THE ENCEPHALON. 377 
 
 The Eighth Pair of Nerves is composed of the Glosso-Pharynr 
 geal, the Pneumogastric and the Spinal Accessory. 
 
 The Glosso-Pharyngeal Nerve (JVervus Glosso-Pharyngeus, of 
 Eighth Pair,) arises from the posterior cord of the medulla ob- 
 longata, just above, and somewhat anterior to the superior fila- 
 ments of the next nerve, with which it is very closely connected. 
 Its filaments, which are five or six in number, spring, therefore, 
 from the anterior margin of the corpus restiforme, or from the 
 fissure separating it from the corpus olivare, under the posterior 
 margin of the tuber annulare. , 
 
 Its filaments soon collect into a round cord, and anastomose, 
 even in the cavity of the cranium, by a considerable branch 
 with the pneumogastric. It runs outwards and backwards to 
 the foramen lacerum posterius, and goes through the same divi- 
 sion of it that the pneumogastric does, but in its own canal of 
 the dura mater. About half an inch from this canal it en- 
 larges within the cranium, into a small oblong ganglion of five 
 or six lines long, which extends itself as far as the foramen lace- 
 rum.* 
 
 Its general distribution is to the tongue and to the pharynx, 
 as its name implies. 
 
 The Pneumogastric Nerve (Nervus Pneumogaslricus or Vagus$ 
 of Eighth Pair,) arises from the corpus restiforme of the medulla 
 oblongata, just behind, or on the borders of the fissure separating 
 it from the corpus olivare, somewhat above, and posterior to the 
 highest root of the accessory nerve. It commences by a num- 
 ber of parallel filaments, varying in number from ten to fifteen, 
 which are placed very near each other, so as to form two or 
 three flattened fasciculi of half an inch or more in length. The 
 fasciculi below adhere to the spinal accessory, and those 
 above to the glosso-pharyngeal nerve. The fasciculi, finally, 
 collect into a single flattened cord of one and a half lines in 
 breadth. 
 
 This cord goes outwards and backwards to the foramen lace- 
 rum posterius, and gets through it in front of the internal jugular 
 
 * This ganglion is described by Andersech and by Huber, but its existence is 
 questioned by Bichat. 
 
378 NERVOUS SYSTEM. 
 
 vein, being separated from the latter by the small spine which 
 arises from the pars petrosa of the temporal bone. It passes 
 through its own canal in the dura mater, being thus kept distinct 
 from the glosso-pharyngeal, and from the accessory nerve, and 
 in this canal the fasciculi which form it are collected into a single 
 cylindrical trunk. After getting through the canal it then ad- 
 heres by a close, strong, cellular substance, to the glosso-pharyn- 
 geal and to the accessory. 
 
 The general plan of distribution of the pneumogastric nerve 
 is, as its name implies, to the organs of respiration, and to the 
 stomach. 
 
 The Accessory Nerve (Nervus Accessories, of Eighth Pair,) 
 arises from the posterior fasciculus of the medulla oblongata, just 
 behind the nervus hypoglossus, and also from the posterior fasci- 
 culus of the medulla spinalis, sometimes as low down as the 
 seventh cervical nerve. There are six or seven roots front 
 the medulla spinalis, and about three or four from the medul- 
 la oblongata: the former are single, and run, successively, 
 into the same trunk ; but the latter are each composed of two 
 branches, consisting respectively of tw r o filaments. These roots 
 are, successively, larger and longer, as they ascend to join the 
 common trunk. The latter goes up between the posterior fasci- 
 culi of spinal nerves and the ligamentum denticulatum, and gets 
 into the cavity of the cranium, behind the vertebral artery, 
 through the foramen magnum occipitis. 
 
 This nerve varies in respect to the number of its roots, and 
 the mode of their origin. In all cases, the trunk, thus formed, 
 passes from the cranium through the foramen lacerum posterius, 
 traversing there the dura mater, either in a sheath common to it 
 and to the pneumo-gastric nerve, or in its own particular open- 
 ing behind that of the latter. 
 
 Its general distribution is to the muscles and to the integu- 
 ments of the neck. 
 
 The Hypoglossal Nerve, (Nervus Hypoglossus, or Ninth Pair,) 
 arises from the medulla oblongata, by several fasciculi placed 
 one above the other. The roots of thesejasciculi [spring from 
 the fissure which separates the^corpus pyramidale from the cor- 
 
ARTERIES OF THE BRAIN. 379 
 
 pus olivare. The fasciculi are from four to eight in number, be- 
 ing subject to vary in different individuals. They unite into two 
 or three trunks, which coalesce into one, after penetrating the 
 dura mater by distinct openings ; and then proceed through the 
 anterior condyloid foramen of the occipital bone. 
 
 The general distribution of this nerve is to the muscles of the 
 tongue. 
 
 SECT. VII.- Of THE ARTERIES OP THE BRAIN". 
 
 The arteries of the brain, or pia mater, are derived from the 
 two internal carotids, and from the two vertebrals. 
 
 The Internal Carotid Artery (Carotis Inlerna) gets into the ca- 
 vity of the cranium through the carotid canal of the temporal 
 bone, conforming itself of course to the curvature of this canal, 
 and is brought by it to the posterior part of the body of the 
 sphenoidal bone. In escaping from the petrous bone it has to 
 ascend, and also to advance somewhat, by which it is brought 
 to the posterior part of the sella turcica. From this point it 
 goes horizontally forwards through the cavernous sinus; and 
 reaching its fore part, it then ascends again, and towards the fis* 
 sure of Sylvius. While in the carotid canal, it gives a small 
 branch to the tympanum of the ear, and as it lies on the side of 
 the sella turcica it gives off the anterior and the posterior arte- 
 ries of the cavernous sinus. When it reaches the anterior cli- 
 noid process it sends off a large branch through the optic fora- 
 men to the parts contained within the orbit of the eye. This 
 branch is the ophthalmic artery, and what remains of the inter- 
 nal carotid is then distributed to the brain after the following 
 order : 
 
 There are, first of all, some small branches sent to the adja* 
 cent parts; as the pituitary gland, the infundibulum, and the 
 lower part of the third ventricle. 
 
 The Arteria Communicans Posterior is directed backwards 
 and inwards, and runs into the corresponding trunk* of the basi* 
 
380 NERVOUS SYSTEM. 
 
 lar artery called the posterior cerebral. There are some varie- 
 ties in regard to the size and precise point of origin of this trunk, 
 which it would be needless to mention particularly. Besides the 
 important anastomosis formed by it, it detaches several ramus- 
 cles to the adjacent parts of the pia mater. 
 
 The Arteria Choroidea is the next branch from the internal 
 carotid. It goes outwards and backwards, and after detaching 
 some minor branches, it penetrates into the inferior cornu of the 
 lateral ventricle, by the side of the Pons Varolii, and expends it- 
 self in ramifications upon the plexus choroides. 
 
 The Arteria Callosa, or Anterior Cerebri, is detached from 
 the internal carotid, opposite the last. It advances in front of 
 the union of the optic nerves, converging rapidly at the same 
 time towards its fellow. Just before the chiasm of the optic 
 nerves, a transverse branch passes between it and its fellow. 
 This branch, the Arteria Communicans Anterior, is of variable 
 length and size in different subjects, being sometimes a line, and 
 on other occasions three or four lines long. 
 
 The arteria callosa then keeps near its fellow on the under 
 surface of the hemisphere, giving out small branches ; and having 
 got on a line with the anterior margin of the corpus callosum, it 
 ascends on the flat side of the hemisphere; and divides into 
 anterior and into posterior twigs. The former supply the fore 
 flat part of the hemisphere ; the latter the corpus callosum and 
 "the adjacent surface of the brain. These several branches of 
 the arteria anterior reach as far as the upper convex surface of 
 -the brain, and there anastomose with other arteries. 
 
 The Internal Carotid may now be considered to have lost its 
 name, and the trunk is continued as Arteria Cerebri Media. It 
 is directed outwards, and engages in the fissure of Sylvius; 
 while there it detaches a great number of branches to the ad- 
 joining surfaces of the anterior and of the middle lobe. Some 
 of these branches are of considerable magnitude, and winding 
 along the convolutions of the brain, they at length ascend to the 
 upper surface of the hemisphere, and anastomose with the 
 branches of the anterior and of the posterior cerebral artery. 
 
 The Vertebral Artery (Jlrteria Vertebralis) is a branch of 
 
ARTERIES OF TflE BRAIN. 381 
 
 the subclavian. In order to reach the cavity of the cranium it 
 has to traverse the foramina of the transverse processes of the 
 six upper vertebrae of the neck. It ascends in a straight line 
 till it reaches the second vertebra, but there, in order to pass 
 through the transverse process, it takes a direction upwards and 
 outwards. It then ascends vertically again till it has passed 
 through the transverse process of the first vertebra. After which 
 it takes a horizontal course, winding around the posterior face 
 of the upper oblique process of the same vertebra, in a depres- 
 sion for the purpose, and having reached the internal extremi- 
 ty of this process, it ascends upwards and inwards through the 
 occipital foramen into the cavity of the cranium: perforating 
 the dura mater just above the condyle of the occipital bone. 
 Having got into the cranium, it is first on the side and the/i on 
 the under surface of the medulla oblongata, and continues to ap- 
 proach its fellow till it reaches the posterior margin of the tu- 
 ber annulare. At this point the two vertebral arteries coalesce, 
 and from their union results the basilar artery. 
 
 The vertebral artery in this course, from its origin to its ter- 
 mination, detaches several arterioles to the heads of the adjoin- 
 ing muscles, to the membranes of the spinal marrow, and to the 
 nerves as they come out of the intervertebral foramina: they 
 are generally too small and irregular to deserve a special de- 
 scription. At its upper extremity, however, it sends off three 
 branches of some consequence: the Spinalis Posterior, the Spi- 
 nalis Anterior;* and the Inferior Cerebelli. 
 
 The Arteria Inferior Cerebelli divides shortly after its ori- 
 gin, or otherwise is double from the beginning. The most pos- 
 terior trunk is distributed about the bottom of the fourth ven- 
 tricle, on the fundamental portion of the cerebellum, and the 
 contiguous faces of the two hemispheres or lobes of the latter. 
 The other trunk of this artery is distributed on the under surface 
 of the cerebellum. 
 
 The Basilar Artery (firteria Basilaris) is on the middle line 
 of the tuber annulare, and extends from its posterior to its an- 
 terior margin. In this course it detaches some arterioles to the 
 
 * See Arteries of Medulla Spinalis. 
 VOL. IL 49 
 
3S2 NERVOUS SYSTEM. 
 
 tuber; others to the meatus auditorius internus, (Jlrterise Jludi- 
 tivae LiternsBj] which are spent upon the labryinth, and anas- 
 tomose with twigs from the internal and external carotids. At 
 its anterior extremity it detaches on each side two considerable 
 trunks; first the superior artery of the .cerebellum, and imme- 
 diately afterwards the posterior artery of the cerebrum. 
 
 The Arteria Superior Cerebelli goes outwardly from its ori- 
 gin just behind the anterior edge of the tuber annulare, until it 
 gains the front margin of the cerebellum. It then divides into 
 several branches, some of which are distributed on the upper 
 surface of the cerebellum and run to its posterior margin, where 
 they anastomose with the branches of the arteria inferior: others 
 are spent upon the substance of the cerebellum near its anterior 
 edge. 
 
 The Posterior Artery of the Cerebrum, {Jlrleria Cerebri 
 Posterior^) one on each side, is the termination of the basilar 
 artery. It proceeds abruptly outwards, and has gone but a few 
 lines when it receives the arteria communicans posterior of the 
 internal carotid. It then continues outwardly parallel with the 
 anterior margin of the tuber annulare, and near it crosses the 
 crus cerebri, and is then distributed, on the inferior and on the 
 posterior part of the hemisphere and of the corpus callosum. 
 As mentioned, its branches anastomose with those of the ante- 
 rior and of the middle arteries of the cerebrum. 
 
 It will now be understood, that an arterial circle or link en- 
 'closes the chiasm of the optic nerves and the corpora albicantia. 
 The fore and lateral parts of the circle are formed by the inter- 
 nal carotids and their branches; while the hind part is formed 
 by the Basilar Artery and its bifurcation. This is the circle of 
 Willis, and establishes a very free communication between the 
 vessels of the two sides of the brain. 
 
 The~veins of the' Brainwave been sufficiently alluded to in 
 the account of the Pia Mater, and of the sinuses of the Dura 
 Mater, 
 
BOOK IX. 
 
 PART III. 
 
 Se?ises. 
 
 To the peripheral portion of the nervous system, belong all 
 the nerves which are sent off from the Medulla Spinalis and 
 Encephalon, as well as the, Sympathetic. Some of these nerves 
 have a special apparatus attached to their external extremities, 
 for the purpose of augmenting and facilitating their appropriate 
 powers of sensation; of this class are the Olfactory, the Optic, 
 and the Auditory. Others of them, as the nerves of the tongue 
 and of the skin, though they are the means of special sensations, 
 yet the apparatus upon which they are spread is applied to 
 many purposes, more striking and useful, than that of indicating 
 the presence of surrounding bodies. And, lastly, the remaining 
 nerves, being by far the most numerous and large, are distri- 
 buted to the muscles and to the viscera. 
 
 CHAPTER I. 
 
 OF THE ORGAN OF SMELLING, OR THE NOSE. 
 
 THE two succeeding senses are so insulated in their offices, 
 that there can be no doubt of the propriety of considering them 
 
384 NERVOUS SYSTEM. 
 
 as belonging to the peripheral portion of the nervous system: 
 but the nose being, in the human subject, though not in all 
 animals, associated with the function of respiration, its allo- 
 cation is less exceptionable. Without detailing the considera- 
 tions which have induced me to put its description under this 
 head, I will only mention that I have been principally actuated 
 by its office of smelling and by its position. 
 
 In common language, the term nose is applied to the part of 
 the organ of smelling which manifests itself externally; but a 
 very extensive cavity of the same vertical diameter, and divided 
 into two equal compartments, exists behind it, the form of 
 which has been described in the account of the bones of the 
 nose. This cavity extends from the bottom of the cranium to 
 the roof of the mouth, and backwards to within an inch and a 
 quarter of the vertebra of the neck. The nose, externally, is 
 generally pyramidal, and has its base below; what is technically 
 called the root of the nose is the part contiguous to the fore- 
 head. The base, on each side, is marked from the cheek, by 
 a semicircular depression; which becoming more and more 
 shallow at its upper extremity, and increasing its breadth, is 
 insensibly lost upon the side and point of the nose. The ala 
 nasi is the swell of the posterior part of the base, being bounded 
 behind by the depression. The base of the nose offers on each 
 side an oblong oval orifice, looking downwards and having its 
 long diameter forwards and slightly inwards. These openings 
 are commonly about two lines below the floor of the nose, but 
 there is a diversity in this respect. 
 
 The Nasus Cartilagineus, or the cartilaginous portion of the 
 nose, is placed wholly at its anterior extremity, and serves to 
 elongate the cavity in that direction. It presents a vertical 
 cartilage, which is in continuation of the bony septum: on 
 each side of this, there is an oval cartilage, and behind and 
 below the latter, several distinct and small pieces of cartilage, 
 which preserve the form of the alae nasi, and, in fact, constitute 
 them. 
 
 The Vertical Cartilage, or Cartilaginous Septum (Septum 
 Cartilagineum) is placed in the middle line of the nose, and 
 
ORGAN OF SMELLING. 385 
 
 has its anterior angle projecting beyond the bony orifice of the 
 anterior nares. Occasionally, from a faulty conformation, it 
 inclines more to one side than to the other. It adheres, by its 
 superior margin, to the nasal lamella of the ethmoid and to the 
 middle nasal suture, and behind to the anterior margin of the t 
 vomer. The inferior margin is free in the greater part of its 
 extent, but adheres behind to the suture between the maxillary 
 bones. The anterior margin sends out, on each side, a trian- 
 gular plate, the upper edge of which adheres to the inferior 
 margin of the nasal bone, and of the nasal process of the upper 
 maxillary. These plates form the upper part of the cartilagi- 
 nous nose, and from their ligamentous attachment to the bones, 
 admit of a slight motion from side to side. 
 
 The Oval Cartilages, one on each side, are a species of ellip- 
 tical ring, but deficient or open at their posterior end. The 
 external side of the ring, is an oblong oval plate, which is di- 
 rected upwards and backwards. The internal half of the ring 
 is much narrower, and proceeds backwards from the preceding 
 part at a very acute angle: its superior margin is in contact 
 with the septum; its inferior margin reaches below the latter, 
 and its anterior extremity is in contact with its fellow, owing 
 to the cartilaginous septum not reaching so far forwards. The 
 place of contact of the two oval cartilages to each other, forms 
 the tip of the nose and the columna nasi, and gives the apparent 
 thickness, before dissection, to the lower part of the septum 
 narium. 
 
 The Alse Nasi, or the convexities on each side of the base 
 of the nose, it has been said, owe their shape to the presence 
 of several small pieces of cartilage, whose form, size, and num- 
 ber are too variable to admit of a standard description: occasion- 
 ally they are all collected into but one cartilage. They serve 
 a similar purpose with the oval cartilage, and with it are the 
 means by which the orifice of the nose is kept patulous. They 
 are deposited in, and held together by a ligamentous membrane. 
 This membrane attaches them to the lateral margin of the an- 
 terior bony nares, and also unites the upper edge of the ex- 
 ternal plate of the oval cartilage to the inferior margin of the 
 triangular plate of the cartilaginous septum. It is the length 
 and looseness of this ligament which permits such free motion 
 
386 NERVOUS SYSTEM. 
 
 to the end of the nose. In addition there exists a small liga- 
 ment described by Caldani, which goes from the posterior end 
 of the columna nasi to the anterior inferior margin of the bony 
 nares. 
 
 
 
 The skin which covers the upper half of the nose is loosely 
 attached, by cellular substance, to the subjacent parts, but it 
 adheres very closely to the surface of the cartilaginous and li- 
 gamentous structure, and is abundantly furnished with seba- 
 ceous glands and follicles. The exterior orifices of the latter 
 are apparent, and are often filled with their appropriate fluid in 
 an inspissated state, which, when forced out by pressure, as- 
 sumes the form of small worms, the blackness of the end of 
 which is only dirt. 
 
 There are several muscles destined to move the cartilaginous 
 structure of the nose, which have been described among those 
 belonging to the face. 
 
 The Levator Labii Superioris Alasque Nasi, which lies upon 
 the side of the nose and comes from the superior part of the 
 nasal process and body of the upper maxillary bone, is, besides 
 its insertion into the upper lip, connected with the ala nasi, and 
 will draw the latter upwards. 
 
 The Compressor Naris, arising from the ala nasi by a small 
 pointed beginning, is spread out upon the upper edge of the 
 cartilage and upon the triangular plate, so as to cover it, and is 
 inserted into its fellow on the middle line. 
 
 The Depressor Labii Superioris Ala3que Nasi, by arising from 
 the roots of the alveolar processes of the incisor and canine 
 teeth of the upper jaw, and going to be inserted into the ala 
 nasi, as well as into the upper lip, will draw the ala nasi down- 
 wards. 
 
 The Nasalis Labii Superioris, or Depressor Narium, which 
 is the pointed production from the orbicularis oris, going into 
 the columna nasi, will draw the latter downwards and back- 
 wards. 
 
 The Mucous Membrane of the Nose (Membrana Pituitaria, 
 Schneideriana) lines^the whole of each side of the nose, pene- 
 trates into the several sinuses and cavities communicating with 
 
ORGAN OF SMELLING. 387 
 
 ijt, and is continuous, at the orifice of the nostrils, with the 
 skin, and at the posterior nares, with the mucous membrane of 
 the pharynx. 
 
 It is not of essential importance to trace its course from any 
 particular point, but for the sake of perspicuity, we may begin 
 at the floor of the nostril, which it covers in a smooth even 
 manner. From this it ascends on the septum narium, which it 
 covers also smoothly without forming any fold or duplicature, 
 and adheres so loosely that it may be detached with great fa- 
 cility. Behind, it covers the body of the sphenoid bone, and 
 lines its cell; in front, it covers smoothly the os nasi and nasal 
 process of the upper maxillary bone, and also the cartilaginous 
 nose. Above, it is reflected upon the cribriform plate of the 
 ethmoid bone, and blocks up all its foramina. At this point, 
 the olfactory nerves seem to terminate on its surface and ad- 
 here very closely to it. 
 
 From the cribriform plate, the Schneiderian membrane passes 
 to the cellular part of the ethmoid, and covers smoothly its an- 
 terior half. But behind, as it passes over the upper spongy 
 bone, a pendulous duplicature is formed along its inferior mar- 
 gin, and is continued beyond the bone, backwards as far as the 
 spheno-palatine foramen. It then lines the upper meatus and 
 the posterior cells of the ethmoid, and is extended upon the 
 convex surface of the middle spongy bone. At the inferior 
 margin of the latter, it forms another loose and somewhat pen- 
 dulous duplication, which does not go beyond the posterior ex- 
 tremity of the bone. The membrane is then reflected into the 
 middle meatus of the nose, and penetrates into the maxillary 
 sinus which it lines completely. The orifice through which it 
 enters, is about the size of a crow-quill; is variable in its situa- 
 tion, being sometimes in the middle of the meatus, sometimes 
 more forward, and on other occasions higher up and concealed 
 by irregularities, in the conformation of the ethmoid. This ori- 
 fice, which was found to be so large and jagged in the dried 
 bone, is reduced to its present size entirely by the mode of re- 
 flection of the mucous membrane over its margins. In front of 
 the latter orifice, beneath the anterior margin of the middle tur- 
 feinated bone, the rmicous membrane is reflected into the ante- 
 
388 NERVOUS SYSTEM. 
 
 rior ethmoidal cells by one or more foramina, and through the 
 most anterior of these cells into the frontal sinus. 
 
 From the middle meatus, this membrane passes upon the 
 lower turbinated bone so as to cover it, and also to form a loose 
 duplication along its inferior margin; it then lines the inferior 
 meatus of the nose, and is continued on its floor into the part 
 from which its description commenced. Under the anterior 
 part of the inferior spongy bone, this membrane is continued 
 into the lining membrane of the lachrymal sac, and there forms 
 a fold, frequently resembling a valve. Along the posterior mar- 
 gin of the vomer, the membrane of the nostril is continued into 
 the corresponding one of the other side, whose arrangement is 
 in all respects the same. 
 
 The pituitary membrane, in its structure and appearance, re- 
 sembles other mucous membranes; its colour, however, is na- 
 turally of a deeper red. It consists of two laminae, which can- 
 not be readily separated: the one next to the cavity of the nos- 
 tril has the mucous structure; the exterior one is fibrous, and 
 resembles the periosteum of other parts of the body. This 
 composition is best seen on the part belonging to the septum 
 narium. 
 
 By floating the pituitary membrane in water its mucous la- 
 mina is made to exhibit, very satisfactorily, the villous and 
 spongy appearance. This is particularly evident on the turbi-. 
 nated bones. Its whole surface is studded with pits or folli- 
 cles of various sizes, irregularly arranged and resembling pricks 
 made into a plastic substance with the point of a pin. From 
 these cavities or cryptae proceeds the mucus of the nose. In the 
 thickness of the pituitary membrane, there exist numerous and 
 thickly set glands, of a size so small that they escape common 
 observation, but their existence is generally admitted, both on 
 the authority of anatomists who have described them,* and on 
 the principle of their being always the concomitants of mucous 
 membranes.f 
 
 Jt is owing to the great abundance of blood vessels in this 
 membrane, to their very superficial course, and to the habitual 
 
 * Ruyschii, Epist. Anat. Probl, vii. Mayer, 
 f Bicliat, Anat. Descrip. 
 
ORGAN OP SMELLING. 389 
 
 residence of blood in them, that it always presents a deep red 
 colour in the living state. These blood vessels bleed very 
 freely from slight mechanical causes, and are also disposed to 
 congestions, which are relieved by the blood being poured out 
 through their exhalent orifices, withoift laceration or any solu- 
 tion of continuity. 
 
 Though the description just given corresponds with the tex- 
 ture, generally, of the pituitary membrane, yet there are modi- 
 fications of the latter at particular points which it does not fully 
 suit. For example, at the anterior orifice of the nostril it is 
 insensibly changed into a thin skin, furnished in the male adult 
 with stiff hairs ( Vibrissse;} and in all the sinuses it is more thin 
 and white than elsewhere, being also smooth and shining, and 
 not presenting clearly the little pits which are so distinct in the 
 nose. The surface which adheres to the sides of the sinuses, 
 is destitute of a fibrous structure, and is so loosely attached that 
 it peels off with a very inconsiderable force. When the mem- 
 brane of the sinuses is inflamed, it then thickens, admits more 
 red blood, and is thus brought to resemble the pituitary else- 
 where. 
 
 It is extremely difficult to assign a proper use to the sinuses 
 bordering on and entering into the nose; for, accprding to Des- 
 sault, the sensation of smell does not exist in them. Bichat be- 
 lieved that they, by being filled with air charged with odorous 
 particles, were reservoirs of the latter, serving to prolong the 
 sensation of smell, which would have been too fugitive if it had 
 depended only on the passage of air during respiration. Ano- 
 ther problem in regard to these cavities, is the manner in which 
 they discharge the mucus which they secrete. Perfectly rigid 
 and unyielding, and so situated that the most frequent attitudes 
 of the head would rather serve to retain, than to discharge the 
 contents of most of them by gravitation, we yet seldom see 
 more than their surface smeared with mucus, and accumulations 
 of it are quite uncommon, except in the diseased state. The se- 
 cretion in them, it is to be observed, is much less abundant than 
 it is in the nose. 
 
 VOL. II. 50 ' 
 
390 NERVOUS SYSTEM. 
 
 Of the Nerves of the Pituitary Membrane.* 
 
 The pituitary membrane is furnished with nerves from two 
 sources; from the olfactory, and from the fifth pair. 
 
 The Olfactory Nerve having formed its bulb, which reposes 
 in the ethmoidal fossa, sends off from the under surface of the 
 bulb, the succession of filaments which penetrate to the nose 
 through the cribriform plate of the ethmoidal bone. The lat- 
 ter, when examined from the upper surface, has its foramina ar- 
 ranged into two rows, one next to the crista galli, and the other 
 next to the cellular portion of the ethmoid. Each row consists 
 of about six or eight foramina, and between these rows there 
 are other foramina, smaller, and not so much in a line with each 
 other. The same cribriform foramina, when examined from 
 the cavity of the nose, are more numerous, especially those be- 
 longing to the two first rows, in consequence of the latter 
 branching out below into several canals, which may be seen 
 very distinctly on the side of the base of the nasal lamella, and 
 on that of the cellular portion of the ethmoid. 
 
 The distribution of the olfactory nerve corresponds with this 
 arrangement of the cribriform plate, for it has three rows of 
 branches proceeding from the under surface of its bulb, each 
 branch going through its appropriate foramen, and subdividing 
 in it, but sometimes two filaments pass through the same fora- 
 men. In a short space after their origin, they become invested 
 by sheaths of the dura mater, which are extended a considera- 
 ble distance, and which, by a close adhesion to the nerves, make 
 them appear much larger below than they are at the roots. 
 When the nerves reach the cavity of the nose they anastomose 
 together, and descending between the bone and the pituitary 
 membrane, they ramify into an infinitude of small branches, the 
 terminating filaments of which reach the nasal surface of the 
 membrane. 
 
 The Internal Branches, or those next to the crista galli, di- 
 verge from the cribriform plate, and pass downward between 
 
 * Antonii Scarpa, Anatom. Annotationes, Lib. ii. 
 
ORGAN OP SMELLING. 391 
 
 the septum and the pituitary membrane : where they first appear 
 in the nose, there 'are some few adhesions or anastomoses be- 
 tween them ; but their filaments afterwards keep perfectly dis- 
 tinct, and, spreading themselves out on the pituitary membrane 
 of the septimi, make an appearance resembling a flat camePs- 
 hair pencil. The middle ones are the longest, and may be 
 traced almost to the floor of the nose ; the anterior are shorter 
 somewhat ; the posterior do not reach obviously below the middle 
 of the septum. 
 
 The External Branches have a very different mode of distri- 
 bution. While still in their canals they divide into many fila- 
 ments, which anastomose frequently with each other, and when 
 they have fairly got into the cavity of the nose, the same fre- 
 quency of anastomosis continues, so that they form a net- work of 
 numerous and small meshes, which prevails from the cribriform 
 plate to the inferior margin of the middle turbinated bone. Their 
 filaments cannot be traced below the latter line, and, therefore, 
 do not descend so low as the filaments of the internal row, nei- 
 ther are they so close to each other. They do not penetrate to 
 the ethmoidal cells. The posterior ones are very abundant, on 
 the upper turbinated bone, and incline backwards in their de- 
 scent ; the anterior are also abundant on the flat anterior half of 
 the ethmoid, and when they get below the line of the upper 
 meatus, they extend backwards to the posterior end of the mid- 
 dle turbinated bone, and to its inferior margin. On this bone 
 they are less abundant than above it; their meshes are larger, 
 and their distribution is confined to the Schneiderian membrane 
 covering its convex surface. 
 
 The filaments of the middle row associate themselves indis- 
 criminately with those of the external and of the internal row, 
 according to local convenience. 
 
 The other nerves of the Pituitary Membrane . come from the 
 first and from the second branch of the Trigeminus. The first 
 branch gives off from its nasal branch the nerve called Internal 
 Nasal, which penetrates from the orbit into the cavity of the 
 cranium, through the anterior internal orbitary foramen, and lies 
 covered by the dura mater, at the side of the'crista galli; thence 
 
392 NERVOUS SYSTEM. 
 
 it passes into the cavity of the nose through the most anterior 
 foramen of the cribriform plate. 
 
 This Internal Nasal Nerve (Nasalis Intermix) having got into 
 the nose, divides into two fasciculi, an internal and |in external. 
 The internal descends along the anterior margin of the septum, 
 between the mucous membrane and the bone, and, after a short 
 course, is divided into two filaments, one of which, applying it- 
 self to the posterior face of the os nasi, terminates by smaller 
 filaments in the integuments of the lower part of the nose; the 
 other filament continues along the margin of the septum to the 
 lower part of the latter, where it terminates by smaller filaments. 
 The external fasciculus of the Nasalis Internus gives off early a 
 filament, which descends along a groove on the posterior face 
 of the nasal bone, and winding over the lower edge of the latter, 
 or passing through a foramen in it, is lost upon the integuments 
 of the corresponding part of the nose. Other filaments from 
 the external fasciculus descend upon the mucous membrane, 
 along the external anterior part of the nose, or that which- cor- 
 responds with the nasal process of the upper maxilla, and ter- 
 minate near the anterior extremity of the inferior spongy bone: 
 they are three or four in number. The internal nasal nerve is 
 also said to send one or more filaments to the frontal sinuses, but 
 they are so fine that doubts of their existence are entertained 
 by Bichat, though they are admitted by J. F. Meckel. 
 
 The Spheno-Palatine Ganglion, a part of the second branch of 
 the Trigeminus, detaches to the nose, through the spheno-palatine 
 foramen, several filaments. One of these, discovered by Cotun- 
 nius, and admirably delineated by Scarpa and by John Hunter, 
 called the Naso Palatinus, runs across the front of the sphenoidal 
 sinus to the upper posterior part of the septum narium, beneath 
 the mucous membrane. It then descends obliquely along the 
 septum to the foramen incisivum, and passes through it to the 
 roof of the mouth. In many cases, however, a distinct foramen 
 is formed in the middle palate suture for it, anterior to the fora- 
 men incisivum. The nerve of the left side is anterior to that on 
 the right. When the two reach the roof of the mouth, or are 
 near it, they unite to form a little swelling, called the naso-pa- 
 
ORGAN OF SMELLING. 393 
 
 latine ganglion,* from which several filaments arise and are 
 spent upon the membranous caruncle at this point, and upon the 
 contiguous part of the palatine membrane. 
 
 The spheno-palatine ganglion sends several filaments to the 
 mucous membrane of the upper spongy bone and of the upper 
 meatus, and to that of the posterior end of the middle spongy 
 bone. The palatine nerve, one of its largest branches, in de- 
 scending along the posterior palatine canal to the soft palate of 
 the mouth, also contributes to the supply of nerves to the nose. 
 Shortly after it has arisen from the ganglion, it sends one or 
 more filaments to the middle spongy bone, and to the superior 
 part of the lower spongy bone, and when it has got, in its descent, 
 on a level with the posterior end of the latter, it detaches another 
 filament, which supplies the mucous membrane, along the infe- 
 rior margin of this bone. 
 
 An opinion advanced by Mery about the close of the seven- 
 teenth century, has lately been revived by M. Magendie, of Paris, 
 that the olfactory nerves are not those which communicate the 
 impressions of odorous bodies. In contradiction, however, to 
 his experiments, it should be stated, that several respectable 
 anatomists have seen cases where the privation of the sense of 
 smell during life, was found, upon examination after death, to be 
 attended with the absence of the olfactory nerves, 
 
 Of the Blood Vessels of the Nose. 
 
 The extreme vascularity of the Schneiderian Membrane is 
 derived from several sources. The Internal Maxillary Artery 
 sends through the Spheno-Palatine Foramen a large branch, 
 which is distributed upon the septum and upon the spongy bones. 
 The palatine artery also supplies this membrane with one or 
 more small branches. The Ophthalmic also sends the anterior 
 and the posterior ethmoidal branches to it, from the orbit of the 
 eye. The infra-orbitar artery likewise contributes to its vas- 
 cularity by one or more branches, sent off in its course through 
 the infra-orbitar canal. 
 
 * J. Cloquet, Anat. 
 
394 NTERVOUS SYSTEM. 
 
 % 
 
 The veins follow the course and distribution of the arteries. 
 Some of them, however, unite with the trunks called emissaries 
 of Santorini, which reach the sinuses of the brain through the 
 foramen ovale and rotundum of the sphenoid bone. 
 
 CHAPTER II. 
 
 OF THE EYE, AND ITS DEPENDENCIES. 
 
 THE organ of vision which depends upon the optic nerve for 
 its usefulness, is formed by the Ball of the Eye and many Depen- 
 dencies or Auxiliary parts, all of which are situated within the 
 orbit, and fill up its cavity. 
 
 SECT. I. OF THE AUXILIARY PARTS OF THE EYE. 
 
 The Eyelids (Palpebra) are placed at the anterior orifice of 
 the orbit, and serve to shut out the light from the eye, by their 
 closing ; and also, by their frequent motions, to sweep the front 
 of the eyeball, so as to remove, from its transparent part, moats 
 and dust. They are distinguished into upper and lower, and 
 the place at each end, where the horizontal fissure between them 
 ceases, is called their Commissure, Angle or Canthus. The angle 
 next to the nose, or the internal, is called the Great one, and the 
 other, the Little one. 
 
 The Internal Canthus is united to the nasal process of the su- 
 perior maxillary bone by a rounded tendon, (Ligamentum Palpe- 
 brale Internum,) which passes horizontally inwards, and is nearly 
 half an inch in length. It throws the skin into a small ridge, 
 which may be distinctly seen and felt at this point. The Exter- 
 nal Canthus is held in place by its general attachments of cellu- 
 lar substance and by the external palpebral ligament. 
 
 The upper eyelid is somewhat larger than the lower, but the 
 structure of both is the same, for each one is formed by skin ex- 
 
THE EYE. 395 
 
 ternally; next to it a plane of muscular fibres, being the orbicu- 
 laris palpebrarum; then a plate of cartilage; and, lastly, a thin 
 membrane uniting it to the eyeball. 
 
 There is nothing in the texture of the skin of the eyelid which 
 needs description in a more particular manner, than that of 
 stating its fineness, its thinness, the looseness of its attachment 
 to the muscle beneath by long yielding cellular substance, and 
 the deficiency of adipose matter. It is rendered prominent at 
 the superior margin of the orbit, both by the projection of the bone 
 there, and by the presence of the corrugator supercilii muscle 
 at its internal extremity. This prominence is furnished with an 
 arched cluster of hairs, (Supercilia,) which have their loose ends 
 inclined horizontally outwards, and are rather more abundant 
 at the root of the nose than externally. The supercilia of the 
 two sides are separated commonly by a small bare space called 
 Glabella, the existence of which adds much to the calm and in- 
 tellectual expression of the human countenance ; whereas, the 
 junction of the two eyebrows, by the hairs filling up this space, 
 gives a gloomy, and, occasionally, a ferocious appearance. 
 
 The margins of the eyelids are also furnished with hairs, 
 (Cilia,) the roots of which are insinuated between the skin and 
 the tarsus cartilage: the most deeply seated seem, indeed, to pe- 
 netrate the latter. The hairs of the upper lid are longer and 
 more numerous than those of the lower; they are concave up- 
 wards, while the latter are concave downwards, so that the con- 
 vexities of the two ranges of hairs come in contact when the 
 eyelids are closed. The hairs of each cilium are disposed into 
 three or four rows, by which a long brush is formed, the central 
 hairs of which are longer and larger than any others. 
 
 The hairs of the supercilia and of the cilia resemble one ano- 
 ther strongly, for, when examined closely, each one will be found 
 to have a bulbous soft root, just beyond which there is a narrow 
 part. The middle of the hair is swollen, and its external extre- 
 mity is brought to a fine point. These hairs correspond in co- 
 lour with the hairs of the head. 
 
 When the orbicularis muscle is removed, a ligamentous or 
 fibrous membrane is found passing from the external margin of 
 the orbit to the corresponding margin of the palpebral cartilages, 
 
396 NERVOUS SYSTEM. 
 
 and separating the eyelids from the parts contained within the 
 orbit. There is a partial decussation of the fibres of this mem- 
 brane, from the external commissure of the cartilages to the ex- 
 ternal edge of the orbit ; it has more firmness than any other 
 part of the membrane, and is the external palpebral ligament, 
 (Ligamentum Palpebrale Externum.) On the side of the internal 
 canthus of the orbit there is no corresponding ligamentous ex- 
 pansion, but a few irregular fibres, which allow the masses of 
 fat beneath to project forwards between their fasciculi. 
 
 The Palpebral Cartilages (Tarsi) are two in number, one at 
 the margin of each eyelid, to which they communicate a smooth, 
 even surface, from the internal to the external commissure. 
 They are between the orbicularis muscle and the tunica conjunc- 
 tiva. The upper one is larger than the lower, resembles an oval 
 cut in half in its long diameter, and is about six lines broad in 
 its middle : the lower one is of a breadth, nearly uniform, of 
 about two lines. Their internal extremities cease just before 
 they reach the puncta lachrymalia, and are attached to the in- 
 ternal palpebral ligament, which has been described as one of the 
 origins of the orbicularis oculi muscle, at the nasal process of 
 the upper maxillary bone ; their external extremities cease just 
 before their commissure, and are firmly attached to the external 
 palpebral ligament. 
 
 These cartilages are thicker where they form the margin of 
 the eyelids, and have there a slope or bevel, by which, when in 
 contact, a small groove is formed on their posterior surface. 
 From their resistance to the concentric contractions of the or- 
 bicularis, they keep the eyelid smooth, and favour its sliding 
 upon the eyeball. Certain animals, being destitute of these car- 
 tilages, when they wink, the skin, by the contraction of the or- 
 bicularis, is drawn up like the mouth of a purse. 
 
 Conjunctiva. Below the palpebral cartilage is the fourth layer 
 of the eyelid, the conjunctiva. It is a white, thin, and diapha- 
 nous membrane, in the uninflamed state. Beginning at the roots 
 of the cilia, where it is continuous with the skin, it covers the 
 posterior face of each eyelid, is reflected for eight or ten lines 
 towards the bottom of the orbit, and then passes to the eyeball, 
 
THE EYE. 397 
 
 of which it covers the anterior half, not excepting the cornea. 
 It penetrates into the lachrymal passages, to be continuous with 
 the lining membrane of the lachrymal sac. 
 
 From this description, it is evident that the tunica conjunctiva 
 has one surface presented against itself when the eyelids are 
 closed; this surface is lubricated and very smooth, so as to per- 
 mit a free motion of the lids and ball of the eye. The other 
 surface is connected in its anterior half by cellular substance to 
 the eyelids, and in its remaining part to the ball of the eye, by 
 the same means. It is united rather loosely to the sclerotica till 
 it gets near the margin of the cornea; but to the latter it ad- 
 heres so firmly, and changes there so much its texture, that it 
 seems like a portion of the cornea. 
 
 This membrane, from its continuity with the skin and the 
 lining membrane of the nose, from its sympathies with them, 
 from the nature of the discharge from it, and from its extreme 
 sensibility, is ranked by Bichat among the mucous membranes. 
 It has, however, some peculiarities in its structure, for it is en- 
 tirely deficient in villosities, and though most abundantly fur- 
 nished with capillary vessels, they do not obviously admit red 
 blood, but in a state of irritation. 
 
 Glandule Palpebrarum. These bodies, also called the glands 
 of Meibomius, from an anatomist who has described them par- 
 ticularly, are situated at the margin of each eyelid, between its 
 cartilage and the conjunctiva. They are about two or three 
 lines long, and appear like small, white, serpentine threads, run- 
 ning at right angles to the margin of the lid, near to, and paral- 
 lel with one another. They are more abundant on the upper 
 than on the lower lid. They terminate by a row of small ori- 
 fices in the margin of the lid, just behind the cilium. For prevent- 
 ing the overflowing of the tears, and the sticking together of the 
 eyelids, they discharge an unctuous fluid, which may be made 
 manifest by squeezing them. Their secretion is occasionally 
 much augmented, and then has a large quantity of serum and 
 glutinous matter in it : in this case the evaporation of the serum 
 makes it adhesive, and causes the eyelids to adhere after they 
 have been closed for- some time, as in sleep. 
 
 VOL. II. 51 
 
398 NERVOUS SYSTEM. 
 
 Muscles. 
 
 f The Musculus Levator Palpebrae Superioris is placed in the 
 superior part of the orbit. It arises by a small round tendon 
 from the upper margin of the optic foramen, and, becoming 
 fleshy, it expands itself into a long thin triangle, of which the 
 base is in front. It covers the rectus superior muscle. 
 
 Terminating in front by a thin tendinous expansion, it is in- 
 serted into the superior margin of the upper palpebral cartilage ; 
 but some of its fibres continue on between the latter and the or- 
 bicularis to the lower edge of the cartilage. 
 
 It raises the upper lid, by drawing it towards the bottom of 
 the orbit. 
 
 There are six muscles concerned in moving the eyeball, four 
 of which, from their direction, are said to be straight ; and the 
 other two, for the same reason, are called oblique. With the 
 exception of the inferior oblique, they all arise from the bottom 
 of the orbit. 
 
 1. The Rectus Oculi Superior, being placed immediately be- 
 low the levator palpebrse, arises from the superior margin of the 
 optic foramen. It runs forward, increasing somewhat in breadth, 
 and is inserted by a broad thin tendon into the sclerotica, two 
 lines from the cornea. 
 
 It turns the eye upwards. 
 
 2. The Rectus Oculi Externus arises from the external mar- 
 gin of the optic foramen. It then advances along the middle of 
 the external wall of the orbit, near the periosteum, to which it 
 adheres slightly, and is, finally, inserted, by a thin broad tendon, 
 into the external side of the sclerotica, about two or three lines 
 from the cornea. 
 
 It abducts the eye, or turns its outwards. 
 
 3. The Rectus Oculi Inferior arises also from the optic fora- 
 men, at its inferior margin, and, lying upon the floor of the orbit 
 
THE EYE. 399 
 
 as it advances forwards ; it is inserted, tendinous, into the under 
 surface of the sclerotica, two lines from the cornea. 
 It depresses the eye, or turns it downwards. 
 
 4. The Rectus Oculi Internus arises from the internal margin 
 of the optic foramen, and goes forwards along the internal wall 
 of the orbit, being separated from it by a layer of adipose mat- 
 ter. It is inserted, by a tendinous expansion, into the inner side 
 of the sclerotica, two or three lines from the cornea. 
 
 It adducts the eye, or turns it inwards. 
 
 5. The Obliquus Oculi Superior is placed along the upper' in- 
 ternal angle of the orbit. It arises from the corresponding mar- 
 gin of the optic foramen, by a small round tendon; it then ad- 
 vances forwards, and when it has got near the margin of the 
 orbit, it is converted into a long round tendon. 
 
 The tendon passes through a cartilaginous loop which is 
 formed for it, just at the inner margin of the supra orbitary fo- 
 ramen, and is connected to the loop by long loose cellular sub- 
 stance, which permits it to play freely backwards and forwards. 
 The tendon from this point changes its direction by going back- 
 wards and outwards: it also becomes more flat, and is then in- 
 1 serted into the upper face of the sclerotica near its middle, just 
 beneath the internal margin of the rectus superior muscle. 
 
 This muscle is the longest, but the most delicate of those be- 
 longing to the eyeball. According to Scemmering, it draws the 
 eyeball forwards, and towards the internal canthus, and directs 
 the pupil towards the cheek. By the aid of the inferior oblique, 
 it draws the eyeball towards the nose : it expresses pride : it ap- 
 pears to be greatly excited in anger.* 
 
 The preceding muscles are all connected, either directly or 
 indirectly, with the theca of the optic nerve. 
 
 6. The Obliquus Oculi Inferior is at the bottom of the orbit. 
 
 * Bulbum in priora et angulum internum versus movet; pupillam deorsura ad 
 genam dirigit; juvante musculo obliquuo inferiorc bulbum nasum versus trahit $ 
 animi fastum exprimit; ira valde commoveri videtur. 
 
400 NERVOUS SYSTEM. 
 
 It arises, by a small tendinous beginning, from the os maxillare 
 superius at the side of the os unguis, and, increasing in size, it 
 goes below the rectus inferior outwards and backwards, and 
 gets between the eyeball and the rectus externus. It is then in- 
 serted into the outer face of the sclerotica, about half way be- 
 tween the optic nerve and the cornea. 
 
 It causes the eye to revolve on its axis, and turns the cornea 
 towards the nose. Its action, however, is much modified by that 
 of the other muscles. As one axis of the eye is a line passing 
 from the centre of the optic nerve, forwards and outwards, it 
 will be found that each of the oblique muscles is inserted, at 
 right angles, to this line; consequently, their simple and un- 
 modified action is to produce a revolution of the eye, on its axis, 
 in the line of their insertion, the first making the eye roll in- 
 wards, and the latter outwards, on the two poles: they, there- 
 fore, are strictly antagonists. I 
 
 Of the Lachrymal Apparatus. 
 
 The apparatus for the tears (Organa Lachrymalia, vice Lachry- 
 males) consists in the Lachrymal Gland, the Lachrymal Ducts, 
 the Lachrymal Sac, and a few other parts. 
 
 The Lachrymal Gland ( Glandula Lachrymalis) is situated in 
 the orbit, immediately below and within the external angular 
 process of the os frontis. It secretes the moisture that lubri- 
 cates the eyelids and eyeball, and which, when it becomes abun- 
 dant, is called the Tears. It is a flattened oblong or oval, con- 
 vex above and concave below, of ten lines in length, six in 
 width, and about two lines at. its thickest part, for its edges are 
 somewhat bevelled. It may be considered as divided into two 
 parts or lobes, of which the superior is the larger and occupies 
 the depression attributed to it in the frontal bone, while the in- 
 ferior, being the smaller, is placed at the anterior margin of the 
 depression.* It is lined below by the conjunctiva, and is pro- 
 tected in front by the margin of the orbit which it touches. 
 
 This gland resembles much a salivary gland in its light pink 
 colour, and in its consisting in a congeries of lobules united by 
 
 * These lobes are frequently marked off by a lig-amentous band passing- from 
 between them to the .external angular process. 
 
THE EYE. 401 
 
 cellular substance. Unless we are to consider the latter as such, 
 it has no regular capsule. From the lachrymal gland there pro- 
 ceed six or seven excretory canals, extremely fine, and found 
 with so much difficulty that many distinguished anatomists have 
 sought for them in vain.* The orifices of these ducts have been 
 laid, down, by Soemmering, as equi-distant; forming in the con- 
 junctiva, a row half an inch long, and parallel with the superior 
 margin of the upper tarsus cartilage, beginning a quarter of an 
 inch above its external end and going inwards. By squeezing 
 the gland, small drops like tears, will appear on the nearest sur- 
 face of the conjunctiva, but not in the regular order laid down 
 by anatomists for the lachrymal orifices. 
 
 The Lachrymal Ducts (Canaliculi Lachry males) are situated 
 immediately beneath the skin, at the internal commissure of the 
 eyelids, in their posterior margin, and behind the orbicularis 
 muscle. There is one for each eyelid. They are about half 
 an inch long, though the lower one is rather longer than the 
 upper. 
 
 The lachrymal ducts commence at a small elevation of the 
 margin of each eyelid, bordering immediately upon the internal 
 end of the tarsus cartilage, but perfectly distinct from it. This 
 elevation is conical, has a vermicular motion during life, and 
 points towards the ball of the eye ; in its centre is a very small 
 foramen, called the Punctum Lachrymale, which is the begin- 
 ning of the lachrymal duct. The punctum is about a line in 
 length; and enlarging in its course, it runs at right angles to the 
 duct into which it empties, of which it may be called the Orbital 
 Orifice: the upper one will, therefore, ascend, and the lower one 
 descend. 
 
 The lachrymal ducts are much larger than the puncta, and 
 are in their whole course about one line in diameter. At their 
 
 * These are Morgagni, Haller, Zinn, and Durverney. Meckel, Scemmering, 
 and many others, speak with all confidence concerning them. Bichat admits 
 that he only acknowledges their existence inductively. Dr. Monro, of Edinburgh, 
 claims to have discovered them by plunging the eye into a coloured fluid which 
 was absorbed by them. Dr. W. Hunter seems to have a prior claim to Dr. 
 Monro. See Mcd. Comment, p. 54. Mascagni also acknowledges their exist- 
 ence: Prodromo della Grande Anatomia, vol. i. p. 60. 
 
402 NERVOUS SYSTEM. 
 
 orbital extremities, they go rather beyond the puncta, so as to 
 form a small cul-de-sac. These canals converge, and having 
 got to the internal angle of the eyelid, they are there placed be- 
 hind the internal palpebral ligament. They then discharge, by 
 distinct orifices, but very near each other, into the lachrymal sac 
 at its external anterior part, where they form a small round pro- 
 jection into the interior of its cavity, and are overlapped, some- 
 times, by a small duplicature of its lining membrane. When the 
 eyelids are closed, the lachrymal ducts are horizontal and nearly 
 parallel, but when the eye is open the upper duct is elevated, 
 and thereby becomes oblique ; it is hence more proper for the 
 introduction of the instruments into the lachrymal sac. 
 
 The Lachrymal Caruncle (Caruncula Lachrymalis] is placed 
 in the angle formed by the internal junction of the eyelids. It 
 is a red-coloured tubercle, differing in size in different individuals, 
 but commonly as large as a grain of wheat. It is conical, and 
 obtains its redness from the conjunctiva being reflected over it: 
 when accurately examined, it will be found to consist in a group 
 of sebaceous glands ; of which, according to some anatomists, 
 there are "seven ranged two in a row, and one on the top of the 
 others. The surface of this body is beset with very fine hairs, 
 and the orifices in it are distinguishable with a glass. 
 
 The Semilunar Valve, or Fold, (Plica Semilunaris,) is situated 
 immediately at the outer margin of the caruncle. It has the 
 form of a triangle, the point of which runs into the caruncle, and 
 the base, which is somewhat crescentic, is directed towards the 
 eye. It is a duplicature of the conjunctiva, becomes very mani- 
 fest from behind, and, in some cases, has its base furnished with 
 a very small strip of cartilage.* I have seen several cases of 
 the kind very well marked ; they occur more frequently in the 
 African, according to my personal experience. Between the 
 base and the caruncle it is formed into a number of loose wrin- 
 kles, which disappear when the eye is very much abducted. 
 
 This body, in the human subject, is evidently intended to per- 
 mit to the eye a great freedom of abduction. Its analogy, how- 
 
 * Meckel. 
 
THE EVE. 403 
 
 ever, with the third eyelid of animals is very striking, and the 
 difference is rather in the full development of the latter, than in 
 the organization. It is very properly remarked by J. F. Meckel, 
 that in descending the scale of animals, the third eyelid is al- 
 ways in an inverse ratio to the other two, till it ends by being a 
 complete substitute for them. 
 
 Surrounding the caruncle, may be observed a depression on 
 the adjoining part of the plica semilunaris. Into this depression 
 the puncta lachrymalia are directed, and there play up and 
 down: the tears accumulate in it; from which cause the depres- 
 sion is called Lacus Lachrymalis. 
 
 The Lachrymal Sac (Saccus Lachrymalis) is placed at the in- 
 ternal canthus of the orbit; in the depression of the os unguis, and 
 of the nasal process of the upper maxillary bone. It is an ob- 
 long cylindroid cavity; and extends from the transverse facial 
 suture to the anterior extremity of the inferior meatus of the 
 nose; being concealed there by the anterior part of the inferior 
 turbinated bone. It is crossed at its front part by the tendon of 
 the orbicularis, which, with a few fibres of this muscle, adheres 
 to it. 
 
 The course of the lachrymal sac, is, at first, slightly forwards 
 in the descent to the nose ; but when it reaches the lower part 
 of the orbit, it is afterwards slightly backwards : so that it may 
 be considered as forming an obtuse angle forwards. It also de- 
 creases somewhat in size from above downwards, and at its 
 lower orifice is flattened from side to side. 
 
 The lachrymal sac consists in two membranes, an exterior 
 fibrous one continuous with the periosteum of the contiguous 
 bones ; and an interior mucous one, which is thick, villous, of a 
 red colour, from the abundance of its blood vessels, and abound- 
 ing in mucous follicles. The interior is continuous above with 
 the lachrymal ducts, and below with the Schneiderian membrane. 
 On a line with the floor of the orbit, this internal membrane is 
 thrown into a circular duplicature, considered by some anatomists, 
 as forming the proper boundary of the lachrymal sac: all below 
 this is called by them nasal canal. The distinction is rather 
 arbitrary, and, in some degree, hurtful to clearness of descrip- 
 tion: a much better 'plan is to call the part above the valve, the 
 
404 NERVOUS SYSTEM. 
 
 orbital portion of the sac; and the part below the valve, its nasal 
 portion. Sometimes there is a second valve about three lines 
 below the first, and generally another at the nasal orifice, formed 
 by a duplication of the Schneiderian membrane. 
 
 The Tensor Tarsi is a small muscle on the orbital face of the 
 lachrymal sac, of which I gave a detailed account some few years 
 ago.* It arises from the posterior superior part of the os un- 
 guis, just in advance of the vertical suture between the os pla- 
 num and the os unguis. Having advanced three lines, it bifur- 
 cates; one bifurcation is inserted along the upper lachrymal 
 duct, and terminates at its punctum, or near it; and the lower 
 bifurcation has the same relation to the lower lachrymal duct. 
 The base of the caruncula lachrymalis is placed in the angle of 
 the bifurcation. The superior and the inferior margins of 
 the muscle touch the corresponding fibres of the orbicularis 
 palpebrarum, where the latter is connected with the margin 
 of the internal canthus of the orbit, but may be readily dis- 
 tinguished by their horizontal course. The nasal face of this 
 muscle adheres very closely to that portion of the sac which it 
 covers, and also to the lachrymal ducts. The lachrymal sac 
 rises about a line above its superior margin, and extends in the 
 orbit four lines below its inferior margin. The orbital face of 
 the muscle is covered by a lamina of cellular membrane, and 
 between this lamina and the ball of the eye are placed the val- 
 vula semilunaris, and a considerable quantity of adipose matter. 
 
 As the bifurcated extremities of the muscle follow the course 
 of the ducts, they are covered by the tunica conjunctiva. When 
 this muscle is examined from behind, the eyelids being in situ, 
 it becomes obvious that it is concave on its orbital surface, and, 
 consequently, convex on the nasal; that the muscle is an oblong 
 body, half an inch in length, and about three lines wide, bifur- 
 cated atone end: and that it arises much deeper from the orbit 
 than any acknowedged origin of the orbicularis. The superior 
 fork, however, has a few of its fibres blended with the orbicu- 
 laris. 
 
 In regard to the use of this muscle: its attachment to the 
 posterior face of the sac is such, that it draws the orbital parts 
 
 * Philadelphia Journal of Med. and Phys. Sciences, 1824. 
 
THE EYE. 405 
 
 *)f the sac away from the nasal, and dilates the sac, from the na- 
 sal face of the latter being fixed to the bones. As this mus- 
 cle is cylindrically concave on its orbital side, it is evident that 
 when it contracts, the fibres become straight, or nearly so, like 
 the fibres of the diaphragm, and the cavily of the sac is enlarged 
 after the same manner as the cavity of the thorax. A tendency 
 to a vacuum being thus produced by it, the valves or folds of the 
 internal membrane of the sac permit the vacuum to be filled 
 more readily through the puncta than from the nose; and the 
 puncta being continually bathed in the tears of the lacus lachry- 
 malis, both in the waking and in the sleeping state, the tears are 
 constantly propelled through them by atmospheric pressure. 
 The evacuation of the sac is no doubt accomplished by its own 
 elasticity, and by the contraction of the orbicularis; probably 
 in a chief degree by the latter, because in persons who have 
 epiphora, or a tendency to obstruction in the nasal duct, the ac- 
 cumulation of tears and matter principally takes place at night, 
 when the action of the orbicularis is suspended by sleep. For 
 these reasons, we should argue that this little muscle is active 
 at all times, both night and day. To Dr. Physick I am indebt- 
 ed for suggesting another use for it; to wit, that of keeping the 
 lids in contact with the ball of the eye. Some persons posess 
 unusual voluntary power over this muscle, of which I have seen 
 several examples. In each instance the individual could short- 
 en so much the internal angle of the eyelids, as to conceal it, 
 along with the puncta, in the internal canthus of the orbit* 
 
 * Having laboured, first of all, to convince the profession of the existence of 
 this muscle, the next step, as is usual on such occasions, was to vindicate my own 
 pretensions to its discovery, and to attempt to remove such objections as re- 
 quired attention. For the arguments on this subject, I refer to the Philadelphia 
 Journal of Medical and Physical Sciences, of Nov. 1824, edited by Professor Chap- 
 man. My claims have been unequivocally admitted by Messrs. Breschet and 
 Jourdan, of Paris, anatomists of unusual distinction, in the translation which they 
 have made of J. F. Meckel's Manual of Anatomy, vol. iii. p. 219; by Gery, in the 
 Melanges de Chirurgie etrangere, Geneva, 1824, p. 415; and by Professor Giu- 
 seppe Trasmondi, in the Arcadica Journal of Rome, vol. xix. p. 1, 1823. 
 
 VOL. II. 52 
 
406 NERVOUS SYSTEM. 
 
 Of the Nerves of the Orbit. 
 
 In addition to the optic nerve, there are several belonging to 
 the eye and to its auxiliary parts; they are derived from the 
 Motor Oculi or third pair; from the Trochlearis, or fourth pair; 
 from the first branch of the Trigeminus, or fifth pair; and from 
 the Motor Oculi Externus or sixth pair. For an account of 
 which, see Nerves. 
 
 Of the Arteries of the Orbit. 
 
 The Eyeball, and it auxiliary parts, are principally supplied 
 by the Ophthalmic Artery, which, as was mentioned in the ac- 
 count of the Brain, is a considerable branch given off by the In- 
 ternal Carotid at the fore part of the Sella Turcica. This branch 
 gets into the orbit on the outer side of the optic nerve through 
 the optic foramen, and, after a short course, crosses obliquely 
 above the optic nerve, so as to pass to the internal side of the 
 orbit. It sends off a great many small trunks, which are very 
 inconstant both in their size and origin; they are as follow: 
 
 1. Arteria Lachrymalis arises, commonly, soon after the oph- 
 thalmic has got into the orbit: it goes forwards, between therec- 
 tus superior and the rectus externus muscle, to which it dis- 
 tributes arterioles; it then reaches the lachrymal gland, and 
 having left branches with it, what remains issues out at the ex- 
 ternal angle of the eye, so as to supply the contiguous part of 
 the upper eyelid. 
 
 2. Arterise Ciliares. According to Soemmering, before the 
 prigin of the lachrymal artery, the ophthalmic detaches from 
 one to three ciliary, which penetrate into the ball of the eye 
 near the optic nerve. Other arteries of the same class arise sub- 
 sequently from the ophthalmic, and, occasionally some of them 
 from the lachrymal itself. They go to the choroid coat of the 
 eyeball and to the iris. 
 
THE EYE. 407 
 
 3. The Arteria Centralis Retinae arises from among the clus- 
 ter of ciliary arteries, and, like them, has no invariable root. It 
 penetrates the optic nerve about the middle of its orbitar por- 
 tion, and, going in its centre, gets into the eye through the crib- 
 riform part of the sclerotica. It is then distributed by ramus- 
 cles to the retina, to the tunica hyaloidea, and to the capsule of 
 the lens. 
 
 4. The Arteria Ethmoidea Posterior is inconstant in exist- 
 ence, and comes at one time from the trunk, at another from a 
 branch of the ophthalmic. It passes over the superior oblique 
 muscle, and penetrating through the posterior orbitary foramen, 
 is spent by arterioles upon the neighbouring part of the dura 
 mater, and upon the posterior ethrnoidal cells, where it anasto- 
 moses upon the Schneiderian membrane, with branches from 
 the internal maxillary. 
 
 5. Arteriae Musculares. Of these there are two ; one of them* 
 the inferior, sends branches to the rectus interims, rectus infe- 
 rior, and obliquus inferior oculi; also to the lachrymal sac, and 
 to the parts about the bottom of the orbit. It occasionally de- 
 taches some of the ciliary arteries. The superior muscular 
 branch is also called the supra orbitar. It supplies the muscles 
 of the superior part of the orbit, and then issuing through the 
 supra orbitary foramen, it is spent in arterioles, upon the os 
 frontis and its periosteum, and upon the orbicularis oculi, cor- 
 rugator supercilii, and occipito-frontalis. It anastomoses there 
 with other branches of the ophthalmic, and with the temporal 
 artery. 
 
 It is usual for the anterior ciliary arteries to come from the 
 muscular branches. 
 
 The Ophthalmic Artery, after having detached all the afore- 
 said branches, is much diminished in volume, and, advancing 
 along the internal parts of the orbit, its next branch is 
 
 6. The Arteria Ethmoidea Anterior, which dips into the an- 
 terior internal orbitary foramen, and is divided into small 
 branches, some of which are spent upon the adjacent portion of 
 
408 NERVOUS SYSTEM. 
 
 the dura mater, others upon the frontal sinus and the anterior 
 ethmoidal cells. Some of these branches penetrate from the 
 cranium through the cribriform bone into the nose, and, rami- 
 fying upon the Schneiderian membrane, anastomose with the 
 internal maxillary. 
 
 7. The Arterise Palpebrales are two in number: they come 
 sometimes from a common trunk, and on other occasions arise 
 separately. One is the Superior, and the other the Inferior. 
 The latter arises first, and is distributed to the conjunctiva, the 
 caruncula lachrymalis, lachrymal sac; and finishes by many 
 small branches to the lower eyelid, that anastomose with the 
 infra-orbital artery, so as to form the lower tarsal arch. It 
 also anastomoses with the lachrymal artery by its extreme 
 branches. 
 
 The Superior Palpebral Artery also distributes branches to 
 the conjunctiva, sac, and caruncle; it then emerges above the 
 inner palpebral ligament, around the margin of the superior eye- 
 lid, and forms, along with the lachrymal and the supra orbital 
 artery, the superior tarsal arch, which distributes small branches, 
 in great profusion, to the orbicularis muscle, and to the struc- 
 ture, generally, of the lid. It anastomoses, externally, with the 
 lower palpebral artery. 
 
 S. The Arteria Nasalis is sometimes a well marked continu- 
 ation of the ophthalmic. It passes out of the orbit at its inter- 
 nal canthus, above the internal palpebral ligament, and anas- 
 tomoses at the root of the nose with the facial artery. It is 
 distributed to the side of the nose, and to the lower part of 
 the forehead. Its chief contribution to the eyelids is at the in- 
 ternal end of the orbicularis, where it anastomoses with the pal- 
 pebral arteries. 
 
 9. The Arteria Frontalis passes out of the orbit, at the supra 
 orbitary foramen. It is quickly divided into branches, which 
 go to the orbicularis and corrugator muscles, to the occiplto- 
 frontalis, and to the frontal sinus. 
 
THE EYE. 409 
 
 Of the Veins of the Orbit. 
 
 The blood distributed to the eyeball and to its auxiliary parts> 
 has two routes for returning to the heart, one through the ca- 
 vernous sinus, and the other by the superficial veins of the face. 
 As a general rule, all the branches of the ophthalmic artery which 
 reach the eyelids, or become otherwise superficial, return their 
 blood by the latter route; and those whose distribution is to the 
 ball of the eye and to the parts deeply seated in the orbit, re- 
 turn their blood by the sinus. 
 
 When the veins are well injected, a very considerable num- 
 ber is manifested in both eyelids. They form a handsome net- 
 work, the meshes of which are small and numerous, and com- 
 mence by small roots at the margin of the eyelids. The vessels of 
 this net-work becoming, successively, larger from the centre to 
 the circumference of the orbicularis, cover the whole surface of 
 the latter, and from the thinness of the skin are readily seen be- 
 neath it. The veins of the lower eyelid are discharged into 
 the facial vein, where it borders on the orbicularis; and the 
 veins of the upper lid, being bordered along the superior mar- 
 gin of the orbicularis by a horizontal branch of the temporal 
 vein, discharge themselves into it. 
 
 The Ophthalmic Vein (Sinus Ophthalmicus] is the large 
 trunk within the orbit which receives, successively, the remain- 
 ing blood of the eye, and, passing along the internal parts of the 
 orbit, crosses over the optic nerve, and penetrates through the 
 optic foramen into the cavity of the cranium, where it termi- 
 nates in the cavernous sinus. It may be considered as com^ 
 mencing by an anastomosis with the facial vein at the internal 
 c'anthus; it then receives the following branches: 
 
 1. The nasal, which arises from the parts about the internal 
 canthus of the eye. 
 
 2. The anterior ethmoidal, which comes from the nose and 
 frontal sinus. 
 
 3. Branches from, the recti and obliqui muscles. 
 
410 NERVOUS SYSTEM. 
 
 4. The lachrymal vein, from the lachrymal gland and leva- 
 tor palpebrae muscle. 
 
 5. Posterior ethmoidal vein, from the nose. 
 
 6. The ciliary veins, or those of the choroid coat, which are 
 very numerous. 
 
 7. The central vein of the retina, which is collected from 
 three or four principal branches, and follows the course of the 
 artery of the same name, through the cribriform part of the 
 sclerotic coat, and through the centre of the optic nerve. The 
 trunks of this vein anastomose, at the anterior margin of the 
 retina, with those of the Ciliary Body. 
 
 There are, of course, frequent anastomoses between the veins 
 of the eyelids and the primitive branches of the ophthalmic 
 vein. 
 
 SECT. II. OF THE BALL OF THE EYE. 
 
 The Eyeball (Bulbus Oculi) is situated within the anterior 
 half of the orbit, from which it is kept separated by its auxili- 
 iary parts, and by a large quantity of adipose matter which fills 
 up their interstices. It is very nearly spherical, but not so 
 much so as to prevent its antero-posterior diameter, which is 
 about an inch long, from exceeding in measurement every other. 
 Such, at least, is the general opinion of anatomists: but from 
 some recent experiments, made by distending the eye with mer- 
 cury, I have been induced to doubt its correctness, and especial- 
 ly in the African; for, in the latter, I found the transverse dia- 
 meter to exceed the antero-posterior by a line or more. The 
 Eyeball is also somewhat flattened at the insertion of each of 
 the straight muscles. 
 
 It is formed by a series of concentric tunics, one investing 
 the other, and by humours contained within those tunics. Of 
 the former, the Sclerotica and the Cornea are external, the Cho- 
 roidea and the Iris next, and the Retina is internal: of the lat- 
 ter, the Vitreous Humour is, by far, the most abundant, and 
 constitutes a principal part of the eyeball; the Crystalline Hu- 
 mour is in front of the vitreous; and the Aqueous is placed be- 
 tween the crystalline and the cornea. 
 
THE BALL OF THE EYE. 411 
 
 Tunics, or Membranes of the Eyeball. 
 
 The Sclerotic Coat (Tunica Sclerotica, Jllbuginea) forms 
 about five-sixths of the exterior investment of the eyeball, the 
 remaining sixth of which is obtained from the cornea. At its 
 posterior part it is joined by the optic nerve: this junction does 
 not occur precisely at its axis or centre, but at the inner side of 
 it. When the optic nerve is detached at this junction, a small 
 round hole is perceptible in the sclerotica, or, rather, it is more 
 frequently perceived as a thin cribriform lamella, through the 
 holes of which the pulpy part of the optic nerve passes, so as 
 to get within the eye. This cribriform lamella, or the appear- 
 ance of it, is no doubt produced artificially by the nerve being 
 commonly cut through very near the eye; and, as Mr. Jacobs, 
 of Dublin, very properly suggests, should be considered as the 
 most anterior termination, or the point of the optic nerve in- 
 stead of as a portion of the sclerotica. The neurileme of the 
 optic nerve, is so arranged, that small round longitudinal canals 
 are left, which contain the nervous matter: from this cause it 
 happens that a thin section of the optic nerve in any part of its 
 course in the orbit, will, if held up to the light, manifest the 
 same cribriform arrangement with the part alluded to. This 
 part of the structure of the optic nerve will be readily under- 
 stood by the American student, in comparing it with the pith 
 of the Indian corn-stalk, which, being traversed longitudinally, 
 by many fibres, upon the drawing of them out, an equal num- 
 ber of longitudinal canals is left in their places. 
 
 At its fore part, the edge of the sclerotica is bevelled all 
 around for its junction with the cornea; and though nearly cir- 
 cular, is not completely so, from its horizontal diameter being 
 vsomewhat greater than any other. There are several orifices 
 of inconsiderable size scattered over the sclerotica, some of 
 which are oblique and others direct: they transmit the blood 
 vessels and nerves. The Sclerotica is nearly a line in thick- 
 ness at its back part, from which it gradually becomes reduced 
 to half that thickness in front, where it is strengthened by the 
 tendinous insertions of the recti muscles. Its internal surface 
 
412 NERVOUS SYSTEM. 
 
 is smooth and somewhat shining, being loosely attached to the 
 cellular substance intervening between it and the choroid coat; 
 but the external surface is rough, and more obviously fibrous, 
 and is attached somewhat strongly to all the adjoining parts. 
 
 This membrane is of a white colour, and consists of a single 
 layer, whose structure is essentially fibrous. The fibres are 
 very closely compacted, and compose an intertexture which can- 
 not be unravelled. It is so closely united to the dura mater co- 
 vering of the optic nerve, that many anatomists, notwithstand- 
 ing its greater thickness, are disposed to speak of it as a conti- 
 nuation of the same. Its strength and its want of elasticity suit 
 it remarkably to maintain the form of the eye, and to resist in- 
 juries. Out of the many blood vessels that penetrate it, but 
 few ramify in its structure, and the existence of nerves in it is 
 by no means evident. 
 
 The tunica arachnoidea follows the course of the optic nerve, 
 within its coat of dura mater, and forms, in the eye, just around 
 the cribriform plate, or foramen of the sclerotica, a circular pad: 
 it is then reflected on the internal face of the sclerotica, as 
 far as its anterior edge. It is this which causes the inter- 
 nal face of the sclerotica to be smooth and shining, and there- 
 by to correspond with that of the dura master.* This circum- 
 stance is more readily proved in a very young eye, than in 
 the adult one. 
 
 The Cornea, as mentioned, fills up the aperture at the fore 
 part of the sclerotica, and, of course, has the same diameters, 
 measuring thereby more transversely than in any other direc- 
 tion. It is a segment of a smaller sphere than the sclerotica, 
 and is, consequently, more convex than it. Its thickness is 
 uniform, and commonly exceeds that of the sclerotica at the 
 fore part of the latter. 
 
 Its circumference adheres very closely to the sclerotica, and 
 presents a bevelled or oblique edge, which is inserted into the 
 corresponding bevel of the sclerotica, so that the latter includes 
 the former. The closeness of this junction induced the older 
 anatomists to consider these membranes as one and the same, 
 
 * J. F. Meckel. Zinn supposed this surface to be derived from the pia ma- 
 ter. 
 
THE BALL OF THE EYE. 418 
 
 notwithstanding their obvious difference of structure and of pro- 
 perties. Their adhesion yields to protracted maceration. The 
 cornea is covered in front by a continuation of the tunica con- 
 junctiva, which unites the eyeball to the eyelids. This may be 
 proved by dissection, by maceration, and by its sloughing off 
 entirely along with the epidermis of animals that are subject to 
 this process, as the locust, snakes, and others. On its posterior 
 face, it is covered by the membrane of the aqueous humour, 
 which may be rendered evident by steeping it in spirits of wine; 
 whereby the latter membrane is made more hard, and may be 
 torn off. 
 
 The cornea, in a natural state, is perfectly transparent, and 
 readily transmits the rays of light. It consists of an indefi- 
 nite number of laminae, which are placed one againt the other 
 like the leaves of a book, and are united by a delicate trans- 
 parent cellular substance which permits the laminae to slide 
 upon each other. These laminsa are kept moist and pellucid 
 by an interstitial secretion of a fluid equally pellucid with them- 
 selves, the abundance of which in health gives to the eye its 
 brilliancy, and the deficiency of it in illness and in death causes 
 the eye to look dim and somewhat opaque. Its evaporation, 
 which no doubt is continually occurring, is as constantly sup- 
 plied by a fresh and abundant secretion. The motion of the 
 eyelids sweeps the residuum, after the evaporation of its wa- 
 tery particles, from the surface of the cornea: without this pro- 
 cess, the residuum appears as a thin layer or film of albuminous 
 matter spread over the cornea, when the eye is kept open 
 without winking for a considerable time. 
 
 The cornea has not the fibrous structure of the sclerotica, 
 yet the application of mechanical force to the eyeball shows 
 that it is stronger. Neither has it vessels, conveying red blood 
 naturally, yet, in a state of inflammation, its capillaries dilate 
 so as to admit red blood, and deposite coagulating lymph be- 
 tween its layers. It is common for anatomists to attribute a 
 want of sensibility to it in a natural state: as a general rule, 
 this is fallacious; for many persons, where the eyes are not in- 
 flamed, suffer extremely from its being cut in cataract, and some- 
 times faint from the pain, while others are truly unconscious of 
 the incisions made through it. Of this opinion, I have a full 
 VOL. II. 53 
 
414 NERVOUS SYSTEM. 
 
 assurance from repeated observations on the practice of Dr. 
 Physick, as well as in instances in my own hands. 
 
 The Choroid Coat (Tunica Choroidea, Vasculosa^ is placed 
 immediately within the circumference of the sclerotica, and is 
 of equal extent At its posterior part it furnishes, for the pas- 
 sage of the optic nerve, a singular annular opening, the margin 
 of which is somewhat thickened, and perfectly distinct from 
 the pia mater investment of the nerve, from which some anato- 
 mists have desired to trace this coat. The anterior opening 
 of the choroid is bounded by the ciliary ligament and by the 
 iris. On its outer side may be seen an abundance of loose 
 flocculent cellular substance which joins it to the sclerotica. 
 Internally, it is spread over the retina, but does not adhere 
 to it. 
 
 The choroid coat is closely fastened, at its anterior margin, 
 to the corresponding part of the sclerotica, by a ring which 
 surrounds it, of a short compact cellular tissue. This ring, 
 called the Ciliary Ligament, (Ligamentum Ciliare, Orbiculus 
 Ciliaris,) is from a line to two lines in breadth, and may be 
 readily distinguished by its whiteness, contrasted with the dark 
 colour of the choroid. It is intimately united to the latter, and 
 seems to form a part of its structure, whereby it is caused to 
 detach itself entirely from the sclerotica, and to adhere, by pre- 
 ference, to the choroid when these two membranes are sepa- 
 rated.* The iris is set in the front margin of the ciliary liga- 
 ment, so that the sclerotica and the cornea may be peeled from 
 the choroidea and iris, without impairing the continuity of the 
 two latter. Just beyond the junction of the two last, the liga- 
 ment presents a small ridge or elevation all around, which is 
 fitted into a corresponding fossa at the circumference of the 
 posterior face of the cornea. 
 
 The internal face of the choroid coat, as well as its anterior 
 margin, undergo a very remarkable change from the general 
 plan of this tunic, by forming what is called the Ciliary Body, 
 (Corpus Ciliare, Corona Ciliaris.) In order to see this in 
 
 * Fontana asserted that a circular canal was to be found in this ligament; 
 rnanv examiners have failed in finding it, and its existence is denied. 
 
THE BALL OP THE EYE. 
 
 415 
 
 the most favourable manner, the eye should be laid on the cor- 
 nea, and its posterior half cut away. It will then be evident, 
 that just behind the iris, and within the circumference of the 
 ciliary ligament, the internal face of the choroid coat forms a 
 considerable number of radiated folds or little ridges, which 
 converge from behind forwards and inwards. These folds 
 commence by striae, almost imperceptible to the naked eye, 
 which are in contact with the fore part of the vitreous humour, 
 and with the canal of Petit, and thereby not only impress the 
 neighbouring portion of the tunica hyaloidea with their shape, 
 but evd&n leave upon it the black pigment with which they 
 themselves are covered. These folds, when they get near the 
 circumference of the iris, coalesce one with another, and ter- 
 minate in a considerable number (from fifty to sixty, accord- 
 ing to Soemmering,) of processes, (Processus Ciliares,) the 
 central extremities of which are loose, and float in the aqueous 
 - humour. Some of these processes are longer than others. As 
 a whole, the ciliary processes constitute a ring of radiating fila- 
 ments, which are a line or more in length, placed along side of, 
 and in contact with, one another; the external periphery of the 
 ring adheres to tjie ciliary ligament, and through it to the greater 
 circumference of the iris, so that the ring appears, but falla- 
 ciously, to be continuous with the iris. In certain animals, as 
 the sheep, the radiated appearance of the iris, on its posterior 
 face, favours this notion still more. The internal periphery of 
 the ring presents the central ends of the filaments detached 
 from one another, and of a downy appearance; with the handle 
 of a knife they may be readily pushed backwards and forwards. 
 Generally speaking, the ciliary processes are so much con- 
 cealed by the iris, that they cannot be seen in the living body 
 through the cornea: in cases, however, of extreme dilatation of 
 the pupil by narcotic applications, their central extremities are 
 brought into view. 
 
 The choroid coat always appears, when uninjected, of a very 
 dark brown or black colour, arising from a black paint (Pig- 
 mentum Nigrum) being very thickly spread over the whole 
 of that surface of it which is adjacent to the retina, and being 
 also diffused through its thickness. This paint is more abun- 
 dant near the iris than posteriorly, being laid on there in flakes, 
 
416 NERVOUS SYSTEM. 
 
 in the intervals between the ciliary striae, and tinging also the 
 ciliary processes. It may be removed in a considerable degree, 
 indeed almost entirely, by maceration, or by careful washing 
 with a camel's-hair pencil. It is supposed to be an exhalation 
 from the vessels. Its particular colour is of a most durable 
 kind. According to the observations of Bichat, the long-con- 
 tinued action of light upon it, when this pigment is transferred 
 from the choroid to a piece of paper, does not affect it; neither 
 is it changed by being submitted to very strong chemical agents, 
 as sulphuric, muriatic, or nitric acid, alcohol, or caustic potash. 
 This degree of indestructibility of colour is an invaluable pro- 
 perty, and almost singular; for it is well known to the keepers 
 of medicinal articles, that the colours of all of them yield to the 
 continued influence of light, and that they also become weaker 
 by the same cause. 
 
 In regard to structure, the choroid coat is thin, soft, and easily 
 lacerated: when cleared of its pigment by maceration, it is semi- 
 transparent, and is then seen evidently to consist of but one la- 
 mina; unless we may be disposed to consider as a second one 
 the pigment, naturally on its internal face. It has no appear- 
 ance of fibres in its composition, but, when injected, seems to 
 consist almost wholly of arteries and of veins. 
 
 The arteries are branches of the ophthalmic, and are called 
 ciliary. There are two Long Ciliary Arteries, which pene- 
 trate the sclerotic coat not far from the optic nerve, and pass, 
 one of them, on the external and superior part of the choroides, 
 and the other on its inferior and nasal side, to the front of the 
 eye. In this course, they do not send off any branches of con- 
 sequence till they reach the iris, on which they are distributed. 
 The Short Ciliary Arteries are much more numerous than the 
 others, and also smaller; their number sometimes amounts to 
 twenty; the most of them penetrate the sclerotica from behind, 
 near the optic nerve also.* They quickly divide into a great 
 number of branches, which depart at very acute angles, and 
 have frequent anastomoses with one another. These branches 
 run forwards, nearly parallel, and, at the fore part of the cho- 
 
 * Soemmering, Icones Oculi Hiunani. 
 
THE BALL OF THE EYE. 417 
 
 roides, form a very intricate intertexture, which is continued 
 upon the ciliary processes, and communicates with the vessels 
 of the iris.* 
 
 The veins of the choroid coat are also extremely abundant. 
 They run from before backwards, and the branches which con- 
 cur to form them, being adjacent with, and parallel to each other, 
 for the most part, form large curves, the convexity of which is. 
 for wards j they, moreover, anastomose freely, and thereby pro- 
 duce a vascular sort of net-work, filling up the concavity of some 
 of the curves. These veins, called the Vasa Vorticosa, are 
 nearer the external surface of the choroides than the arteries, 
 and are assembled into twelve or fourteen trunks, which, en- 
 gaging in the sclerotica, near its middle, run for some distance 
 in its substance, and then, by their junction, are reduced to four 
 or five in number. The latter, disengaging themselves from 
 the eye, join, subsequently, the ophthalmic vein. 
 
 In addition to the veins mentioned, the long ciliary arteries 
 have their venae comites, which take a course parallel to and ad- 
 joining them. These veins do not observe the vortical arrange- 
 ment of the others; they bring back the blood of the iris, and 
 terminate in the larger trunks of the others. 
 
 This structure has been most cautiously explored by the ce- 
 lebrated Soemmering, and his observations have tended very 
 much to determine the opinions of anatomists concerning many 
 parts of the eye. A curious remark of his is, that " the human 
 eye may be distinguished from that of animals by a form of this 
 vascular net- work, entirely peculiar; for example, in the eye of 
 the ape, its vascular tissue differs not only from that of the hu- 
 man subject, but also from that of the dog, and still more evi- 
 dently from that of the calf. From which cause, it would be as 
 easy to distinguish with a microscope, the choroides, well in- 
 jected, of different animals, even a piece of only the forty- 
 eighth part of an inch in extent, as it is easy to distinguish a 
 poplar stripped of its leaves from an oak, a pear tree, an apple 
 tree, or any other tree, by the arrangement of its trunk and 
 branches." 
 
 * Icones Oculi Humani. 
 
418 NERVOUS SYSTEM. 
 
 The choroides, on its internal face, is not smooth, but velvety, 
 which becomes still more conspicuous when the eye is finely 
 injected and examined with a microscope. Meckel considers 
 the appearance to depend upon its very fine tissue of vessels. 
 This surface is called Tapetum, in the bullock, and some other 
 animals, at a particular part, it presents a shining, silvery ap- 
 pearance, and may be torn off from the external surface. 
 Ruysch attributed two laminae to the membrane in the human 
 subject, the internal of which was called after his name, but the 
 distinction is now generally abandoned. 
 
 The Iris is a circular plane placed at the front of the cho- 
 roides, and having, in its centre, a round opening called the pu- 
 pil (jpupilla^ Its external circumference is attached to the ci- 
 liary ligament, and by it to the choroid coat, and is exactly at 
 the junction of the cornea with the sclerotica. Professor Sum- 
 mering has bestowed much attention in ascertaining whether 
 this membrane is perfectly flat or somewhat convex in front, 
 and, by repeated observations, carefully made, has assured him 
 self that it is flat* My own observations and preparations have 
 induced me to believe that in many cases it will be found slight- 
 ly convex in front, as Petit asserted more than a century ago. 
 In a moderate state of dilatation, its nasal or internal border 
 is somewhat narrower than its external or temporal. With the 
 exception of its external circumference, every part of the iris is 
 free from any attachment; by which arrangement it moves free- 
 ly in the aqueous humour, so as to contract or dilate its pupil, 
 according to the quantity of light admitted upon the eye. 
 
 The iris, with the exception of its central or pupillary cir- 
 cumference, where it is thinner than elsewhere, is much thick- 
 er than the choroid coat. The posterior face of the iris, some- 
 times called uvea, is covered in great abundance with pigmen- 
 tum nigrum. When this is removed by maceration, which may 
 be readily done, the membrane becomes semi-transparent. Its 
 anterior surface is the seat of the colour, which characterizes 
 every individual's eyes. There are but two of these colours, 
 light blue and orange, the predominance of one or the other of 
 
 * Icones Oculi Hutnani. 
 
THE BALL OP THE EYE. 419 
 
 which, assisted by the dark ground on the back of the iris, gives 
 the cast of hue to the eye. The front surface, when examined 
 on the living eye with the microscope, is seen to be downy or 
 flocculent, and is traversed by filaments forming an intertex- 
 ture, some of which are circular, others oblique; and others ra- 
 diated. This arrangement is remarkably distinct in the eye of 
 the seal. % 
 
 The power which the iris has of dilating the pupil when there 
 is but little light, and of contracting it when there is much, 
 has induced many anatomists to think that it is formed of mus- 
 cular radiated fibres, which by their contraction produce the first 
 motion, and of circular ones which produce the last. Among 
 these anatomists may be mentioned, Ruysch, Morgagni, Zinn, 
 Sabatier. Ruysch asserted that the radiated fibres extended 
 from the greater circumference of the iris to the pupil, and were 
 fixed there by very delicate tendons. The late Doctor Monro, 
 of Edinburgh, has described particularly the circular fibres, and 
 a preparation of the bullock's eye which belonged to him is still 
 exhibited there, where these fibres are seen around the margin 
 of the pupil. The several fibres can only be seen distinctly, when 
 the pigmentum nigrum is washed away. Demours and Meckel 
 deny the existence of the radiated fibres. The late distinguished 
 Professor Wistar taught that the contraction of the pupil was 
 produced by circular fibres, and the dilatation of it by its elas- 
 ticity. In objection to this, Dr. Physick remarks, that as elas- 
 ticity is as much a property of dead as of living matter; in death, 
 therefore, we should always find the pupil dilated from the want 
 of active contraction in the circular fibres; also, in cases of con- 
 cussion of the brain, where there is a sudden loss of sensibility 
 and of muscular motion, the pupil should be invariably dilated; 
 but the fact is, that the pupil remains just in the same state that 
 it was at the moment of the accident* 
 
 Notwithstanding the extreme sensibility and mobility of the 
 iris on the admission of light, one is occasionally astonished to 
 find it not contracting when instruments are applied to it, as I 
 
 * It would appear that the question of the muscularity of the iris has been 
 settled almost conclusively by Mr. Bauer. See Ph. Trans, for 1822. 
 
420 NERVOUS SYSTEM. 
 
 have had an opportunity of twice observing, upon the removal 
 of a considerable portion of it, in making an artificial pupil for 
 opacity of the cornea. In these cases, upon the letting out of 
 the aqueous humour, it became quite as flaccid as we are accus- 
 tomed to see it in our dissections. The same remark has been 
 made by Mr. now Sir Charles Bell. 
 
 The Blood Vessels of the Iris are principally branches of the 
 Long Ciliary, which have been alluded to. Each of the two 
 J^ong Ciliary Arteries having gained the greater circumference of 
 the iris, bifurcates; the bifurcations run along this circumference, 
 meet, and join with the corresponding ones of the other arterial 
 trunk. From the circle thus formed there proceed radiated 
 branches, that run towards the pupil, and form around its mar- 
 gin, by their frequent anastomoses, a fine vascular net-work. 
 The radiated branches themselves give off collateral branches, 
 which supply the intermediate spaces of the iris.* The veins 
 of the iris are also numerous, but cannot be quite so distinctly 
 seen: they enter into the long ciliary veins, and also into the 
 vasa vorticosa. 
 
 The nerves of the Iris belong, in part, also to the choroid coat, 
 and are classed under the term Ciliary, (Nervi Ciliares.) They 
 arise from the ophthalmic ganglion, and from the trunks contri- 
 buting thereto, and are about twenty in number. They penetrate 
 the posterior part of the sclerotica obliquely, and then run for- 
 wards between it and the choroides. Having reached the pos- 
 terior part of the ciliary ligament, they penetrate it, and distri- 
 bute their filaments in its substance, after the same fashion 
 that the trigeminus nerve is divided in its glanglion. This cir- 
 cumstance has given occasion to Soemmering to consider the 
 ligament as a true ganglion, and to call it Annulus Gangliformis. 
 The nerves then get to the front of the iris, and are there dis- 
 tributed as white radiating filaments; in the course of which may 
 be observed small nodes, supposed by Meckel to be Ganglions. 
 
 The trunks of the ciliary nerves depart from the common 
 form of such bodies, by being flattened instead of cylindrical: 
 they are small, and resemble sewing threads. From their num- 
 ber, the iris is probably more abundantly supplied with nerves 
 than any other organ of the body. 
 
 * Soemmering, Icones Oculi Humani. 
 
THE BALL OF THE EYE. 421 
 
 The Retina forms the third coat of the eye, and lines the in- 
 ternal face of the choroides almost in its whole extent. The 
 optic nerve having passed through the selerotica, terminates on 
 its inner side by a bulb or button-like end, from the circumfe- 
 rence of which the retina begins to expand, and may be traced 
 satisfactorily as far as the commencement of the ciliary plaits of 
 the choroid coat, where it terminates by a straight edge, some- 
 what thickened. Just at the edge, the retina adheres to the 
 vitreous humour, and is supposed, erroneously by some anato- 
 mists, as Bichat and Monro, ta be continued on to the circum- 
 ference of the lens. Repeated dissections, and the substantial 
 testimony of Soemmering,* have satisfied me that the retina 
 cannot be fairly traced beyond the greater circumference of the 
 impressions made on the vitreous humour by the ciliary striae 
 of the Choroidea. When the eye is slightly macerated, the re- 
 tina always parts from the vitreous humour at this line; more- 
 over, when its structure is still more slightly changed by 
 freezing and then thawing, the retina manifests a decided pre- 
 ference to separate there, and, under the most careful dissec- 
 tion, it is very difficult to prevent it. In addition to these con- 
 siderations, these is a well marked change of colour at the line 
 mentioned: in front of this line, the surface is transparent when 
 cleaned from thepigmentum nigrum; whereas, if it were retina, 
 it should be the colour of ground glass, as is usual in the dead 
 body: also the veins of the retina never trespass beyond this 
 line, but are seen to cruise along it. 
 
 Most anatomists teach that the retina is an expansion of the 
 optic nerve. Bichat believed that the latter terminated at the 
 bulb, and that the retina was another part of the structure, but 
 still consisting of the same sort of nervous matter. The latter 
 opinion is probably the more strictly correct, because there is 
 more pulpy matter in a section of the retina than- can be found 
 in the same length of the optic nerve; also, if the retina were 
 simply an expansion of the nerve without any addition of mat- 
 ter to it, it should, from its hollow globular shape, be thinner 
 in the middle, where it is most expanded, than it is where the 
 expansion first begins at the bulb of the optic nerve. 
 
 * Icones Oculi Human!. 
 VOL. II. 54 
 
422 NERVOUS SYSTEM. 
 
 The retina does not adhere to the choroid coat, neither to the 
 vitreous humour which it encloses, except at the line mentioned: 
 when this line of attachment is broken, the retina quickly col- 
 lapses. 
 
 The texture of the retina is extremely soft and pulpy; in the 
 living state, it is probably perfectly transparent, but this can 
 only be conjectured from the readiness with which the vessels 
 of the choroid coat can be seen in animals destitute of pigmen- 
 tum nigrum. It is composed of two laminse, of which the ex- 
 ternal is medullary, and the internal, or that next to the vitre- 
 ous humour, is formed of a fine reticulated cellular membrane 
 with blood vessels running through it. The external lamina 
 may be removed by a camel's hair-pencil, or by slight putrefac- 
 tion and washing, so as to leave the internal entire. The cele- 
 brated John Hunter succeeded, however, in separating the two 
 laminae fairly from each other, and preserving them, so as 
 to show their difference. This specimen may be considered 
 unique, and every way deserving of the source from which it 
 proceeded.* t 
 
 Exactly in the axis of the eye, or at its centre, posteriorly, 
 consequently, about a line and a half from the outer side of the 
 bulb of the optic nerve, Soemmering discovered, in 1791, a 
 yellow spot of a line in diameter, with a small hole in its middle, 
 made by a deficiency of medullary matter. From the optic 
 nerve there goes, towards the foramen, a small-fold of the retina, 
 pointed at its internal end, and obtuse or bifurcated externally. 
 Unless the eye be fresh, these things cannot be seen distinctly, 
 for the evaporation of the aqueous humour causes a collapse or 
 wrinkling of the retina, which obscures them. But, in a per- 
 fectly fresh eye, which is well managed, they may be seen 
 both from before and behind. It was thought, for some time, 
 that the yellow spot and the foramen were peculiar attributes 
 of the human being: more extended and successful observation 
 has corrected this mistake, by detecting them in several classes 
 of animals. 
 
 In the centre of the optic nerve, where it enters the eye, is 
 
 * The fact was communicated to me by Dr. Physick, who studied under Mr. 
 Hunter, and frequently saw the preparation. 
 
THE BALL OP THE EYE. 423 
 
 a foramen for the passage of the artery and vein belonging to 
 the retina. These vessels ramify, by a few branches, on the 
 internal surface of the membrane, and form a sort of circle sur- 
 rounding the yellow spot. Neither the branches of the ar- 
 teries nor of the veins communicate with those of the cho- 
 roides; and, as observed, never go beyond what we just con- 
 sidered as the anterior margin of the 'retina, but rather run 
 along it. 
 
 Interposed between the retina and the choroides, is a most 
 delicate serous membrane, lately discovered by Mr. Jacobs, 
 Demonstrator of Anatomy in Trinity College, Dublin. By 
 preparing the retina in the usual way, and then floating the 
 eye in a saucer of water, this membrane may be turned down 
 with the handle of a knife from the optic nerve to the termi- 
 nation of the retina. It is supposed to be the seat of the ossi- 
 fications which are sometimes met with in the eye. 
 
 Humours of t he, Eyeball. 
 
 The Vitreous Humour (Humor Vitreus, Corpus Vitreum,} 
 occupies, with the exception of a very small part just behind 
 the iris, the whole of the space posterior to the latter. It is, 
 therefore, very nearly globular; is in contact the greater part 
 of its extent with the retina, at least as far as the latter mem- 
 brane proceeds; in front it is in contact with the crystalline 
 humous^ and from the margin of the retina to the circumference 
 of the lens it is in contact with the ciliary body, meaning there- 
 by the ciliary striae and processes of the choroides. 
 
 Two parts compose the vitreous humour, the hyaloid mem- 
 brane and a thin fluid. In a natural state they are perfectly 
 transparent, and, therefore, cannot be readily distinguished 
 from each other; but by immersion in spirits of wine the mem- 
 branous portion is brought to the colour of ground glass, and 
 may then be studied very advantageously. The membrane, 
 though extremely delicate, is generally strong enough to permit 
 the whole vitreous body to be suspended in the air by a thread 
 passed through it,. and it may also be momentarily held up with, 
 a pair of forceps. 
 
424 NERVOUS SYSTEM. 
 
 The Tunica Hyaloidea may be traced as a complete capsule, 
 forming the periphery of the vitreous humour; and from the 
 internal face of this capsule there proceeds a great number of 
 partitions dividing the whole cavity into cells of various mag- 
 nitudes and forms. Some anatomists, who have frozen the eye, 
 and then picked out the pieces of ice from the cells, have got 
 the idea of their being all cuneiform, and of their edges pointing 
 forwards. Our preparations in the anatomical cabinet are per- 
 fectly satisfactory in exhibiting the existence of an arrange- 
 ment of cells, but do not manifest a regular cuneiform shape in 
 them. 
 
 When the capsule of the tunica hyaloidea has got to the dis- 
 tance of two lines, or thereabouts, from the circumference of 
 the lens, it divides into two laminae, which reunite at the cir- 
 cumference of the lens. They then divide again, and one goes 
 before the capsule of the lens, and the other behind it. The 
 space between the two layers, around the circumference of the 
 lens, is the canal of Petit, and is that part of the tunica hya- 
 loidea which is impressed by the ciliary striae and ridges of the 
 choroides. At intervals, passing in a radiated manner from 
 the exterior to the interior circumference of the canal, there is 
 a sort of shortening or constriction of it, producing partial 
 septa in its cavity; so that when the canal is inflated, it seems 
 to consist of a series of small cells, arranged circularly. The 
 cells of the colon will give some idea of this arrangement, though 
 ttajy are produced in an entirely different manner. 
 
 The fluid part of the vitreous humour, by analysis, gives out 
 9S.40 water, .16 albumen, and the remainder is saline. In con- 
 sequence of the very small quantity of albumen in it, neither 
 acids nor heat coagulate it to a striking degree. 
 
 The vitreous humour is supplied with a branch from the cen- 
 tral artery of the retina. This branch does not convey red 
 blood, but only serum, except in the foetal eye. It may be in- 
 jected, at almost any age, with size, coloured with vermilion; 
 but is then, of course, put very much on the stretch. It has 
 been well described by Zinn. It penetrates the vitreous hu- 
 mour near the optic nerve, and is disseminated by very fine 
 branches on the periphery, and on the internal cellular struc- 
 ture of the tunica hyaloidea. M. J. Cloquet has described par- 
 
THE BALL OP THE EYE. 425 
 
 ticularly one branch, which, running through the centre of the 
 vitreous humour, in an appropriate canal, is spent by small ra- 
 mifications upon the posterior part of the capsule of the lens. 
 
 Some anatomists* speak of a fluid between the tunica hyaloi- 
 dea and the retina: when it does exist, it in all probability is 
 the fluid of the vitreous humour, which has strained through 
 the tunica hyaloidea after death. 
 
 The Lens (Lens Crystallind] or the Crystalline Humour, as 
 it is very generally called, is placed immediately behind the 
 pupil, in a depression on the front of the vitreous humour. Its 
 shape is that of a doubly convex lens, of which the posterior 
 convexity is greatest, being the section of a sphere whose dia- 
 meter is from four to five lines, while the anterior convexity 
 is in the proportion of a sphere of from six to nine lines. The 
 usual breadth of the lens is about three and a half lines. It, 
 however, varies its shape in a remarkable degree at the differ- 
 ent periods of life; immediately after birth it is spheroidal, in 
 about six years afterwards its lenticular shape is well marked, 
 and, subsequently, it becomes more flat and thin. 
 
 The lens naturally is perfectly transparent. In the greater 
 part of, its thickness it has the consistence of half dissolved glue, 
 but its centre is much more solid; this change, however, is ef- 
 fected successively. When it is subjected to the mineral acids, 
 to heat, to alcohol, and several other agents, it becomes much 
 more solid throughout; it may then be separated, like an onion, 
 into a series of concentric lamellae, subdivisible into longitu- 
 dinal fibres. Besides these, there are fibres more or less ob- 
 lique which hold the lamellae together. These arrangements 
 prevail from the centre to the circumference of the lens; and 
 between its laminse there is a diaphanous humour resembling 
 that between it and its capsule.t 
 
 The lens is invested by a capsule which is a complete sac, 
 having exactly its shape, but separated from it, to a very in- 
 considerable extent, by the transparent humour just alluded 
 to, called the Liquor Morgagni. The capsule is covered in 
 front by a layer of the tunica hyaloidea adhering very closely 
 
 Bichat, Anat. Descrip. f J. F. Meckel. 
 
426 NERVOUS SYSTEM. 
 
 to it, but which, in one instance, I was enabled to peel off par- 
 tially in the eye of a sheep, from one side to the other. The 
 capsule is covered, in like manner, on its posterior face by the 
 tunica hyaloidea; but the two may be separated there more ea- 
 sily, according to the observations of Bichat. Some of the 
 most distinguished continental anatomists are decidedly in fa- 
 vour of the capsule of the crystalline being a complete bag; but 
 it is rather unsettled whether the exterior margin of the capsule 
 bounds the lesser circumference of the canal of Petit, or whether 
 the two layers of the tunica hyaloidea unite previously at the 
 circumference of the capsule. The latter seems to be the opi- 
 nion of M. J. Cloquet. Dr. Physick, in some cases of mem- 
 branous cataract, has succeeded in drawing out the capsule en- 
 tire, so as to exhibit its whole extent when floated in water. 
 
 The capsule in front of the lens is much thicker than the tu- 
 nica hyaloidea, and its difference of character from the latter 
 appears to me to be very strongly marked. For, notwithstand- 
 ing its immersion in spirits of wine, it retains its transparency; 
 it is hard and elastic, and when clipped with the scissors, gives 
 nearly the same sensation as the thin paring of a finger nail 
 would; or, as has been observed by Haller, it, in this respect, 
 resembles the cornea. The analogy with the cornea ceases, 
 however, at this point: for the cornea has always so much albu- 
 minous matter in it as to be rendered turbid when it is immersed 
 in alcohol. The posterior section of the capsule of the lens, is 
 not so well marked either by its thickness or specific characters 
 as the anterior, yet our preparations in the University demon- 
 strate its existence equally as conclusively. It is more assimi- 
 lated to the nature of the tunica hyaloidea. 
 
 In the injected foetal eye, the artery of the tunica hyaloidea 
 which comes from the central one of the retina, is seen to fur- 
 nish several minute ramifications to the posterior face of the 
 lenticular capsule; some of its branches also go to the front of 
 the capsule, but the latter part is furnished principally by arte- 
 rioles from the ciliary body of the choroides. The two sets of 
 arteries anastomose with each other; some of the latter are also 
 spent upon the membrana pupillaris. 
 
 The point is yet doubtful whether any of these arteries pene- 
 trate into the body itself of the crystalline humour. Ruysch, 
 
THE BALL OF THE EYE. 427 
 
 Albinus, and Haller, assert the fact of their having seen and in- 
 jected them in the human species and in animals, and J. F. 
 Meckel admits their testimony. Yet there are not many ana- 
 tomists who can corroborate it by their personal observations. 
 It is sufficiently reasonable to admit it; for without, we cannot 
 conveniently account for the growth and nutrition of the lens, 
 as well as the morbid changes which occur in it. It should be 
 observed that if this vascular connexion do exist, it is a very 
 weak one: for the lens seems to be simply surrounded by its 
 capsule without adhering to it. 
 
 Some veins which discharge into the veins of the choroid 
 coat, have been observed by Walter* on the posterior part of 
 the capsule. It should be continually borne in mind that nei- 
 ther the arteries nor veins of the healthy crystalline, nor of its 
 capsule convey red blood: in which respect they correspond 
 with the hyaloidea; for if this were the case, vision would be 
 very much disordered by it. It may be that the moats or 
 speck seen in ophthalmia arise from the grosser particles of the 
 blood, getting into these serous vessels by the dilatation of the 
 latter. 
 
 The Lens and its Capsule are devoid of nerves, at least none 
 have been as yet traced into them. 
 
 The Aqueous Humour (Humor *flquosiis} occupies the space 
 which is between the anterior face of the crystalline capsule, 
 and the posterior face of the cornea. This space is unequally 
 divided by the iris into two chambers, of which the anterior is 
 in front of the latter membrane, and the posterior behind it. 
 In consequence of the convexity of the lens, the posterior cham- 
 ber has but very little depth just behind the pupil; but its space 
 is augmented at the circumference of the crystalline, so as to 
 leave room for the floating of the ciliary processes and for the 
 motions of the iris. The posterior chamber is,, therefore, a 
 circular vacuity ; the centre of which, from the projection of the 
 centre of the crystalline, has scarcely any appreciable depth. 
 The anterior chamber, in its shape resembles the segment of a 
 sphere: its depth depends essentially on the size and the projec- 
 tion of the cornea. 
 
 * De Oculis. Berlin, 1778. 
 
428 NERVOUS SYSTEM. 
 
 The aqueous humour is perfectly transparent, and almost as 
 fluid as water. The analysis of Berzelius exhibits 98 parts of 
 water, 1 of hydrochlorate and lactate of lime, .75 of some ani- 
 mal matter soluble in water, and a very small quantity of albu- 
 men. From the latter circumstance it will be understood how 
 this fluid refuses to coagulate on the addition of alcohol or of 
 mineral acids to it, and is only rendered in a very slight de- 
 gree turbid by them. The rapidity of the exhalation of this 
 fluid is remarkable; when the whole of it is lost in the opera- 
 tion for cataract, it is regenerated in from twenty-four to thirty- 
 six hours. Its source has been sought for in supposititious canals 
 and glands, but the more probable opinion is, that it may come 
 from any or all of the exhalent arteries of the chambers of the 
 eye. 
 
 Like the other two humours of the Eye, the aqueous is fur- 
 nished with a capsule, but whether it is complete or not is yet 
 undetermined. By immersing the eye in hot water, or in al- 
 cohol, this capsule may be readily detected on the posterior face 
 of the cornea, and to the greater circumference of the iris; it 
 may even be traced for some distance on the front surface of 
 Che latter. Some of the French anatomists, as Demours,* De- 
 scemet, and J. Cloquet, have asserted that it continued also 
 through the pupil to line the posterior chamber. An opinion 
 like this, from the extreme tenuity of .the part, must be rather 
 the result of conjecture than of accurate observation; it has, 
 therefore, never found its way with full force into the writings 
 of anatomists. The condition of the pigmentum nigrum on the 
 posterior face of the iris, and on the ciliary processes, would 
 seem to be an objection to the existence of this capsule in the 
 posterior chamber of the eye. But if it really does exist there, 
 as is pretended by M. Portal, who supposes it to be derived 
 from the tunica hyaloidea, its structure is incomparably more 
 delicate than that part on the cornea, and, indeed, is merely 
 glutinous. 
 
 The Chambers of the Eye, till the seventh month of foetal 
 existence, and sometimes later, are perfectly separated from 
 each other by the Membrana Pupillaris, called so from,its po- 
 
 Demours, Lettre, 1767. 
 
THE BALL OF THE EYE. 429 
 
 sition in the pupil of the iris. It was discovered in 1740, by 
 Wachendorf, and is sometimes called after his name. It is 
 a thin, delicate, and transparent membrane, which is stretched 
 across the pupil from its circular margin, and may, by its co- 
 lour, be readily distinguished from the iris, when it has been 
 made somewhat turbid by alcohol. 
 
 The Membrana Pupillaris consists, according to M. J. Clo- 
 qu*et,* of two laminae placed back to back, of which the fore- 
 most is a continuation of the membrane which lines the ante- 
 rior chamber of the eye, and the hindmost of that which lines 
 the posterior chamber. According to this, it may be noted 
 that each chamber has its distinct capsule. This membrane is 
 very vascular; some of its arteries are those which subsequently 
 form the internal arterial circle of the iris, and they radiate from 
 the circumference to the centre of the membrane; others come 
 directly from the long ciliary arteries, and others again from 
 the arteries of the crystalline capsule. These several vessels 
 are found principally on its posterior face. Its veins have not 
 not been observed. 
 
 This membrane first shows itself about the third month of 
 foetal existence, and is most perfect at the seventh; from the 
 latter period it begins to decline, by disappearing from the cen- 
 tre to the circumference. At the ninth month it consists only 
 in a few loose flocculent masses adhering to the pupil. M. J. 
 Cloquet has ascertained that its vessels do not participate in its 
 destruction, but that the arches which they form are retracted 
 to the margin of the pupil, and there form the lesser arterial 
 circle of the iris. From the observations of Drs. Jacob and 
 Tiedemann, it appears that traces of the membrana pupillarls 
 exist for ten or fifteen days after birth. The latter, in one case, 
 injected its vessels in a foetus at full term.t 
 
 * Journal Universelle cles Sc. Med. Paris, 1818. Mem. sur la Memb. Pupill, 
 Paris, 1818. 
 
 j; Am. Med. Jour. vol. i. p_ 192. 
 
 VOL. II. 55. 
 
430 NERVOUS SYSTEM. 
 
 CHAPTER III. 
 
 OF THE EAR. 
 
 THE ear, the organ of hearing, is placed principally within 
 the petrous portion of the temporal bone, and consists in the Ex- 
 ternal Ear, the Tympanum, and the Labyrinth. 
 
 SECT. I. OF THE EXTERNAL EAR. 
 
 The position of this portion of the organ is familiar to every 
 one. It is useful in collecting the rays of sound, and in convey- 
 ing them to the more internal parts. It is formed by the struc- 
 ture, exterior to the petrous bone, called, in common language, 
 the Ear; and by a bony canal which leads internally to the tym- 
 panum. The basis of the first portion is cartilaginous, on which 
 circumstance it depends for the permanency of its shape. 
 
 The ear, of common language, is divided into two parts, Pin- 
 na* and Lobus: the former is the most extensive, as it compre- 
 hends all the cartilaginous portion : the latter is attached to the 
 inferior margin of the former, and, having no cartilage in its 
 composition, is soft and pendulous. 
 
 In the centre of the external ear is a deep depression called 
 the Concha ; in the bottom of it is the orifice of the canal lead- 
 ing to the tympanum, and called Meatus Auditorius Externus. 
 The circumference of the pinna is convoluted into a scroll called 
 the Helix, and commences just above the meatus by a ridge. 
 This ridge divides the concha into two unequal cavities, of which 
 the lower is the larger. The scroll becomes gradually less pro- 
 minent, till it terminates at the posterior inferior part of the pin- 
 na, in the lobus. 
 
 The Antihelix is the slightly curved and vertical eminence in 
 
 * From some resemblance to a certain shell fish. 
 
THE EXTERNAL EAR* 431 
 
 the middle of the pinna; its lower part forms the posterior boun- 
 dary of the concha, and its upper part bifurcates into two small 
 ridges, between which there is a depression called the Scapha. 
 Between the antihelix and the posterior half of the helix, is an 
 oblong depression called the Fossa Innominata. 
 
 The Tragus is a cartilaginous elevation of the pinna placed in 
 front of the concha, and inclining somewhat over it ; opposite to 
 it, at the inferior part of the concha, is the Antitragus. 
 
 The cartilaginous plate upon which the external ear depends 
 for its shape is of a thickness very nearly uniform ; of course, the 
 ridges and depressions on its exterior surface have correspond- 
 ing depressions and ridges on the side next to the head. It is 
 interrupted at several places by fissures ; for example, there is 
 one of considerable size filled up with ligamentous matter, which 
 separates the upper margin of the tragus from the beginning of 
 the helix : there is another between the lower extremity of the 
 antihelix and the antitragus. In the tragus, there are two and 
 sometimes three small narrow ones, said, by Santorini, to be 
 filled with muscular fibres; but the latter assertion does not cor- 
 respond with the observations of subsequent anatomists, as the 
 matter appears fibrous. 
 
 The external ear is united to the side of the head by three 
 ligaments. The anterior arises from the root of the zygomatic 
 process above the articulation of the lower jaw, and is inserted 
 into the pointed production of cartilage on the fore part of the 
 helix. The posterior arises from the swell of the temporal bone, 
 which runs into the front margin of the base of the mastoid pro- 
 cess, and is inserted into the convex side of the concha, at the 
 beginning of the meatus auditorius. The superior arises from the 
 temporal aponeurosis, and is inserted into the upper part of the 
 concha. These ligaments lie immediately below the muscles 
 destined to move the ear. 
 
 The Meatus Auditorius Externus, is, in the adult, an inch in 
 length, reckoning from its external orifice to the membrane of 
 the tympanum, which closes it inwardly. It is about three lines 
 in diameter, is rather oval than cylindrical, and somewhat smaller 
 in the middle than at either of its extremities. It runs inwards, 
 
432 NERVOUS SYSTEM. 
 
 with a slight inclination forwards ; the exterior half is formed by 
 the cartilage of the pinna, and the internal half by the temporal 
 bone : it departs from the horizontal course, in being curved at 
 its middle where the two sections join. This curvature has its 
 convexity upwards, so that when we wish to look to the bottom 
 of the canal, the external ear must be pulled upwards and back- 
 wards. 
 
 The cartilaginous portion of the meatus auditorius, is formed 
 by a triangular piece springing from the base of the tragus and 
 from the inferior anterior part of the concha. This portion 
 is nearly a tube, but is interrupted above and behind by the in- 
 tervention of a dense fibrous tissue, continuous with, arid indeed 
 the same with that which joins the helix and the tragus. The 
 internal margin of the cartilaginous meatus forms a point below ; 
 and adheres by ligament very closely to the asperities on the 
 margin of the bony meatus. If there were no fissures in the ex- 
 ternal ear, it would, therefore, be almost immoveable. 
 
 The skin covering the external ear, is more delicate than in 
 most other parts of the surface of the body. Its sebaceous 
 glands or follicles are very abundant, and in infants secrete free- 
 ly their peculiar fluid. When a slight inflammation occurs, this 
 discharge is frequently purulent without erosion. A duplication 
 of the skin, containing a delicate granulated adeps with some 
 fibrous matter, constitutes the lobe of the ear. 
 
 The skin, after lining the concha, descends into the meatus 
 auditorius, and lines it also as well as the external face of the 
 membrane of the tympanum. It adheres moderately to the 
 cartilaginous part of the tube, and more tenaciously to its fibrous 
 portions: between it and the latter, are found many small reddish 
 bodies, generally oval, the Glandulse Ceruminosae,* from which 
 proceeds the earwax. , The skin is extremely thin in the bony 
 meatus, adheres closely to its periosteum, and is highly sensible : 
 where it forms the exterior layer of the membrane of the tym- 
 panum, it may be detached from the latter with the slightest 
 force, and seems to be converted almost entirely into cuticle. 
 
 % 
 
 * Duvcrney, (Euvres Anatoroiqites. 
 
THE EXTERNAL EAR. 433 
 
 A slight maceration or incipient putrefaction frequently enables 
 one to draw the cuticle out entire from the meatus, so that it 
 looks in shape like the finger of a small glove. 
 
 The dermoid lining of the meatus is studded with fine hairs, 
 which serve to keep out small bodies that may be floating in the 
 air. A considerable number of small pores are also seen in it, 
 which are the orifices of the ducts of the ceruminous glands. 
 The discharge of the latter, when first secreted, is thin and 
 white : by evaporation, it becomes thick and yellow, and by ac- 
 cumulating obstructs the passage. 
 
 There are several small muscles situated on the external ear, 
 which are for the most part so feebly developed that they cannot 
 always be found, and when they do exist they seem more like 
 the rudiments of what is well marked in animals, than intended 
 for a special purpose in the human body. 
 
 1. The Helicis Major is an oblong fasciculus, situated on the 
 front of the helix. By its lower end it is attached to the point 
 of cartilage on the front of the helix, and its other extremity ex- 
 tends to the top of the latter. 
 
 2. The Helicis Minor is a small square fasciculus, also on the 
 front of the helix, between the folded margin of the latter and 
 the inferior half of the helieis major. 
 
 3. The Tragicus is a square fasciculus, on the front surface of 
 the tragus, near its margin : its upper extremity sometimes runs 
 into the helieis major. 
 
 4. The Antitragicus is a small oblong fasciculus, which 
 arises from the upper extremity of the antitragus, and going 
 upwards it is inserted into the inferior extremity of the anti- 
 helix. 
 
 5. The Transversus Auriculae is on the internal surface of the 
 pinna. It arises from the prominence of the concha, and is in- 
 serted into the hollow dorsum of the antihelix. 
 
434 NERVOUS SYSTEM. 
 
 There are some other muscles which may be uniformly found 
 and are intended to move the external ear upon the side of the 
 head, though from the want of exercise there are very few in- 
 dividuals capable of making them contract. They are as fol- 
 low: 
 
 1. The Attollens Auriculae is placed on the side of the head 
 beneath the integuments : it is a broad, thin, and somewhat tri- 
 angular muscle, which arises from the inferior margin of the 
 tendon of the occipito-frontalis, and from the temporal aponeu- 
 rosis. It becomes narrower in its descent, and is inserted ten- 
 dinous into the upper end of the pinna by the elevation corre- 
 sponding with the scapha. 
 
 Its name implies its action to be that of raising the pinna. 
 
 2. The Retrahens Auriculae, consists in two or three oblong 
 fasciculi, placed parallel, and one above the other. It arises 
 from the mastoid portion of the temporal bone, above the mas- 
 toid process, and is inserted tendinous into the convex side of 
 the concha near the meatus auditorius. 
 
 It draws the pinna backwards. 
 
 3. The Anterior Auriculae is a small quadrangular slip, just 
 above the root of the zygomatic process. It arises from the 
 temporal fascia, and is inserted tendinous into the fore part of 
 the helix just above its beginning. 
 
 It draws the pinna forwards and upwards. 
 
 SECT. II. OF THE TYMPANUM. 
 
 The Tympanum is the middle portion of the organ Of hear- 
 ing, being interposed between the meatus' auditorius and the 
 labyrinth. Its depth is about three lines, its antero-posterior di- 
 ameter about six, and its vertical diameter rather more, though 
 from the general inequality of the cavity, and its communication 
 with adjoining cavities, it is not easy to fix upon very precise 
 measurements. 
 
THE TYMPANUM. 435 
 
 The Membrana Tympani, is a complete membranous septum, 
 interposed between the meatus externus and the tympanum. It 
 is placed very obliquely, so that its upper edge inclines outwards, 
 and its under edge inwards ; the latter, therefore, forms a very 
 acute entering angle with the inferior part or floor of the meatus, 
 and gives to that portion of the meatus an additional length, 
 which renders it difficult to see to its bottom. The membrane 
 of the tympanum is nearly circular, and has its circumference 
 adhering very closely to the external orifice of the tympanum. 
 It is slightly tense, and has its middle drawn inwards by being 
 attached to the handle of the malleus. 
 
 The membrana tympani consists of four laminae ; the two ex- 
 terior of which, being the cuticle and the cutis vera, which line 
 the meatus auditorius, are easily detached, as mentioned before, 
 and seem scarcely to adhere to the layer below. The third layer 
 is the proper membrane, and is distinguished by its dryness and 
 by its transparency. Sir Everard Home was enabled to de- 
 tect radiated muscular fibres, forming it in the elephant.* In 
 the human subject, its fibrous character is best seen on its inter- 
 nal face, but the radiated arrangement is not so distinct. Cal- 
 dani considers it as formed by filaments, decussating each other 
 at right angles, and intermixed with blood vessels.t The inter- 
 nal layer is a continuation of the lining membrane of the tym- 
 panum; it is separated with some difficulty, owing to its tenuity. 
 
 The proper membrane of the tympanum, when successfully 
 injected, exhibits a high degree of vascularity ;J though, in its 
 natural state, but very few red blood vessels are seen in it. 
 
 The floor of the tympanum, or the side next to the labyrinth, 
 presents an unequal surface. In its middle is a well marked 
 rising, the Promontory, (Promontoriumj) formed by one end of 
 the labyrinth. Just above the superior margin of this promi- 
 nence, near its centre, is an oval opening, called, from its shape, 
 Foramen Ovale, or Fenestra Ovalis; having its long diameter 
 horizontal, its superior margin rounded or concave, and its infe- 
 rior straight. At the posterior inferior part of the promontory 
 
 * Philosophical Transactions, for 1800. London. 
 
 f Plate XCVII1,. Anat. 
 
 $ Ruyschii, Epist. Anat. Probl. viii. Anatomical Museum. 
 
436 NERVOUS SYSTEM. 
 
 is another opening, which, though somewhat triangular, is called 
 the Foramen Rotundum, or Fenestra Rotunda, and in the dried 
 bone leads to the cochlea, but is naturally stopped by the lining 
 membrane of the tympanum. According to M. Ribes, this 
 membranous plug has also two other layers, an internal one, the 
 continuation of what lines the cochlea, and a middle one, which 
 is peculiar. In these respects, there is a correspondence with 
 the membrana tympani. 
 
 The Eminentia Pyramidalis is a small conical eminence pro- 
 jecting from the posterior part of the tympanum, on a line with 
 the fenestra ovalis. It is hollow, contains a muscle, and com- 
 municates at the other end with the Canal of Fallopius. Lower 
 down, and more externally, there is a small orifice, (Apertura 
 Chorda,} through which the nerve called Chorda Tympani 
 
 The Mastoid Portion of the Temporal bone, in the adult, 
 abounds in large cells or sinuses, which communicate freely 
 with one another. They are distinct from the diploic structure 
 of the bone, as they contain no meditullium, and are lined by a 
 continuation of the internal membrane of the tympanum, which 
 is extremely thin upon them. The orifice of communication be- 
 tween these cells and the tympanum, is placed at the superior 
 posterior part of the latter : it is rough and irregular, and par- 
 tially occupied by the short leg of the incus. Just in front of 
 this opening, the cavity of the tympanum is extended vertically, 
 for the purpose of accommodating the body of the malleus and 
 of the incus, whereby they are in a great degree concealed, 
 unless the corresponding margin of the tympanum be cut away. 
 
 At the fore part of the tympanum is the Eustachian Tube, 
 which runs for six or eight lines in the substance of the petrous 
 bone, near its exterior margin ; and then terminates in a carti- 
 laginous and membranous portion, which communicates with 
 the pharynx at the posterior naris. The latter extremity of the 
 Eustachian Tube is placed on a line with the posterior end of 
 the inferior spongy bone. Its orifice is rounded or oval, is large 
 enough to admit the tip of the little finger, and reposes against 
 
THE TYMPANUM. 437 
 
 the side of the internal pterygoid process of the sphenoid bone. 
 Though almost within the precincts of the posterior naris, this 
 orifice is to be considered as opening into the pharynx. 
 
 This canal, in its whole length, measures nearly two inches, 
 and, with the exception of the portion in the petrous bone, is 
 cartilaginous and membranous. The cartilage is a single, thick, 
 triangular plate, flat, and adhering by one of its edges to the 
 pterygoid process. The under part of the tube is membranous, 
 thin, and affords attachment to some of the muscles of the soft 
 palate. Its course is nearly horizontally, backward and out- 
 ward. 
 
 It is lined in its whole extent, by a very fine mucous mem- 
 brane continuous with that of the pharynx and of the tympanum. 
 This membrane is thickened at its anterior extremity by the 
 mucous glands beneath it, which assist in giving the marked 
 elevation to its orifice. The canal diminishes as it goes back- 
 ward, so as to receive with difficulty a small probe. 
 
 Parallel with the bony part of this canal, but above it, and se- 
 parated by a very thin partition of bone, is another canal which 
 lodges a muscle of the malleus. On the outer side of the Eusta- 
 chian tube is the glenoid foramen, by which, in the dried bone, 
 the tympanum communicates with the glenoid cavity ; in the re- 
 cent state the foramen receives the long process of the malleus 
 and its^muscle, and transmits the chorda tympani. 
 
 There are four bones in the tympanum, which, being succes- 
 sively articulated with each other, form a chain, one end of 
 which is fastened to the membrana tympani, and the other end 
 rests upon the foramen ovale. They are the Malleus ; the Incus; 
 -the Orbiculare ; and the Stapes. 
 
 The Malleus forms the fore part of the chain, and is placed 
 almost vertically. Its superior extremity is the head, which is 
 rounded, with the exception of the posterior face, where a small 
 concavo-convex surface is observable, for its articulation with 
 the incus. Its lower extremity is long and tapering, inclines in- 
 wardly, terminates by a little knob, and forms an angle with the 
 part above ; this portion is the manubrium, and adheres its whole 
 
 VOL. II. 56 
 
438 NEKVOUS SYSTEM. 
 
 length to the membrana tympani, commencing at the superior 
 margin of the latter, and insinuating itself between the internal 
 and the proper layer, as far as the centre of the membrane. It 
 is this adhesion with the inclination inwards of the manubrium, 
 that causes the membrane to be depressed in its centre. 
 
 Between the head and the manubrium is a short portion called 
 the neck. From the superior external extremity of the manu- 
 forium there proceeds outwardly the short process, (Processus 
 Brevis;) and from the front of the neck, there proceeds the long 
 and very delicate process, concave externally and convex inter- 
 nally, which is insinuated into the glenoid foramen, and is the 
 Processus Longus, or Gracilis. 
 
 The Incus is behind the malleus, and is also upright. It con- 
 sists in a body and two branches, which diverge very conside- 
 rably, and has a general resemblance to a molar tooth. The 
 loody presents, on its fore part, a deep concavity, which articu- 
 lates with the convex head of the malleus. The branch which 
 arises from the back part of the body is horizontal, looks into 
 the orifice of the mastoid cells, and is much shorter than the 
 other. The inferior branch is long, upright, tapering, and near- 
 ly parallel with the manubrium of the malleus, but somewhat 
 within it. 
 
 The Orbiculare is a very small flattened sphere of bone, which 
 articulates with the lower end of the long process of the incus, 
 and in adult life is most generally fused into it, so as to lose its 
 distinctive character: the latter change sometimes occurs even 
 in early infancy. 
 
 The Stapes is the last of the chain. It resembles very strong- 
 ly the common stirrup iron, from whence its name, and is placed 
 horizontally at right angles to the incus, being separated from 
 the extremity of the long process of the latter by the os orbicu- 
 lare, and being directed inwards to the foramen ovale. It is 
 composed of a head, two crura, and a base. 
 
 The head is oblong and flattened : it has a slight depression 
 where it joins the orbiculare. The crura are slightly curved, 
 with the concavities towards each other : the anterior is some- 
 
THE TYMPANUM. 439 
 
 what straighter than the posterior, and is also shorter. They 
 are both excavated, longitudinally, on their concave surfaces, 
 and between them is stretched a process of the lining membrane 
 of the tympanum. The base is precisely adapted to the fenestra 
 ovalis, and is connected to it by the lining membrane of the 
 tympanum, but not so closely as to prevent it from executing 
 slight vibratory movements. 
 
 Between the malleus and the incus there is a moveable arti- 
 culation with a syriovial membrane, but the other joints of the 
 chain are simply ligamentous. - 
 
 This chain of bones is moved by several muscles, which in- 
 fluence the degree of tension of the membrana tympani. 
 
 1. The Laxator Tympani arises from the posterior end of the 
 spinous process of the sphenoid bone, and passing behind the 
 articulation of the lower jaw into the glenoid foramen, is in- 
 serted, tendinous, along the processus g^acilis of the malleus. 
 
 It draws the malleus forwards and outwards, so as to relax 
 the membrana tympani. 
 
 2. The Tensor Tyrnpani is placed in the canal just above the 
 Eustachian tube. It arises from the posterior extremity of the 
 cartilaginous portion of the latter, and having got into the tym- 
 panum, is changed into a small tendon, which, going outwardly, 
 is inserted into the neck of the malleus, just below its processus 
 gracilis. 
 
 It draws the malleus inwardly; consequently makes tense 
 the membrana tympani, and drives the stapes intp the fenestra 
 ovalis. 
 
 3. The Stapedius arises from the bottom of the cavity in the 
 pyramid, and terminates in a small round tendon, which, going 
 through the apex of the latter, is inserted into the head of the 
 stapes. 
 
 It draws the stapes backwards, and perhaps fixes it more 
 firmly by its contractions. 
 
 4. There is a fourth muscle mentioned by anatomists, the ex- 
 
440 NERVOUS SYSTEM. 
 
 istence of which is more equivocal ; it is called the Laxator 
 Tympani Minor. It arises from the superior margin of the ori- 
 fice of the tympanum, and is inserted into the processus brevis 
 of the malleus. It is by some considered only as a ligament, to 
 which opinion I am inclined. 
 
 Of the Lining Membrane of the Tympanum. 
 
 This membrane is a continuation of the lining membrane of 
 the pharynx, being introduced into the tympanum through the 
 Eustachian tube. It covers completely the surface of the tym- 
 panum, and is reflected over its little bones so as to give them a 
 covering also : in addition to which, it lines such of the mastoid 
 cells as communicate with the tympanum. 
 
 This membrane is extremely delicate : on its surface, adja- 
 cent to the bones, it is somewhat fibrous, and thereby resembles 
 periosteum ; but the other surface has the characters of the mu- 
 cous membranes generally, in the nature of its secretion, and in 
 its vascularity, which is very strongly marked in inflammations, 
 and by fine injections. Bichat mentions, that in certain catar- 
 rhal affections its mucous secretion is so abundant as to fill the 
 whole cavity of the tympanum, and that without ulceration. 
 Sometimes, in such cases, the membrane of the tympanum is 
 ruptured, and the discharge finds its way out through the mea- 
 tus externus, presenting itself under a purulent form, as if an 
 abscess had formed in the ear. 
 
 SECT. III. OF THE LABYRINTH.* 
 
 The Labyrinth (Labyrinthus) is placed on the inner side of 
 the tympanum, in the thickness of the petrous bone. Its ex- 
 terior parietes are bone, but internally there is a membranous 
 structure, having, in many respects, the same shape. It is got 
 at with great difficulty in the adult, owing to the compactness 
 of the petrous bone which envelops it ; but in the foetus of the 
 full period, where it is almost as large as in the adult, the sur- 
 rounding bone is of a softer and more spongy texture, and may 
 be pared away with a pen-knife without much trouble. In the 
 
 * Antonio Scarpa, Disquisit. de Auditu et Olfacto. 
 
THE LABYRINTH. 441 
 
 latter case, the parietes of the bony labyrinth remain about 
 the thickness of an egg-shell, and have very much the same de- 
 gree of consistency and strength. 
 
 The bony labyrinth consists of three portions: the Vestibu- 
 lum, the Semicircular Canals, and the Cochlea. 
 
 The Vestibulum is the cavity to which the foramen ovale 
 leads; it, with the cochlea, occasions the protuberance into the 
 tympanum, known as the promontory. It is an irregular round- 
 ed excavation, the surface of which is impressed by its contents; 
 thus, at the superior posterior and external part, next to the 
 semicircular canals, there is a superficial Fossa, called, from its 
 shape, Semi-Elliptica, and at its anterior and inferior part, nearer 
 the cochlea, another, called Fossa Hemi-spherica. These fossae 
 are marked off from each other by a ridge of bone, at the lower 
 end of which there is a third fossa between the other two, called, 
 by Soemmering, Cavitas Sulciformis. 
 
 There are seven orifices belonging to the vestibulum besides 
 the foramen ovale; five at its posterior part leading into the se- 
 micircular canals; one anteriorly leading into the upper scala of 
 the cochlea: and the last placed in its internal paries is the aque- 
 duct of the vestibule. In addition to these orifices, the parietes 
 of this cavity are cribriform in the fossa semi-elliptica and near 
 the foramen rotundum.* 
 
 The Semicircular Canals (Canales Semicirculares) are at the- 
 posterior extremity of the vestibulum. They are three in num- 
 ber, and are named from their relative situation, Superior or An- 
 terior, Posterior or Inferior, and External. Each one forms 
 rather more than the half of a semicircle, and has its cavity,, 
 about half a line in diameter: their orifices are somewhat dilated 
 beyond this measurement. The apparent thickness of their pa- 
 rietes is greater in the adult than in the infant. 
 
 The Superior Canal runs from without inwards and backwards* 
 Its anterior orifice is above the fenestra ovalis, and is enlarged 
 into an ampulla or elliptical cavity. At its posterior extremity,, 
 
 * Ant. Scarpa, loc. cit. 
 
442 NERVOUS SYSTEM. 
 
 it joins the upper extremity of the inferior canal, so that a com- 
 mon trunk is thus formed, the orifice of which is at the internal 
 posterior part of the vestibulum. and is dilated into the shape of 
 a funnel.* 
 
 The Posterior or Inferior Canal is nearly vertical; has its 
 concavity in front, and its convexity behind, and joins, as just 
 remarked, with the superior; its inferior orifice, which is near 
 the foramen rotundum, is also enlarged into an ampulla or ellip- 
 tical cavity. It is the longest of the three canals, and has its 
 branches nearer together. 
 
 The External Canal is nearly horizontal, and is placed in the 
 space left by the divergence of the other two. It is the shortest 
 and the largest of the three. Its exterior orifice is also enlarged 
 into an ampulla or elliptical cavity, and is just behind the fora- 
 men ovale, or below the ampulla of the upper canal; the inter- 
 nal orifice is below the common opening of the other two ca- 
 nals. 
 
 It is the union of the superior and of the posterior canals at 
 one of their extremities, which reduces the number of openings 
 into the vestibulum, from the semicircular canals to five instead 
 of six. 
 
 The Cochlea forms the fore part of the labyrinth, and resem- 
 bles very strongly the shell of the common snail. Its base is 
 the bottom of the meatus auditorius interims, and its apex,.is di- 
 rected towards the cavity of the tympanum, so that the axis of 
 the cochlea is turned downwards and outwards. It consists in 
 a conoidal tube wound spirally twice and a half around a co- 
 lumn of bone termed the Modiolus. The tube then of course 
 diminishes in size from the base to the apex of the cochlea. 
 
 This conical tube is divided in its length by a plate called 
 Lamina Spiralis. Of the two compartments thus formed, one 
 is above the other. The inferior is the larger, and communi- 
 cates at its base, through the foramen rotundum, with the tym- 
 panum; it is, therefore, called Scala Tympani. The other com- 
 partment communicates at its base with the vestibulum, and is, 
 therefore, called Scala Vestibuli. 
 
 * Scarpa, loc. cit. 
 
THE LABYRINTH. 443 
 
 The Mocliolus is of a conical shape and cribriform: one 
 canal, larger than the others, runs from its base to its sum- 
 mit. This canal is surrounded by many others, which dimi- 
 nish successively as they advance towards the apex, and ter- 
 minate in orifices upon the lamina spiralis. This cribriform 
 arrangement of the modiolus is the Tractus Spiralis Foraminu- 
 losus. The base of the modiolus is towards the meatus audi- 
 torius internus, and its point does not go to the apex of the 
 cochlea, but stops short of it, and is expanded into a cavity 
 called the infundibulum, the base of which is towards the apex 
 of the cochlea. That portion of the apex of the cochlea which 
 covers over the infundibulum, is the Cupola. 
 
 It was just mentioned that the lamina spiralis divides the 
 cochlea into two tubes; the septum thus formed, does not, how- 
 ever, run their whole length, for it ceases in the infundibulum 
 by a small crooked process of bone, called the Hamulus Coch- 
 lea. The lamina, when examined by strong glasses, is seen 
 to consist of four distinct structures called its Zones. 1. The 
 Zona Ossea is next to the modiolus, and is composed of two 
 bony laminae, with an intermediate diploic structure, in which 
 are the canals for transmitting the filaments of the portio mollis 
 or auditory nerve. 2. The Zona Coriacea, on the outer side 
 of this, the structure of which is cartilaginous. 3. The Zona 
 Vesicularis, said to contain in its cells a pellucid fluid. 4. The 
 Zona Membranacea, which is probably only the lining mem- 
 brane of the cochlea, and completes the lamina spiralis on its 
 edge next to the periphery of the cochlea. Some very re- 
 spectable anatomists pass over this minute distinction in the 
 structure of the septum, and merely divide it into Zona Ossea, 
 and into Zona Mollis. 
 
 Of the Membranous Labyrinth. 
 
 The whole internal face of the bony Labyrinth is lined by 
 a very delicate and vascular membrane, which is more, distinct 
 during the early periods of intra uterine life. Besides this, 
 there is a membranous labyrinth, consisting in three semicir- 
 cular canals, nearly filling up the cavities, and having the same 
 - shape and general arrangement of the bony canals; and in two 
 sacs contained in the vestibule. 
 
444 NERVOUS SYSTEM. 
 
 The Semicircular Membranous Canals have also at their 
 ends the elliptical enlargements called ampulla?; they termi- 
 nate by both extremities in the sac of the superior part of the 
 vestibule. This sac is generally called, from its shape, Sac- 
 culus Ellipticus; and by Scarpa, from its function, the Alveus 
 Communis. In front of the Sacculus Ellipticus, nearer the 
 cochlea, and opposite the foramen ovale, is the Sacculus Sphe- 
 ricus; it is a complete bag, having no communication with the 
 other, or with the membranous canals. Both of the sacs adhere 
 to the vestibulum at their posterior parietes. 
 
 The sacs of the vestibule and the membranous semicircular 
 canals are filled with a very fluid transparent liquid. Accord- 
 ing to the observations of M. Ribes, it is not necessary to the 
 function of hearing that this fluid should be so abundant as to 
 distend the membranous labyrinth, inasmuch as in his dissec- 
 tions he met with individuals in whom the latter was only half 
 filled, and yet they had heard very well. He also met with 
 similar cases in which the fluid was abundant in the vestibulum, 
 but deficient in the canals, and the reverse. Corresponding 
 observations have been made by M. Brugnone, of Turin,* where 
 lie had adopted the precaution of previously freezing the bone, 
 so that none of the fluid could be said to have been lost by ac- 
 cident. From the frequency with which this deficiency was 
 observed, his opinion seems to be well founded, that it is the 
 most natural state of the labyrinth. 
 
 The parietes of the membranous labyrinth are very thin and 
 transparent; there is a very loose cellular tissue between them 
 and the bone, and they are susceptible of being highly coloured 
 'by injection. 
 
 A fluid of the same character with the preceding also fills the 
 scalse of the cochlea, and extends itself into the bony vestibu- 
 lum and the bony semicircular canals upon the outer surface of 
 the membranous labyrinth. 
 
 Mem. de Turin, 18051808. 
 
LABYRINTH. 445 
 
 Of the Aqueducts of the Ear. 
 
 The Aqueducts (rfqusednctus] of Cotunnius, as they are 
 tailed, are two small canals which go through the petrous bone 
 from the labyrinth. There is one for the vestibule, and ano- 
 ther for the cochlea. 
 
 The Aqueduct of the Vestibulum, commences in the latter 
 cavity, somewhat in advance of the common orifice of the two 
 semicircular canals; it goes inwards and opens on the posterior 
 face of the petrous bone, behind the meatus internus. It en- 
 larges gradually in its course, which causes it to have somewhat 
 of a triangular shape, and it is lined by a continuation of the 
 dura mater. It is about four lines long. 
 
 The Aqueduct of the Cochlea commences in the Scala Tym- 
 pani, near the foramen rotundum, and, enlarging in its course, 
 terminates on the under surface of the petrous bone, in the in- 
 ternal margin of the jugular fossa, at the root of the little 
 spine which separates the eighth pair of nerves from the jugu- 
 lar vein. 
 
 The anatomist* from whom these canals were named, and 
 who first described them, was under an impression that the fluid 
 of the labyrinth always filled it completely; and that without a 
 sort of waste gate for it on an occasion, the vibration of the 
 stapes would be prevented from putting it in motion, conse- 
 quently, hearing must cease. These canals, the existence of 
 which is sufficiently obvious in many subjects, were, therefore, 
 considered by him as the desired avenues for the discharge of 
 the superabundant fluid, and his theory and descriptions were 
 very generally adopted. Of late years, the investigation of this 
 subject has been renewed by MM. Ribes and Brugnone, and 
 their observations are considered by the French anatomists, to 
 have proved conclusively, the error into which Cotunnius and 
 others have fallen. 
 
 In regard to the aqueduct of the vestibule, M. Ribes has found 
 it only in three instances emptying into the vestibule; for most 
 
 * Dominici Cotunnii, Anat. Dissert, de Aquzeduct. Naples, 176L 
 VOL. II. 57 
 
446 NERVOUS SYSTEM. 
 
 commonly it leads, after a course somewhat tortuous, into the 
 spongy structure of the petrous bone, at the posterior part of 
 the vestibule, and smaller canals diverge from it in different di- 
 rections. In the cases where it was connected with the laby- 
 rinth, it was so by several orifices leading into the vestibule, 
 and into the posterior semicircular canal. He has not found 
 this canal in the foetus nor till some time after birth, and from 
 his injections he believes that, in all cases, it and its branches 
 are only intended to convey blood vessels throughout the pe- 
 trous bone and to the labyrinth. 
 
 In regard to the supposed aqueduct of the cochlea, M. Ribes has 
 also found it diverging into collateral branches, and occupied 
 by blood vessels, which are distributed to the spongy structure 
 of the petrous bone, and to the tympanum. 
 
 In my own researches on this point, on the dried bones, the 
 canals, as described by Cotunnius, were closed at the labyrinth, 
 in the case of subjects advanced in life; but, in the middle aged, 
 and in infantile specimens, I have been more successful in 
 tracing them fairly into the labyrinth, and have the prepara- 
 tions in the Wistar Museum. At the same time, I think it 
 much more probable that they only contained blood vessels, 
 and that Cotunnius was in error. Besides these vascular ca- 
 nals, M. Ribes has described some others having the same 
 use. 
 
 SECT. IV. OF THE NERVES OP THE ORGANS OF HEARING. 
 
 The Nerves which pass through the petrous bone, and are 
 either wholly or partially spent upon the organ of hearing, come 
 from three sources. 1. The Auditory Nerve; 2. The Portio 
 Dura; 3. The Trigeminus, or Fifth Pair. 
 
 The Meatus Auditorius Internus conducts the two first, and 
 has its bottom divided by a ridge into two fossae, of which the 
 upper one is the smaller. This bottom, it has been observed, cor- 
 responds with the base of the modiolus, and is cribriform. One 
 foramen, larger than any of the others, and in the superior fossa, 
 transmits the portio dura or facial nerve: all the others are oc- 
 cupied by the filaments of the auditory nerve. 
 
NERVES OF THE ORGANS OF HEARING. 447 
 
 1. The Auditory Nerve divides at the bottom of the meatus 
 into fasciculi of filaments; one of which penetrates into the ves- 
 tibulum through the foramina behind that for the portio dura, 
 and is distributed upon the sacculus ellipticus, and upon the am- 
 pulla of the superior and of the exterior membranous canal; 
 other filaments get to the sacculus sphericus; and a third fasci- 
 culus of filaments is distributed to the ampulla of the posterior 
 membranous canal. These several filaments are said to preserve, 
 when they first penetrate into the bony labyrinth, a fibrous ap- 
 pearance, and are interlaced; they also penetrate the parietes of 
 the membranous labyrinth, and have their extremities bathed in 
 its fluid, in which place they are converted into soft pulp, resem- 
 bling mucus, or the retina. 
 
 Another very considerable fasciculus of filaments penetrates 
 into the canals of the modiolus, and enters through them into 
 the cavity of the cochlea, along the Zona Ossea, and between 
 its tables; they terminate also by a soft pulp on the internal face 
 of the lining membrane of the cochlea. One of these filaments, 
 conspicuous for its size, goes through the central canal of the 
 modiolus and terminates in the infundibulum.* 
 
 2. The Facial Nerve, or Portio Dura, is only connected to 
 the organ of hearing by sending a few filaments to the muscles 
 of the bones of the tympanum. The canal of the petrous bone, 
 through which it passes, is very crooked; beginning at the 
 larger orifice of the meatus interims in its upper fossa, it passes 
 outwards until it nearly reaches the Vidian foramen, on the front 
 of the petrous bone; it then turns very abruptly backwards, form- 
 ing an angle, and is continued in a circuit around the superior and 
 the posterior parietes of the tympanum, till it terminates in the 
 stylo-mastoid foramen. Its course is marked by a ridge pro- 
 jecting into the tympanum, above the foramen ovale, and pass- 
 ing between the semicircular canals and the cochlea. This canal 
 has been very much misnamed by the calling of it the aqueduct 
 of Fallopius, as its only use is to conduct nerves and blood vessels. 
 It is lined by a delicate fibrous membrane, between which, and 
 
 * For a knowledge of the minute distribution of the auditory nerve, the pro- 
 fession is signally indebted to the distinguished Scarpa, in his Disquisitiones de 
 Auditu et Olfactu. 
 
443 NERVOUS SYSTEM, 
 
 its contained parts, there is so little adhesion, that the latter may 
 be drawn out entire. 
 
 The facial nerve is joined at the Vidian foramen by the Vi- 
 dian. nerve, shortly after which it sends a filament to the tensor 
 tympani muscle.* As it passes the base of the pyramid it de- 
 taches another filament, which supplies the stapedius muscle.- 
 
 Shortly after this, it is abandoned by the Vidian nerve, and 
 does not give off any more branches till it escapes from the sty- 
 lo-mastoid foramen, when it sends off a branch, the posterior 
 auricular (Auricularis Posterior,} which is distributed by filaments, 
 some of which run into the mastoid process; other branches 
 mount on the side of this process, to the skin which covers it, 
 and to the occipital muscle: others go to the concha of the ear, 
 being spent upon its skin, upon the posterior auricular muscle, 
 and some of them, penetrating the pinna, are lost upon the in- 
 teguments of the meatus externus. The trunk of the fascial then 
 goes to its destination on the face. 
 
 4. The Chorda Tympani or Superficial Petrous Nerve, is 
 a branch of the Pterygoid branch of the Trigeminus, and leaves 
 it near the anterior part of the carotid canal of the petrous bone. 
 It, as just mentioned, under the name of Vidian nerve, joins the 
 facial nerve at the angle of the canal of Fallopius, and continues 
 to adhere closely to it, almost to the styloid foramen; it then 
 abandons the facial nerve at a very acute angle, and running 
 upwards and forwards, gets into the cavity of the tympanum, 
 on a level with, but a line or two exterior to the pyramid. It 
 then crosses the tympanum nearly horizontally, between the 
 long crus of the incus and the handle of the malleus, adhering 
 to the latter so as to be affected by its vibrations. At the fore 
 part of the tympanum, it anastomoses with some other filaments 
 of the fifth pair, by which its size is augmented, but it gives no 
 branches to the parts contained in the tympanum. It then is- 
 sues from the latter cavity through the glenoid foramen, and 
 descending a short but somewhat variable distance along the 
 ramus of the lower jaw, terminates by anastomosing at an acute 
 angle with the lingual branch of the trigeminus. 
 
 * The tensor tympani is also supplied by a nerve from the Third Branch of the 
 Trigeminus. 
 
NERVES OF THE ORGAN OF HEARING. 449 
 
 To Mr. John Hunter is due the merit of having traced the 
 continuity and identity of the Vidian nerve with the chorda 
 tympani. The continental European anatomists, for the most 
 part, seem ignorant of his observations, and give a very differ- 
 ent account of the matter. Some consider it to arise from the 
 facial at its angle, and to anastomose at the other end with the 
 pterygoid, or the reverse; and they very generally agree in re- 
 garding the chorda tympani as a filament from the facial, just 
 before the latter gets out of the stylo-mastoid foramen. 
 
 The Vidian Nerve, or Superficial Petrous, also traverses the 
 tympanum in another place. Just below the posterior extre- 
 mity of the Eustachian Canal, there is a small foramen, which 
 leads upwards to the superior surface of the petrous bone, and 
 downwards to a small gutter upon the promontory: this gutter 
 is converted into a canal that opens upon the under surface of 
 the petrous bone, between the carotid canal and the jugular 
 fossa. Through the course indicated, passes a filament from 
 the superficial petrous nerve: this filament is joined by another 
 detached from the sympathetic while in the carotid canal, and 
 the two communicate at the base of the cranium with the gang- 
 lion of the glosso-pharyngeal nerve.* These filaments were 
 discovered by Professor Jacobson of Copenhagen. 
 
 * Meckel, Man. D'Anat. vol. iii. p. 174. Jacobson, Supplemata Act.Hafiu 
 vol. v. p. 292. An. 1818. 
 
BOOK IX. 
 
 PART IV. 
 
 Special Anatomy of the Nerves. 
 
 CHAPTER I. 
 
 OF THE NERVES OF THE ENCEPHALON. 
 
 SECT. I. 
 
 THE course and distribution of the first pair, or the olfactory 
 nerves, have been described fully in the account of the brain 
 and nose. 
 
 SECT. II. NERVUS OPTICUS. 
 
 The Optic Nerve, as mentioned in the account of the basis 
 of the brain, gets into the orbit by the optic foramen, and is 
 there entirely surrounded by the origins of the muscles of the 
 eyeball. It then describes a slight curvature, of which the con- 
 vexity is outwards, and runs forwards for an inch, when it pe- 
 netrates into the ball of the eye, where it gives origin to or ex- 
 pands into the retina. Between the muscles and it, except at 
 their origins, there is a mass of adipose matter. 
 
452 NERVOUS SYSTEM. 
 
 SECT. III. NERVTJS MOTOR OCULI. 
 
 The Nervus Motor Oculi, or third pair, having reached from 
 the basis of the brain to the external side of the cavernous si- 
 nus, is placed there within and above the optic nerve and the 
 sixth pair; it then changes its direction, and penetrates through 
 the sphenoidal fissure into the orbit, on the outer side of these 
 nerves, and below them. 
 
 The motor oculi divides, in the sphenoidal fissure, into two 
 branches, one above the other. The first crosses over the op- 
 tic nerve and the nasal branch of the ophthalmic, having some 
 anastomoses with the latter, and then distributes its filaments 
 upon the rectus superior muscle: some of them also penetrate 
 the latter to get to the levator palpebrae. The second branch is 
 much larger than the first. It passes between the optic nerve 
 and the rectus inferior muscle, and is subdivided into three 
 fasciculi: one for the rectus internus muscle; another for the 
 rectus inferior; and a third, which is the longest and the small- 
 est, for the obliquus inferior muscle. The latter fasciculus, not 
 far from its root, gives off a filament, which, going along the 
 external margin of the optic nerve, runs into the posterior mar- 
 gin of the lenticular or ophthalmic ganglion, and is its short 
 root. 
 
 The Lenticular Ganglion is situated on the outer side of the 
 optic nerve, in the orbit of the eye, and is about a line in dia- 
 meter, being flattened. Two nerves concur to form it: the 
 branch just alluded to, from the motor oculi, and one from the 
 ophthalmic branch. of the trigeminus. From this ganglion arise 
 the most of the ciliary nerves; which, as stated, are about twen- 
 ty in number, and go to. the choroid coat of the eye and to the 
 iris. 
 
 SECT. IV. NERVUS TROCHLEARIS. 
 
 The Nervus Trochlearis, or fourth pair, having got into its 
 canal in the cavernous sinus, as it goes along the internal mar- 
 gin of the ophthalmic nerve, receives there a small filament from 
 
NERVUS TRIGEMINUS. 453 
 
 it* It then rises a little, and enters the orbit at the internal 
 extremity of the sphenoidal fissure; and, going forwards, next 
 to the periosteum of the upper part of the orbit, it enters into 
 the superior oblique muscle of the eye, near its middle, and is 
 distributed upon it. This nerve augments in volume as it ad- 
 vances towards its destination. 
 
 SECT. V. OF THE NERVUS MOTOR EXTERNUS. 
 
 The Nervus Motor Externus, or sixth pair, having got into 
 the cavernous sinus, is placed there at the external side of the 
 internal carotid artery, and adheres closely to it. It there sends 
 off one or more filaments, which follow the internal carotid 
 artery through its canal, and anastomose in their descent with 
 a branch of the pterygoid nerve: the junction of these two forms 
 the upper end of the great sympathetic nerve, and runs down 
 to the superior cervical ganglion of the sympathetic in two or 
 more filaments generally. The sixth nerve enters the orbit 
 through the sphenoid fissure, and is there closely connected 
 with the nervus motor oculi and the nasal nerve. It penetrates 
 into the substance of the rectus externus muscle, and is entirely 
 distributed upon it; with the exception that sometimes it sends 
 a filament to the ophthalmic ganglion. 
 
 SECT. VI. OF THE NERVUS TRIGEMINUS. 
 
 This nerve, having formed the ganglion of Gasser, (Plexus 
 Gangliformis,) on the side of the petrous bone, then divides, 
 as mentioned, into three large trunks, the foremost of which is 
 the Ophthalmic Nerve: the second fasciculus is the Superior 
 Maxillary; and the third the Inferior Maxillary Nerve. 
 
 The Ophthalmic Nerve, or the first branch of the trigeminus, 
 is smaller than either of the other two branches, and comes 
 from the superior part of the plexus gangliformis. It passes 
 along the external border of the cavernous sinus, and penetrates 
 
 * Simmering, Icones Oculi Humani. 
 VOL. II. -58 
 
454 NERVOUS SYSTEM. 
 
 the orbit through the sphenoidal fissure, on the outer side of, 
 and near the motor oculi. 
 
 In its whole course it is united to the trochlearis nerve by 
 close cellular membrane, and does not give off any ramifications 
 before it reaches the orbit, with the exception of the filament 
 sent to the trochlearis nerve. While engaged in the sphenoi- 
 dal fissure it divides into three branches; the nasal, the lachry- 
 mal, and the frontal. 
 
 The Nasal branch of the ophthalmic, is between the other two 
 in size. It ascends obliquely above the optic nerve to gain the 
 internal face of the orbit of the eye, and then passes forwards 
 just below the superior oblique muscle, involved in a quantity 
 of adipose matter. Shortly after its origin the nasal nerve de- 
 taches a branch (the ramus ciliaris) which, situated at the ex- 
 ternal margin of the optic nerve, runs into the ophthalmic or 
 lenticular ganglion, and constitutes the long root; it then sends 
 off one or more filaments, which, without communicating with 
 this ganglion, penetrate into the eyeball, and are amongst the 
 ciliary nerves which have been described. 
 
 The nasal nerve, continuing to pass forward along the inter- 
 nal paries of the orbit, when it reaches the anterior internal or- 
 bitary foramen, detaches through it the internal nasal or eth- 
 moidal branch, which, thus getting into the cavity of the cra- 
 nium, goes along side of the crista galli, and then passes into 
 the nose through the foremost hole of the cribriform plate. It 
 then descends along the anterior part of the nose, on the outer 
 side of the Schneiderian membrane, and is spent by ramifi- 
 cations upon the contiguous portions of the latter. Some of 
 its terminating branches reach the tip of the nose and the 
 alae.* 
 
 The nasal nerve, after this branch is sent off, is frequent- 
 ly called external nasal, or nervus infra-trochlearis. It con- 
 tinues to advance along the under margin of the trochlearis 
 muscle and gets to the trochlea, near which it divides into 
 an upper and an under ramuscle; from them filaments pro- 
 teed to the upper and under eyelids, to the lachrymal sac, 
 
 See Nerves of Nose. 
 
NERVUS TRIGEMINUS. 
 
 455 
 
 the caruncle, the tunica conjunctiva, and the muscles on the 
 root of the nose. These filaments anastomose with the ter- 
 minating branches of the frontal nerve, the facial, and the in- 
 fra-orbitary. According to Dr. G. Trasmondi,* of Rome, two 
 filaments may be traced very distinctly from the external na- 
 sal nerve to the tensor tarsi muscle of the lachrymal sac. They 
 adhere to the muscle b^ means of cellular structure, and pass 
 on to its bifurcated extremities and to the puncta lachryma- 
 lia. 
 
 The Frontal Nerve is the largest of the three branches of 
 the ophthalmic. It proceeds forward between the levator pal- 
 pebrae superioris and the contiguous part of the orbit, and in 
 this course is divided into two branches, the internal and the 
 external frontal nerve. The former approaches the trochlea 
 of the upper oblique muscle, and detaches a filament to join 
 with one from the nasal nerve. Other filaments are detached 
 to the upper eyelid, some of which anastomose with filaments 
 from the lachrymal nerve. The internal branch of the frontal 
 then issues from the orbit just by the trochlea, and, in ascend- 
 ing, is lost upon the occipito-frontalis, the corrugator super- 
 cilii, and the orbicularis. The external branch of the frontal 
 issues from the orbit, through the supra-orbitary foramen. It 
 quickly detaches a filament, which goes outwardly to anasto- 
 mose with the facial; the remaining part of the nerve is distri- 
 buted to the occipito-frontalis, to the corrugator supercilii, to 
 the integuments of the forehead, and to the scalp. This dis- 
 tribution, according to Bichat, is best followed by detaching 
 the skin, muscles, and periosteum from the cranium, from be- 
 hind forwards as far as the orbit. 
 
 The Lachrymal Branch of the ophthalmic nerve goes for- 
 wards along the external side of the orbit near the superior 
 margin of the rectus externus muscle. In this course it sends 
 off a filament through the spheno-maxillary fissure which unites 
 with one from the second branch of the fifth pairj it afterwards 
 
 * Intorno la scoperta di due nervi del Occhio umano ragguaglio del Dr. Giu- 
 seppe Trasmondi, Professore di Anatomia Practica nel ven. ospidale della Con- 
 solazione. Roma, 1823.' 
 
456 NERVOUS SYSTEM. 
 
 sends off another filament, which, passing through a foramen 
 in the malar bone, anastomoses with a filament of the facial 
 nerve. What remains of the lachrymal nerve is then distri- 
 buted by several filaments upon the lachrymal gland, the upper 
 eyelid, and some of them reach the conjunctiva. 
 
 Second Branch of the Trigeminus. 
 
 The Second Branch of the Fifth Pair, (Nervus Maxillaris 
 Superior,} arising from the middle of the plexus gangliformis, 
 or ganglion of Gasser, and also, in part, from the common 
 trunk formed from the anterior and posterior roots of the tri- 
 geminus, gets from the cranium through the foramen rotundum 
 of the sphenoid bone. While still in the cranium, it sometimes 
 forms an anastomosis, described by Laumonier with the begin- 
 ning of the sympathetic nerve, but generally it does not detach 
 any filament till it reaches the ptery go-maxillary fossa. 
 
 At a short distance after jts exit from the cranium, it gives 
 off a small filament, the Nervus Subcutaneous Malae, which 
 ascends into the orbit through the spheno-maxillary fissure, 
 and then divides. One of the branches, the malar, anasto- 
 moses with the lachrymal nerve, and leaves filaments with 
 the lachrymal gland; it then gets, by one or more filaments, 
 through the holes of the malar bone to the face, and termi- 
 nates on the orbicularis muscle and the skin of the cheek, anas- 
 tomosing with the extremities of the facial nerve. The other 
 branch, the temporal, gets into the temporal fossa by pene- 
 trating the internal part of the malar bone, and, having anas- 
 tomosed with a branch of the inferior maxillary nerve, it goes 
 outwards and backwards, becomes superficial by penetrating 
 the temporal aponeurosis, and terminates on the integuments 
 of the temple, anastomosing there with the branches of the 
 facial nerve. 
 
 The superior maxillary then divides into two trunks much 
 larger than the preceding, and of a volume nearly equal; the 
 Infra-Orbital and the Pterygo-Palatine. 
 
 The Infra-Orbital (Nervus Infra-Orbitalis) passes forwards, 
 with a slight ascent, to the posterior part of the orbit, and en- 
 
NERVOUS TRIGEMINUS. 457 
 
 ters the infra-orbitar canal. As it is about engaging in the lat- 
 ter, it detaches a considerable branch, the Posterior Dental. 
 This branch descends a little distance, externally, along the poste- 
 rior paries of the maxillary sinus, then penetrates into the cavi- 
 ty of the latter. It terminates by filaments, some of which supply 
 the lining membrane of the antrum; others pass through the little 
 canals leading to the three large grinders, and enter the roots of 
 the latter; others go to the corresponding gums. One branch 
 goes along the outer side of the sinus to anastomose with the 
 anterior dental nerve. The posterior dental, before it enters 
 the bone, also detaches a branch of some size, which winds around 
 the tuberosity of the maxillary bone, and is spent upon the buc- 
 cinator muscle and upon the gums. 
 
 The infra-orbitary nerve afterwards, in its course through the 
 canal, sends off the anterior dental nerves from one or more 
 roots. Some of them detach fibres to the mucous membrane 
 of the nose, where it covers the anterior part of the inferior 
 turbinated bone. With this exception, they are distributed, 
 through their appropriate canals in the bone, to the incisor and 
 canine teeth, and to the corresponding gums. The small mo- 
 lar teeth are most frequently supplied by a union of filaments, 
 from the anterior and posterior dental nerves. 
 
 The infra-orbitar nerve, on issuing from the infra-orbitar fo- 
 ramen, is most frequently found already divided into several 
 fasciculi, which may be classed into superior and into inferior. 
 The former, called Palpebral, radiate, externally and internal- 
 ly, into filaments which supply the lower eyelid. One of these 
 filaments may be traced to the end of the nose, where it anasto- 
 moses with the internal nasal branch of the ophthalmic; another, 
 which terminates about the internal angle of the eye, anasto- 
 moses there with the external nasal nerve. Others of its termi- 
 nating filaments, anastomose with the extremities of the facial 
 nerve on the eyelid. The inferior fasciculi are more numerous 
 and large than the superior. They descend upon the face co- 
 vered by the levator muscles of the upper lip, and from their 
 distribution are called Labial. The most internal of these fas- 
 ciculi terminate on the skin, the muscles, and the beginning of 
 the mucous membrane of the nose, where they anastomose with 
 the extremities of the internal nasal nerve. The middle fasci- 
 
458 NERVOUS SYSTEM. 
 
 culi go to the muscles of the upper lip and the skin of the lat- 
 ter, and to its mucous glands. The external fasciculi go to the 
 zygomatic muscles and to the contiguous skin. All the fore- 
 going branches of the infra-orbitar nerve anastomose with the 
 extremities of the fascial, and are so minutely distributed to the 
 skin and muscles of the face, that it would require a very pro- 
 tracted description to point them out particularly. 
 
 The Ptery go-palatine Nerve (Nervus Pterygo-palatinus] de- 
 scends, as a single or a double trunk, from its root to the out- 
 side of the spheno-palatine foramen, and there forms the gang- 
 lion of Meckel,* or the spheno-palatine ganglion, the existence 
 of which is not constant. From this ganglion, or from the nerve 
 itself proceed several branches. 
 
 A filament, described by Bock, is detached from it, which 
 enters into the sphenoidal sinus to be distributed on its lining 
 membrane, and sometimes to anastomose with the motor exter- 
 nus oculi. 
 
 Then arise the spheno-palatine branches, which enter the nose 
 through the spheno-palatine foramen, and are distributed upon 
 the mucous membrane of its septum and turbinated portions, 
 after the manner described in the account of the nose. 
 
 The Vidian, or Pterygoid Nerve (Nervus Vidianus, recurrens, 
 pterygoideus) arises from the inferior part of the ganglion, and is 
 a recurrent branch, which goes backwards through the pterygoid 
 foramen of the sphenoid bone. From it there arise some fila- 
 ments, which get to the mucous membrane about the anterior 
 orifice of the Eustachian Tube, either through the spheno-pala- 
 tine foramen, or by small foramina in the pterygoid process of the 
 sphenoid bone. They are sometimes united into a single trunk, 
 called pharyngeal, by Bock. The Vidian nerve, while still in 
 its canal, then divides into two trunks, the superficial, and the 
 deep petrous. 
 
 The Superficial Petrous (Nervus Petrosus Superficialis) tra- 
 verses the cartilaginous matter at the point of the petrous bone, 
 in the anterior foramen lacerum of the basis of the cranium, 
 
 * Discovered by Meckel, 1749. 
 
NERVUS TRIGEMINUS. 459 
 
 gets there into the cavity of the latter, continues its progress 
 backwards on the superior face of the petrous bone, in a gntter 
 marked on the bone, and disappears through the Vidian fora- 
 men. It, in a short space, reaches the aqueduct of Fallopius, 
 and then continues to adhere to the facial nerve till the latter 
 almost reaches the stylo-mastoid foramen: it then abandons 
 the facial nerve, and, as mentioned in the account of the ear, 
 traverses the tympanum under the name of chorda tympanij 
 and, finally, emerging at the glenoid foramen, it runs to asso- 
 ciate itself with the lingual branch of the trigeminus. The su- 
 perficial petrous, in the early part of its course, at the point of 
 the petrous bone, detaches one or more filaments to the sym- 
 pathetic in the carotid canal. 
 
 The Deep Petrous (Nervus Petrosus Profundus) is larger 
 than the other. It also penetrates through the cartilaginous 
 matter at the point of the petrous bone, and enters the cavity 
 of the cranium under the dura mater. It then advances to the 
 internal carotid artery, and anastomoses there with a filament 
 from the motor externus. This anastomosis is commonly called 
 the beginning of the sympathetic nerve. 
 
 The Palatine Nerve (Nervus Palatinus] proceeds from the 
 inferior part of the ganglion of Meckel, and gets to the soft 
 palate of the mouth through the posterior palatine foramen. In 
 this course, it detaches several filaments to the Schneiderian 
 membrane, which reach it either through the spheno-palatine 
 foramen, or by perforating the nasal lamella of the palate bone. 
 These are described in the account of the nose. 
 
 The trunk of the palatine nerve, having reached the r*oof of 
 the mouth, bends forwards, and is divided into many filaments, 
 some of which are distributed along the gums of the upper jaw, 
 others are distributed on the lining membrane of the hard pa- 
 late and upon its mucous glands. 
 
 There are two other nerves, which arise either immediately 
 from the palatine, or from the ganglion of Meckel, and go to 
 supply the soft palate. They are called the smaller palatine. 
 One of them, having proceeded for a short distance in the pos- 
 
460 NERVOUS SYSTEM. 
 
 terior palatine canal, departs from it in a little canal of its own, 
 which opens behind the hook of the internal pterygoid process. 
 It then radiates into filaments, which supply the tonsil gland 
 and the muscular and membranous structure of the soft palate. 
 The other smaller palatine also traverses, after the same man- 
 ner, its own canal, and is likewise distributed to the tonsil gland 
 and to the soft palate. 
 
 Third Branch of the Trigeminus. 
 
 The Third Branch of the Trigeminus (Nervus Inframaxil- 
 laris] is the largest of the three. It 'arises from the posterior 
 inferior part of the ganglion of Gasser, and having anastomosed 
 with the cavernous ganglion of the sympathetic nerve by fila- 
 ments, which are not constant, it emerges from the cranium 
 through the foramen ovale of the sphenoid bone. A portion 
 of this branch, as mentioned, does not enter into the composi- 
 tion of the ganglion of Gasser, but proceeds immediately from 
 the pons varolii. 
 
 The inferior maxillary nerve, at its exit from the foramen 
 ovale, is covered by the pterygoideus externus muscle, and 
 commonly divides there into two branches, one anterior and 
 the other posterior. 
 
 The anterior branch, which is much smaller than the other, 
 radiates into five fasciculi; the masseter nerve; the two tem- 
 poral; the buccal; and the pterygoid. 
 
 a. The Masseter Nerve is. directed horizontally outwards 
 and backwards, along the external margin of the pterygoideus 
 externus, and in front of the temporo-maxillary articulation: 
 it leaves some filaments with the latter, and then passing be- 
 tween the insertion of the temporal and of the external ptery- 
 goid muscle, over the concave edge of the bone, between the 
 condyle and the coronoid process of the lower jaw, it passes 
 into the substance of the masseter muscle, and is distributed 
 through it. 
 
 b. The two Temporal branches arise by a common fascicu- 
 lus, but sometimes differently. They pass outwards, horizon- 
 tally, between the external pterygoid muscle and zygomatic 
 
NERVUS TRIGEMINUS. 461 
 
 fossa. They then ascend on the side of the temporal bone, be- 
 tween it and the temporal muscle, and are distributed through 
 the latter by a great number of filaments. Some of these fila- 
 ments penetrate the aponeurosis, to anastomose with the super- 
 ficial temporal nerves. And one of them anastomoses with 
 that branch qf the superior maxillary which sends filaments to 
 the lachrymal gland, and afterwards escapes from the orbit, 
 through the foramina in the malar bone, into the temporal fos- 
 sa. It is at the latter place that the anastomosis occurs. 
 
 c. The Buccal Branch is the largest of the five. It advances 
 between the pterygoid muscles, to which it furnishes a few fila- 
 ments, and then descends between the temporal and external 
 pterygoid muscle to the posterior part of the buccinator. It is 
 principally distributed on the latter, upon the buccal glands, 
 and the corresponding part of the lining membrane of the 
 mouth. Some of its branches advance under the integuments 
 of the face, as far as the commissure of the lips to the muscles 
 there, and anastomose with the facial nerve. 
 
 d. The Pterygoid Branch is the smallest, and is distributed 
 principally on the internal pterygoid muscle. 
 
 The posterior branch of the inferior maxillary nerve is so 
 large, that it looks like a continuation of the trunk. It is di- 
 vided into the superficial temporal, the inferior dental, and the 
 lingual nerve. 
 
 a. The Superficial Temporal Branch is formed by a union of 
 two fasciculi, between which passes the middle artery of the 
 dura mater; the inferior of these fasciculi comes from the infe- 
 rior dental nerve. The nerve is directed outwardly, and winds 
 horizontally around the posterior face of the neck of the con- 
 dyle of the lower jaw, between it and the meatus auditorius ex- 
 ternus. It is there divided into several small fasciculi, two or 
 three of which penetrate into the substance of the parotid gland, 
 and anastomose with the facial nerve or its ramifications; one or 
 two others go backwards, penetrate between the bony and the 
 cartilaginous meatus to the auditory canal, and are dispersed 
 by fine filaments upon the concha, and the meatus externus. 
 According to Bock, one of these filaments supplies the mem- 
 brane of the tympanum, and also anastomoses with the chorda 
 VOL. II. 59 
 
462 NERVOtS SYSTEM. 
 
 tympani. Another, branch of the superficial temporal, which 
 is the largest of any, traverses the parotid gland, and thereby 
 becomes superficial, just in front of the external ear. It then 
 divides into filaments, which follow the course of the superfi- 
 cial temporal artery, and thereby supply the middle part of 
 the integuments on the side of the head. It anastomoses with 
 the filaments of the frontal nerve, and with those of the occi- 
 pital.. 
 
 b. The Inferior Dental Nerve is placed between the other 
 two branches, and exceeds them in size. It descends between 
 the two pterygoid muscles, towards the posterior mental fora- 
 men. Just above the latter it detaches a small branch, the mylo- 
 hyoid, which occupies the small gutter on the bone leading 
 downward from the posterior mental foramen. This branch 
 sends a filament to the submaxillary gland, then passes between 
 the anterior belly of the digastric muscle and the mylo-hyoi- 
 deus, to both of which it gives filaments, and finally winding 
 over the base of the lower jaw in front, it is lost upon the mus- 
 cles of the chin. 
 
 The inferior dental nerve then enters the posterior mental 
 foramen, and divides into two branches, which run parallel 
 with one another, through the canal in the middle of the spongy 
 structure of the bone, and send a great number of anastomotic 
 filaments to each other. One of the branches, the dental, properly 
 speaking, as it passes along the ends of the roots of the teeth, 
 detaches a filament to each root, from the last grinder to the 
 first incisor tooth inclusively: it also sends a filament to the gum 
 intermediate to every two teeth. All of these filaments arise 
 from the dental nerve, at places behind the points of destina- 
 tion; so that they have, before reaching the latter, to run for- 
 wards and upwards through little canals in the cellular struc- 
 ture of the bone. 
 
 The other branch of the inferior dental nerve is the mental; 
 it does not advance so far forward in the bone as the preceding, 
 but issues from it at the anterior mental foramen, and immedi- 
 ately is divided into two fasciculi, the inferior labial nerves. 
 The internal fasciculus is distributed by filaments upon the 
 muscles of the chin and lower lip, the contiguous lining mem- 
 brane of the mouth and the labial glands. The external fas- 
 
NERVUS TRIGEMINUS. 463 
 
 ciculus rises upwards and is distributed on the muscular struc- 
 ture, about the under part of the commissure of the lip, and 
 to the contiguous lining membrane and glands of the mouth. 
 
 c. The Lingual Nerve descends in company with the infe- 
 rior dental, but in advance of it, and diverging slightly. While 
 between the two pterygoid muscles it receives the chorda tym- 
 pani at a very acute angle. It then passes towards the side of 
 the root of the tongue, deeply concealed by the angle of the 
 lower jaw, and above the submaxillary gland, to which it gives 
 some considerable filaments. Occasionally, however, a gan- 
 glion, called the maxillary, is formed here by one or more fila- 
 ments of the lingual nerve, and from this ganglion proceed fila- 
 ments to the submaxillary gland. 
 
 The lingual nerve then proceeds forwards between the mylo- 
 hyoideus and the hyo-glossus muscle, and between the sublin- 
 gual gland and the latter, having in front of it the excretory 
 duct of the submaxillary gland. It anastomoses frequently 
 with the hypoglossal nerve, sends several filaments to the lining 
 membrane of the mouth, below the tongue, and to the sublin- 
 gual gland. It then divides, or radiates, into seven or eight 
 fasciculi, which run upwards and forwards on the side of the 
 stylo-glossus muscle, and the genio-hyo-glossus, and are finally 
 spent by very fine filaments penetrating into the structure of 
 the papillae, on the upper surface of the tongue. 
 
 The third branch of the trigemirius, according to Dr. Arnold, 
 forms, by several filaments, a ganglion near the foramen ovale. 
 This ganglion is below the spinous process of the sphenoid 
 bone, and sends off several filaments: one contributes to the ner- 
 vous anastomosis of Jacobson,* which connects the pterygoid, 
 sympathetic, and glosso-pharyngeal nerves: the other filament 
 passes to the tensor tympani, and is distributed upon it. Other 
 filaments join the superficial temporal nerve; that part of it 
 which supplies the membrana tympani. There is also an anas- 
 tomosis with the portio mollis.t 
 
 * This nervous anastomosis is described, page 449, article Vidian Nerve, 
 f Am. Med. Jour. vol. v. p, 192. 
 
464 NERVOUS SYSTEM. 
 
 SECT. VII. - NERVUS FACIAL1S. 
 
 The Facial Nerve (Nervus Facialis; portio dura septimi; 
 par septimum) having gained the meatus auditorius internus, 
 passes in front of the auditory nerve into the canal of Fallopius, 
 and winding through it, around the tympanum, it emerges at 
 the stylo-mastoid foramen, having sent in this course one or 
 more filaments to the muscles of the little bones of the 
 
 panum. 
 
 Afterwards, the facial nerve gives off several branches, which 
 are distributed as follows: 
 
 a. The Posterior Auricular (Auricularis Posterior] arises 
 /iear the stylo-mastoid foramen, as stated in the account of the 
 Nerves of the Ear; and having sent several filaments into the 
 mastoid process, it winds over the anterior face of the base of 
 the latter, and divides into two fasciculi. The anterior is dis- 
 tributed in filaments upon the back of the external ear, the car- 
 tilaginous meatus, and the posterior aurrs muscle; the posterior 
 ascends upon the mastoid portion of the temporal bone to the 
 posterior belly of the occipito-frontalis muscle, and is spent 
 by filaments to the latter, and to the corresponding integu- 
 ments, anastomosing likewise wit(i ramifications of the occipi- 
 tal nerve. 
 
 b. The facial nerve .then detaches filaments to the muscles 
 of the styloid process, and to the posterior belly of the digas- 
 tric muscle. It also sends filaments of anastomosis to the su- 
 perior part of the sympathetic nerve; to the cutaneous cervical; 
 and to ramifications of the glosso-pharyngeal, of' the pneumo- 
 gastric, and of the accessory. 
 
 The facial nerve, having given off the foregoing filaments and 
 branches, penetrates downwards and forwards into the substance 
 of the parotid gland, where it rs divided into a number of 
 branches, varying from two to five, which form a plexus by 
 their anastomosis. This plexus is re-enforced, as mentioned, 
 by branches from the superficial temporal of the inferior max- 
 illary, which wind around the neck of the lower jaw. It is 
 
NERVUS FACIALIS. 466 
 
 then distributed to the side of the face in radiating clusters or 
 columns of filaments, called the temporo-facial, the buccal, and 
 the cervico-facial. 
 
 The Temporo-Facial Nerves, or Branches, are hid, for som'e 
 distance, in the upper part of the parotid gland, which they 
 traverse below the neck of the lower jaw. They divide into 
 filaments, some of which go to the temple, and others to the 
 cheek. The temporal branches are commonly two or three in 
 number; they leave filaments with the parotid gland, mount 
 over the zygoma, and are distributed to the anterior auris mus- 
 cle, to the outer section of the orbicularis palpebrarum, and to 
 the integuments of the temple; they anastomose in their distri-* 
 bution with each other, with the superficial and deep temporal 
 branches of the inferior maxillary nerve, and with the frontal 
 and lachrymal branches of the ophthalmic. The malar branches 
 are primitively, also, two or three in number: they cross the 
 malar bone, dividing, subdividing, and anastomosing again, and 
 are spent upon the integuments and muscles of this part of the 
 face. They also anastomose with filaments of the lachrymal 
 nerve, and with those of the infra-'orbitar nerve. 
 
 The Buccal Branches are three in number, sometimes two 
 only; and pass across the masseter muscle under the skin. The 
 superior anastomoses with the temporo-facial, and the inferior 
 with the cervico-facial. The buccal branches supply the skin 
 and muscles of the face intermediate to the eye and to the low-* 
 er lip. The numerous filaments into which they divide anas- 
 tomose frequently with each other, and with the branches of 
 the fifth pair, which appear about the same parts, as the exter- 
 nal and internal nasal nerve, the infra-orbitar, and so on. The 
 middle buccal is parallel with the duct of the parotid gland, and 
 adheres to it. 
 
 The Cervico-Facial Branch descends in the substance of the' 
 parotid gland, behind the ramus of the lower jaw; when it 
 reaches the angle of the latter it goes obli-quely forwards, be- 
 neath the platysma myodes muscle. Though it sends off many 
 fasciculi, they may be referred to two divisions, a superior and 
 in inferior. The first crosses the inferior part of the masseter 
 nuscle, and may be traced in its numerous distribution of fila- 
 nents, to the integuments and muscles lying upon the body of 
 
466 NERVOUS SYSTEM. 
 
 the lower jaw. These filaments anastomose with each other, 
 and with the mental branches of the inferior dental nerve. The 
 inferior division supplies the skin and the platysma myodes 
 muscle on the upper part of the neck along the base of the 
 lower jaw. Its filaments are joined by several coming from 
 the anterior fasciculus of the third cervical nerve. 
 
 The anastomoses of the facial nerve, derived from its own 
 branches and from those of the trigeminus, which reach the face, 
 are entirely too numerous for a detailed description of them; 
 it, indeed, appears unnecessary to extend the latter beyond a 
 certain point. The most satisfactory account has been pub- 
 lished by Meckel.* 
 
 SECT. VIII. NERVUS HYPOGLOSSUS. 
 
 The Hypoglossal Nerve, (Nervus Hypoglossiis, Lingualis,} 
 having arisen from the medulla oblongata, and escaped from 
 the cranium through the anterior condyloid foramen, adheres 
 closely for an inch to the pneumogastric nerve. It descends 
 between the external carotid artery and the internal jugular 
 vein, the latter being behind the other; and then winds over 
 the carotid, externally, just below the origin of the occipital ar- 
 tery. It is there covered by the posterior belly of the digas- 
 tricus and by the stylo-hyoideus. It then passes forwards be- 
 neath the external jugular vein, and lower down somewhat than 
 the tendon of the digastric muscle, and, finally, ascends to the 
 tongue, being covered or concealed by the mylo-hyoideus mus- 
 cle. The nerve in this course, from the external carotid to the 
 tongue, forms a remarkable curve, the convexity of which is 
 downwards. 
 
 The Hypoglossal, while adhering to the par vagum, com- 
 monly leaves a few filaments with it. As it crosses the ex- 
 ternal carotid, it detaches a large branch, the Ramus Descen- 
 dens Noni, which goes down the neck, along the sheath of 
 the carotid artery and the internal jugular vein, in front of the 
 latter. 
 
 * J. F. Meckel, de Nervis Faciei, Mem, de 1'Acad. des S. de Berlin, 1751, 
 Caldani, Tab. 247. 
 
NERVUS HYPOGLOSSUS. 467 
 
 The ramus descendens has been heautifully figured by Scar- 
 pa, in his Plates of the Nerves. According to him, when it 
 has got about half way down the neck, but still resting on the 
 sheath of the vessels, it detaches, in front, two filaments, which, 
 after the course of an inch forwards, unite, and then separate 
 again to be distributed to the upper ends of the omo-hyoid and 
 sterno-hyoid muscles. The descendens noni then forms, an 
 inch lower down, a small gangliform plexus, resting upon the 
 sheath of the great vessels of the neck, under the omo-hyoid 
 muscle. This plexus is joined by two fasciculi, which descend 
 from the first and second cervical nerves, and from it pro- 
 ceed downwards and backwards, two filaments, which join the 
 phrenic nerve; also, one to the lower part of the omo-hyoid 
 muscle; and three or more, which are divided and distributed 
 upon the sterno-hyoid and thyroid muscles, and upon the mus- 
 cles of the larynx. Meckel states, that some of these ramifica- 
 tions, on the left side principally, penetrate to the thorax, and 
 reach the pericardium. 
 
 The hypoglossal nerve, having sent off the ramus descendens, 
 reaches the external face of the hyo-glossus muscle, and is there 
 concealed by the mylo-hyoideus, where it gives filaments to the 
 muscles of the larynx, to the hyo-glossus, genio-hyoideus, and 
 genio-hyo-glossus. These filaments anastomose frequently with 
 each other, and in two or three places at the anterior part of the 
 tongue with the lingual branch of the nervus trigeminus. Af- 
 ter these branches are given off, the trunk of the hypoglossal 
 nerve penetrates into the substance of the genio-hyo-glossus 
 muscle, and extends itself near its fellow, and not far from the 
 middle line of the tongue to the point of the latter. It first dis- 
 tributes filaments near the posterior part of the tongue, and 
 then, successively, as far as its anterior extremity. They can- 
 not be traced to the papillae, but are lost upon the muscular 
 structure. 
 
 It is a general opinion among anatomists that the hypo-glos- 
 sal nerve is only intended to excite the muscular movements 
 of the tongue. The opinion is founded upon the circumstance 
 of its filaments not reaching the papillae, whereas those of the 
 lingual branch of the trigeminus do. Colombo narrates a case, 
 
468 NERVOUS SYSTEM. 
 
 in which there was a congenital privation of taste, where the 
 lingual branch of the trigeminus was distributed upon the occi- 
 put instead of upon the tongue, which goes far to prove the dif- 
 ference of function in the two nerves. 
 
 SECT. IX. NERVUS ACCESSORIUS. 
 
 The Accessory Nerve, (Nervus JZccessori us, Willisii^ having 
 arisen, as described, from the cervical medulla and the medulla 
 oblongata, is directed outwards to the posterior foramen lace- 
 rum, in company with the pneumogastric or par vagum. Some- 
 times it is separated from it in its passage through the base of 
 the cranium, by a thin partition of dura mater; on other occa- 
 sions merely by a fold of the tunica arachnoidea: but at the in- 
 ferior part of this foramen it adheres so closely to the par. va- 
 gum that the two look like but one nerve. 
 
 Near its exit it is divided into two fasciculi. The most in- 
 ternal gives off one or two filaments, which, joining a branch 
 of the par vagum, forms the superior pharyngeal nerve; the 
 internal branch then descends, and being divided into several 
 branches, they, successively, join the upper part of the par 
 vagum. The external fasciculus descends for two inches be- 
 hind the internal jugular vein, being placed first of all between 
 it and the occipital artery, but subsequently between the vein 
 and the sterno-mastoid muscle. It then pierces this muscle 
 about one-third of the length of the latter from its superior 
 extremity, and leaves filaments in it which anastomose with 
 some from the third cervical nerve. In continuing its descent, 
 it is re-enforced and augmented considerably in volume, by 
 branches from the second and third cervical. Having reached 
 the anterior margin of the trapezius muscle, it then distributes 
 itself to the latter, by internal and by external branches. 
 
 SECT. X. NERVUS GLOSSO-PHARYNGEU9. 
 
 The Glosso-Pharyngeal Nerve (Nervus Glosso-Pharyngeus,) 
 though commonly considered as distinct from the pneumogas- 
 
NERVUS ACCESSORIUS. 469 
 
 trie, has so many connexions with it, both at its root, in its 
 course through the posterior foramen lacerum, and, in its dis- 
 tribution, that it seems like a part or branch of the same. At 
 the base of the cranium in front of the pneumogastric, it forms, 
 according to some anatomists,* a ganglion of five or six lines 
 in length, the existence of which was denied by Bichat. From 
 this ganglion proceeds a filament,! which penetrates into the 
 tympanum and divides into two branches; one of them ascends 
 along the promontory, having detached a filament to the mem- 
 brane of the foramen rotundum: it then penetrates the petrous 
 bone; and anastomoses or joins with the superficial petrous 
 nerve. The other branch passes below the bony Eustachian 
 Tube, and, gaining the carotid canal, anastomoses there with the 
 Sympathetic Nerve. This is part of the anastomosis of Jacob- 
 son, and is also described in the account of the Vidian Nerve. 
 The ganglion also gives off other filaments, which traverse the 
 canal of the dura mater, to join the pneumogastric nerve, the 
 accessory and the sympathetic. 
 
 On issuing from the posterior foramen lacerum, the glosso- 
 pharyngeal is separated from the pneumogastric by the internal 
 jugular vein. It is then directed downwards and forwards be- 
 tween the internal carotid and the stylo-pharyngeus muscle; 
 afterwards between the latter and the stylo-glossus; it fol- 
 lows the direction of the latter to the side of the root of the 
 tongue. 
 
 In this course, it sends off many filaments. Shortly after 
 leaving the cranium, it detaches one backwards to the digas- 
 tric branch of the facial, and another to the pneumogastric. It 
 then sends off two filaments, which descend along the internal 
 and the common carotid, and are divided into several branches, 
 some of which anastomose with the pharyngeal branch of the 
 pneumogastric, others descend (fti the common carotid with 
 filaments from the pharyngeal branch, and being joined by two 
 or three small twigs from the superior cervical ganglion, they 
 reach the lower part of the neck, and concur in the forming 
 
 * Andersach and Huber. This ganglion is considered by some as commencing 
 before the nerve penetrates the foramen lacerum. 
 f Rosenmuller, Jacobson, Lobstein. 
 
 VOL. II. 60 
 
470 NERVOUS SYSTEM. 
 
 of the superficial cardiac nerve. Farther down after the origin 
 of these branches the glosso-pharyngeal detaches two or three 
 filaments to the stylo-pharyngeus muscle, as well as some to the 
 upper and middle constrictors of the pharynx, to the pharyngeal 
 plexus of the sympathetic and pneumogastric, and to the pos- 
 terior lateral and superficial part of the tongue. 
 
 The glosso-pharyngeal nerve having got between the stylo 
 and hyo-glossus muscles, is placed intermediately to the lingual 
 branch of the fifth pair and hypo-glossal nerve. Some of its 
 branches then go to the integuments of the base of the tongue, 
 to its mucous glands, large papillae, and may be traced to the 
 mucous membrane of the soft palate, to the amygdalae, and to 
 the covering membrane of the epiglottis. Others go into the 
 muscles of the tongue, and others may be traced along the ex- 
 ternal margin of the tongue, beneath its mucous membrane for 
 some distance. Scarpa has delineated a remarkable plexus, 
 which he denominates Circulus Tonsilkris Anderschii or Anas- 
 tomosis Plexuosa, formed by these several filaments and by 
 branches of the lingual, on the side of the root of the tongue, 
 at the base of the tonsil gland. 
 
 SECT. XI. NERVUS PNEUMOGASTRICUS. 
 
 The Pneumogastric Nerve (Nervus Pneumogastricus, Vagus, 
 Par Octavum, Decimum of Andersecti} at its exit from the cra- 
 nium through the posterior foramen lacerum, in front of the in- 
 ternal jugular vein, is closely united to the hypo-glossal, glosso- 
 pharyngeal, and accessory nerves, by compact cellular substance. 
 It is first placed in front of the hypo-glossal nerve, but, in a short 
 Space, gets behind it, and is also separated from the glosso-pha- 
 ryngeal by the internal jugular vein. Opposite the transverse 
 process of the atlas, it leaves the hypo-glossal nerve, and as- 
 sumes a position between the internal carotid and the internal 
 jugular, on the vertebral side of these vessels, and is enveloped 
 in their sheath of dense cellular substance. It maintains this 
 relative position along the common carotid to the root of the 
 neck. 
 
 At the latter place, the pneumogastric of the right side goes 
 in front of the subclavian artery, near its root, but on the left 
 
PNEUMOGASTRIC NERVE. 471 
 
 side it crosses the root of the left subclavian artery, and the arch 
 of the aorta to the left of the origin of the left carotid. In get- 
 ting fairly into the cavity of the thorax, it is directed hackwards 
 and downwards from these points, towards the posterior face of 
 the bronchia, between it and the pleura. It then abandons the 
 bronchia, and applies itself to the oesophagus, and follows it 
 through the diaphragm to the stomach. The nerve of the left 
 side, in its course along the oesophagus, is on the front surface 
 of the latter, and the nerve of the right side, on its posterior 
 surface. 
 
 The pneumogastric anastomoses with the accessory while 
 passing through the foramen lacerum posterius. Somewhat 
 lower down, it also anastomoses with the glosso-pharyngeal and 
 with the superior cervical ganglion of the sympathetic. The 
 branches which it afterwards sends off, go to the neck to the 
 viscera of the thorax, and to those of the abdomen, after the fol- 
 lowing manner: 
 
 A. Cervical Branches. The Superior Pharyngeal Nerve 
 (Ramus Pharyngeus) arises just below the preceding anastomo- 
 sis. It is directed downwards on the internal face of the inter- 
 nal carotid, and having sent an anastomotic filament to the glos- 
 so-pharyngeal nerve, it forms on the middle constrictor of the 
 pharynx, the pharyngeal plexus which is re-enforced by fila- 
 ments from the superior cervical ganglion of the sympathetic, 
 from the glosso-pharyngeal, and from the superior laryngeal 
 nerve. The filaments departing from this plexus, are spent 
 principally upon the middle constrictor, but a few of them also 
 go to the superior constrictor; and others, descending along the 
 primitive carotid, anastomose with ramifications from the glos- 
 so-pharyngeal, and from the superficial cardiac nerve. A fila- 
 ment, called the inferior pharyngeal, sometimes proceeds from 
 the pneumogastric a little below the other, and also is spent upon 
 the pharynx. 
 
 The pneumogastric, at the place where it detaches these pha- 
 ryngeal branches, or a little above them, becomes softened in 
 its texture, enlarges somewhat, and has the fasciculi which 
 compose it moderately separated by a sort of red gelatinous 
 substance interposed between them. This portion is its gang- 
 
472 NERVOUS SYSTEM. 
 
 liform plexus, and into it is joined one or more branches from 
 the accessory nerve. 
 
 The Superior Laryngeal Nerve (Nervus Laryngeus Supe- 
 rior) arises from the gangliform plexus. It descends between 
 the internal carotid and the superior cervical ganglion, anasto- 
 mosing on the way with the latter, with the pharyngeal plexus, 
 and the hypo-glossal nerve; it then divides into an external and 
 an internal laryngeal branch. The former sends its filaments 
 to the muscles situated on the fore part of the thyroid cartilage; 
 lo the thyroid gland; and some of them penetrate through the 
 crico-thyroid membrane to the lining membrane of the larynx. 
 The internal laryngeal branch is placed above the other; it is 
 directed towards the thyreo-hyoid membrane, which it pene- 
 trates and then begins to ramify. Some of the branches go to 
 the epiglottis cartilage, its covering membrane, and the adjacent 
 portion of the lining membrane of the pharynx. Other branches 
 are distributed to the small muscles which move the arytenoid 
 cartilages, and to the lining membrane of the larynx. The fila- 
 ments which go to the epiglottis have an arrangement indicated 
 by Bichat; that of going into the foramina which perforate it, 
 but they cannot be traced farther. 
 
 The pneumogastric afterwards does not send off any regular 
 branches till it reaches the lower part of the neck. It then 
 detaches two or three filaments, (rami cardiaci,) which, on the 
 right side, have their roots about an inch above the subclavian 
 artery, and on the left side, an inch lower down. On the right 
 side, they descend along the subclavian and the arteria innomi- 
 nata, on the left along the left carotid; they reach the arch of 
 the aorta, and in their course, as well as there, anastomose very 
 freely with the superficial cardiac nerve. The rami cardiaci 
 are frequently more abundant on the right side than on the left. 
 
 The Inferior Laryngeal Nerve (Nervus Laryngeus Inferior, 
 Recurrens) is a considerable branch of the pneumogastric, which 
 comes off next to the cardiac. On the right side it arises im- 
 mediately after the trunk has passed between the subclavian 
 artery and the subclavian vein. It then winds around the sub- 
 clavian artery so as to retain the latter in its loop; having thus 
 
PNEUMOGASTRIC NERVE. 473 
 
 got behind the artery, it then ascends towards the larynx, on 
 the side of the trachea, covered by the common carotid and by 
 the inferior thyroid artery. 
 
 In this course the inferior laryngeal nerve detaches the fol- 
 lowing branches: 1. From the convexity of its loop it sends 
 filaments to the assistance of the cardiac branches just spoken 
 of, arising from the pneumogastric, and to those coming from 
 the inferior cervical ganglion of the sympathetic. 2. It de- 
 taches the pulmonary branches, the origin of which is compli- 
 cated with the plexus of nerves existing about their roots; these 
 descend in front of the trachea, reach the pulmonary artery, 
 and follow its ramifications into the lungs; some of the fila- 
 ments, however, go to the cardiac plexus. 3. The inferior 
 laryngeal then sends many filaments to the oasophagus; 4. 
 Branches which go to the inferior part of the thyroid gland; 
 5. Filaments to the trachea, some of which penetrate the mem- 
 brane on its posterior part, others go between the cartilages; 
 they are then distributed to the lining membrane and to the 
 mucous glands of the part. 6. The inferior laryngeal nerve is 
 then distributed in branches to the inferior constrictor of the 
 pharynx and its lining membrane, but the most of its termi- 
 nating filaments penetrate to the larynx, between the thyroid 
 and the cricoid cartilage, and are lost upon the lining membrane 
 of the larynx, and upon the small muscles which move the ary- 
 tenoid cartilages. These terminating filaments anastomose with 
 such as come from the superior laryngeal nerve. 
 
 It is generally stated by anatomists that the distribution of 
 the inferior laryngeal nerve to the larynx, is confined to the 
 thyreVarytenoid,and posterior and lateral crico-arytenoid mus- 
 cles. Mr. G. Rainy, states, in the London Medical Gazette, 
 that he has repeatedly traced its filaments, also, to the trans- 
 verse and oblique arytenoid.* The recurrent of the left side 
 forms a much larger loop than the other, and arises lower down, 
 inasmuch as it has to wind around the arch of the aorta, at the 
 origin of the left subclavian artery; with some inconsiderable 
 exceptions, its course and distribution afterwards are precisely 
 the same with those of the nerve of the right side. 
 
 * Am. Med. Journ. vol. iv. p. 198. 
 
474 NERVOUS SYSTEM. 
 
 B. The Thoracic Branches of the pneumogastric are as fol- 
 low: The inferior tracheal nerves come from it just below the 
 recurrent: they are five or six in number; some of them go in 
 front of the trachea and bronchia, and others behind them. 
 They are complicated by anastomoses with the branches of the 
 recurrent nerve, and with those of the inferior cervical ganglion, 
 and form a small plexus, denominated the anterior pulmonary, 
 which lies upon the front of the root of the lung, and has its 
 filaments following the branches of the pulmonary artery 
 through the lung. The posterior filaments supply the structure 
 of the bronchia by penetrating it, and some of them go to join, 
 the posterior pulmonary plexus. 
 
 As the pneumogastric gets behind the trachea and the bron- 
 chia, it is sensibly enlarged and somewhat flattened, the cohe- 
 sion of its fasciculi being somewhat looser. Several filaments 
 depart there from it, which form an intertexture with each olher; 
 some of them pass inwards, to be distributed on the bronchia, 
 trachea, and resophagus. Others, which are given off as the 
 nerve lies upon the posterior face of the root of the lung, 
 amounting to six or seven in number, but being of various 
 sizes, run transversely outwards, and form an intertexture with 
 one another. The latter are joined by filaments from the infe- 
 rior cervical and the first dorsal ganglion of the sympathetic, 
 and thus constitute the posterior pulmonary plexus. The fila- 
 ments from this plexus follow the distribution of the bronchia, 
 and, according to Bichat, are all destined to the mucous mem- 
 brane and the mucous glands of the lung; as they may be traced 
 piercing successively the ramifications of the bronchia, in order 
 to reach its lining membrane. 
 
 On the right side, the par vagum, while furnishing the pul- 
 monary plexus, and for some distance lower down, is divided 
 into from four to six considerable fasciculi, which form with 
 each other a plexus or series of anastomoses, having very large 
 meshes, and from which proceed many filaments to the oesopha- 
 gus. Afterwards these fasciculi are assembled into a single 
 chord, which proceeds on the posterior face of the ossophagus, 
 along with it into the abdomen. 
 
 On the left side, the par vagum, after forming, the posterior 
 pulmonary plexus, is split into two or three fasciculi; which 
 
SYMPATHETIC NERVE. 475 
 
 likewise furnish branches to the oesophagus, and unite to form 
 a single chord, which proceeds on the front surface of the oeso- 
 phagus, along with it into the abdomen. 
 
 The two nerves, while descending in this way, send frequent 
 anastomotic filaments to each other, and to the oesophagus. 
 
 C. In the Abdomen the par vagum is distributed as follows: 
 Filaments are sent from each nerve, which form a plexus around 
 the cardiac orifice of the stomach. The right nerve is then 
 divided into many branches; some are distributed on the poste- 
 rior face of the stomach; others go along the lesser curvature 
 of this viscus, and reach thereby the pylorus, where they anas- 
 tomose with filaments from the left nerve, and from the gastric 
 plexus of the sympathetic; others go behind the stomach to join 
 the solar plexus, and are blended with the latter in its distribu- 
 tion to the liver, vena portarum, duodenum, and pancreas. The 
 left par vagum, being placed in front of the cardia, is resolved 
 into several radiating filaments or fasciculi, some of which sup- 
 ply the anterior face of the stomach, others go along its lesser 
 curvature to the pylorus, to anastomose with the right nerve 
 and the gastric branches of the sympathetic, and are finally 
 blended, after the same manner as the preceding, with the so- 
 lar plexus. 
 
 CHAPTER II. 
 
 OF THE SYMPATHETIC NERVE.* 
 
 THE Sympathetic Nerve (Nervus Sympatheticus Magnus, 
 Intercostalis Maximus, Gangliosits,) differs, in a great num- 
 ber of respects, from every other nerve of the body; and if we 
 were actuated only by its peculiarities, with Bichat, Meckel, 
 and others, we might with great propriety, set it apart as some- 
 
 * Anton. Scarpa, Tabul. Neurolog, 
 
476 NERVOUS SYSTEM. 
 
 thing having a claim to an, insulated description and location. 
 The dissection of it, however, is so much blended with that 
 of the par vagum, that the descriptions of the two go best 
 hand in hand; and are, therefore, most conveniently studied 
 together. 
 
 This nerve consists in a series or chain of ganglions, extend- 
 ing from the base of the cranium to the lower end of the sac- 
 rum. They are placed on the lateral part of the bodies of the 
 vertebrae, are united to each other by intermediate nervous 
 chords, and send off continually filaments to the adjacent organs. 
 With the exception of the neck, there is a ganglion for each 
 intervertebral space, both of the true vertebra and sacrum. Be- 
 sides these ganglions, there are others which are situated 
 around the trunks of some of the large vessels of the abdomen. 
 
 The superior extremity of the sympathetic nerve, opposite 
 to the transverse process of the second cervical vertebra, and 
 behind the internal carotid artery, forms a ganglion, which, for 
 the purpose of description, may be considered as the first of the 
 series. This ganglion is the superior cervical. The nervus 
 motor externus oculi, in passing through the cavernous sinus, 
 and the Vidian nerve, in passing by the point of the petrous 
 bone, both send a filament downwards through the carotid canal; 
 which two filaments unite to form a single chord, that runs 
 into the superior extremity of this ganglion. The filament 
 from the Vidian nerve is, as mentioned, the deep petrous nerve. 
 The common view taken by anatomists of this nervous con- 
 nexion is, that it is the beginning of the sympathetic, though 
 by Bichat it is described as the termination, or one of its ex- 
 tremities. The distinction, though important physiologically, 
 is less so when the object is simply to describe the course and 
 anatomical relations of this nerve, as they may be equally un- 
 derstood by either mode of description. 
 
 The branch from the motor externus most frequently forms, 
 on the external face of the internal carotid, in the cavernous 
 sinus, a ganglion, (Ganglion Cavernosum, Caroticum,) dis- 
 covered by Laumonier, which is sometimes made by several 
 filaments, from the motor externus, instead of one. M. Lob- 
 
SYMPATHETIC NE&VE. 477 
 
 stein, in his Essay on the Sympathetic, has attributed this 
 ganglion to the deep petrous nerve, in which I think he is 
 mistaken.* From the ganglion cavernosum, it has, of late, 
 been ascertained that filaments may be traced to the ganglion 
 of Gasser, (Plexus Gangliformis,) of the trigeminus, to the 
 pituitary gland, to the infundibulum; and, moreover, a fasciculus 
 which, according to H. Cloquet, forms a plexus around the 
 ophthalmic artery, and may be traced along all its branches, 
 even the central artery of the retina. This plexus anastomoses 
 with the lenticular ganglion, and consequently establishes a di- 
 rect nervous communication between the sympathetic, the mo- 
 tor externus oculi, and first branch of the fifth pair. The know- 
 ledge of this connexion has caused anatomists to locate the len- 
 ticular ganglion and the ciliary nerves in the ganglionic system 
 of the sympathetic, as forming a part of the latter. 
 
 The sympathetic, in descending the neck, is placed behind 
 the carotid artery and internal jugular vein. It is common- 
 ly said to be enclosed in the sheath of these great vessels, but 
 the statement is loose and inaccurate, as it is fastened to the 
 front surface of the longus colli muscle by cellular substance 
 distinct from the sheath, as may be manifested by pushing 
 a knife handle between them and raising up the sheath. The 
 chord which comes down from the carotid canal is close to 
 the pneumogastric and hypoglossal nerves. Having formed 
 the first cervical ganglion, it descends as mentioned; and, op- 
 posite to the space between the fifth and sixth cervical ver- 
 tebrae, it is again enlarged into the Middle Cervical Ganglion, 
 which is much smaller and more irregular than the first. 
 The sympathetic is then traced with some difficulty, in con- 
 sequence of the numerous branches coming from it; but, with 
 attention, a trunk may be found as the continuation of it. This 
 trunk passes to the interval between the head of the first rib 
 and the transverse process of the last cervical vertebra, and 
 there enlarges into another ganglion, called Inferior Cervical, 
 or First Dorsal. 
 
 To understand well the connexions of the sympathetic in the 
 
 * De Nerv. Sympathetic. Paris, 1823, 
 
 VOL, II. 61 
 
47S NERVOUS SYSTEM. 
 
 neck, each of the cervical ganglions must be studied particu- 
 larly. 
 
 1st. The Superior Cervical Ganglion varies considerably in 
 its extent; commencing very generally opposite to the second 
 cervical vertebra, it is sometimes elongated to the lower part 
 of the third and even of the fourth. In cases of unusual elon- 
 gation, it is smaller than in others. 
 
 It sends off, from its external margin, several filaments, about 
 four, which cross the anterior face of the rectus anticus major 
 muscle, and terminate by anastomosing with the anterior fasci- 
 culi of the occipital nerve and of the three first cervical: when 
 the ganglion is short, the two lower filaments come from the 
 sympathetic below it, instead of from the ganglion. 
 
 Several filaments also proceed from this ganglion to the con- 
 tiguous muscles on the vertebral column, to the pharynx, to the 
 larynx, and to the thyroid gland. 
 
 This ganglion also sends off what are called its Anterior 
 branches, which are peculiar for their reddish colour and for 
 their softness; the latter quality has obtained for them the name 
 of Nervi Molles. They may be referred, by their position, to 
 three orders. The superior ascends to anastomose with the 
 pneumogastric, hypoglossal, and facial nerves, near their exit 
 from the cranium. The middle are two or three in number, 
 but immediately divide into many filaments, forming the caro- 
 tid plexus by assistance from the pneumogastric, glosso-pha- 
 ryngeal, and facial nerves. Some of the branches of this plex- 
 us descend behind the primitive carotid, at the place of its bi- 
 furcation, and accompany it to its origin, continually interlacing 
 with each other. Others surround, after the same manner, the 
 external carotid, and subdivide into a plexus for each of its 
 branches, so that very fine filaments may be traced along the 
 superior thyroidal, the lingual, facial, occipital, and temporal 
 arteries. These nerves are, for the most part, difficult to trace, 
 from their extreme tenuity. The primitive branches, from 
 which these plexuses come, are sometimes previously united 
 into a small ganglion, which serves as a common centre to all 
 these nervous irradiations. The third order of anterior branches, 
 amounting to from four to six, come either from the ganglion 
 
THE SYMPATHETIC NERVE. 479 
 
 or from the sympathetic just below it. The chord formed by 
 their union, called the Superficial Cardiac Nerve, descends on 
 the external side of the primitive carotid, anastomosing with 
 filaments from the pneumogastric and from thedescendens noni. 
 It gives small ramifications to the contiguous parts, as to the 
 pharynx, oesophagus, the sterno-hyoid and thyroid muscles. It 
 terminates in the lower part of the neck, by detaching anasto- 
 mosing branches to the branches of the recurrent nerve; some 
 of them also go along the inferior thyroid artery to the thy- 
 roid gland. What remains of it is lost in the middle cardi- 
 ac nerve; for it cannot be traced, in an insulated and distinct 
 manner, to the heart; from which cause, its appellation is ob- 
 jectionable. 
 
 2. The Middle Cervical Ganglion, placed intermediately to 
 the fifth and sixth cervical vertebrae, upon the longus colli mus- 
 cle, is there concealed by the common carotid, the internal ju- 
 gular vein, and the pneumogastric nerve. It is sometimes de- 
 ficient: according to Meckel, in the proportion of once in three 
 times. In my own dissections I have always found it, though 
 under various circumstances of size and form. It is more flat- 
 tened than the preceding, and never so long. Sometimes it is 
 double. Like the preceding, it has a great many filaments at- 
 tached to, or emanating from it. 
 
 The external filaments, amounting to about three in number, 
 pass from it to the anterior fasciculi of the fourth, fifth, and sixth 
 cervical nerves, between the origins of the scaleni muscles. 
 Some of its filaments accompany the inferior thyroid artery, 
 and, along with the superficial cardiac, form a plexus around it, 
 which reaches to the thyroid gland. 
 
 The Middle Cardiac Nerve is formed by several of the ante- 
 rior branches, collecting into a single chord. The latter de- 
 scends along the external side of the primitive carotid, crosses, 
 on the right side of the body, the root of the subclavia^n artery, 
 and then going along the posterior face of the arteria innomina- 
 ta, it gets between the aorta and the bifurcation of the trachea, 
 where it is merged in the commencement of the cardiac plexus 
 of nerves. On the left side, the middle cardiac nerve is formed 
 by an assemblage of filaments from the middle and inferior cer- 
 
480 NERVOUS SYSTEM. 
 
 vical ganglions, which descend along the left subclavian artery 
 to the aorta, and are joined, on the front of the latter, by the su* 
 perficial cardiac nerve. On both sides, these cardiac nerves 
 form intricate anastomoses with the pneumpgastric nerve and 
 its recurrent branch. 
 
 3. The Inferior Cervical Ganglion, situated as mentioned, 
 near the head of the first rib, like the others, is subject to vari- 
 ations in its form and size. Several filaments may be traced 
 between it and the middle cervical ganglion. One penetrates 
 into the canal of the transverse processes along with the verte- 
 bral artery, and, forming a plexus around it, may be traced dis- 
 tributing branches to the heads of the contiguous muscles, as 
 high up as the second cervical vertebra. 
 
 The external branches of the inferior cervical ganglion are 
 numerous and small. Some of them anastomose with the ante- 
 rior fasciculi of the two or three inferior cervical and the first 
 dorsal nerve. Others form a plexus around the subclavian ar- 
 tery, and follow the latter, in its distribution, to the upper ex- 
 tremity and to the shoulder. 
 
 The anterior branches of this ganglion concur, after some 
 anastomoses with each other, to form a single chord, the Infe- 
 rior Cardiac Nerve, which goes, on the right side, along the ar- 
 teria innominata, to be blended with the cardiac plexus. On 
 the left side, it is not so distinct, but is blended with the mid- 
 dle cardiac nerve, and forms its' inferior root. 
 
 Of the Cardiac Plexus of the Sympathetic- 
 
 The Cardiac Plexus (Plexus Cardiacus) is situated between 
 the arch of the aorta, and the lower part of the trachea and the 
 bronchiae, and extends from the division of the pulmonary ar- 
 tery to the commencement qf the arteria innominata. It is 
 formed, almost wholly, from the branches sent by the three 
 cervical ganglions of the sympathetic of each side, and prin- 
 cipally from that of the middle one, or the middle cardiac nerve. 
 The filaments which come from the recurrent nerve and the 
 
THE SYMPATHETIC NERVE. 481 
 
 par vagum are blended into the cardiac plexus in such a man- 
 ner that they cannot be traced immediately to the heart. It 
 is worthy of remark, that the three cardiac nerves of the right 
 side are more constantly found than the same number on the 
 left, in consequence of the lower one of the latter soon merging 
 itself, after its origin into the middle cardiac nerve of that 
 side. 
 
 The cardiac plexus is formed by the common assemblage of 
 the nerves from the two sides of the neck, and is therefore 
 single. From this plexus arise all the nerves which go to the 
 heart, so that in tracing them the distinction between right and 
 left is confounded. Scarpa, has pointed out, in this circum- 
 stance, an analogy between them and the nerves which supply 
 the abdominal viscera. 
 
 The cardiac plexus is distinguished by the softness of its tex- 
 ture. For the purpose of description, its branches may be di- 
 vided into Anterior, Posterior, and Inferior. 
 
 The Anterior Branches are but few. They are found on the 
 front of the arch of the aorta. One of them crosses it on the right 
 side of the arteria innominata; others cross it from the root of 
 the left carotid and subclavian, downwards. In both cases, se- 
 veral of the terminating filaments run into the anterior corona- 
 ry plexus.* 
 
 The Posterior Branches are more numerous; but run only a 
 short course, when they are merged in the anterior pulmonary 
 plexus formed by the par vagum. 
 
 The Inferior Branches are the largest and the most abundant. 
 Some of them follow the pulmonary artery until its entrance 
 into the lungs, others are distributed upon the pulmonary veins; 
 but the greater number of them are arranged into two plexuses 
 called Coronary, from their observing the course of the corona- 
 ry arteries. The posterior coronary plexus is larger than the 
 other. It reaches the base of the heart, along the pulmonary 
 artery, and has its filaments distributed principally to the left 
 
 * Scarpa. 
 
482 NERVOUS SYSTEM. 
 
 auricle and left ventricle, observing the course of the left coro- 
 nary artery and of its branches. The anterior coronary plexus 
 gets in front of the heart, between the aorta and the pulmonary 
 artery. It anastomoses freely at its superior part with the 
 other, and is then distributed to the right auricle and ventricle, 
 along the course of the right coronary artery and of its branches. 
 
 Of the Thoracic Ganglions of the Sympathetic. 
 
 These ganglions are twelve in number, and are placed on or 
 near the heads of the ribs, at the commencement of each inter- 
 costal space, and are only covered by the pleura. Their shape 
 is irregular, and they differ also in size, being always smaller 
 than the cervical ganglions. The chord of the sympathetic is 
 continued, successively, from one ganglion to another, so that 
 they form a complete chain by their connexion with each other. 
 
 From each ganglion there proceeds one or more external 
 branches which go outwards to anastomose with the intercostal 
 nerve of the corresponding part. Each ganglion also detaches 
 one or more internal branches or filaments to the adjacent parts 
 lying on the vertebral column: some go to the cellular substance, 
 others to the longus colli muscle, others to the aorta, others to 
 the cardiac and to the pulmonary plexuses. Among these in- 
 ternal branches there are several which concur to form the 
 Splanchnic Nerves, of which there are two; the Great and the 
 Small. 
 
 The Great Splanchnic Nerve arises, by filaments, from the 
 sixth to the ninth or tenth thoracic ganglions, inclusively; one 
 or more filaments coming from each ganglion. They are di- 
 rected downwards and forwards on the sides of the dorsal ver- 
 tebra, covered by the pleura, and unite, successively, into a 
 trunk about the eleventh dorsal vertebra. This trunk penetrates 
 into the cavity of the abdomen, between the middle and the in- 
 ternal head of the lesser muscle of the diaphragm, and some- 
 times by the opening for the aorta. 
 
 Having got into the abdomen, the great splanchnic divides 
 into several fasciculi, which diverging from each other, are con- 
 cealed on the right side by the liver, and on the left by the sto- 
 
THE SYMPATHETIC NERVE. 483 
 
 mach. On each side of the aorta there is a large ganglion 
 formed by an assemblage of several smaller ones; it is called the 
 Serai-lunar. Into it terminate, for the most part, these fasciculi: 
 some of them, however, go immediately into the solar plexus, 
 which emanates from the semi-lunar ganglion. 
 
 The Small Splanchnic Nerve is derived, by filaments, from 
 the tenth and the eleventh thoracic ganglions. Having united, 
 they penetrate the crus of the diaphragm, and, reaching the ab- 
 domen, the trunk is divided into two branches, of which the 
 uppermost ascends to join the great splanchnic before its divi- 
 sion, and the lower descends to join the renal plexus. 
 
 Besides these two splanchnic nerves, it frequently happens 
 that there are others which come from the eleventh and twelfth 
 thoracic ganglions, and from the communicating branch between 
 the last thoracic and the first lumbar. They unite into a trunk 
 which goes to the renal plexus, and have been called, by Walter r 
 the Posterior Renal Nerves. 
 
 Of the Solar Plexus. 
 
 The Semi-lunar Ganglion, situated, as mentioned, on the side 
 of the aorta, is somewhat semicircular or oval, and is about an 
 inch long; its form, however, is much diversified in different 
 subjects. The several ganglions of which it is composed, are 
 frequently fused into a single one. That of the right side is 
 more voluminous than the other, and is placed between the as- 
 cending vena cava and the crus of the diaphragm, somewhat 
 above the right renal artery. That of the left is situated upon 
 the left crus of the diaphragm, somewhat below the splenic ar- 
 tery. Between their inferior extremities, there are generally 
 two or three smaller ganglions. 
 
 These several ganglions are united by numerous filaments, 
 which send out many ramifications, and anastomose freely with 
 each other. 
 
 The preceding arrangement may be considered as the root 
 of the solar plexus, which extends from the coeliac artery to the 
 lower margin of the emulgents, and as it is common to the 
 ganglions of the two sides, it is an inch and a half or two inches 
 
484 NERVOUS SYSTEM. 
 
 wide. Bichat has very properly remarked, that this plexus 
 seems to exist for the aorta, as all the divisions which it sends 
 out follow so exactly the branches of this artery, that we are 
 forced to adopt the latter as the basis of the description. The 
 intertexture and the number of the branches emanating from the 
 solar plexus are so complicated, that a description of individual 
 branches would be almost endless, as well as unintelligible; ana- 
 tomists are, therefore, generally agreed to describe the plexus 
 according to the order of the arteries which its detachments ad- 
 here to and surround. 
 
 1. The Diaphragmatic Plexus consists of a few filaments 
 coming from the superior part of the solar, and following the 
 course of the phrenic arteries. Some of them anastomose with 
 the terminating filaments of the phrenic nerve, in the thickness 
 of the diaphragm. 
 
 2. The Plexus ivhich surrounds the Coeliac rfrtery, like it, 
 is quickly disposed into three divisions, which follow the 
 branches of this artery. 
 
 a. The Superior Coronary Plexus of the stomach, is the 
 smallest of the three. It attends the corresponding artery 
 along the lesser curvature of the stomach to the pylorus, sup- 
 plying the stomach continually with very fine filaments. In 
 its course, it anastomoses with the par vagum, and sends fila- 
 ments to the hepatic plexus. 
 
 b. The Hepatic Plexus is the largest of the three. It sur- 
 rounds the hepatic artery and the vena portarum, and, in its 
 course, detaches branches which go with the right gastro-epi- 
 ploic artery to the great curvature of the stomach, and constitute 
 the inferior coronary plexus. Branches are also sent to the pan- 
 creas and to the duodenum. The hepatic plexus then enters 
 the transverse fissure of the liver, and its branches may be 
 traced to the several lobes and to the gall-bladder. 
 
 c. The Splenic Plexus is but small, and surrounds the sple- 
 nic artery. The few branches of which it is composed, anasto- 
 
SYMPATHETIC! NERVfc'. 
 
 mose but rarely with each other. Some of them are distri- 
 buted upon the pancreas, along with the pancreatic branches of 
 the splenic artery; others go with the left gastro-epiploic ar- 
 tery to the left extremity and to the greater curvature of the 
 stomach; the remainder penetrate into the substance of the 
 spleen, through its fissure, along with the branches of the sple- 
 nic artery. 
 
 3. The Superior Mesenteric Plexus is derived from the so- 
 lar, near the superior mesenteric artery; it descends some short 
 distance on the aorta, before it reaches the latter. It passes 
 with the artery between the pancreas and the duodenum, and 
 is then included between the two laminae of mesentery; it is 
 then distributed, by very numerous filaments, along with the 
 branches of the artery, to the whole of the small intestines, to 
 the coecum, and to the ascending and transverse colon. 
 
 4. The Renal Plexus, one on each side, is derived from the 
 lower lateral part of the solar. Two or three ganglions, on the 
 root of the renal artery, contribute to it, and it is also re-en- 
 forced by an addition from the lesser splanchnic nerve. The 
 branches which form this plexus do not anastomose much, till 
 they get near the kidney; they then penetrate into its substance, 
 through the fissure. Some filaments from this plexus go to the 
 capsule renales: others follow the course of the spermatic arte- 
 ry, and constitute the spermatic plexus which goes to the testi- 
 cle in the male, and to the ovarium in the female. 
 
 5. The Inferior Mesenteric Plexus is a continuation of the 
 solar, on the anterior face of the abdominal aorta. It is much 
 smaller than the superior mesenteric plexus, though it receives 
 continually, in its descent, filaments from the lumbar gangli- 
 ons of the sympathetic. It forms frequent anastomoses around 
 the root of the inferior mesenteric artery, and near the superior 
 strait of the pelvis, is resolved into two columns of fibres. One 
 column is distributed along with the, artery to the rectum, to 
 the sigmoid flexure of the colon, and to the left section of the 
 latter, thereby anastomosing with the colic branches of the su* 
 
 VOL. IL 62 
 
486 NERVOUS SYSTEM. 
 
 perior mesenteric plexus. The other column descends into the 
 pelvis, in front of the sacrum, and contributes to form the hy- 
 pogastric plexus, but several of its branches also follow the ex- 
 ternal and the internal iliac arteries. 
 
 Of the Lumbar Ganglions of the Sympathetic. 
 
 These ganglions are five in number, on either side, and are 
 placed anteriorly on the sides of the bodies of the lumbar ver- 
 tebrae, near the anterior margin of the psoas magnus muscle. 
 Their form is irregular; they are smaller than the cervical gan- 
 glions, but larger than the dorsal. 
 
 The last thoracic ganglion is united to the first lumbar by a 
 small branch, which may be considered as the. continuation of 
 the sympathetic. A deficiency of this branch has, however, 
 been several times observed by anatomists; also a deficiency in 
 the connecting nervous chord of the ganglions below. The gan- 
 glions themselves are inconstant in their number, being some- 
 times less than five; they vary likewise in their situation. It 
 is to be understood, however, that- in a majority of subjects, the 
 sympathetic goes on uninterruptedly from one ganglion to ano- 
 ther, sometimes by one branch; on other occasions, by two or 
 three. 
 
 Each lumbar ganglion sends outwards one or more external 
 branches, which applying themselves to the body of the conti- 
 guous vertebra, reach the corresponding intervertebral foramen 
 of the loin?, and join with the anterior branch of the corre- 
 sponding lumbar nerve. Some of these external branches are 
 spent upon the quadratus lumborum muscle. 
 
 Each lumbar ganglion, or the intermediate chord of the sym- 
 pathetic, also detaches branches internally, which are very small, 
 and more or less interwoven with each other. These branches 
 get to the abdominal aorta, and, joining the inferior mesenteric 
 plexus upon it, are distributed along with the latter. 
 
THE SYMPATHETIC NERVE. 487 
 
 Of the Sacral Ganglions of the Sympathetic. 
 
 There are generally three of these ganglions which may be 
 readily found: sometimes four or five. They are situated in 
 a line, on the anterior face of the sacrum, near the correspond- 
 ing foramina for the transmission of the sacral nerves; and are 
 united with each other by intermediate fibres, from one to three 
 in number, which are the continuation of the sympathetic nerve. 
 Bichat asserts, that frequently the first of these ganglions is 
 not united to the last of the lumbar by an intermediate nerve, 
 so that there the continuity of the sympathetic is interrupted. 
 
 Each ganglion sends off, externally, one. or more filaments, 
 by which it is united to the corresponding sacral nerve: it also 
 detaches filaments in this direction to the pyriformis and the 
 levator ani muscles. 
 
 Each ganglion likewise detaches, from its internal margin, 
 ramifications, which go obliquely downwards on the front of 
 the sacrum, and anastomose with corresponding filaments from 
 the opposite side. 
 
 From these ganglions many branches pass forwards to the 
 hypogastric plexus; which is formed by them, by the inferior 
 mesenteric plexus, and by a great many filaments from the lower 
 sacral nerves, principally the third. This plexus is distributed 
 upon the rectum, the bladder, vesiculse seminales, and prostate 
 of the male; and, in place of the two latter in the female, upon 
 the vagina and the uterus. 
 
 The last sacral ganglion detaches downwards one or more 
 filaments, which lie upon the front of the os coccygis, and 
 anastomose with the corresponding filaments from the other 
 side, to form a sort of arch, the convexity of which is down- 
 wards. In this manner, terminates the chord of the sympa- 
 thetic nerve. 
 
488 NERVOUS SYSTEM. 
 
 CHAPTER III. 
 
 OF THE NERVES OF THE MEDULLA SP1NALIS. 
 
 THE nerves of the medulla spinalis, with the exception of 
 the first, which, from its position, is generally called the Sub- 
 occipital by anatomists, are arranged into cervical, dorsal, lum- 
 bar, and sacral, according to the order of the inter-vertebral 
 foramina, through which they pass out: but a much better 
 division would be Cervical,* Thoracic, and Abdominal. Their 
 mode of origin, and the ganglions formed by them, have been 
 pointed out in the account of the medulla spinalis. 
 
 SECT. I. OF THE UPPER NINE SPINAL NERVES. 
 
 These are spent upon the neck, upon the upper extremities, 
 and upon the diaphragm. They consist in the Sub-occipital 
 Nerve, the Cervical, and the First Dorsal. 
 
 Of the Sub-occipital Nerve. 
 
 The Sub-occipital Nerve (Nervus Infra-occipitalis, decimits 
 cerebri] is one of the smallest that proceeds from the medulla 
 spinalis. It has the peculiarity, generally, of arising by a single 
 root, which comes from the anterior chord of the medulla spi- 
 nalis, between the occiput and the first cervical vertebra. This 
 root consists of from two to six or seven fasciculi, situated one 
 above another. When the posterior root exists, it is very 
 small, is composed of from one to three fasciculi, and anasto- 
 moses with the accessory nerve. 
 
 The trunk of this nerve passes from the vertebral cavity 
 through the foramen formed in the dura mater by the vertebral 
 
 In this case, the term Cervical would include the first eight. 
 
UPPER NINE SPINAL NERVES. 489 
 
 artery; it goes out below the latter, and between the occiput 
 and the first vertebra, behind its superior oblique process. It 
 there forms a small long ganglion, like the other spinal nerves, 
 and then divides into an anterior and a posterior fasciculus. 
 
 The anterior fasciculus is the smaller of the two; it follows, 
 in some measure, the course of the vertebral artery, and going 
 forwards to the front of the transverse process, is then divided 
 into several fine filaments, some of which go to the contiguous 
 muscles on the front of the vertebrae; others join themselves 
 to the pneumogastric and hypoglossal nerves, and to the supe- 
 rior cervical ganglion of the sympathetic; others anastomose 
 with the first cervical nerve. 
 
 The posterior fasciculus runs backwards, and is distributed 
 to the recti and the obliqui muscles on the back of the neck and 
 to the complexus. 
 
 Of the Cervical Nerves. 
 
 These are seven in number: the 'first one gets frorrTthe 
 spinal cavity between the atlas and the dentata, and the last 
 betweeg the seventh cervical and the first dorsal vertebra. 
 After the ganglion is formed upon the posterior fasciculus of 
 each, the trunk, made by the union of the two fasciculi, di- 
 vides almost immediately again into an anterior and a posterior 
 trunk. 
 
 Of the First Cervical Nerve. 
 
 The posterior trunk is the largest, and goes directly back- 
 wards. It has its filaments distributed to many of the mus- 
 cles on the upper posterior part of the cervical vertebrae, and 
 to the integuments of the part. Some of the branches ascend 
 through the muscles, near the occiput; and, rising up on the 
 latter, are distributed upon its integuments, and upon the occi- 
 pito-frontalis muscle. 
 
 The anterior trunk is directed forwards under the inferior 
 oblique muscle of the neck, and then divides into two branches: 
 the superior joins the anterior branch of the sub-occipital nerve, 
 and anastomoses with the first cervical ganglion of the sym- 
 
490 NERVOUS SYSTEM. 
 
 pathetic, and with the par vagum and the hypoglossarnerve; 
 the inferior joins the anterior branch of the second cervical 
 nerve. 
 
 Of the Second Cervical Nerve. 
 
 This nerve issues between the second and the third cervical 
 vertebra. Its posterior trunk is spent upon the trapezius, corn- 
 plexus, and other muscles on the back of the neck, and upon 
 the integuments of the latter; it also anastomoses with the pos- 
 terior trunk of the nerve above and below. 
 
 The anterior branch or trunk detaches, first of all, some small 
 filaments to the muscles on the front of the cervical vertebrae; 
 it then divides into two principal fasciculi, one of which ascends 
 and the other descends. 
 
 The ascending branch goes upwards and backwards, and 
 early in its course anastomoses with the first cervical nerve, 
 thereby forming with it a nervous noose; it then mounts upon 
 the occiput, and is distributed upon the parts on the latter 
 region, anterior to the occipital branches of the preceding 
 nerve. 
 
 The descending branch turns over the posterior margin of 
 the sterno-cleido mastoideus muscle, and gives filaments to it. 
 It is distributed afterwards by branches, some of which go to 
 the integuments of the middle and inferior parts of the neck, 
 (nervi subcutanei colli medii et inferiores;) others go to the 
 integuments of the neck upon the angle and the base of the 
 lower jaw, (nervi subcutanei superiores;) and one to the ex- 
 ternal ear, (nervus auricularus cervicalis. ) 
 
 From the anterior fasciculus of the second cervical nerve, 
 there proceeds a filament downwards, which is the upper root 
 of the phrenic nerve; another filament from it joins the superior 
 cervical ganglion of the sympathetic. 
 
 Of the Third Cervical Nerve. 
 
 This nerve comes out between the third and the fourth cer- 
 vical vertebra. Its posterior fasciculus is distributed to the mus- 
 
UPPER NINE SPINAL NERVES. 491 
 
 cles on the back of the cervical vertebrae, and to the integu- 
 ments of the part; anastomosing, by its branches, with the nerve 
 above and below. 
 
 The anterior fasciculus is larger than the posterior, and goes 
 obliquely downwards and outwards at first; it sends anastomo- 
 tic branches to the nerve above and below; it also anastomoses 
 with the superior cervical ganglion of the sympathetic and with 
 the descendens noni. One of its branches, being joined by the 
 branch just spoken of, from the second cervical nerve, consti- 
 tutes the root of the phrenic nerve. But the principal number 
 of its branches are distributed to the integuments along the cla- 
 vicle, (nervi supra-clavicular es,) the upper part of the sternum, 
 and the shoulder; some of them going into the contiguous mus- 
 cles, as the trapezius, subclavius, &c. Several anastomoses exist 
 between the branches of this nerve and the terminating branches 
 of the nervus accessorius. 
 
 The three preceding cervical nerves form, by their anasto- 
 moses with each other, a plexus, consisting in a number of large 
 loops or arches, which lie upon the sides of the muscles con- 
 nected with the transverse processes of the cervical vertebrae. 
 There are commonly two series of anastomoses: the branches 
 of the first, form the second series, and from the latter proceed, 
 for the most part, the several branches which have been de- 
 scribed. These anastomoses are covered by the upper half of 
 the sterno-cleido mastoid muscle, are involved in the cellular 
 membrane surrounding the great vessels of the neck, and are 
 covered by the lympathetic glands. Their intertexture and dis- 
 tribution are such, that no adequate idea of them can be con- 
 veyed without dissection. From this plexus several branches 
 go to the sterno-mastoid muscle, and it is united above to the 
 sub-occipital nerve and below to the fourth cervical. 
 
 Of the Phrenic Nerve. 
 
 The Phrenic Nerve (Nervus Phrenicus, Diaphragmaticus) 
 arises, in the manner seated above, from the anterior fasciculus 
 of the second and of the third cervical, and is assisted generally 
 by two or three filaments from the upper part of the brachial 
 
492 NERVOUS SYSTEM. 
 
 plexus. It descends, vertically, on the humeral side of the in- 
 ternal jugular vein, but removed a considerable distance from it r 
 and is attached, by cellular substance, to the front of the scale- 
 nus anticus muscle. Getting, in its descent, to the internal mar- 
 gin of the latter, it passes into the thorax, at the inner margin 
 of the first rib, between the subclavian artery and the subclavian 
 vein, the latter being before it. It then goes along the superior 
 mediastinum to the pericardium, to the side of which it adheres 
 in front of the root of the lung, being between the pericardium 
 and the corresponding portion of the pleura; it finally reaches 
 the diaphragm, to which it is distributed. 
 
 Just before the phrenic nerve reaches the diaphragm, it radi- 
 ates into several branches, which interchange filaments. Some 
 of the branches are distributed to the convex surface of the dia- 
 phragm; others penetrate the muscle, and are distributed in its 
 thickness and upon its concave surface. On the right side some 
 of these branches pass through the opening for the ascending 
 vena cava, and, thus getting into the abdomen, anastomose with 
 the solar plexus, and with the pneumogastric nerve. 
 
 The phrenic nerve of the left side is nearer to the root of the 
 lung than that of the right, in consequence of the projection of 
 the apex of the heart on that side. Its distribution in other re- 
 spects does not present any remarkable difference from the other; 
 its branches radiate in the same way to the diaphragm, and sup- 
 ply its thickness, as well as its upper and under surfaces. It 
 sends some filaments to the lower part of the oesophagus. 
 
 The phrenic gives off in the neck a few filaments to the sca- 
 lenus anticus, and the rectus anticus major muscle. It also com- 
 municates there, with filaments from the inferior cervical gang- 
 lion, and sometines from the superior cervical. 
 
 Of the Four Inferior Cervical Nerves. 
 
 The trunks of these nerves, on issuing from the intervertebral 
 foramina, have one general mode of distribution, which permits 
 them to be described together or in common. 
 
 The posterior branches are much smaller than those of the 
 preceding cervical nerves; they go backwards between the 
 
UPPER AND LOWER SPINAL NERVE. 493 
 
 complexus and the transversalis colli, and leave filaments in 
 their passage with 'them; they then reach the splenius and the 
 trapezius, to which and to the integuments of the neck they are 
 distributed. 
 
 The anterior branches are large ; they appear on the side of 
 the neck, between the scalenus antic us and medius muscle; some- 
 times perforating the substance of one or the other of these mus- 
 cles. They each detach filaments to the sympathetic. The 
 fourth, also, commonly sends one to the phrenic. They then 
 form the Brachial Plexus, 
 
 Of the Brachial Plexus and the Nerves of the Upper Extremity. . 
 
 The Brachial or the Axillary Plexus is formed by the junction 
 and the intertexture of the four inferior cervical nerves, and the 
 first dorsal or thoracic. It extends from the scaleni muscles to 
 the axilla, on a level with the neck of the os humeri. The nerves 
 at first converge, and are situated somewhat behind the subcla- 
 vian artery where it passes over the first rib ; but are at various 
 heights above it, according to their origin, with the exception of 
 the first dorsal nerve, which has to ascend in order to pass out 
 of the thorax. 
 
 The plexus is formed in the following manner. The fourth 
 and the fifth cervical nerves unite near the scaleni muscles into 
 a single trunk, which runs a short distance downwards, and 
 then splits into two. The seventh cervical and the first dorsal 
 do the same. The sixth cervical is the central nerve of the 
 plexus, and after going downwards two or three inches, it bi- 
 furcates also. Combinations of these primary divisions are formed, 
 which are dissolved, and then reformed, in such a way that a 
 thorough intertexture of the original nerves takes place. This 
 intertexture surrounds the axillary artery somewhat like the 
 braids of a whip-cord, from the clavicle to the os humeri below 
 its head. In this course the axillary plexus passes along with 
 the artery between the subclavius muscle and the first rib, lies 
 in contact with the superior part of the serratus major anticus 
 muscle, and immediately below the articulation of the shoulder 
 joint. The axillary vein is in front of it. 
 
 VOL. II. 63 
 
494 NERVOUS SYSTEM. 
 
 The nerves which proceed from the axillary plexus are the 
 Scapular ; the Thoracic ; the Axillary; the two Cutaneous ; the 
 Radial ; the Ulnar ; and the Median. They supply the superior 
 extremity, including the shoulder and the axilla. 
 
 1. The Nervus Scapularis is a small branch coming common- 
 ly from the upper part of the plexus, as formed by the fourth 
 cervical nerve. It goes backwards in company with the arte- 
 ria dorsalis superior scapulae, through the notch or foramen of 
 the upper costa of the scapula; and having thus got to the pos- 
 terior face of the latter, it gives filaments to the supra spinatus 
 muscle ; continuing its course then on the posterior face of the 
 cervix scapulae, it is lost in filaments upon the infra-spinatus and 
 teres minor muscles. 
 
 2. The Newi Subscapulares of Bichat present some varieties 
 in their origin ; occasionally they come from the same trunk, but 
 commonly each one has its peculiar root from the central parts 
 of the axillary plexus. They are generally three of them. One 
 of them descends behind the axillary vessels, between the sub- 
 scapularis and the serratus major anticus ; it crosses the teres 
 major, and is lost upon the contiguous part of the latissimus dor- 
 si. Another is distributed upon the subscapularis muscle. The 
 third descends along the anterior margin of the subscapularis for 
 a short distance, and distributes filaments to it, to the teres mi- 
 nor and major muscles. 
 
 3. The Nervi Thoracici are primarily two or three in number, 
 and proceed from about the middle of the plexus. The fascicu- 
 li into which they are resolved, may be distinguished as anterior 
 and posterior. The former are distributed, by filaments, to the 
 subclavian muscle, to the pectoralis minor and major, and to thie 
 integuments covering the latter. The posterior thoracic has its 
 origin somewhat concealed by the scalejius anticus muscle. It 
 descends into the axilla, adhering to the serratus major muscle 
 for some distance, and is then distributed by many filaments to 
 this muscle. 
 
 4. The Nervus Axillaris, or Circwnflextts, comes from the infe- 
 
UPPER NINE SPINAL NERVES. 495 
 
 rior part of the plexus. Immediately after its origin, it goes 
 downwards and outwards over the upper extremity of the sub- 
 scapularis muscle. It then winds around the os humeri, between 
 the teres minor and major muscles, observing the course of the 
 posterior circumflex artery, and, finally, terminates on the under 
 surface of the deltoid muscle. 
 
 This nerve sometimes gives off the subscapular, and, indeed, 
 it is usual for anatomists to include the description of the latter 
 in it. As it turns around the bone, it divides into two principal 
 trunks ; the superior goes to the inferior margin of the infra-spi- 
 natus, and to the posterior margin of the deltoides ; the inferior 
 is distributed principally in the substance of the deltoid muscle, 
 but some of its filaments, by perforating the latter, reach the skin, 
 and constitute the nervus cutaneus humeri. Filaments go from 
 the nervus axillaris, in the early part of its course, to the subsca- 
 pularis and the two teres muscles. 
 
 5. The Nervus Cutaneus Internus* arises from the lower part 
 of the axillary plexus, and is one of the smallest of those which 
 go to the arm. It is situated between the median and the ulnar 
 nerve, and adheres almost as far as the elbow, to the basilic 
 vein. In its descent, this nerve detaches several small filaments, 
 which, perforating the fascia of the arm, are distributed to the 
 integuments of the biceps muscle, and to those on the internal 
 face of the triceps. 
 
 Somewhat above the bend of the elbow, at the place where 
 the median basilic vein joins the basilic, but occasionally some 
 inches higher up, the internal cutaneous becomes superficial, and 
 splits into two branches of nearly equal magnitude, which di- 
 verge but little from each other at first. The branch nearest the 
 internal condyle of the os humeri, lies in front of the basilic vein, 
 as it passes over the elbow joint ; and continues in this position 
 for two or three inches : it goes down the front of the fore arm 
 on its ulnar side, but inclines continually to the back of the fore 
 arm. In this course, it detaches small ramifications to the inte- 
 guments about the internal condyle, and about the heads of the 
 flexor muscles ; it also detaches continually, from its sides, small 
 
 * Antonius and Caldani, Tabul. CCLVIII. 
 
496 NERVOUS SYSTEM. 
 
 filaments to the integuments of the ulnar side of the fore arm 
 both anteriorly and posteriorly, some of which reach to the hand. 
 The other, or the external branch of the internal cutaneous, 
 which is nearer the radius, passes beneath the median basilic 
 vein, about six lines from the basilic ; but, just before it does so, 
 it detaches a very superficial cutaneous filament, which crosses 
 in front of the median basilic vein about its middle, and is lost a 
 little below the bend of the arm. The outer branch of the in- 
 ternal cutaneous having got from beneath the median basilic 
 vein, goes superficially as far as the middle of the fore arm 
 without sending off any filaments of note ; it is then divided suc- 
 cessively into several, which diverge to supply the skin down to 
 the wrist. 
 
 6; The Ne-rdus Musculo*Culaneous, or Cutaneous Externus, is 
 somewhat larger than the preceding, and arises from about the 
 middle of the brachial plexus. It descends a short distance, and 
 then perforates obliquely the upper part of the coraco-brachialis 
 muscle. Having passed through this muscle, it continues its 
 course obliquely, between the brachialic internus and the bi- 
 ceps flexor, and, finally, makes its appearance superficially on 
 the outer side of the tendon of the latter. In this course, it 
 distributes filaments to the several muscles with which it is con- 
 nected. 
 
 It afterwards passes the elbow joint under the median cepha- 
 lic vein near its middle, and descends between the skin and 
 the fascia of the fore arm, near the outer margin of the me* 
 dian vein, to the hand : in this course, it is parallel with and 
 on the front of the supinator radii longus. It distributes many 
 filaments to the corresponding integuments on the radial side of 
 the fore arm, and, having at length got near the lower end of 
 the radius, it divides into two orders of fibres, one of which 
 is distributed to the integuments on the dorsal, and the other 
 to those on the palmar side of the hand, about the root of the 
 thumb. 
 
 7. The Nervits Radinlis, or Muscuto Spiralis, arises from 
 the upper portion of the brachial plexus, but in such a way, 
 that filaments from almost every part of the latter run into it. 
 
NERVES OF THE UPPER EXTREMITY. 497 
 
 It is a large trunk which winds spirally around the os humeri, 
 between the triceps muscle and the bone, entering the fissure 
 between the first and the third head of the triceps. It appears 
 on the outside of the 03 humeri, between the brachialis internus 
 and the triceps muscle; running for some inches in contact with 
 their intermuscular ligament. While beneath the triceps, it 
 sends several branches to its heads. There are three principal 
 trunks afterwards from this nerve. 
 
 a. The Ramus Superficialis Dorsalis is sent from it on a line 
 with the point of the deltoid muscle. This branch then goes 
 just below the skin, parallel with and over the external ridge 
 of the os humeri; it, of course, crosses the origin of the mus- 
 cles of the external condyle. Jt continues superficial on the 
 posterior external edge of the supinator radii longus muscle, 
 and terminates in the integuments on the back of the hand. 
 
 The continued trunk of the muscular spiral goes in the inter- 
 stice between the extensor muscles and the brachialis inter- 
 nus, and, at the external condyle, divides into the other two 
 branches, from which filaments proceed to the contiguous heads 
 of the muscles. 
 
 b. The Ramus Profundus Dorsalis perforates the supinator 
 brevis muscle, getting beneath the radial extensors to the back 
 of the fore-arm; it is then distributed in numerous filaments to 
 the muscles on the back of the fore arm, some of its branches 
 reaching to the wrist. 
 
 c. The Ramus Superficialis Anterior seems to be a continua- 
 tion of the main trunk of the nerve, and descending at the an- 
 terior margin of the supinator radii longus muscle, it joins 
 with the radial artery and continues in its company to a short 
 distance below the middle of the radius. Here it crosses the 
 bone obliquely beneath the tendon of the supinator longus, 
 and then divides into a palmar and a dorsal ramuscle; the 
 first being distributed to the muscles and integuments of the 
 thumb, the second terminating so as to supply the back of 
 the hand, of the thumb, fore, middle, and ring fingers to their 
 extremities. , 
 
 8. The Nervus Medianus descends the arm at the inner 
 edge of the biceps muscle; along the anterior surface of the 
 
498 NERVOUS SYSTEM. 
 
 brachial artery, adhering firmly to it, and the deep-seated veins, 
 by cellular substance. As far as the elbow, it sends off no 
 branch of importance. There it lies at the side of the biceps 
 tendon, crosses the lower part of the brachialis internus, and is 
 beneath the aponeurosis of the biceps. It then perforates the 
 pronator teres and gets between the flexor sublimis digito- 
 rum, and the flexor longus pollicis, and enters the palm of 
 the hand under the ligament of the wrist, at the radial edge 
 of the tendons of the flexor sublimis. In the palm it is situ- 
 ated beneath the aponeourosis pulmaris and the arcus sublimis 
 of the arteries. 
 
 The median nerve dispenses the following branches: At 
 the bend of the arm, it furnishes filaments to the heads of the 
 first layer of muscles of the fore arm; and a little below, it de- 
 taches the nervus interosseous, which supplies filaments to the 
 flexor longus pollicis and flexor profundus digitorum. The in- 
 terosseous nerve then descends with the interosseous artery in 
 front of the interosseous ligament, and terminates in the prona- 
 tor quadratus. 
 
 Before the median nerve reaches the wrist, it sends a branch 
 which supplies with filaments the muscles and integuments of 
 the ball of the thumb. In the palm of the hand, it divides and 
 subdivides so as to send a branch to each side of the thumb, of 
 the fore, and of the middle finger, and to one side of the ring 
 finger. These branches go along with the arteries to the ends 
 of the fingers and thumb. 
 
 9. The Nervus Ulnaris comes from the lowest section of 
 the brachial plexus. It descends along the internal anterior 
 part of the triceps muscle, in a groove formed between it, and 
 the intermuscular ligament; it diverges, in this course, gradu- 
 ally from the median nerve till it reaches the elbow, when it is 
 at its greatest point of separation. At the elbow, it is behind 
 the internal condyle, in the groove between it and the olecra- 
 non, and separates the two heads of the flexor ulnaris mus- 
 cle. It then gets to the fore arm between this muscle and 
 the flexor profundus digitorum, and continues between them 
 to within two inches of the wrist joint, when it detaches the 
 Ramus Dorsalis. 
 
NERVES OP THE UPPER EXTREMITY. 499 
 
 The Ramus Dorsalis dips between the ulna and the tendon 
 of the flexor ulnaris, runs along the internal margin of the ulna 
 to the carpus; it then divides into ramuscles, which supply the 
 ulriar side of the integuments on the back of the hand, and on 
 the backs of the two last fingers. At the interval behind, be- 
 tween the heads of the metacarpal bones of the middle and 
 ring fingers, a considerable ramuscle joins one from the branch 
 of the muscular spiral nerve which attended the radial ar- 
 tery. 
 
 The Ulnar Nerve, having given off this dorsal branch, de- 
 scends along the radial margin of the tendon of the flexor ul- 
 naris and the os pisiforme, above the annular ligament, to the 
 palm of the hand. Getting beneath the aponeurosis, it there 
 detaches first a deep-seated branch, which penetrates the mus- 
 cles of the little finger to supply them, the interossei, and the 
 short flexor of the thumb. The ulnar nerve then furnishes a 
 superficial branch, and afterwards divides into three; one for 
 the ulnar side of the little finger, another for the opposing sides 
 of the little and ring finger, and a third which joins the most 
 internal digital branch of the median nerve. 
 
 SECT. II. OP THE THORACIC SPINAL NERVES. 
 
 The Dorsal or Thoracic Spinal Nerves (Nervi Thoracici, 
 Dorsales) consist in twelve pairs, the first pair goes through 
 the intervertebral foramina, between the 'first and the second 
 dorsal vertebra, and the twelfth pair between the last dor- 
 sal and the first lumbar vertebra. The common trunk, formed 
 after the ganglion of each nerve, goes but a short distance when 
 it divides into an anterior and a posterior branch. 
 
 The Posterior Branch (Ramus Dorsalis) of each nerve, 
 goes backwards between the transverse process of the corre- 
 sponding vertebrae, and, having got beneath the multifidus spinae r 
 is commonly subdivided into internal and external ramuscles. 
 The internal are the smaller, and are distributed upon the mus- 
 cles lying upon the spine, as the multifidus, the sacro-lumbalis, 
 
500 NERVOUS SYSTEM. 
 
 longissimus dorsi, and so on: their terminating filaments reach 
 the skin. The external branches descend obliquely outwards 
 beneath the longissimus dorsi, and then issue between the latter 
 and the sacro-lumbalis, to both of which they dispense filaments: 
 they afterwards are divided into branches, which go to the tra- 
 pezius, latissimus dorsi, rhomboideus and to the corresponding 
 integuments. 
 
 The Anterior Branches of the Dorsal Nerves (Kami Sub- 
 costales) correspond with the intercostal spaces of the ribs. 
 Each one, in a short course after its origin, applies itself to the 
 rib just above it, and accompanies the intercostal vessels in the 
 groove, formed in the under margin of each rib. After it pro- 
 ceeds about two-thirds of the length of the rib, it separates gra- 
 dually from it, and goes nearer the middle of the intercostal 
 space and the superior margin of the rib below. To the angle 
 of the rib, each nerve is only covered in front by the pleura, 
 but afterwards it goes between the intercostal muscles. Near 
 the sternum, the branches become superficial by escaping from 
 between the intercostal muscles, and are distributed upon the 
 pectoral muscles, and the adjacent skin. These terminating 
 branches of the five or six inferior dorsal nerves go to the upper 
 portions of the abdominal muscles and their integuments. Not 
 far from its origin, each dorsal nerve anastomoses with the gang- 
 lion or chord of the sympathetic, after the manner described in 
 the account of the latter nerve. 
 
 There are some differences between the thoracic nerves in 
 their manner of distribution. 
 
 The anterior fasciculus of the first, as mentioned, forms the 
 lower part of the axillary plexus ny joining itself to the se- 
 venth cervical. It sends out, however, a subcostal branch 
 which goes along the inferior face of the first rib, supplying'the 
 intercostal muscles and having the general distribution al- 
 luded to. 
 
 The Second Subcostal Branch, besides the common distribu- 
 tion, detaches a fasciculus, which, penetrating between the ribs, 
 gets into the axilla and is augmented by a branch from the 
 
THORACIC SPINAL NERVES. 501 
 
 internal cutaneous nerve of the upper extremity. It then de- 
 scends along the internal posterior face of the arm to the elbow, 
 and in this course detaches several fine filaments to the integu- 
 ments. 
 
 The Third Subcostal Branch in like manner detaches an 
 axillary fasciculus which goes to the inferior part of the arm- 
 pit, to the integuments of which, and to those on the internal 
 face of the arm, it is distributed. It does not descend quite so 
 low as the preceding. These two nerves are called Intercosto- 
 Humeral, and from their origin and course, are supposed to 
 account for the numbness of the arm, in cases of angina pec- 
 toris. 
 
 The Fourth, Fifth, Sixth, and Seventh Subcostal Branches 
 of the Dorsal or Thoracic Nerves, about the middle of the ribs 
 to which they respectively belong, are all divided into two 
 branches. One of them, which is properly speaking the in- 
 tercostal, continues in the intercostal space, giving filaments to 
 its muscles and to the triangularis sterni; it then emerges near 
 the sternum to terminate upon the great pectoral muscle, the 
 mamma, and the integuments of the front of the thorax. The 
 other branch is the external pectoral: it extricates itself earlier 
 from the intercostal space, and is distributed upon the muscles 
 and the integuments on the side of the thorax. 
 
 The remaining subcostal branches, to the eleventh inclu- 
 sively, have very much the same principle of distribution. 
 Their intercostal fasciculi, having reached the anterior ends 
 of the intercostal spaces, pass on to the abdominal parietes, be- 
 tween the transversalis muscle and the internal oblique, to both 
 of which they give filaments. They reach the external margin 
 of the rectus abdominis muscle, and then divide into filaments, 
 some of which go to this muscle, others pierce the fore part of 
 its sheath and are ramified upon the integuments of the front of 
 the abdomen. 
 
 The Twelfth Subcostal Branch of the Dorsal Nerves, sends 
 first a branch downwards, which joins with the first lumbar 
 nerve. It then crosses in front of the quadratus lumborum 
 muscle, to which it gives filaments as well as to the adjoining 
 portion of the diaphragm. It afterwards divides into two 
 branches, the superior of which goes for some distance between 
 VOL. II. 64 
 
502 NERVOUS SYSTEM. 
 
 the two oblique muscles of the abdomen, detaching filaments 
 to them, and finally terminates on the integuments of the ab- 
 domen; the other branch goes between the transversalis and 
 the internal oblique, and is extended to the lower part of the 
 rectus, and to the pyramidalis muscle, to all of which it distri- 
 butes filaments. 
 
 SECT. III. OP THE ABDOMINAL SPINAL NERVES. 
 
 There are five lumbar, and five, sometimes six, sacral nerves 
 on each side; the first of them passes out of the intervertebral 
 foramen, between the first and the second lumbar vertebra; and 
 the remaining lumbar and sacral nerves go, successively, through 
 the foramina in the loins and in the sacrum. 
 
 The anterior fasciculi of these nerves, form a plexus which 
 extends from the upper part of the loins to the lower part of 
 the sacrum; it is designated under the general term of Plexus 
 Cruralis. The posterior fasciculi are much smaller. Those of 
 the loins go backwards between the transverse processes, and 
 are distributed upon the sacro-lumbalis, the longissimus dorsi, the 
 multifidus spinse, and the corresponding integuments. The pos- 
 terior fasciculi of the sacral nerves are not so large, generally, 
 as those of the lumbar: they get out through the foramina, on 
 the posterior face of the sacrum, are distributed to the same 
 muscles; to the origin of the glutaeus magnus, and to the inte- 
 guments of the sacrum, and of the adjoining portion of the but- 
 tocks. 
 
 The Plexus Cruralis, for the purpose of description, has been 
 divided by anatomists into the Plexus Lumbalis, formed by the 
 four superior lumbar nerves, and the Plexus Ischiadicus, formed 
 by the last lumbar and the sacral nerves. 
 
 The Lumbar Plexus (Plexus Lumbalis} is concealed by the 
 psoas magnus muscle, and is placed between it, the lumbar ver- 
 tebrae, and the quadratus lumborum: frequently the roots of the 
 nerves forming this plexus penetrate through the substance of 
 the psoas magnus, and form their unions in it. The plexus is 
 narrow and pointed above, where it commences by the fasci- 
 culus of the last dorsal nerve joining the first lumbar; but it in- 
 
ABDOMINAL SPINAL NERVES. 503 
 
 creases continually afterwards in breadth, owing to the nerves 
 composing it, successively anastomosing farther and farther from 
 the spinal column. From this plexus proceed three principal 
 trunks: the upper one (Cruralis interior) is of considerable 
 size; and goes to the skin and the muscles on the front of the 
 lower extremity; the middle (Nervus Obturator) is not so 
 large as the preceding, and goes through the obturator foramen 
 to the adductor muscles of the thigh; the inferior, formed by the 
 whole of the fifth and a fasciculus from the fourth lumbar nerve, 
 joins the upper part of the sciatic plexus in the pelvis. Besides 
 these, there are several branches of smaller size and of less im- 
 portance, proceeding from the lumbar plexus. 
 
 The Mdomino Crural Branches, according to Bichat, are 
 most commonly three in number, and come from the two upper 
 lumbar nerves. The first of them goes obliquely downwards and 
 outwards, in front of the quadratus lumborum, to the posterior 
 part of the spine of the ilium, and runs for a short distance along 
 the crista of the bone: it gives filaments to the iliacus internus, 
 and to the abdominal muscles, where they border on this part 
 of the bone. Some of the filaments become cutaneous, but the 
 main trunk of the nerve reaches the anterior superior spinous 
 process, by going between the transversalis and the internal ob- 
 lique muscle; it then follows the inguinal arch to the external ring, 
 through which it passes, and is distributed in filaments upon the 
 groin, the pubes, and the scrotum. The second or middle branch 
 arises from the plexus near the preceding; it descends along the 
 external margin of the psoas magnus, and crosses the ilia- 
 cus internus, covered by the peritoneum; near the anterior 
 superior spinous process, it gets between the lower margins 
 of the abdominal muscles, and is distributed upon them there: 
 some of its ramifications get also through the external ring, and 
 may be traced to the scrotum. The third, or the inferior branch, 
 arises from the plexus still lower down, and, after having tra- 
 versed the front of the iliacus internus, it emerges from the pel- 
 vis beneath Poupart's ligament, near the anterior superior spi- 
 nous process; it then divides into filaments which penetrate to 
 the skin through the femoral fascia, and are distributed along 
 the external anterior face of the thigh. 
 
504 NERVOUS SYSTEM. 
 
 The Spermaticns Externus arises from the upper part of 
 the plexus, by a fasciculus from the first lumbar nerve, which 
 is increased by one from the second lumbar. It descends at 
 first in the body of the psoas magnus muscle and then in front 
 of it: it crosses the iliacus internus, somewhat above Poupart's 
 Ligament, by directing its course towards the anterior superior 
 spinous process of the ilium. Here, it involves itself in the 
 edge of the abdominal muscles, and goes on the posterior face 
 of Poupart's ligament; at the internal abdominal ring it joins 
 the spermatic chord of the male, or the round ligament of the 
 uterus of the female. In the first case, it is distributed to the 
 spermatic chord and scrotum; in the second, to the labium ex- 
 ternum and mons veneris. 
 
 The Cutaneus Externus arises from the lumbar plexus be- 
 low the external spermatic. It passes across the iliacus in- 
 ternus towards the anterior superior spinous process, about an 
 inch below 1 the spermaticus externus, and crosses the latter 
 nerve just at that process. Emerging from the abdomen, by 
 penetrating the commencement of Poupart's ligament, it is dis^ 
 tributed in several branches to the integuments of the vastus 
 externus muscle, and along the edge of the rectus femoris: one 
 of the latter extends to the patella. 
 
 The Cutaneus Medius is detached from the anterior crural, 
 an inch or so above Poupart's ligament. It arises among the 
 cluster of branches, which come off there to be distributed to 
 the iliacus internus muscle, and to the muscles of the thigh. It 
 appears, superficially, on the thigh, for the first time, by pene- 
 trating the sartorius muscle, about the internal edge of the rec- 
 tus femoris: it descends then along the same edge of the latter 
 muscle, and is distributed to its integuments. It does not de- 
 scend so low as the external cutaneous. 
 
 The Cutaneus interior arises, also, from the crural nerve. 
 It is on the inner side of the cutaneus medius, emerges from the 
 fascia of the thigh, and crosses the sartorius muscle two or three 
 inches below the cutaneus medius. It is distributed on the in- 
 teguments of the vastus internus muscle, and some of its branches 
 extend to the internal edge of the patella. 
 
ABDOMINAL SPINAL NERVES. 505 
 
 The Cutaneus Infernus arises from the anterior crural nerve, 
 among the same cluster, above Poupart's ligament. It divides 
 into four or five branches of different lengths, and is distributed 
 to the integuments of the adductor muscles, and along the inner 
 front side of the thigh. One branch observes very much the 
 course of the tendon of the adductor magnus, and reaches as far 
 down as the inner side of the knee. 
 
 The Cruralis interior arises from the middle of the lum- 
 bar plexus; at first, it is beneath the psoas magnus muscle; it 
 then gets to its outside, and passes from the abdomen, under 
 Poupart's ligament, about half an inch from the outside of the 
 femoral artery. Before it reaches Poupart's ligament, it gives 
 off a cluster of nerves, several of which go to the iliacus inter* 
 mis muscle; others form the superficial or cutaneous nerves of 
 the thigh just mentioned; and others, the deep-seated or mus- 
 cular branches, which supply the adductor muscles, the four 
 extensors, the pectineus, the sartorius, and the gracilis. 
 
 One of the branches of the anterior crural nerve is seen to 
 accompany the femoral artery, till the artery penetrates the 
 adductor magnus; it then runs along the front margin of the 
 tendon of the adductors in a theca formed by this tendon and 
 the origin of the vastus internus. The nerve alluded to is the 
 Saphenus; it passes afterwards between the internal condyle 
 of the os femoris and the sartorius muscle, attaches itself to 
 the saphena vein, and is distributed to the integuments of the 
 inner side of the leg, and of the upper internal parts of the 
 foot. 
 
 The Nervus Obturatorius is derived from the middle of the 
 lumbar plexus, also; and has very much "the same position, in 
 regard to the psoas magnus, as the anterior crural nerve. It 
 descends into the pelvis from beneath the psoas magnus, near 
 the sacro-iliac articulation; and passes forwards and downwards 
 to the obturator foramen; having got through which it divides 
 into an anterior and posterior branch. The first is distributed 
 to the head of the adductor longus and brevis, and to the gra- 
 cilis and integuments. The second terminates in the obturator 
 externus, and the adductor magnus. 
 
506 NERVOUS SYSTEM. 
 
 The Sciatic Plexus (Plexus Isthiadicus) is formed by the 
 union of the last lumbar with the four upper sacral nerves; 
 the last lumbar, before it joins the plexus^ receiving the branch 
 of the fourth lumbar nerve, which is left after the lumbar plex- 
 us is formed. This plexus is situated at the side of the rectum 
 before the pyriformis muscle. 
 
 The volume of the posterior branches of the Sacral Nerves 
 increases till the fourth; but the fifth and the sixth are much 
 smaller, in fact only fibrillae. 
 
 The anterior branches of the sacral nerves are much larger 
 than the posterior. The four first communicate with the sacral 
 ganglions of the great sympathetic, besides forming the ischi- 
 atic plexus. The third and the fourth, assisted by the sympa- 
 thetic, form the hypogastric plexus. The fifth, and the sixth, 
 when it exists, are distributed to the coccygeus, sphincter, and 
 levator ani.* 
 
 The following small branches go from the Sciatic Plexus.f 
 
 a. Nervi Glutsei: one passes through the upper part of the 
 sciatic notch along with the artery, to the glutseus medius and 
 minimus; another below the pyriformis muscle to the glutseus 
 magnus. 
 
 b. Nervus Pudendalis Longus Inferior, passes under the 
 tuber of the ischium to the glutaeus magnus; perineal mus- 
 cles; urethra and integuments of the penis and scrotum in 
 men; and to the inferior parts of the labium externum in wo- 
 men. 
 
 c. Ramus Femoralis Cutaneus Posterior. This nerve is 
 placed between the integuments of the thigh and the muscles 
 which arise from the tuberosity of the ischium. It sends many 
 branches, successively, to the skin on the back of the thigh; one 
 of its branches, longer than the others, goes down to the ham, 
 
 This is only given as the most frequent arrangement of the sciatic plexus, 
 and of the branches of nerves which proceed from it; other arrangements will 
 often be met with in the cavity of the pelvis, in which not so many sacral nerves 
 are sent to the plexus ischiadicus, and the several branches proceeding from it, 
 depart in a different manner. 
 
 f They sometimes come from a common trunk called, in such case, the Small 
 Sciatic. 
 
ABDOMINAL SPINAL NERVES. 507 
 
 and there divides in|to several filaments, which are distributed to 
 the integuments on the back of the leg. 
 
 The Nervus Pudendalis Longus Superior comes from the 
 third and fourth sacral. It goes in company with the internal 
 pudic artery between the sacro-sciatic ligaments, and then di- 
 vides into two branches; the inferior is distributed to the in- 
 teguments and muscles of the perineum, to the urethra and 
 scrotum; the superior passing along the ramus of the ischmm 
 and pubes with the trunk of the internal pudic artery, is dis- 
 tributed to the obturator internus, accelerator urinse, urethra, 
 and afterwards, getting between the symphysis of the pubes 
 and the penis, terminates on its integuments and the glans 
 penis. 
 
 The Nervus Ischiadicus, or the Great Sciatic, is the com- 
 mon trunk, formed from the sciatic plexus; it is much the 
 largest nerve in the body, and passes from the pelvis between 
 the pyriformis and the geminus superior. It crosses, vertical- 
 ly, the small rotator muscles of the thigh, being concealed by 
 the inferior edge of the glutaeus magnus; it is there about half- 
 way between the tuberosity of the ischium and the trochanter 
 major. Thence it descends on the back of the adductor mag- 
 nus, at the outer edge of the long head of the biceps flexor cru- 
 ris. About half way down the thigh, sometimes a little lower, 
 the Sciatic Nerve divides into the Popliteal, or Posterior Tibi- 
 al, and Peroneal. Occasionally this division takes place as high 
 as the exit of the nerve from the pelvis; but in this case the 
 fasciculi are parallel with each other as far as the middle of the 
 thigh. From the trochanter minor to its usual place of division, 
 this nerve is parallel with, and on the back of the thigh bone; 
 afterwards the two branches begin to diverge. The popliteal 
 nerve continues straight downwards to the back and middle 
 of the knee-joint, and to the interstice between the heads of the 
 gastrocnemius muscle; whereas the peroneal nerve goes along 
 the inner posterior edge of the biceps flexor cruris, and passes 
 between its tendinous insertion and the external head of the 
 gastrocnemius muscle. 
 
 In this course, the following branches are sent from the scia* 
 
50S NERVOUS SYSTEM. 
 
 tic. Twigs to the little rotator muscles of the thigh. The Cu- 
 taneus Internus Superior, which arises near the upper part of 
 the thigh, and is distributed to the skin of the corresponding 
 part. The Cutaneus Internus Inferior, which arises just below 
 the last, and, descending upon the inner head of the gastrocne- 
 mius, is distributed to the integuments of the calf of the leg.- 
 A large trunk, and sometimes, instead of it, distinct branches, 
 which go to the Adductor Magnus, Semi-membranosus, Biceps, 
 and Semi-tendinosus. 
 
 The Peroneal Nerve (Nervus Peroneus) divides at the head 
 of the fibula into two branches, the Peroneus Externus and 
 the Tibialis Anterior; but, before this division, it sends a small 
 branch to the external parts of the knee-joint, and two cutane- 
 ous branches called Peroneo-Cutaneous. The Internal Pero- 
 neo-Cutaneous descends behind the external head of the gas- 
 trocnemius, and, at the bottom of the leg, is united to a division 
 of the posterior tibial called the External Saphenus, or Commu- 
 nicans Tibiae. The External Peroneo-Cutaneous is distributed 
 to the skin, along the fibula. 
 
 The External Peroneal Nerve (Peroneus Externus) gets 
 between the head of the peroneus longus and the fibula, then 
 between the peroneus longus and the extensor longus digito- 
 rum. It descends, at the outer edge of the last muscle, to the 
 inferior third of the leg, giving out, in the mean time, many 
 muscular branches. Here it penetrates the aponeurosis, and 
 divides into cutaneous branches, which supply the lower part 
 of the leg, and the upper surface of the foot and toes. This 
 nerve is called, by the French, the Musculo-Cutaneous of the 
 
 The Anterior Tibial Nerve (Tibialis interior) gets oblique- 
 ly between the fibula, the peroneus longus, and the extensor 
 longus digitorum, to the front of the interosseous ligament, 
 where it accompanies the anterior tibial artery. It passes, with 
 the artery, under the annular ligament of the ankle, and has its 
 terminating filaments going to the muscles and integuments of 
 the upper surface of the foot, as far as the end of the two first 
 
ABDOMINAL SPINAL NERVES. 509 
 
 toes. One of its branches sinks down with the anterior tibial 
 artery to the sole of the foot. High up in the leg it gives fila- 
 ments to the knee-joint, and, in its course downwards, it fur- 
 nishes the muscles on the front of the leg. 
 
 The Posterior Tibial, or Popliteal Nerve, (Nervus Popli- 
 teuSj) having the direction mentioned, is placed between the 
 skin and the popliteal vein. It gets between the heads of the 
 gastrocnemius muscle, and perforates the origin of the soleus; 
 going with the posterior tibial artery, between this muscle and 
 the flexor longus digitorum, to the bottom of the leg. It gives 
 off the following branches: 
 
 a. The External Saphenus, (Saphenus Extermis, or Com- 
 municans Tibise?) which arises above the knee-joint, and, de- 
 scending between the skin and the gastrocnemius, turns out- 
 wardly, and anastomoses with the cutaneous branch, alluded to, 
 of the peroneal nerve. The common trunk, thus formed, passes 
 behind the external ankle, along the external margin of the 
 foot, and terminates on the last toes, having given off a great 
 number of cutaneous branches. 
 
 b. Branches to the heads of the gastrocnemius, soleus, plan- 
 taris, and popliteus. 
 
 c. Branches to the flexor longus digitorum, tibialis posticus, 
 and to the flexor longus pollicis pedis. 
 
 d. A branch through the interosseous ligament, above, to the 
 tibialis anticus. 
 
 e. At the inferior part of the leg many cutaneous filaments, 
 one of which gets to the sole of the foot. 
 
 The Posterior Tibial Nerve, having givea off these branches, 
 divides, in the hollow of the os calcis, into Internal and Exter- 
 nal Plantar Nerves. 
 
 The Internal Plantar (Plantaris Internus) proceeds along- 
 side of the tendon of the flexor longus muscle of the great toe, 
 and the flexor longus digitorum, and gives filaments to the con- 
 tiguous muscles. It then divides in such a way as to furnish 
 VOL. II. 65 
 
510 NERVOUS SYSTEM. 
 
 the two sides of the three first toes and the internal side of the 
 fourth. 
 
 The External Plantar (Plantaris Externus) proceeds with 
 the artery of the same name to the outer edge of the foot, be- 
 tween the flexor brevis digitorum and the flexor accessorius. 
 It is distributed to the two sides of the little toe, and to the ex- 
 ternal side of the fourth toe. One branch penetrates to the in- 
 terosseous muscles and to the transversalis pedis. A branch of 
 considerable size is detached, near the heel, to the muscles and 
 integuments connected with the as calcis* 
 
INDEX TO VOL. II. 
 
 Page 
 
 Abdomen, generally, 5 
 
 General 'Situation of the Viscera of, 7 
 
 Veins of, 264 
 
 Abdominal Aorta, Branches of, . . 222 
 
 Absorbent Glands of the Abdomen, . . 303 
 
 Head and Neck, . . 292 
 
 Lower Extremity, . , 296 
 
 Upper Extremity, . . 294 
 
 Thorax, . . . 310 
 
 Absorbents of the Pelvis, .... 297 
 
 Head and Neck, . . 290 
 Upper Extremities, and the Contiguous 
 
 Parts of the Trunk of the Body, . 293 
 Inferior Extremities, and the Contigu- 
 ous Parts of the Trunk of the Body, 295 
 Organs of Digestion, . . 299 
 Parietes of the Trunk, . . 307 
 Viscera of the Thorax, . . 305 
 Absorbent System, Special Anatomy of, . . 290 
 General Anatomy of, . 281 
 Accelerator Urinae, . . . .98 
 Aorta, and the Branches from its Curvature, * 195 
 Aqueous Humour, ... 427 
 Aqueducts of Ear, .... 445 
 Arachnoidea, ..... 345 
 Areola, ..... 121 
 Arcus Sublimis, . . . . .219 
 Arteries, .... 195 
 Texture of, . . . .164 
 Arteria Basilaris, . 381 
 ad Cutem Abdominis, . , 238 
 Alveolaris Superior, > . . 207 
 Anastomotica, (Arm,) . , 215 
 Anastomotica, (Thigh,) . , 241 
 Articularis Superior Interna, Thigh, . . 241 
 Articularis Superior Externa, " . . 242 
 Articularis M'edia, * . 342 
 Axillaris, . , 212 
 
f>12 INDEX. 
 
 Page 
 
 Arteria Articularis Inferior Externa, Thigh, . 242 
 
 Articularis Inferior Interna, . . . 242 
 
 Auricularis Posterior, . . . 204 
 
 Brachialis, .... 212 
 
 Buccalis, . . . . 207 
 
 Callosa, ..... 380 
 
 Carotis Primitiva, . . . 197 
 Carotis Interna, . . . .198 
 
 Carotis Externa, . . . 199 
 
 Cavernosa Profunda Penis, . . . 235 
 
 Coeliaca, . . . . 223 
 
 Cerebri Posterior, .... 382 
 
 Cervicalis Posterior, . . . 210 
 Choroidea, . . . .380 
 Ciliaris, .... 406, 420 
 
 Circumflexa Anterior of Axillaris, . . 214 
 
 Circumflexa Posterior, . . . 214 
 
 Circumflexa Externa, . . . 239 
 
 Circumflexa Interna, . . . 239 
 
 Circumflexa Ilii, .... 237 
 
 Colica Sinistra Superior, . . . 227 
 
 Colica Sinistra Media, , . . . 227 
 
 Colica Sinistra Inferior . . . 227 
 
 Communicans Posterior of Brain, . . 379 
 
 Dentalis Inferior, . . . 206 
 
 Dorsalis Carpi, . . . . 217 
 
 Dorsalis Hallucis, ... 245 
 
 Dorsalis Manus, .... 219 
 
 Epigastrica, . 236 
 
 Facialis, ..... 201 
 
 Femoralis, .... 237 
 
 Frontalis, . . . 408 
 
 Gastrocnemea . . . 243 
 
 Gastrica, ..... 223 
 
 Gastrica Dextra, . . . 224 
 
 'Gastrica Sinistra, .... 224 
 
 Glutea, .... 233 
 
 Hsemorrhoidea Inferior Externa, . . 235 
 
 Haemorrhoidea Media, ... 232 
 
 Haemorrhoidea Superior Interna, . . 227 
 
 Hepatica, .... 223 
 
 Iliaca Interna, .... 230 
 
 Iliaca Externa, . . . 236 
 
 llio-Lumbaris, .... 230 
 
 Innominata, . . . . 197 
 
 Intercostalis Superior, . . . 209 
 
 Interossea Anterior, . . . 219 
 
 Interossea Posterior, . . . 219 
 
 Infra-Orbitalis, . . . 207 
 
 Inferior Cerebelli, .... 381 
 
 Ischiadica, . 234 
 
INDEX. 513 
 
 Page 
 
 Arteria Lachrymalis, .... 406 
 
 Lingualis, .... 200 
 
 Magna Pollicis, ... 217 
 
 Mammaria Externa, . . . 212 
 
 Mammaria Interna, . . . .210 
 
 Maxillaris Interna, . . . 205 
 
 Malleolaris Externa, . . 244 
 
 Malleolaris Interna, . . . 244 
 
 Mesenterica Inferior, . . . 226 
 
 Mesenterica Superior, . . . 225 
 
 Metatarsea, .... 245 
 
 Meningea Parva, . . . 205 
 
 Meningea Magna .... 205 
 
 Muscularis of Orbit, . , . 407 
 
 Nutritia, Brachialis, .... 215 
 
 Nasalis, .... 408 
 
 Obturatoria, . . . .231 
 
 Occipitalis, .... 203 
 
 CEthmoidea, .... 407 
 
 Palatina Superior, . . . 207 
 
 Palrnaris Profunda, .... 217 
 
 Palpebralis, .... 408 
 
 Peronea, . . . . 246 
 
 Pedioea, .... 245 
 
 Perinea, ..... 235 
 
 Pharyngea Inferior, . . . 202 
 
 Pharyngea Superior, .... 208 
 
 Plantaris Interna, . . . N 247 
 
 Plantaris Externa, .... 247 
 
 Poplitea, .... 241 
 
 Profunda Femoris, .... 238 
 
 Profunda Major Humeri, . . . 215 
 
 Profunda Minor, " . . . ' . 215 
 
 Pterygoidea, .... 206 
 
 Pudica Interna, .... 234 
 
 Radialis, .... 216 
 
 Radialis Indicia, . ... 217 
 
 Recurrens Radialis, . . . 217 
 
 Recurrens Ulnaris, .... 218 
 
 Sacra Media, . . . 229 
 
 Scapularis, . . . 21 S 
 
 Superior Scapulae, . . . 212 
 
 Spheno-Palatina, .... 208 
 
 Superficialis Volae, . . . 217" 
 
 Superior Cerebelli, . . . . 332 
 
 Splenica, .... 224 
 
 Subclaviana, .... 208 
 
 Tarsea, .... 244 
 
 Temporalis, , . . . 204 
 
 Thyroidea Inferior, . . . 209 
 
 Thyroidea Superior, . . . .199 
 
514 INDEX. 
 
 Page 
 
 Arteria Thoracica Longa, .... 218 
 
 Thoracica Acromialis, . . , 213 
 
 Thoracica Axillaris, .... 213 
 
 Transversalis Faciei, . 204 
 
 Temporalis Media, .... 205 
 
 Temporalis Profunda, . . 206 
 
 Aorta, Thoracic Branches of, . . . 220 
 
 Thoracica Superior, . . . 213 
 
 Tibialis Anterior, . . . 243 
 
 Tibialis Postica, "... 246 
 
 Tibialis Recurrens, .... 244 
 
 Tympanica, ... 205 
 Ulnaris, . . . . .218 
 
 Uterina, .... 232 
 Vertebralis, . . . 209, 380 
 
 Arteriae Bronchiales, .... 220 
 
 (Esophageae, .... 221 
 
 Capsu lares, .... 227 
 
 Emulgentes, .... 227 
 
 Gastricae Breves, ... 225 
 
 Gemellse, . 243 
 
 Intercostales Inferiores Aorticae, . . 221 
 
 Iliacas Primitivae, .... 230 
 
 Lumbares, .... 228 
 
 Mediastinales Posteriores, . . . 221 
 
 Pancreaticae Mediae et Sinistrae, . 224 
 
 Phrenicae, . . . . 222 
 
 Profundae Perforantes Fempris, . * 240 
 
 Pudendae Externae, . . . 238 
 
 Sacrae Laterales, . . 231 
 
 Spermaticae, .... 228 
 
 Vesicales, ... 232 
 
 Arytenoid Cartilages, . 125 
 
 Aryteno-Epiglottideus, . 129 
 Arytenoideus Obliquus, . . .129 
 
 Trans versus, . . . 129 
 
 Auditory Nerve, ..... 447 
 Axillary Artery, Branches of, . .212 
 
 Biliary Ducts, ... 61 
 
 Bile, ..... 62 
 
 Bladder, . . . . .76 
 
 Structure of, ... 7? 
 Blood, . . . . . .173 
 
 Coagulating Lymph of, . . . 177 
 
 Red Globules of, . . . 178 
 
 Serum of, . . . . 176 
 
 Bones of Tympanum, . . . 437 
 
 Brachial Artery, Branches of, . . 212 
 
 Broad Ligaments of the Uterus, . , 112 
 
 Brain, ..... 335 
 
INDEX. 515 
 
 Page 
 
 Brain, Veins of, . . 382 
 
 Carotids, Branches of, . . . . 198 
 
 Capillaries, . 158 
 
 Capsule of Glisson, .... 13 
 
 Caul, Situation of, .... 8 
 
 Coecum, 37 
 
 Cerebellum, ..... 351 
 
 Cerebrum, ..... 354 
 
 Chambers of Eye, . . . . 428 
 
 Choroidea, ..... 414 
 
 Chorda Tjmpani, ..... 448 
 
 Chylopoietic Viscera, .... 22 
 
 Assistant, . . .54 
 
 Cilia, ..... 395 
 
 Circulation of the Foetus, Peculiarities of, . . 271 
 Peculiarities of, connected with 
 
 its Nourishment, . 276 
 
 Circulatory System, .... 151 
 
 General Anatomy of, . . 151 
 Considerations on General Anatomy 
 
 of, . . . 151 
 
 Special Anatomy of, . . 183 
 
 Clitoris, . . . . .105 
 
 Coccygeus, Muscle, .... 100 
 
 Cochlea, ..... 442 
 
 Colon, . . . . . . 38 
 
 Commissura Anterior, .... 369 
 
 Conjunctiva, ..... 396 
 
 Corona Glandis, .... . 84 
 
 Cornea, ..... 412 
 
 Corpus, Callosum, . . . 360 
 
 Cavernosurn, .... 85 
 
 Ciliare, ..... 414 
 
 Dentatum, . . . . 353 
 
 Fimbriatum, . . . .115 
 
 Spongiosum, .... 86 
 
 Spongiosum Vaginae, . . .108 
 
 Corpora Striata, .... 359 
 
 Grura Cerebri, - . . . . . 357 
 
 Couper's Glands, .... 90 
 
 Coronary Arteries, . . . 193, 197 
 
 Veins, . . . . 194 
 
 C remaster Muscle, . . . .95 
 
 Cricoid Cartilage, .... 124 
 
 Crico-Arytenoideus Posticus, . . . 128 
 
 Lateralis, . . . 128 
 
 Crico-Thyroideus, . . . . 128 
 
 Dartos Muscle, : . . . 91 
 
 Ductus Ejaculatorius, . . . .88 
 
 
516 INDEX. 
 
 Page 
 
 Ductus Lactiferi, . . . . 119 
 
 Duodenum, . . . . . 31 
 
 Dura Mater, , 336 
 
 Sinuses of, ... 339 
 
 Ductus Wirsungii, . . . .67 
 
 Ear, . . . . 430 
 
 Eminentise Mammillares, .... 
 
 Olivares, ... 
 Epididymis, ..... 
 
 Epiglottis, ... . . . 125 
 
 Erector Clitoridis, .... 106 
 
 Penis, .... 98 
 
 Eustachian Valve, . . . . .186 
 
 Tube, .... 
 
 External Iliac Artery, Branches of, . . 236 
 
 Eye, ..... 394 
 
 Eyeball, . . . . 410 
 
 Eyelids, . . * 394 
 
 Fallopian Tubes, . . . . .115 
 
 Foetus, Peculiarities of, arising from want of Respiration, 272 
 Fornix, .... 
 
 Fossa Navicularis, .... 87 
 
 Ovalis, . . . . .186 
 
 Fourchette, ..... 105 
 
 Fourth Ventricle, . . . .370 
 
 Frsenum Penis, . . . 84 
 
 Frontal Nerve, .... 455 
 
 Fundamental Portion of Cerebellum, . 354 
 
 Ganglion Cavernous, .... 476 
 
 Cervical, ... 478 
 
 Lumbar, .... 486 
 
 Lenticular, .... 452 
 
 Spheno-Palatine, .... 392 
 
 Sacral, . . . . 487 
 
 Thoracic, .... 482 
 
 Gall Bladder, .... 59 
 
 Glandulse Odoriferae Tysonii, . . .84 
 
 Pacchioni, .... 344 
 
 Palpebrarum, .... 397 
 
 Glandula Pituitaria, .... 358 
 
 Pinealis, .... 364 
 
 Globus Major, .... 95 
 
 Minor, . . . . .95 
 
 Glands of Brunner, .... 26 
 
 Peyer, . . . . .31 
 
 Head and Neck, Veins of, . . 249 
 
 Heart, . . . . . .183 
 
 Right Auricle of, ... 185 
 
 Right Ventricle of, . . . .178 
 
INDEX. . 517 
 
 Page 
 
 Heart, Left Auricle of, . . . .189 
 
 Left Ventricle of, . , . 190 
 
 Blood Vessels of, . . . 193 
 
 Texture of, . . . 191 
 
 Hymen, . . . . .109 
 
 Ileo-Colic Valve, . . . 37 
 
 Ileum, . . . . . .32 
 
 Incus, . . . . . 438 
 
 Internal Iliac Artery, Branches of, . . 230 
 
 Inguinal Glands, .... 296 
 
 Intestinal Canal, . . . . .27 
 
 Intestine, Small, .... 28 
 
 Large, . .... 34 
 
 Small, Situation of, ... 8 
 
 Large, Situation of, ... 8 
 
 Iris, . . . . . 418 
 
 Jejunum, . . . . t. 32 
 
 Kidneys, . . . . . 70 
 
 Situation of, . . . .9 
 
 Minute Structure of, . . . 71 
 
 Labia Interna, . . . . . 106 
 
 Externa, . . . . 104 
 
 Labyrinth, ..... 440 
 
 Lachrymal Apparatus, .... 400 
 
 Caruncle, . . , . . 402 
 
 Ducts, . . . . . v 401 
 
 Gland, . . . .400 
 
 Nerve, . . . 455 
 
 Sac, . . . . .403 
 
 Larynx, . . . . % 123 
 
 Lateral Ventricles, .... 366 
 
 Levator Ani, . . , 101 
 
 Lens, . . . . .425 
 
 Ligamentum Ciliare, . . . . 414 
 
 Denticulatum, . . . 329 
 
 Palpebrale Internum, . 394 
 
 Externum, . . . 396 
 
 Liver, . . . . . 54 
 
 Organization of, . , . 57 
 
 Situation of, . . . 7 
 
 Lower Extremity, Veins of, . . . , 262 
 
 Lungs, . . . . 141 
 
 Texture of, . . . .142 
 
 Lymphatic Glands, i 287 
 
 Mesocolon, .... 34 
 
 Malleus, . ... 437 
 Meatus Externus, ..... 430 
 VOL. II. 66 
 
518 INDEX. 
 
 Mediastinum Anterior, .... 147 
 
 Posterior, .... 147 
 
 Superior, .... 148 
 
 Medulla Oblongata, .... 346 
 
 Spinalis, Nerves of, . . 325, 488 
 
 Membrana Pupillaris, .... 429 
 
 Tympani, . . . 435 
 
 Membranous Labyrinth, .... 443 
 
 Mesentery, . . . . . 33 
 
 Mitral Valve, . . . . .190 
 
 Mons Veneris, . . . . 104 
 
 Mucous Glands, and Apparatus, . . .88 
 
 Membranes, General Anatomy of, . . 48 
 
 Musculus Anterior Auriculae, . . . 434 
 
 Antitragicus, . . . 433 
 
 Attollens Auriculae, . . . 434 
 
 Helicis, Major et Minor, . . 433 
 
 Laxator Tympani, . . . 439 
 
 Levator, Palpebrae Su periods, . . 398 
 
 Obliquus Oculi Superior, . . . 399 
 
 Obliquus Oculi Inferior, . . 399 
 
 Rectus Oculi Superior, . . . 398 
 
 Rectus Oculi Externus, . . 398 
 
 Rectus Oculi Inferior, . . .398 
 
 Rectus Oculi Internus, . , . 399 
 
 Retrahens Auriculas, . . . 433 
 
 Stapedius, .... 439 
 
 Tensor Tarsi, .... 404 
 
 Tensor Tympani, . . . 439 
 
 Tragicus, .... 433 
 
 Transversus Auriculae, . . 433 
 
 Mucous Coat, minute Anatomy of, . .- . 40 
 
 Nervous System, .... 315 
 General Anatomy of, . . .315 
 
 Nasal Nerve, .... 454 
 
 Nerves of Encephalon, .... 370 
 
 Ear, . . . . 446 
 
 Nervus Abclomino Cruralis, . . . 503 
 
 Abdominal Spinal, . . 502 
 Accessorius, . . . 378, 468 
 
 Auditorius, .... 376 
 
 Auricularis, .... 464 
 
 Cervical es, . . . . 489 
 
 Circumflexus, .... 494 
 
 Cruralis Anterior, . . . 505 
 
 Cutaneus Externus, . . . 496 
 
 Cutaneus Internus, . . . 495 
 
 Cutaneus Femuris Externus, . . 504 
 
 Cutaneus Medius, . . . 504 
 
 Cutaneus Femoris Internus, . 505 
 
INDEX. 519 
 
 Nervus Cutaneus Anterior, 
 
 Cutaneus Femoris Posterior, 
 
 Descendens Noni, 
 
 Facialis, 
 
 Glosso-Pharyngeus, 
 
 Glutei, . 
 
 Hypoglossus, . 
 
 Infra Maxillaris, 
 
 Infra Orbitalis, 
 
 Ischiadicus, 
 
 Laryngeus Inferior, 
 
 Laryngeus Superior, 
 
 Maxillaris Superior, 
 
 Medianus, 
 
 Motor Externus, 
 
 Motor Oculi, 
 
 Nasalis Internus, 
 
 Naso-Palatinus, 
 
 Obturatorius, . 
 
 Olfactorius, 
 
 Opticus, 
 
 Patheticus, 
 
 Palatinus, 
 
 Peroneus, 
 
 Petrosus Superficialis, 
 
 Petrosus Profundus, . 
 
 Pharyngeus Superior, 
 
 Phrenicus, . 
 
 Plantaris Externus, 
 
 Plantaris Internus, . 
 
 Pneumogastricus, 
 
 Portio Dura, 
 
 Portio Mollis, . 
 
 Popliteus, . 
 
 Pudendalis Superior, 
 
 Pudendalis Inferior, 
 
 Pterygo-Palatinus, 
 
 Radialis, . 
 
 Scapularis, 
 
 Saphenus Externus, . 
 
 Spermaticus Externus, 
 
 Splanchnicus, 
 
 Spiralis, 
 
 Subcostales, 
 
 Suboccipitalis, . 
 
 Subscapularis, 
 
 Sympatheticus, . 
 
 Sympathi 
 Tris:emin 
 
 Thoracici, 
 Tibialis Anterior, 
 Trochlearis, 
 
520 INDEX. 
 
 Page 
 
 Nervus Ulnaris, . . . 498 
 
 Vidianus, .... 449, 458 
 
 Neurilemma of Nerves, .... 317 
 
 Nose, . . ... 383 
 
 Blood vessels of, . . . . 393 
 
 Nerves of, . . 390 
 
 Omenta, . . . . 13 
 
 Omentum Colicum, . .14 
 
 Omentum Gastro Splenicum, . . .15 
 
 Majus, or Gastro Colicum, . . 14 
 
 Minus, or Hepatico Gastricum, . . 13 
 
 Ophthalmic Nerve,. . . . 453 
 
 Optic Nerve, . .. . . .371 
 
 Orbit, Arteries of, . . 406 
 
 Nerves of, . . . . . 406 
 
 Veins of, .... 409 
 
 Orbiculare, os, . . . . .438 
 
 Organs of Assimilation, . . . 4 
 
 Generation, . . . .83 
 
 Generation in the Male, . . 83 
 
 Generation in the Female, . . . 104 
 
 Respiration, . . . . 123 
 
 OsTincae, . . . . .111 
 
 Ostium Venosum* .... 187, 190 
 
 Ovaries, . . . . .116 
 
 Pancreas, . . . . .66 
 
 Situation of, . . . . 8 
 
 Minute Structure of, .. . .67 
 
 Papilla Mammae, . . . . 118 
 
 Pelvic Fascia, . . . . .102 
 
 Penis, . . . . . 83 
 
 Pericardium, ... r . . 184 
 
 Perineal Fascia, .... 93 
 
 Perineum, Muscles and Fascia of, . .97 
 
 Peritoneum, ..... y io 
 
 Pia Mater, ..... 344 
 
 Pigmentum Nigrum, of Eye, . . . 415 
 
 Pituitary Gland, ..... 358 
 
 Membrane, .... 386 
 
 Pleurae, ..... 145 
 
 Plexus Brachialis, .... 493 
 
 Cardiacus, . 480 
 
 Choroides, .... 368 
 
 Cceliacus, ..... 484 
 
 Coronarius, .... 484 
 
 Hepaticus, .... 484 
 
 Ischiadicus, .... 506 
 
 Lumbalis, . . . . - s 502 
 
 Mesentericus Inferior, . . . 485 
 
 Mesentericus Superior, . . . 485 
 
INDEX: 521 
 
 Page 
 
 Plexus Diaphragmaticus, . . . 484 
 
 Renalis, .... 485 
 
 Solaris, ..... 483 
 
 Splenicus .... 484 
 
 Plica Semilunaris, . . . 402 
 
 Pori Biliarii, . . . . 58 
 
 Prepuce, . . . . .84 
 
 Primitive Iliac Artery, Branches of, . . 230 
 
 Processus Ciliaris, . . . . 415 
 
 Prostate Gland, .... 89 
 
 Protuberantia Annularis, .... 350 
 
 Pulmonary Artery, . . . . 189 
 
 Recfum, . . . . .38 
 
 Renal Capsules, .... 75 
 
 Minute Structure of, , . . 75 
 
 Situation of, ... 9 
 
 Retina, . . . . . .421 
 
 Round Ligaments of the Uterus, . . . 113 
 
 Sacculus Ellipticus, .... 444 
 
 Sphericus, . 444 
 
 Sclerotica, . . . . .411 
 
 Scrotum, \ 91 
 
 Semicircular Canals, . . . .441 
 
 Seminal Vesicles, . . . . 88 
 
 Senses, . . . . . .383 
 
 Serous Membranes, generally, . . . 10 
 
 General Anatomy of, . .18 
 
 Septum Lucidum, .... 363 
 
 Sinuses of Valsalva, . . . .191 
 
 the Vertebral Column, . . 257' 
 Sinus Cavernosus, .... 342 
 
 Circularis, .... 343 
 
 Laterales, . . . . .340 
 
 Longitudinalis, Inferior, . . . 341 
 
 Longitudinalis, Superior, . . . 339 
 
 Occipitalis, .... 342 
 
 Petrosi, . . . . .341 
 
 Quartus, . . . . 441 
 
 Soemmering's Foramen, .... 422 
 
 Spermatic Chord, .... 95 
 
 Sphincter Ani, . . . . IQQ 
 
 , . . ._ ^ginae, 109 
 
 fepinal Marrow, . 325 
 
 Membranes of, . . . 331 
 
 Nerves of . . . .329 
 
 Vessels of, 334 
 
 Spleen, . . . 62 
 
 , Situation of, . . . . g 
 
 Intimate Structure of, . . 64 
 
522 INDEX. 
 
 Page 
 
 Stapes, . . . 438 
 
 Stomach, . . . . .22 
 
 Situation of, . . 8 
 
 Subclavian Artery, Branches of, . . 208 
 
 Tarsi, ..... 396 
 
 Taenia Striata, . . . . .360 
 
 Tela Choroidea, . . . . . 345 
 
 Testicles, . ... 90 
 
 Minute Structure of, . . . 94 
 
 Thalami Optici, ... .358 
 
 Third Ventricle, .... 367 
 
 Thyraus Gland, ... .139 
 
 Thyreo-Arytenoideus, Muscle, ... 128 
 
 Epiglottideus, .... 129 
 
 Hyoideus, .... 128 
 
 Thyroid Gland, . . . . .137 
 
 Cartilage, .... 124 
 
 Thoracic Aorta, Descending Branches of, . . 220 
 
 Ducts, .... 310 
 
 Trachea, . . . .133 
 
 Transversus Perinei, (Male,) ... 99 
 
 (Female,) . . .109 
 
 Triangular Ligament of the Urethra, . . 101 
 
 Tubuli Seminiferi, ; . . .94 
 
 Tuber Cinereum, .... 358 
 
 Tubercula Quadrigemina, .... 365 
 
 Tunica Albuginea, .... 93 
 
 Hyaloidea, . . . .424 
 
 Vaginalis, .... 92 
 
 Tympanum, ..... 434 
 
 Umbilical Artery, .... 277 
 
 Vein, . . 276 
 
 Upper Extremity, Nerves of, . . . 493 
 
 Veins of, . . . .258 
 
 Ureter, . . . . . . 74 
 
 Urethra, (Male,) ..... 86 
 
 (Female,) . . . .107 
 
 Urinary Organs, . . . . .69 
 
 Uterus, and its Appendages, . . . 110 
 
 Vagina, . . . . . .107 
 
 Valve of Vieussens, . . 353 
 
 Vasa Arteriarum, . . . . .168 
 
 Efferentia, .... 94 
 
 Recta, . . 94 
 
 Vorticosa, . . . . 417 
 
 VasDeferens, ... 96 
 
 Vena Azygos, . 256 
 
 Axillaris, . 261 
 
 Basilica, .... 260 
 
INDEX. 523 
 
 Page 
 
 Vena Cava Inferior, .... 266 
 
 Cava Superior, .... 255 
 
 Cephalica, ... 259 
 
 Choroidea, .... 417 
 Facialis, . . . . .249 
 
 Fernoralis, .... 262 
 
 'Hypogastrica, .... 264 
 
 Hemiazygos, .... 256 
 
 Iliaca Externa, .... 264 
 
 Iliaca Interna, .... 264 
 
 Iliaca Primitiva, .... 266 
 
 Innominata, .... 254 
 
 Intercostalis Superior, . . . 256 
 
 Jugularis Externa, . . . 252 
 
 Jugularis Interna, .... 253 
 
 Lingualis, .... 250 
 
 Mammaria Interna, .... 256 
 
 Maxillaris Interna, . . . 252 
 
 Mediana, ..... 260 
 
 Meseraica Inferior, . . . 269 
 
 Meseraica Superior, . . . . 270 
 
 Occipitalis, .... 251 
 Ophthalmica, . . . .409 
 
 Palatina Inferior, . . . 250 
 Pharjngea, . . . .251 
 
 Poplitea, .... 262 
 
 Portarum, .... 269 
 
 Ranina, .... 250 
 Sacra Media, . . . .266 
 
 Saphena Minor Externa, . . . 262 
 
 Saphena Magna Interna, . . . 263 
 
 Splenica, .... 269 
 
 Subclavia, .... 261 
 
 Submentalis, .... 250 
 
 Temporalis, .... 252 
 
 Temporalis Superficial, . . . 251 
 
 Thjroidea Inferior, .... 255 
 
 Thyroidea Superior, . . . 251 
 
 Vertebralis, .... 255 
 
 Veins, Texture of, . . . 169 
 
 Venae Capsulares, .... 268 
 
 Diploicae, , . . . 251 
 
 Emulgentes, . 268 
 
 Hepaticae, . . . 268 
 
 Lumbales, .... 267 
 
 Phrenicae Inferiores, . . . 269 
 
 Spehnaticae, .... 267 
 
 Ventricles of the Brain, . . . 366 
 Verumontanum, . . . . .89 
 
 Vesical Triangle, . ' . . 78 
 
 Vestibulum of Vulva, .... 107 
 
524 INDEX. 
 
 Page 
 
 Vestibulum, Ear, . . . . 441 
 
 Vitreous Humour, .... 423 
 
 Vulva,. . ... 104 
 
 Willis, Circle of, . . . . 382 
 
 Winslow, Fora-men of, . . .15 
 
 THE END. 
 
A NEW WORK. 
 
 CAREY, LEA & BLANCHARD, Philadelphia, 
 
 HAVE JUST PUBLISHED, 
 
 POPULAR MEDICINE; 
 
 OR, 
 
 FAMILY ADVISER: 
 
 CONSISTING OF 
 
 OUTLINES OF ANATOMY, PHYSIOLOGY AND HYGIENE, 
 
 WITH SUCH HINTS ON THE 
 
 PRACTICE OF PHYSIC, SURGERY, 
 
 AND THE 
 
 DISEASES OF WOMEN AND CHILDREN, 
 
 AS MAY PROVE USEFUL IN FAMILIES WHEN REGULAR PHYSICIANS CANNOT BE 
 
 PROCURED I 
 
 BEING A COMPANION AND GUIDE FOR INTELLIGENT PRINCIPALS OF MANUFACTORIES, PLAN- 
 TATIONS, AND BOARDING SCHOOLS, HEADS OF FAMILIES, MASTERS OF VESSELS, 
 MISSIONARIES, OR TRAVELLERS ; AND A USEFUL SKETCH FOR YOUNG MEN 
 ABOUT COMMENCING THE STUDY OF MEDICINE. 
 
 BY REYNELL COATES, M. D., 
 
 Fellow of the College of Physicians of Philadelphia Honorary Member of the Philadel- 
 phia Medical Society Correspondent of the Lyceum of Natural History of New 
 York Member of the Academy of Natural Sciences of Philadelphia Formerly Resi- 
 dent Surgeon of the Pennsylvania Hospital, &c. Assisted by several Medical Friends, 
 
 IN ONE VOLUME, OCTAVO. 
 
EXTRACTS FROM THE PREFACE. 
 
 "An incalculable advantage which results from the extension of cor- 
 rect medical knowledge beyond the limits of the profession, is the diffi- 
 culty which it throws in the way of the ignorant pretender, by enabling 
 the public to judge more correctly of medical information. For, although 
 the writer contemns the arrogance of those who have ventured, in simi- 
 lar works, to persuade their readers that all opinions differing from their 
 own are the offspring of ignorance or folly, yet he believes that the 
 principles laid down, and the practical directions given, in the following 
 pages, will be found generally in accordance with received doctrines. 
 They will therefore enable the patient, or his friends, so to direct their 
 questions to the practitioner, and to comprehend the replies, as to dis- 
 tinguish between the mere empiric, and the man who has really studied 
 his profession; an advantage of immense value to both parties, in situ 
 ations distant from large cities. 
 
 Among the strongest proofs of the propriety of the present undertak* 
 ing, are the constant demand for a popular medical guide of some kind, 
 and the circumstance that the very few works of this character now 
 extant, which can be considered as adapted to the present state of the 
 science, have their subject matter arranged in alphabetical order: an 
 arrangement which precludes the possibility of preserving the recollec- 
 tion of the mutual relations of facts, and destroys that system which is 
 best calculated to aid the memory, facilitate reference, and impress cor- 
 rect principles. 
 
 In executing his task, the author has endeavoured conscientiously to 
 inculcate such caution as is calculated to secure his readers against a 
 rash dependence upon their own partially enlightened endeavours, when 
 other and more efficient assistance is at hand, while he has exerted 
 himself to communicate, in a form as much condensed as possible, 
 whatever information he considers likely to aid the cause of humanity 
 under less favourable circumstances. 
 
 These explanations are due to the practitioners of an honourable pro- 
 fession. To those who propose to commence the study of that profes- 
 sion, it may be stated that, under the present organization of our 
 universities and medical colleges, the pupil, at the moment of entering 
 upon his career, is overwhelmed by the quantity of scientific matter 
 forced upon his attention by the number and variety of the lectures he 
 is called upon to attend. These lectures treat of a variety of sciences, 
 the very terminology of which is unknown to him; and much of the 
 value of his first year of study is usually lost in obtaining a few general 
 ideas, laboriously gleaned from a great mass of more profound, but, to 
 him, unintelligible learning. Some weeks spent in perusing and reflect- 
 ing upon the contents of the first three chapters of the present work, 
 
will communicate, it is confidently believed, such broad views and im- 
 pressions on anatomical, physiological, and hygienic subjects, as will 
 enable him to listen with pleasure and advantage to the first course of 
 medical instruction; that tedious, and, to many, almost intolerable 
 portion of the labour of a student. 
 
 The best advice that can be given to an individual actually suffering 
 under disease, or desirous of pursuing such a course of diet, exercise, &c. 
 as is likely to promote his health, and invigorate and preserve the force 
 of his constitution, is, most unquestionably, to recommend a consultation 
 with some deservedly eminent physician. But the directions and rea- 
 sonings of a physician are better understood by a patient who has him- 
 self some knowledge of the first principles of medicine. This knowledge 
 is also a protection against the machinations of wonder-working empi- 
 rics; for who, that has the slightest idea of the structure of the most 
 complicate of all the works of nature, would confide the management 
 of such a delicate machine to the hands of an ignorant pretender. 
 
 It is not always possible to obtain the desired assistance in due time, 
 and in many situations it is altogether impracticable to obtain it at alL 
 There is, therefore, no intelligent man who may not find his own com- 
 fort consulted, and his sphere of usefulness increased, by studying the 
 first principles of physiology, hygiene, practical medicine, and surgery. 
 
 To heads of families, principals of large manufactories, seminaries, 
 and landed estates, missionaries on foreign stations, and the captains of 
 vessels, such knowledge is still more important. 
 
 The " Family Adviser" being designed not to supersede the family 
 physician, but merely to supply his place, when inaccessible, it will be 
 found that the practical part of the work dwells chiefly on diseases of 
 an acute character, and that when chronic complaints are mentioned, 
 directions for the management of the earlier stages have received more 
 attention than the after treatment. Those diseases which are incurable 
 in their nature, or which defy domestic treatment at any stage, are omit- 
 ted, or but lightly touched upon ; and when such remedies or operations 
 as are employed only by the profession become the subject of remark, 
 they are introduced merely to gratify the natural curiosity of the reader. 
 When, in the current of a case, the requisite treatment becomes danger- 
 ous, or demands superior skill, the subject is generally fore-closed by 
 referring the reader to competent medical advisers. 
 
 The work is divided into two parts ; of which the first is descriptive 
 and theoretical, the second practical. It is desirable that all who would 
 qualify themselves for rightly comprehending the practical part should 
 peruse, previously and attentively, the first four chapters, which may be 
 regarded as introductory. 
 
 An Appendix contains a list of many of the simple medicines and 
 compound prescriptions recommended in the work, with the mode of 
 preparing the latter. It is remarked, that the most experienced prac- 
 titioners generally employ the smallest number of remedies, as the most 
 able mechanic often uses but few implements. Instead, then, of follow- 
 ing the example of his predecessors, by perplexing the minds of his 
 readers with a history of a great multitude of medicines, the writer has 
 confined his attention to those of^established reputation, and named in 
 the body of the work." 
 
CONTENTS OF THE VOLUME. 
 
 PART FIRST. 
 
 OUTLINES OF ANATOMY, PHYSIO- 
 LOGY AND HYGIENE. 
 
 CHAPTER I. 
 
 PRELIMINARY REMARKS ON THE 
 ORGANIZATION OF ANIMALS. 
 
 CHAPTER II. 
 
 STRUCTURE OF THE HUMAN BODY. 
 
 Of the cellular tissue. 
 Of fat, or adipose tissue. 
 Of the bones, or osseous system. 
 Of the skeleton. 
 
 Of the muscles or muscular system, anato- 
 my. 
 
 Of the digestive apparatus. 
 Of the stomach. 
 Of the duodenum. 
 Of the liver. 
 Of the pancreas. 
 Of the small intestine. 
 Of the great intestine. 
 Of the circulation. 
 Of the circulating fluids. 
 Of the route of circulation. 
 Of the portal vessels. 
 Of the capillaries. 
 Of the function of nutrition. 
 Of the function of absorption. 
 Of respiration. 
 
 Of the apparatus of respiration. 
 Of secretions. 
 Of the urinary apparatus. 
 Of the urine. 
 
 Of the skin or integument. 
 Of the nerves. 
 Of the brain. 
 On the duplicature of certain organs. 
 
 CHAPTER III. 
 
 PHYSIOLOGICAL REMARKS, 
 
 Of assimilation and nutrition. 
 Of the reproduction of parts, as displayed 
 in the healing of wounds. 
 
 Of symptomatic fever. 
 
 Of irritation and hyper-nutrition, inflamma- 
 tion, physiological. 
 
 Of capillary irritation. 
 
 Of nervous irritation. 
 
 Of the balance of vital action and reaction. 
 
 Of vicarious discharges and transformations 
 of tissues. 
 
 CHAPTER IV. 
 
 REMARKS ON HYGIENE. 
 
 Of food. 
 
 Of clothing. 
 
 Of air and moisture. 
 
 Of exercise. 
 
 Of the food and exercise of children. 
 
 Errors of female school discipline. 
 
 Of matrimony. 
 
 PART SECOND. 
 
 PRACTICAL DIRECTIONS FOR THE 
 TREATMENT OF MEDICAL AND 
 SURGICAL DISEASES. 
 
 CHAPTER I. 
 
 OF SURGICAL ACCIDENTS AND 
 DISEASES. 
 
 SECT. 1. 
 
 Of wounds and contusions. 
 Of incised wounds. 
 Of incised wounds of the scalp. 
 Of incised wounds of the neck and throat. 
 Of incised wounds of the chest. 
 Of incised wounds of the abdomen. 
 Of incised wounds of the joints. 
 Of lacerated wounds. 
 Of contused wounds. 
 Of contusions. 
 Of injuries of the head. 
 
 Concussion of the brain, 
 Fractures of the skull. 
 Of contusions in the cavity of the spine. 
 Of fractures, dislocations, and sprains of the 
 spine. 
 
Of concussions of the spine, 
 
 Of contusions of the chest. 
 
 Of contusions of the abdomen. 
 
 Of contusions of the pelvis and perineum. 
 
 Fractures of the pelvis. 
 
 Of contusions or sprains in the joints. 
 
 Of punctured wounds. 
 
 SECT. 2. 
 
 On the dilation of natural passages, and 
 its consequences. 
 
 Dilation of the anus. 
 
 Of dilated or varicose veins. 
 
 Of varicocele. 
 
 Of piles, or hemorrhoids. 
 
 Of dilatations of the heart and arteries. 
 
 Of aneurisms. 
 
 Of aneurismal varix and varicose aneurism. 
 
 Of mother-spots, or aneurism from anasto- 
 mosis. 
 
 Of hernia, or rupture. 
 
 r SECT. 3. 
 
 deformities from imperfect nutrition of 
 the osseous and muscular systems. 
 Of curvatures of the spine. 
 Of club foot. 
 
 SECT. 4. 
 Of fractures. 
 Fractures of the clavicle. 
 Fractures of the shoulder blade. 
 Fractures about the shoulder joint. 
 Fractures of the arm. 
 Fractures of the elbow joint. 
 Fractures of the fore-arm. 
 Fractures of the lower extremities. 
 Fractures of the thigh. 
 Fractures of the leg. 
 Fractures of the fingers and toes. 
 Fractures of the lower jaw. 
 Of dislocations in general. 
 Dislecations of the arm into the arm-pit. 
 Dislocations of the wrist. 
 Dislocation of the ankle, with fracture of 
 the fibula. 
 
 SECT. 5. 
 
 On inflammation and its consequences. 
 External inflammations. 
 Terminations of inflammation. 
 Treatment of inflammation. 
 Of suppuration. 
 Of ulceration. 
 Of gangrene. 
 Malignant pustule. 
 Gangrene of old men. 
 Dry gangrene. 
 Gangrene from excess of inflammation, 
 
 from internal and constitutional causes. 
 Gangrene from pressure. 
 Gangrene from cold. 
 Gangrene from mechanical injuries. 
 Terminations of inflammation coupled with 
 
 collapse. 
 
 Of the sty. 
 
 Ulceration of the eye-lashes. 
 Foreign substances in the eye. 
 Inflammation of the eye. 
 Ulceration of the cornea. 
 Films on the eye. 
 Foreign bodies in the ear. 
 Ear-ache, and suppurations of the ear. 
 Ulcerations of the mouth. 
 Gum-biles. 
 
 Suppurations of the urinary passages. 
 Excoriations about the mucous orifices. 
 Chafing. 
 Of abscesses. 
 Run-round. 
 Whitlow. 
 
 Nails growing into the flesh. 
 Biles. 
 
 Furuncle and carbuncle. 
 Canker, or gangrenous sore mouth of chil- 
 dren. 
 
 Burns and scalds. 
 White swelling. 
 Hip-joint disease. 
 
 SECT. 6. 
 
 Corns, warts, and moles. 
 Soft corns. 
 Warts. 
 Moles. 
 
 SECT. 7. 
 
 Constitutional diseases. 
 Scrofula. 
 Of cancer. 
 Venereal diseases. 
 Scurvy. 
 
 CHAPTER II. 
 
 MEDICAL PRACTICE OR TREAT- 
 MENT OF INTERNAL DISEASES. 
 
 SECT. 1. 
 Fever. 
 
 Intermittent fever. 
 Continued fever. 
 Billious remittent fever. 
 Yellow fever. 
 Petechial or spotted fever. 
 
 .SECT. 2. 
 
 Eruptive diseases. 
 Small-pox. 
 Varioloid. 
 Chicken-pox. 
 Cow-pox. 
 Measles. 
 Scarlet fever. 
 Military fever. 
 Nettle-rash. 
 Prickly heat, or lichen. 
 Shingles. 
 Ring- worm. 
 Itch. 
 
 Rose-rash. 
 Gum-rash. 
 Pruriginous rash. 
 
SECT. 3. 
 
 Erysipelatous affections. 
 Poisoned wounds. 
 
 Erysipelas phlegmonodes, or diffused in- 
 flammation of the cellular tissue. 
 Inflammation of the veins and absorbents. 
 
 SECT. 4. 
 
 Diseases of the respiratory apparatus. 
 Catarrh. 
 Influenza. 
 Pleurisy. 
 Lung fever. 
 Consumption. 
 Spitting- of blood. 
 Pulmonary hemorrhage. 
 Asthma. 
 Angina pectoris. 
 
 SECT. 5. 
 
 Diseases of the throat. 
 Mumps. 
 Quinsy. 
 Croup. 
 
 SECT. 6. 
 
 Diseases of the abdomen. 
 Cholera morbus. 
 Spasmodic or malignant cholera. 
 Diarrhoea, or looseness. 
 Dysentery. 
 Colic. 
 
 Painter's colic. 
 Liver complaint. 
 Inflammation of the kidney. 
 Jaundice. 
 
 Passage of gall stones. 
 Worms. 
 
 SECT. 7, 
 
 Diseases of fibrous tissue. 
 Rheumatism. 
 Gout. 
 
 SECT. 8. 
 
 Nervous diseases. 
 
 Chorea, or St. Titus's dance. 
 
 Shaking palsy. 
 
 Convulsions. 
 
 Epilepsy. 
 
 Hysteria. 
 
 Catalepsy, or trance, 
 
 Apoplexy. 
 
 Palsy. 
 
 SBCT. 9. 
 
 Prominent symptoms and accident*. 
 Dropsy. 
 Heart-burn, 
 Watev-brash, 
 Flatulence. 
 Costiveness. 
 
 Indigestion; or dyspepsia* 
 Vomiting. 
 Hiccough. 
 Crump. 
 
 Bleeding from the nose. 
 
 Strangury. 
 
 Diabetes. 
 
 Gravel. 
 
 Drowning. 
 
 Death from suspension. 
 
 CHAPTER III. 
 
 DISEASES OF MARRIED WOMEN. 
 
 Of pregnancy, and the position and connex- 
 ions of the child in the womb. 
 
 Approach of labour. 
 
 Of labour. 
 
 Uterine hemorrhage. 
 
 Of puerperal convulsions. 
 
 Inversion of the uterus. 
 
 Inflammation of the womb. 
 
 Puerperal fever. 
 
 Swelled leg, milk leg, or phlegmasia do- 
 lens. 
 
 Puerperal nervousness, mania, and melan- 
 choly. 
 
 Of palsy of the bladder. 
 
 Of swelled throat. 
 
 Inflammation and abscess of the mamma. 
 
 Of inflammation of the nipple. 
 
 CHAPTER IV. 
 
 ON DISEASES OF CHILDREN. 
 
 Tongue-tie. 
 
 Swelled breasts. 
 
 Sore navel. 
 
 Of the yellow skin and jaundice of infants. 
 
 On retention and suppression of urine. 
 
 On painful urination. 
 
 Incontinence of urine. 
 
 Excessive urination, urinary consumption, 
 
 or diabetes. 
 
 Sore mouth, thrush, aphthae. 
 Colic. 
 
 Costiveness. 
 Vomiting. 
 Erysipelas. 
 Dentition. 
 Worms. 
 Convulsions. 
 Dropsy in the brain. 
 Whooping-cough. 
 Inflammation of the tonsils, quinsy. 
 Cholera infantum. 
 
 CHAPTER V. 
 
 ON DISEASES OF ADULT FEMALES 
 
 Appearance of the menses. 
 Chlorosis, or green sickness. 
 Suppression of the menses. 
 Obstructed menstruation. 
 Painful menstruation. 
 
Excessive menstruation, or flooding-. 
 Final cessation of the menses. 
 Leucorrhoea, fluoralbus, or whites. 
 Pluritis vulvas. 
 
 Falling-, or prolapsus of the uterus. 
 Retroversion, or falling- of the womb back- 
 wards. 
 Anti version of the womb. 
 
 Polypus of the uterus. 
 Cancer of the uterus. 
 
 Appendix. 
 Formulary. 
 List of drugs. 
 List of apparatus. 
 Index to Part First. 
 Index to Part Second. 
 
 From amongst many commendatory notices of the work, the following are 
 
 selected : 
 
 "This work, by Dr. Reynell Coates, is by far the best of its class. We must even 
 add, that it has contributed not a little to the removal of our fears of the doubtful if not 
 sinister tendency of an attempt to produce a system of Popular or Domestic Medicine. 
 Positive good will result to them who shall study and take pains to acquire a knowledge 
 of the facts and precepts in the First Part, or that which consists mainly of an ' Outline 
 of Anatomy* and 'Remarks on Hygiene,' in the work before us. These are an appro- 
 priate and a necessary introduction to the Second Part, in which the brief indications in 
 the treatment of diseases and accidents by the aids of surgery and medicine, are set 
 forth. After a survey of his labours in these matters, we feel inclined to join in opinion 
 with Dr. Coates, who, in his preface, expresses his belief "that the principal evils which 
 have resulted and are likely to result hereafter from attempts at popular medical instruc- 
 tion, are attributable rather to the manner in which the subject has been treated than to 
 the nature of the subject itself/ So broad is the contrast between both the matter and 
 the manner of his task, and the systems of popular medicine hitherto published, that the 
 author of the present treatise need not be under any apprehensions from his name being 
 placed 'in juxtaposition with that of some previous authors, whom to rival, or with 
 whom to affiliate, falls not within the compass of his ambition.' " 
 
 " Amongst the works calculated to contribute to this desirable end, of enlightening 
 people generally on the above important matters, we would place the ' Family Adviser* 
 of Dr. Coates, especially that portion of it entitled ' Outline of rfnatomy' and ' Remarks 
 on Hygiene* The first is a clear and condensed description, with illustrative engravings, 
 of the several parts of which the living body is composed. The second abounds with 
 sound and practical precepts for the maintenance of these parts in their healthy state 
 separately and in their harmonious relations with each other." 
 
 " Under the successive heads of Clothing and Cleanliness, Air and Moisture, Exer- 
 cises, the Food and Exercises of Children, Errors of Female School Discipline, and, 
 finally, of Matrimony, the reader will find a large amount of highly instructive and avail- 
 able matter. It is pleasant and encouraging to see a man of talents and attainments, and 
 a shrewd, albeit peculiar observer, engaged in enlightening his fellow men on these im- 
 portant subjects. That they will thank him, and prove their appreciation of his services 
 to them by an observance of his precepts, w^ can readily believe, as we sincerely hope." 
 
 ticket Medical Library. 
 
 This is a very neatly executed work, from the prolific press of Carey, Lea & Blanch- 
 ard. The title of the volume, perhaps, would not recommend it to the profession, who 
 have had just occasion to be disgusted with treatises on domestic medicine, medical ad- 
 visers, 8cc. -, but emanating from so high a source, we shall be much disappointed if this 
 volume does not ensure for itself a careful perusal from the scientific practitioner, for 
 which, we will predict, he will be amply repaid. So far as we can allow ourselves to 
 approve of epitomes on medical subjects, we must distinguish this volume as the deposi- 
 tory of a large fund of anatomical, physiological and practical truth. But to families, 
 travellers, members of missionary stations, and all who may be unable to procure the 
 services of a regular practitidner, it is a valuable compendium, and for such the work 
 was expressly designed. 
 
 "But the author, apart from this, had another object to accomplish, which the en- 
 lightened practitioner will deem desirable, viz., the extension of correct medical know- 
 ledge beyond the limits of the medical profession. We have long considered this a 
 desideratum. Such a purpose gained, will do more towards pulling down the strong- 
 holds of quackery and empiricism, in their thousand Protean forms, than the fast-multi- 
 
plying 1 prosecution and accumulated verdicts of homicide can ever accomplish. A volume 
 like this, carefully read, will enable the public to distinguish easily between the pre- 
 tender and the man who has faithfully studied his art. When public opinion is enlight- 
 ened, we may invoke its resistless arm to our aid in the cause of science and humanity. 
 Give to any patient the slightest knowledge of the structure of his system, or the faintest 
 idea of the principles of the medical art, and he will hesitate before he entrusts the re- 
 pairing of such delicate machinery to the hands of the marvellous-loving and wonder- 
 working- quack. 
 
 " We have time only for a cursory notice of the plan of the work. It is divided into 
 two general parts, descriptive or theoretical, and practical. The first embraces a parti- 
 cular notice of human general anatomy, enlivened with many physiological observations 
 a view of the principal animal functions, and their aberration from healthy action and 
 a very valuable chapter on hygiene. Part second treats of the symptoms of diseases and 
 the most approved methods of treatment. 
 
 " W T e cannot close this notice, without special commendation of many portions from 
 which we shall be glad to make extracts. That portion of the chapter on hygiene, treat- 
 ing of clothing, exercise, and errors in female education, should be faithfully studied by 
 every conductor of seminaries for the education of females throughout the Common- 
 wealth. The article on spinal curvatures we commend to them as replete with valuable 
 hints on physical education. The clearness and simplicity of the style of the work will 
 be admired by the profession, as well as the general reader for whom it is adapted." 
 
 Boston Medical Journal. 
 
 "It is with great satisfaction that we announce this truly valuable compilation, as the 
 most complete and interesting treatise on popular medicine ever presented to the pub- 
 lic. Simple and unambitious in its language, free from unintelligible technicalities and 
 embracing the most important facts in Anatomy, Physiology, Hygiene, or the art of pre- 
 serving health, and the treatment of those affections which require immediate attention, 
 or are of an acute character this should be in the hands of every one, more particu- 
 larly those who, by their situation are prevented from resorting to the advice of a physi- 
 cian, nor would the careful perusal of its pages fail to profit the inhabitants of our cities. 
 By giving them a more accurate knowledge of the structure of the human frame and of 
 the laws that govern its various functions, whose perfect integrity is absolutely essential 
 to health, and even to existence; the various systems of medical charlatanry daily imagin- 
 ed to take advantage of the credulity and ignorance of mankind, would be rendered far 
 less prejudicial to the community than they now are. We would particularly direct 
 attention to the chapter on Hygiene, a science in itself of the utmost importance, and 
 ably treated in the small space allowed to it in this volume." New York American. 
 
 " Let it have a fair examination, say we and our word for it, this most useful, and 
 we had almost added, national publication, will progress triumphantly through many 
 editions. Dr. Coates has rightly appreciated the mind of the Americans, and has pro- 
 duced the only really valuable and complete work as a Family Medicine' that we have 
 yet seen; while he has shown the comprehensiveness of his own mind, in devoting the 
 first part of the volume to giving plain and philosophical outlines of Anatomy, Physiolo- 
 gy and Hygiene. A second part developes many of the mysteries of surgery, affording 
 practical directions for the treatment of Medical and Surgical Diseases. In the earlier 
 portion of * Popular Medicine,' therefore, the intelligent reader becomes familiar with 
 the entire structure of the human body. He is then led into the doctrines of assimila- 
 tion, nutrition, nervous and other irritation, inflammation, vital action and re-action, &c. ; 
 while the chapter on Hygiene, gives him valuable information with regard to food, cloth- 
 ing, air, exercise, matrimony, &c. Thus, like a sound and skilful professor of languages 
 the learned Doctor begins with endeavouring to ground his readers in the grammar of 
 the healing art, if we may be allowed such an application of the word; well knowing the 
 danger of total ignorance in those who administer medicine in any form or under any 
 circumstances. 
 
 " To our thinking, and we have carefully examined its pages there should be a copy 
 of it in every American family and in every American ship; and in stating our belief 
 that before many years shall have passed away, such will be almost the result we are 
 of opinion that we only speak the words of a true prophecy." Saturday Chronicle. 
 

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