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Tous las autres exempleires originaux sont fiimis en commenpent par la pramlAre paga qui comporte une empreinte d'impression ou d'illustration at en terminant par la darniire page qui comporte une telle empreinte. Un dee symboles suivants apparattra sur la darnlAre imafie de cheque microfiche, selon le cas: le symbole -*• signifie "A SUiVRE", le symbols V signifie "FIN". Les cartes, planches, tableaux, etc.. peuvent Atre filmAs A des taux de rAduction diffArents. Lorsque le document est trop grand pour Atre reproduit en un seul clichA. il est fiimA A partir de I'angle supArieur gauche, de gauche A droite. et de haut an bas. en prenant le nombre d'images nAcessaire. Las diagrammes suivants illustrent la mAthode. 1 2 3 1 2 3 4 5 6 mm 'A' ^ PUBLICATIONS FROM I UK BIOLOGICAL LABORATORY (IF TFIK UNIVERSITY OF TORONTO. No. III. STUDIES ON THE BLOOD OF AMPHIBIA. By A. B. MACALLUM, M.B., Ph.D. (Reprinted from the Transactions of the Canadian Institute, Vol. It.. Pt. S.) TORONTC*: ThK Corp, C'LAKK COMPANV, LlMlTBD, PrIKTKR.S. - . 1892. '" V 'V'tt^^'-'-i: .'''r. ■ L'^''*'/~ '■f>r-^m / ■>• l^i:4 - .■■.^>;f SI ■•*- . ■ f^l ' 't'-~-. -:...-vf'i*/- 5-* --9' ' 'jy V« -iJ... *■ ' y. Mm^ *? ■> ¥• iV , Mfe ^:- AUG 31 tSSi * '';..C v.<- ^^ s <'.' '. iV f-?-. 'J^. ':A^\ H - V. »' '5 ' ", « .^ 1?. i' ^V' \ ' ) L '> * w'r* '\V -^?^ ^ / S ^ ' '.^ M -«?. .-VJ ''^.- <^^ . V r K. .VS&A l.-T .K\ [Exlnict Jrom Transactions of the Cancutian Institute, l,SH()!lJ.\ STUDIES ON THE BLOOD OF AMPHIBIA. By a. B. Macallum, M.B., Ph.D. Lecturer on Physiology, University of Toronto. (Read lyth January, i8gi.) CONTENTS. Section i. The Origin of Haemoglobin. a. Methods of Study. b. Structure of the Blood Corpuscles. c. The Origin of the Haemoglobin in the Red Discs. Section 2. The Fu.siform Corpuscles. Section 3. The Origin of the Ha^matoblasts. Section 4. Conclusions. Section 5. Appendix. ill I. The Origin of H/Emoglobin.* In the following pages are given the results of studies commenced five years ago and continued with short intermissions till last summer. The length of time taken up in this work was necessarily great because of the lack of previous studies in the same line and because of the want of definite and exact knowledge on the .subject of the micro-chemical reactions of haemoglobin. The difficulty of detecting, by chemical or microscopical methods, any antecedents of haemoglobin appeared so formidable that, at one time early in the work, I was on the point of abandoning the line of investigation altogether. I have used for this investigation our Lake Lizard, Necturus lateralis, and the larvae of Amblystoma punctatum which are readily obtainable in large numbers in the immediate neighborhood of Toronto in April and May. The advantages which the tissues and structures in the Necturus present for cytological work far outweigh those which a comparative study of the blood in a larger number of Amphibian forms would have and there is, therefore, a justification for narrowing the investigation to the two named forms. * The subject matter of this paper was included in a thesis presented for the degree of Doctor of Philosophy in the Johns lIoplI5I. ' • i lii 68 TRANSACTIONS OF THE CANADIAN INSTIIUTK. [Vol. II. found in the blood finally all the intermediate stages between the fusi- form and the red cells. Hizzozero and Torre* reject this view of the haematoblastic nature of the red cells and state that though they are like red cells in some respects they are smaller and unpigmented, while young blood cells are round in form and always contain haemoglobin. These elements are also unlike the leucocytes in their simple oval nucleus and non-contractile proto- plasm. These authors believe that the corpuscles in question are related, in spite of many points of dissimilarity, to the structures in mammalian blood known as platelets. Hlavaf considers the fusiform corpuscle to be a variety of the white cell brought about by the contractile capacity of the latter. LowitJ describes the transformation of the sp'ndles into spherical forms like that of the white cells with which he classes these elements. He maintains that all forms of white blood cells may appear in the spindle form, but he admits that certain stages of the developing red cell exist in this form from which haemoglobin is absent. According to his view the fusiform cell is not a separate species of white blood cell but only a form of the latter which may appear under those conditions offered by the circulating blood, and it may in some cases have a haematoblastic nature. Eberth§ describes the elements as being spindle, club, or almond- shaped, somewhat smaller than the red discs, probably slightly flattened, possessing a finely granulated nucleus and an almost homogeneous cell protoplasm which is chiefly gathered at the poles. Their contour does not change, they have no amoeboid processes, and when they are collected into great masses they never present a trace even of a yellow or haemoglobin tint. When they are Viept for hours in their normal physiological condition, e. g., inside the bloodvessels of an excised piece of mesentery, protected from evaporation, they have never been observed to change in .shape, they exhibit no amoeboid movement whatever and they do not fuse together. In the spindles fixed by osmic acid there is •Virchow's Arch., Bd. 90. +Die Beziehung der I31utplattchen Bizzozero's zur Blutgerinnuiig und Thrombose. Arch, fiir Experim. Pathologic, Bd. XVII., 1883. >Ueber Neulnlduiig and Zerfall weisser Blulkorperchen. Sitzungsber. der Wiener Akad., Bd. XCII., Abth. III., 1885. Also: Ueber den dritten Formbestaiidtheil des Blutes. "Lotos," Jahrbuch fiir Natur- wissenschaft. Prag, 1885. §Zur Kentniss der Biutkorperohen bei den niedern Wirbelthieren. Festschrift fUr Kolliker Leipzig, 1887, p. 37. )L. 11. fusi- 1890-91.] AMPHIBIA BLOOD STUDIES. 60 V the longitudinal stripe, or folding, described by Hayem and Bizzozero and Torre and several refracting bodies in the nucleus, with one larger and rounder than the rest to represent a nucleolus. The spindles undergo change quickly under the microscope with the ordinary conditions of observation. Their protoplasm swells up and disintegrates into a quantity of fine granules which partly dissolve and leave a faint, somewhat irregular body in which the nucleus still persists. The chromatin in the nucleus of the ordinary spindle is more irregular in its arrangement and more fully developed than in the white cells, and it does not form a network as in the latter or in red cells. As salient points in their character, Eberth emphasizes their colorless- ness and their lack of amoeboid movement, both of which separate them from the white and red cells. They are not young red blood cells, for these even, in division, contain from their beginning haemoglobin. That the fusiform cells do not contain even the slightest trace of haemoglobin • is shown by the fact that thick masses of them have not the faintest color, which would not have been the case if some of them contained haemoglobin. Hayem regarded them as haematoblasts in his first paper, but the phenomena of Karyokinesis* in haemoglobin-holding blood cells was then unknown, and it is probable that he mistook the true haemo- globin-holding haematoblast for the forms intermediate between the fusiform and the red cells. Eberth does not advance any view as to the origin or nature of the fusiform elements, simply contenting himself with pointing out the analogies between them and the platelets of mammalian blood. It will be seen by a comparison of the above views that von Reckling- hausen and Hayem postulate the presence of hremoglobin in the fusiform elements while Bizzozero and Torre and Eberth deny this. Again, Hayem and Hlava state that it is contractile and this is expressly opposed by Eberth. Hayem considers them to be haematoblasts, with Hlava they are white corpuscles or a variety of the same, while with Bizzozero and Eberth they can only be compared to the platelets of mammalian blood. Such constitutes, in brief, the diversity of views as to their nature. My own view is that these elements represent the remains of the destroyed or broken up red cells and the following are the facts on which the view is based : I. Their nuclei are oval and nearly the same in size as those of the red ceils {l6fix 14/n. and 20/ax I2ix respectively). The difference between •In his more recent work (Uu Sang Ac.) all reference to these points is omitted. 70 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vol. II. ifi ii the two in the latter respect is caused, I maintain, by the nucleus of tlie fusiform cell enlarging in its transverse diameter and dininishing consequently in its longitudinal diameter. If one keeps a specimen of blood under observation for a while, during which it is protected from evaporation, one finds that the nuclei of the fusiform elements actually undergo this enlargement in its transverse diameter, the trans- versely placed trabeculae of its network elongate till the chromatin appears arranged in a number of parallel bars transversely placed. One can, moreover, by sudden pressure on the cover glass, rupture a number of red cells, set free their nuclei which undergo the same series of changes that the nuclei of the fusiform cells do, and shortly after the rupture the nuclei of the red cells measured exactly the same (i6/^x 13^ and 14/t). In the free nuclei there is the same transverse enlargement, the chromatolysis and nuclear disintegration. 2. When a number of nuclei of red cells are set free by pressure there is the same tendency to adhere to each other that is so marked in the case of the fusiform element. To each of these free nuclei there is enough of cytoplasma adherent to constitute the cement necessary to agglutinate them together, and in the masses so formed there is nothing to distinguish them from the thrombi formed of fusiform cells. I have not yet succeeded in observing in them any pseudopodial movement, but it is not often that this is observed in the fusiform elements and it is possible that it is the result of a survival from a well nourished condition in the blood vessels, ri condition not at all present under the cover glass. 3. The free nuclei and those of the fusiform elements have the same staining reactions. In a cover glass preparation fixed with corrosive sublimate or picric acid, in which free nuclei are abundant, the latter, as well as those of the fusiform cells, give with the Indigo-carmine Fluid a blue-black, sometimes an intense black, and with haematoxylin a black reaction. In fact there is the same, or nearly the same stain with all the dyes. There is one important difference so far as the cytoplasma of both is concerned : eosin takes intensely the cytoplasma of the fusiform cells while it stains lightly or not at all the slender protoplasm around the free nuclei. The explanation of this is that the interfilar chromatin (the haematogen) of the nucleus of the ruptured red cell gradually diffuses out from the nucleus into the cytoplasma without being converted into haemoglobin, as it is in the normal corpuscle and that it is this altered chromatin which takes eosin deeply. In some of the fusiform cells there is the same differentiation of the nuclear substance into network and interfilar chromatin, the latter staining deeply with eosin, the former with haematoxylin. There can be no doubt about the fact that in such cells )L. ir. f the inieii lected iients rans- blasts in Amphibian Emurvo. There is probably no biological subject on which there is a greater diversity of view than that of the origin of the blood corpuscles in the embryo and adult vertebrate. The views on this point have multiplied greatly within the last five years and as they have not much in common, a resumd of them can hardly serve any useful purpose in a paper so limited in its scope as this one is. The observations, nevertheless, which have been already published as to the origin of the ha^matoblasts in Fishes . and Amphibia have an important bearing on the facts which I am about to describe and I shall, therefore, give here an outline sketch of them be- fore proceeding with the description c f my own observations. Goettef found the blood cells arise in the mass of the yolk cells. On the under and lateral edges of the yolk mass in Batrachian larva; blood cells are formed by the breaking up of the large peripheral yolk cells into smaller ones, and at the same time there separates from the inner side of the visceral layer a number of cells forming a covering for the groove in the yolk in which the blood cells are developed. As the interstitial fluidity of the mass increases it extends over the yolk and affects the surrounding tissue just in the same manner as the interstitial fluid shapes the origin of the primary vessels, producing pouch-like diverticula connected with one another, from the yolk vessels. Goette regards the red and white cells of the spleen as direct descendants of the yolk cells. DavidoffJ reservedly expresses the view that the yolk spherules give origin by, possibly, protoplasmic transformation to parablastic elements and that the latter develop, in many cases, into blood cells. On this view the nucleus of the blood cell is but a yolk spherule imbedded in a proto- plasmic basis, and Davidoff thinks that this is, in a sense, a confirmation of Brass' theory that the chromatin of the nucleus of every cell is secreted or stored up food material. * As the red corpuscle in mammalia is comparatively a fragile element its disintegration can scarcely involve the survival of any formed or structural element. If the fusiform element is the nucleus and a small portion of cytoplasma of the red cell in lower vertebrates, we may suppose since the platelets of mammalian blood are recognised generally as the homologues of the fusi- form cells that the former are nuclei which have been extruded from hoematoblasts, an extrusion which Rindfleisch and Howell observed. t Entwicklungsgeschichte der Unke. + Ueber die Entstehung der rothen Blut Korperchen und den Parablast von Salamandra maculosa. Zoologischer Anzeiger, 1884, s. 453. 74 TRAN8AC!T10N8 OF THK CANADIAN INSTITUTE. [Vol. II. I Wenckebach* found that in Telcost enibryo.s the blood cells originate from a mass of cells placed under the notochord and between it and the hypoblastic layer. The origin of this cell mass could not be determined, when he published his first paper, but afterwards he traced it to the mcsoblast and was able, therefore, to corroborate Ziegler'.sf first observa- tions on this point. This intermediate cell mass may arise, as in Be/one, from an impaired organ but in the Salmon it is formed by the fusion of two separate columns of cells. The blood cells arc thus, according to Wenckebach, of mcsoblastic origin and are not derivable in any way from the hypoblast or from the periblastic cells. Ziegler* confirms Wenckebach's observations on the development of the blood cells in the majority of Teleost embryos out of the cellular elements of the intermediate cell mass placed between the entoderm and chorda. This mass is of mesodermal origin and the cells con- stituting it wander away over the yolk and, in a measure, as they do this they make the cavities previously occupied by them larger and larger, the cavities forming, finally, the cardinal veins. Up to this time the blood which is free from cellular elements, flows in closed vessels represented at this stage by the heart, aorta, caudal vein and sub- intestinal veins. The latter empty on the yolk and the blood passes from the posterior surface of the yolk sack to the heart, not in a closed vessel, but free in the space between the yolk and the ectoderm. There arises in the yolk a corresponding furrow to which wandering cells pass to form a vascular wall. These wandering cells are in no way distinguishable from the blood corpuscles of the same stage which are abundant on the surface of the yolk and which arise, as already said, from the elements of the intermediate cell mass. Sometimes, as in the pike, a formation of blood cells, similar to that occurring in the intermediate cell mass, obtains in a portion of the aorta. According to this view the blood cells are derived from the columns of cells which occupy the position of the developing cardinal and other veins and they are not, except accidentally, and through their amoeboid movement, connected with the yolk. * The development of the blood corpuscles in the Embryo of Perca fluviatilis. Jour, of Anat. .ind Phys. Vol. XIX., 1885, p. 231. Also : Beitriige zur Enlwicklungsgeschichte der Knochenfische. Arch, fiir Mikr. Anat,, Bd. XXVIII, p. 225. * Die Enibryonale Entwicklung von Salmo Salar. (Inaugural Dissertation). Freiburg, 1882. * Die Entstehung des Blutes bei Knochenfischembryonen. Arch, fur Mikr. Anat., Bd. XXX, s. 596. Also : Die Entstehung des Blutes der Wirbelthiere. Berichte d. Naturforsch. Gesell. zu Freiburg i. B. Bd. IV. s. 171. i L. II. 18J0-91.] AMPHIBIA BLOOD HTUDIEH. 70 nate the ncd, the rva- lone, )n of g to way Ruckert* gives a full description of the origin of the blood cells in Torpedo embryos. He found them to arise in the peripheral mcsoblast where they constitute groups situated in cavities formed between the spindle-shaped incsoblastic cells. Where the outer and inner layers of the bl.istoderm arc closely applied to the yolk these groups give off cells which constitute the blood islands of the posterior germinal area. At the latter point, according to RUckert, there can be no doubt about the origin of the blood cells out of the mesoblast. Laterally, and in front where the mesoblast is thin, the formation of the blood and of the vessels occurs through the accession to this part of freshly divided yolk cells (mcrocytcs). Far anteriorly, the merocytes may be very large in size and appear then as niegasphcres. The latter may, through unequal, imiircct division, bud- ding and fragmentation, give also origin to blood cells and mesoblast. This brief sketch of the various theories as to the method of blood formation and the origin of blijod cells shows how discordant they are. Goette believes that the peripheral yolk cells break up into h.tmatoblasts, Davidoff thinks that yolk spherules become the nuclei of the red cells and that the discoplasma is ^Icrived from transformed protoplasm of the yolk, Wenckebach and Zieglcr considered that the h;ematoblasts are of mesoblastic origin wholly, while Riickert is apparently disposed to believe that they are derived from the yolk cells on the one hand and from the mesoblast on the other. As far as my observations on the Amblystoina larva; go they are in accord with those of Wenckebach and Ziegler on Telcostean embryos, as to the derivation of the hcxmatoblasts from the mesoblast alone. The first blood corpuscles of the Amhlystoma larva; appear at about the twelfth or thirteenth dayf after the deposition of the ova. At this date the heart is in the process of formation, the endothelial portions of it being derived from the entoblast in the manner described by Rabl* for Salainandra and Triton. The heart cavity, for thirty-six hours after this, even when fully formed, contains no cellular elements of any sort. The first blood vessels to be formed appear also at the twelfth day, constituting the subintestinal veins§ and it is in association with the formation of these that the ha;matoblasts make their appearance. * Ueber die Anla|,'e des mittleren Kiemblattes und die erste Hliubildung bei Torpedo. Anal. Anz., 1887, Nos. 4 and 6. Also : Weitere Beitrage zur Keimblatlbildung l)ci Sclachiern. Anat. Anz., 1889, No. 12. + These dates are only approximate as there is a great variation in the development of the larviB in the same mass of eggs. iMorph. Jahrbuch, Ikl. XII. p. 252. §The occurrence of two subintestinal veins .instead of one in Sclachii was first pointed out l)y Mayer (Mitth. ans des Zool. .Stat, zu Ncapel, Vol. VII., p, 340) and subsequently by Riickert ('.V. ,-/'.! 76 THANSAC'XIONB OF THE CANADIAN INSTITUTE. [Vol. II. .M i I At about the eleventh day the ventral portion of the mesoblastic plate on each .side consists of two layers of cells forming the visceral and parietal portion of the plate. These layers are closely applied to the entoblast and ectoblast respectively, but not at first to each other, for evidences of a slit-like space between them which represents a persistent part of the primitive body cavity, can be very well seen at this date. This slit quickly disappears through the growth of the adjacent parts and the consequent pressure exercised on the mesoblastic cells. The latter are, at first, more or les-- rounded in outline but the pressure exerted on them gives them a somewhat flattened appearance, except at the lower, extreme margin where the visceral and parietal layers become connected, the cells of the visceral layer here retaining, to a considerable extent, their original shape. This part of the mesoblast seems to possess a greater capacity for proliferation than the more dorsally placed portions of the ventral half. The proliferation is limited chiefly to the cells at the extremity of the plate and to those immediately above this belonging to the visceral layer. The latter at the point in question is, about the twelfth day, formed of two or more series of cells, those constituting the rriost internal layer becoming very much flattened and like, in this respect, the cells of the single layer of the parietal portion. The cells placed between are obviously in the position occupied previously by the slit- like space, the more ventrally placed portion of the primary body cavity, and as they undergo division more frequently than the other cells, they cause a still greater flattening of the remaining cells of the visceral layer and of those of the parietal portion, with the result that these resemble fully formed endothelial cells. In a transverse section of the larva at about the thirteenth day, taken a short distance behind the developing heart, the cells first described lie in two large masses one on each of the ventro- lateral margins of the entoblast in which depressions exist to contain the masses of cells. The depressions are lined by the flattened endothe- lial elements derived from the visceral layer which are now recognisable with difficulty, and covered externally by similarly flattened endothelial cells derived from the parietal layer. The visceral and parietal layers above this are still at this time formed each of only one layer of ceils more or less flattened. The cells constituting the masses described are the hsmatoblasts, while the depressions in the yolk or entoblast consti- tute the site of the subintestinal veins. As the subintestinal veins are followed backwards they are seen to ap- proach, with the mesoblast plates, more and more the middle of the line of the ventral side of the yolk and where the mesoblastic plates from 1890-91.1 AMPHIBIA BLOOD STUDIRS. 73 each side unite in the middle line, the veins form a single channel, till a point immediately in front of the anus is reached. In its course backwards the vessel is filled with cells closely packed and derived, in the same manner as those forward arc, from the viscer.il layer of the mesoblast, although it is more difficult to exclude here the participation of the parietal layer in the formation of the h.x-matoblasts. The nieso- blastic plates again diverge at the anus and the venous trunk bifurcates. a branch running separately on e.ich side of the cloacal cavity, the cells contained in them becoming less in number till, for lack of them, it is im possible to follow the veins any distance behind the anus. When these veins and the cellular elements in them have attained the development described the heart is formed and beats. At first it contains no organized elements, the force of the beat being, apparently, exercised on what would appear to be serum. About the fifteenth or sixteenth day cellular elements in every respect like those found in the subintestinal veins are found in large numbers in the heart cavity and as the subintestinal veins are almost empty it is clear that the haimatoblasts are derived from this source. It i.s, in fact, easy in scries of sagittal sections of larvae of the fourteenth and fifteenth days to see the detach- ment of the hjEmatoblasts in the anterior portions of the subintestinal veins and their arrival in the heart cavity. The haematoblasts are derived from this source alone. All the other vessels of the body have a different origin, that is, they are not formed by solid columns of cells exerting a pressure on the immediately adjacent mesoblastic elements, but rather by the extension of the subintestinal vessels and of the cavities of the heart. In Amblystoma larvae therefore the haematoblasts are of mesoblastic origin alone and they are not in- creased in numbers by additions from the yolk elements or entoblast. At first they are large, not differing from mesoblast cells in any- thing except their somewhat spherical shape. They contain in their cytoplasma a large number of yolk spherules which obscure more or less the nucleus. The latter is somewhat irregular, often amoeboid in outline and richer, apparently, in chromatin than the ordinary mesoblastic cells of the same stage of development. To this greater richness in chromatin may be attributed the more abundant proliferation of these cells, for one can see that cell division is more frequent in them than in the neigh- boring cells. As the quantity of yolk spherules is limited, the repeated division, probably accompanied by a digestive action on the part of the cell on the spherules, produces a form of haematoblast (Fig. i6 and 17 a and b) in which the yolk spherules are few and in which nuclear chromatin is very abundant. It is in this stage that one finds the 74 TKANHAimoNB Of THK CANADIAN INSTITUTE. [Vol. II. h.T:matobIast amnnboid in outlines. Its cytoplasma is as yet undiffer- entiated and it docs not possess a membrane althouf,'h the peripheral portion {TJves evidence of its forniatic^n in tlic presence of a scries of rcffularly arranjjcd granulc-lii greenish elements of the cytoplasma in both beiny yolk splieruks coloreil by the reduction of the chromic acid. In the corpuscles at tins st.i^c karyokincsis is not more common than it is in ordinary tissue cells. It would appear that tiie more numerous class of ct)rpusclcs, /'. «•., those reactin^j deeply with eosin, become converted into the mature blood cells existing in the larva up to the twenty-fifth day, for it is these cells onl)- which illustrate the specialization of form and structure already described and partly represented by Vh^s. 19-21. The cells which react with hitmatoxylin alone constitute the persistent elements which ultimately become the ficcjuently dividin;^ h.x-matoblasts of the later staj^es of de- velopment. The cosinophilous cells are api)arently in a condition of degeneration, for the division of their nuclei is not always followed by a division of the cell (Fi^^ iH). Hoth cla.sses of h.eniatoblasts at this time do not specially illustrate division but those which stain with hiema- toxylin only .seem to retain the capacity for proliferation while the cosinophilous elements gradually lose it within the next ten days. At a period which seems to comcide with the formation of the liver as a vascular organ and with the development of tubules in it, ihe ha;mato- blasts, which, from the sixteenth to the nineteenth day, when hardened in chromic acid, stain with ha;matoxylin only, now begin to acc^uire a capa- city for proliferation far in excess of that which they previously had. It would appear that this change is associated with the appearance, in the blood vessels of the body generally and of the liver specially, of a serum which stains very deeply with eosin. This serum stains slightly with alum-cochineal but greenish-blue or green, like the yolk spherules, with the Indigo-carmine Fluid described in the foregoing pages. I regard this staining capacity of the serum as due to the solution of yolk or rather of that constituent of it which has been called haematogen by Bunge. This is but a reserve form of chromatin and as the undifferentiated haima- toblasts float in the serum, it is reasonable to believe that they absorb the dissolved chromatin. It is from this time on that the ha;matoblasts begin to manifest the incessant divisions which characterize the stage repre- sented by Figs. 9, 10 and 1 1. It is at this time also that the chromatic figures of the haematoblasts increase in size. Previously their figures were not larger than those of the other cells of the body. These facts can be explained in no other way than by assuming that the haematoblasts sur- viving as such, absorb the chromatin or " haematogen " which is dissolved in the serum and thereby entered on a phase of renewed vitality. The other cells in the body also exhibit divisions now more frequently than before this stage, though not by any means as frequently as the haemato- blasts, and this increased capacity for proliferation may also be explained 76 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vol. II. I II' by the more abundant supply of dissolved chromatin in the serum bath- ing them. These haematoblasts are met with most frequently in those parts of the circulatory apparatus where the blood current is slow or where physical conditions retard their movement. Such conditions are found between the muscle trabecule stretching through the heart cavity after these are formed, in the concave portions of the aortic arches and especially in a minute branch of the arteria mesenterica distributed in a plate of tissue derived from the visceral layer of the mesoblast. This is the site for the future spleen. The origin of the spleen in the visceral layer of the mesoblast in the toad was pointed out by Goette* who described the cells of the organ as direct descendants of the yolk cells (entoblastic cells). My observations are not yet concluded in the development of the spleen, but they have progressed so far as to allow me to say definitely that the organ increases in bulk by multiplication of the capillaries arising from the branch of the mesenteric artery to accommodate the excessively large number of haematoblasts derived by division from the original haematoblasts which have been caught in the narrow spaces of the capillaries, early in development of the organ. At a date roughly corresponding to the interval between the fortieth and sixtieth days, sec-^ tions of the organ fixed in Flemming's Fluid and stained with haematoxr ylin and eosin, contain a very great number of elements like those repre- sented in Figs. lo and ii. In fact sections of the organ thus prepared have a deep ochre-red or terra-cotta-red color, owing to the great number of mitotic haematoblasts present in it. At later stages of development haematoblasts are rarely found elsewhere than in the spleen, which is, from now on, the organ for their production out of the original elements whose history has been traced above and whose presence in the spleen is to be explained as I have pointed out. Whether there is a secondary formation of haematoblasts -out of the cells of the original tissue of the visceral layer of the mesoblast, it is impossible to say, but as the haematoblasts and the spleen are both formed cut of portions of visceral layer, such a secondary origin is not, theoretically, improbable. All that I can at present say is that early in the development of the spleen its vascular channels become distended with haematoblasts, which are also to be found in other vessels of the body where the blood current is slowed or retarded, that these haematoblasts undergo rapid divisions and in- creaoe thereby the size of the organ and that these divisions are quite sufficient to explain the occurrence there of all the haematoblasts observed. The first appearance of the organ in fact consists in the • Loc. cit. p. 8 1 3. \. 1890-91.] AMPHIBIA BLOOD 81UDIES. 77 presence of a few haematoblasts like those shown in Figs. lo and t i in the channel of the branch of the mesenteric artery. As I have never found in adult caudate Amphibia haematoblasts in any other organ than the spleen and then only in its blood sinuses, these may be regarded as direct descendants of the hiematoblasts which arise by proliferation of the cells of the ventral portion of the visceral plate of the mesoblast. It is, I think, worthy of note that though there is but one source for all haematoblasts, yet there are two stages in their history, the second of which appears when the liver begins to take on its adult structure, the forms belonging to this stage being remarkable for their great capacity for division, while the first series of haematoblasts are, almost wholly, formed in the subintestinal veins and the great majority of them are directly converted into red cells, the remainder persisting to form the haematoblasts of the second stage. IV. Conclusions. 1. The haemoglobin of the blood corpuscles is derived from the abun- dant nuclear chromatin of the hasmatoblast. 2. The fusiform cells of Amphibian blood are derived from the red corpuscles, the latter in this conversion losing the cell membrane and the greater portion of the discoplasma. 3. The haematoblasts in Ambly stoma are direct descendants of cells split off from the extreme ventral portions of the visceral mesoblast and they pass, at first, a portion of their existence in a specialized part of the original body cavity of the embryo. V. Appendix.* The foregoing paper was written, part in 1889, part in 1890. The publication of it now seems opportune since one of the conclusions con- tained in it has been fully confirmed by the results of my investigations during the last year. The chromatin of every cell, animal and vegetable, is an iron compound and this can be proved not only by the use of freshly prepared ammonium sulphide, as described in a communication sent to the Royal Society of London f last year, but also by other methods since discovered, the use of which excludes inorganic and albuminate iron and, at the same time, does not affect the iron in haemoglobin or haematin. With the more recently discovered methods, so easy is their application * Written Feb. 4, 1892. t Proceedings, Toy. Soc, Vol. 50, p. 277. 78 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vol. II. and so definite their reaction, one may make permanently mounted pre- parations of sections of animal and vegetable tissues, in which the distribu- tion of the chromatin is shown by the iron reaction. The latter may thus be quite readily employed instead of the staining methods with haima- toxylin and other dyes which, when carefully used, are supposed to select only chromatin. The results which I have obtained with the new methods are so numerous and so important that I must reserve an ex- tended description of them for another paper. Suffice it at present to soy that the fundamental life substance is an iron cofitpound and that, in;- ren tially, the chemical processes underlying life, in other xvords life itsclj ] n\- to be referred to the constant oxidation and reduction of the iron of this compound. This iron-holding compound being present in every living cell, the mystery of the appearance, here and there in animal and veget- able forms, of haematin* either free, or att iched to a proteid as haimo- globin, is explained. It is to be noted further that the iron, though not held in chromatin as firmly as it is in haematin, is yet as tenaciously held therein as it is in the ferrocyanides, which also yield, under the same conditions, their iron to ammonium sulphide. The methods referred to show further that the stainable substance which diffuses from the nuclei and mitotic figures in hajmatoblasts, is an iron compound in which the iron is less firmly held than in haemoglobin, and that it persists for comparatively a long time as such, before becoming converted into the latter substance. There are also facts which seem to indicate that haemoglobin is a degeneration product and not a substance formed in the synthetical processes of the haematoblasts. The bearing of these conclusions on the currently accepted views as to the pathology of anaemia is obvious. Since haemoglobin is a derivative product of chromatin, and since the latter is an iron compound all important in cellular life, anaemia cannot be, primarily, a deficiency in the formation of haemoglobin, but, first of all, a deficiency in chromatin, not only of haematoblasts, but of every cell in the body. In other words the primary cause of all anaemias, other than haemolytic, is hypochromatosis and the condition wh'ch Virchow called hypoplasia is as much a result of this hypochromatosis, as is the deficiency in formation of hremoglobin. Other points arising out of these investigations may be mentioned : the differences between animal and vegetable chromatin and between the chromatin of highly specialized animal cells on the one hand and that of lower forms of animal life, on the other, the occurrence of haemoglobin *Linossier and Phipson describe (Comptes Rendus Vol. CXII, pp. 40 occurrence of hiematin-like compounds in Aspergillus niger and Palmella cruew : ^ 666) the 'k i 1890-91.] AMPHIBIA BLOOD 8T0DIE8. 79 chiefly in the higher types of animal life, the analogies between chloro- phyll and hxmatin and the derivation of the digestive ferments from chromatin. These and other related subjects I intend to discuss in a future publication. EXPLANATION OF FIGURES. Figs. 1-4 are drawn from preparations from the adult Necturus, and Figs. 5-7 are taken from larval Amblystomata (A. punctatum). Fig. I. Red disc from a cover-glass preparation of the blood. Corrosive sublimate, IndiRo-carmine Fluid— X 700. Fig. 2. Red disc from splenic vein. Chromic acid. Indigo-carmine Fluid — X7oo- Fig. 3. Red disc, cover-glass preparation. Chromic acid, Hematoxylin, Eosin — X 700. Fig. 4. Red disc cover preparation. Corrosive sublimate, Haematoxylin, Eosin — X 7oo. Fig. 5. Red disc from heart cavity. Flemming's Fluid, Haematoxylin, Eosin— X 1,000. Fig. 6. Red disc from gill vessel. Osmic acid, Hasmatoxylin, Eosin— X 1,000. Fig. 7. Cover-glass preparation of red blood cells. Fresh, acetic methyl-green — X 1,000. Fig. 8. Group of blood cells from a vascular sinus in a section of the spleen of Necturus. In the centre is represented a haematoblast in mitosis and with its chro- matin so changed chemically that it takes the sulphindigotate portion of the reagent ; a, a red disc, b a leucocyte. Chromic acid, Indigo-carmine Fluid — X700. Fig. 9. From a free swimming Amblystoma larva. a, Haematoblast from the concave side of one of the aortic arches, in division u showing in the abundant chromatin as well as in the cytoplasma a slate or slate-brown reaction. b, an endothelial cell from same aortic arch in same preparation undergoing mitosis and showing the normal reaction of the staining fluid. Flemming's Fluid, Haematoxylin — X 1000. Fig. 10. Haematoblast from concave side of aortic arch in a free-swimming larval Amblystoma. Flemming's Huid, Haematoxylin, Eosin — X 1,000. Fig. II. Haematoblast from same preparation as last — X 1,000. Fig. 12. A dividing haematoblast in the last stage of its development, showing two kinds of chromatin in the nuclear figures. Cover-glass preparation. Corrosive subli- mate, Haematoxylin, Kosin — X 1 ,000 Figs. 13-14. Haematoblasts in the last stage of their development, showing a de- generated chromatin between the regular chromatin loops of the dividing nuclei. From the heart cavity of a free swimming Amblystoma larva. Flemming's Fluid, Hematoxylin, Eosin— X 1.000. 80 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vol. II. if {•: Fig. 1$, a and b. Two ha?matoblasts from the heart cavity of a very young Ambly- stoma larva (not free swimming). Chromic acid, Hematoxylin, Eosin. x 1250. Figs. 16 and 17, a and b. Amoebiform hsematoblasts from heart cavity of a very young larva (not free from envelope). The chromatin is very dense in the nuclei. The cavities in the cytoplasma were occupied by yolk spherules. Flemming's Fluid, Alum-cochineal — X900. Figs. 18 and 19. Two haematoblasts from the heart cavity of very young larva (not free swimming). Cavities in cytoplasma occupied by yolk spherules. Fig. 19 repre- sents a more fully developed corpuscle with well defined contour and abundant chromatin. Chromic acid, Haematoxylin, Eosin — X1250. Fig. 20, a and b. Two hrematoblasts, from a very young larval Amblystoma, with definite elliptical outlines, uncolored cytoplasma and the nuclei abundantly provided with chromatin. Chromic acid, Haematoxylin, Eosin — X900. Fig. 21, a and b. Two htematoblasts from larva of same age as in last case. P'lem- ming's Fluid, Alum-cochineal — X1200. Fig. 22, a--f. DifTerent forms of fusiform corpuscles met with in the same cover- glass preparation of Necturus' blood, — b was fixed while exhibiting, apparently, the slow vibratory motion of its thorn-like prolongations. Corrosive sublimate, Haema- toxylin, Kosin — X 1,000. Fig. 23, a—d. Fusiform corpuscles of Neduru^ blood exhibiting various intra nuclear arrangements of its chromatin. Cover preparation. Picric acid, Safranin. Fig. 24, a and b. A haematoblast (?) seen at two different optical planes exhibiting, the peculiar yellowish granules (h.Tsmoglobin?) apparently like those described b^ , Cuenot as secreted from the nucleus— a, at the plane passing through the upper surface of the nucleus, b, at the plane passing the centre of the nucleus. There is very little cytoplasma in this cell. Fresh — xiooo. El ' ^^s:W^ via: I % ^^ •% 1. >. 17 ,1 l> IS : \ ■'■fj w o M 'Mfs* /'/ i! .■;■ ".';■■;•'' '''/ /'; 'JO ': f. rc.;' ■^y ■••••■•, I ^. :i-; \ . II W i» l(> o II m ^'£' \ jj lo ■■■(n ^ -;.' /'/ \ ■21 w-i ,1 ' h '^^fc' ■•■•.■■r.^'.°'- ,/ S $ /■ v.. w ,^*^.