THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 LOS ANGELES
 
 Vol. Xffl SEPTEMBER, 1311 
 
 No. 4 PSYCHOLOGICAL REVIEW PUBLICATIONS Whole No. 56 
 
 THE 
 
 Psychological Monographs 
 
 EDITED BY 
 
 JAMES R. ANGELL, UNIVERSITY OF CHICAGO 
 HOWARD C. WARREN, PRINCETON UNIVERSITY (Index) 
 
 JOHN B. WATSON, JOHNS HOPKINS UNIVERSITY (Review) and 
 ARTHUR H. PIERCE, SMITH COLLEGE (Bulletin) 
 
 On the Functions of the Cerebrum: the Occipital Lobes. 
 
 Shepherd Ivory Franz, Ph.D., 
 
 Research Assistant of the Carnegie Institution of Washington ; 
 
 Scientific Director and Psychologist, Government Hospital for the Insane ; 
 
 Professor of Physiology, George Washington University. 
 
 with the cooperation of 
 
 Gonzalo R. Lafora, M.D., 
 Histopathologist, Government Hospital for the Insane. 
 
 PSYCHOLOGICAL REVIEW COMPANY 
 
 PRINCETON, N. J., 
 BALTIMORE, MD. AND LANCASTER, PA. 
 
 AGENTS : G. E. STECHERT & CO., LONDON (2 Star Yard, Carey St., W. C.;) 
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 CONTENTS. 
 
 Introduction ...................... . ..................... I 
 
 The occipital lobes ........................................ 3 
 
 The localization of function in the occipital lobe .............. 9 
 
 Movement .". ........................................ 9 
 
 Sensation ..... 1 1 
 S 
 
 ^ Perceptions, etc. . . .................................... 22 
 
 Experimental 24 
 
 Introduction 24 
 
 Methods 26 
 
 Training 26 
 
 Operation 38 
 
 Post-mortem examination 40 
 
 Results 44 
 
 Discussion of results 100 
 
 Summary and conclusions 112 
 
 References . . n-v
 
 INTRODUCTION 1 
 
 The positive statements regarding the functions of the occipital 
 lobes might lead one unacquainted with the facts to believe that 
 the functions of these portions of the cerebrum were well under- 
 stood. A careful consideration of the experimental and clinical 
 phenomena accompanying disturbances in these areas does not 
 support the general belief, and although they are among the first 
 parts of the brain to have been investigated by physiological 
 methods there remains much to be done before we may say we 
 understand their function and their method of working. We may 
 apply directly to this region of the cerebrum the statement of 
 Hitzig, made a decade ago in regard to the whole brain: "Die 
 Hirnrinde und ihre Zusammenwirkung mit ihre subcortikalen 
 Centren stellen vielmehr noch heute einen dunklen Continent 
 vor (31)." That to some extent and in some manner the cortex 
 in the occipital portion of the brain functions in connection with 
 the retinae is probably true, but how it functions and in what 
 manner it is connected with the retinae have not been determined 
 
 1 The present work was made possible by a grant from the Carnegie In- 
 stitution of Washington to the author as research assistant. This assistance 
 is hereby acknowledged and the author expresses his sense of obligation for 
 it. On the histological side of the work the author has had the opportunity 
 of the cooperation of Drs. N. Achiicarro and Gonzalo R. Lafora, respectively 
 former and present histopathologist at this institution. Assistance in the 
 observation and in the training of the monkeys has been given especially by 
 Dr. A. H. Sutherland, formerly of this institution and now of the University 
 of Illinois, and by Drs. Achiicarro, Barnes, Blackburn, and Lafora and their 
 assistance is hereby gratefully acknowledged. 
 
 The present work deals mainly with the lateral portions of the occipital 
 lobes, and it is expected that articles will appear later dealing with the 
 mesial aspect and with the results of electrical stimulation. 
 
 While this article was in manuscript form there appeared von Bech- 
 terew's Ueber die Funktionen der Nervencentra, which contains a resume 
 of much work on the occipital lobes. Von B. discusses to great length the 
 work of Goltz, of Munk and of Luciani but slights much which is discussed 
 in pp. 9-23.
 
 2 SHEPHERD IVORY FRANZ 
 
 to the complete satisfaction of those who have most carefully 
 investigated the matter. 
 
 The numerous recent histological studies of the architecture 
 of the cerebral cortex emphasizes the fact that the clinical and 
 physiological problems of the localization of function are not 
 simple, either in method or in interpretation. Although there is 
 considerable diversity in the results of the different histological 
 investigators, there is, on the other hand, sufficient uniformity to 
 indicate that the old landmarks of the cerebrum must be given up 
 and that the facts must be viewed in connection with the plans 
 made by recent surveys. Most of the fissures, especially those of 
 a secondary character, are of little value for the limitation of 
 special areas, and it is necessary at the present time to considei 
 the areas from an entirely different standpoint. This standpoint 
 is the intimate structure of the cortex, the number and grouping 
 of the cells, the arrangements of the fibers, and the combination 
 of these. It has been shown that we may almost entirely dis- 
 regard the cerebral fissures and divide the cortex of the cerebrum 
 into approximately fifteen areas, each with an histological struct- 
 ure quite distinct and different from those of the surrounding 
 areas. 
 
 The histological studies have led to the formulation of hy- 
 potheses regarding the probable function of the parts and the 
 statement is made that each of the areas histologically distinct is 
 also physiologically different from the bordering areas. Although 
 all the histologists appear to give to their results an interpretation 
 more or less physiological, Brodmann (9, 10) in particular has 
 expressed this stand more plainly and more positively than most 
 of the investigators. He has written : "Es scheint doch naher zu 
 liegen und vom histologischen Standpunkte aus geradezu gebo- 
 ten, spezifisch differenten Rindenzellen auch qualitativ differente 
 Funktionen zuzuschreiben ;" and in a further discussion of the 
 matter: "Die spezifische histologische Differenzierung von Rin- 
 denarealen beweist unwiderlegbar deren spezifische funktionelle 
 Differenzierung" (9). This leads directly to the anatomical divi- 
 sion of cerebral function, to a sort of phrenology, and to an 
 anatomy of mind which will not bear criticism.
 
 THE OCCIPITAL LOBE 
 
 The gross appearance and the extent of the occipital lobe may 
 be learned from the text books of anatomy (61), or will be re- 
 called by a glance at figs, i and 2. The lobe comprises about one- 
 eighth of the superficial part of the cerebral cortex. On the 
 mesial aspect of the hemisphere the calcarine fissure is included in 
 this area, and its upper and anterior limits are roughly fixed by 
 the parieto-occipital sulcus. On the lateral aspect it reaches to 
 the transverse occipital fissure. In the fresh as well as in stained 
 sections of part of this region there can be seen in the cortex 
 without the aid of the microscope a distinctly lighter streak, ap- 
 parently dividing the cortex into two layers. This is the line of 
 Gennari which, both macroscopically and microscopically, gives 
 to this area an appearance very different from all other parts of 
 the cerebral cortex. 
 
 Further examinations of the cortex by histological methods 
 reveal other differences. The larger region is found to have two 
 or three different types of arrangements of cells and fibers, so 
 that by the more careful methods it is possible to distinguish and 
 to differentiate two or three areas of anatomically (histologic- 
 ally) distinct types. The most characteristic of these areas is the 
 one in which the line of Gennari is prominent, an area which may 
 be called the calcarine area. This area surrounds the calcarint 
 fissure, and in man reaches beyond the occipital pole toward the 
 lateral aspect of the cerebrum for only a very short distance. 
 The limits of this area have been accurately determined by a 
 number of investigators, all of whom report essentially the same 
 results. The structure of this region is described by Campbell 
 as follows (n, p. 17) : "The characters which distinguish the 
 calcarine type of cell lamination are, first, the almost unique layer 
 of large stellate cells usurping the position occupied by the exter- 
 nal layer of large pyramidal cells in other regions ; secondly, the 
 existence of pale-stained zones above and below the uncommonly 
 well-marked layer of stellate cells, the upper of which marks the 
 position of the line of Gennari; thirdly, the presence in the 
 depths of the cortex of the layer of solitary cells of Meynert, 
 cells which differ from homonymous cells in any other part of
 
 4 SHEPHERD IVORY FRANZ 
 
 the brain." The remainder of the occipital lobe is considered 
 by Campbell to be one area, while Brodmann has been able to 
 distinguish two separate areas, which he admits are closely re- 
 lated (10, p. 228). The cortex surrounding the calcarine area, 
 
 FIGS, i and 2. The human cerebrum, with the areal differentiation of the 
 occipital lobe. The dotted part is the calarine type, and the parts marked 
 by horizontal lines and by cross hatching are the remainder of the so-called 
 visual cortex. Adapted from Brodmann, and reduced. 
 
 and extending 1.5 to 2 cm. beyond it, is supposed to have a func- 
 tion somewhat similar to that of the calcarine area, in that it is 
 intimately related to the calcarine area, and has been correlated
 
 THE OCCIPITAL LOBE 
 
 with certain clinical findings relating to vision. To this region 
 Campbell gives the name visuo-psychic as distinguished from the 
 calcarine which is called visuo-sensory. 2 The structural ap- 
 pearance of this surrounding area is somewhat similar to that 
 of the calcarine area, but sufficiently different from the latter to 
 be considered distinct. The cortex is of greater depth, the plexi- 
 form and small and medium-sized pyramidal cells are all appre- 
 ciably deeper, but the latter two are less numerous; the large 
 pyramidal cells are mixed with the other cells and do not form 
 a layer by themselves; the layer of stellate cells has an appear- 
 ance similar to that in the calcarine area, and the other cell ele- 
 ments are not divided into layers as in the calcarine region. 
 
 Figs, i and 2 illustrate the division by histological methods of 
 the occipital cortex in man by Brodmann. Here is shown the 
 
 FIGS. 3 and 4. The occipital pole of the human cerebrum, with the areal 
 distributions of the so-called visuo-sensory and the visuo-psychic regions. 
 The dotted portion is the calcarine type of cortex, and the cross hatched 
 portion is the visuo-psychic area. Adapted from Campbell. 3, the mesial 
 aspect ; 4, the lateral aspect. 
 
 calcarine area, marked by large dots, surrounding that fissure, 
 and in the neighboring regions the two areas closely related to 
 the calcarine but differing from the latter in cell and fiber struct- 
 ure. The two areas, as has been indicated above, are not abso- 
 lutely distinct and have been grouped by Brodmann to make one 
 area. By this grouping Brodmann closely approaches the divi- 
 sions made by Campbell (u), by Elliot Smith (69) and by 
 Bolton (8), as well as those made by the earlier investigators. 
 
 2 These names were previously used by Bolton.
 
 6 SHEPHERD IVORY FRANZ 
 
 The division of the cortex by Campbell is given in figs. 3 and 4, 
 which should be compared with the division by Brodmann in 
 figs, i and 2. It will be seen that the total extent of the cortex 
 supposedly devoted to visual function is approximately the same 
 in the two figures, the apparent difference being accounted for 
 by the different views of the brain which the two investigators 
 have used for the delineation of the areas. The most marked 
 difference between the areal distributions of Campbell and Brod- 
 mann is the larger relative size of the calcarine cortex outlined 
 by Campbell. The surrounding region is, however, not so easily 
 differentiated from the remainder of the brain as is the calcarine 
 cortex, and the variations of the individual observers may be 
 due to actual differences in material, as Bolton (7) suggests in 
 regard to another matter. Bolton reports that in an examination 
 of brains for the exact localization of the visual cortex he found 
 individual differences apart from the age and the visual abilities 
 of the people whose brains he examined, and he remarks that 
 "as such differences exist in a projection area, it is possible that 
 more marked variations will occur in the case of the later special- 
 ized areas of different brains" (7, p. 309). 
 
 In the monkey the occipital lobe is more constant and more 
 easily mapped out by fissures than in the human brain. It may 
 be described as that part of the cortex on the lateral aspect almost 
 inclosed by the parieto-occipital and the inf. occipital fissures, and 
 as the part on the mesial aspect which surrounds the calcarine 
 fissure, bounded above by the parieto-occipital fissure and below 
 by a line drawn from the calcarine fissure to the inferior occipi- 
 tal. The cortex in this area shows types of arrangement similar 
 to those found in the human brain, and it has been found possi- 
 ble to map the region into at least two distinct areas, the so-called 
 visuo-sensory and the visuo-psychic. Figs. 5 and 6 show this 
 division, but into three areas corresponding with the three 
 divisions of the human brain by Brodmann. It will be seen that 
 the calcarine type of cortex occupies a much larger area than in 
 the human brain, not only relatively to the size of the whole 
 cortex, but also absolutely larger than the same type in man if we 
 disregard the infolding of the calcarine fissure. Brodmann has
 
 THE OCCIPITAL LOBE 
 
 6 
 
 FIGS. 5 and 6. Distribution of the various types of cortex in the occipital 
 lobe of the monkey (Cercopithecus). Same designations for the areas as 
 in figure I. Adapted from Brodmann, and reduced. 
 
 not illustrated the extent of this area in the Macacque monkey, 
 but only in the Cercopithecus, the brain of which closely resem- 
 bles that of the Macacque. Mott has given illustrations of the 
 Macacque brain with the distribution of the calcarine type of 
 cortex, which are here reproduced (figs. 7 and 8) for comparison 
 with that of the distribution in the Cercopithecus by Brodmann. 
 The findings of Mott (50) differ very much from those of Brod- 
 mann in the allied family. He does not illustrate the extension 
 of the so-called visuo-psychic type of cortex and it is, therefore, 
 impossible to make a full comparison with the findings of Brod- 
 mann. It may be said, however, that the examination of the brains 
 of the Rhesus monkeys used in the present work has shown a 
 distribution of the calcarine type of cortex more nearly like that
 
 8 
 
 SHEPHERD IVORY FRANZ 
 
 found by Broclmann in Cercopithecus than that illustrated by 
 Mott in the Rhesus. 3 
 
 FIGS. 7 and 8. Illustrating the distribution of the calcarine type of cortex 
 in the Macacque monkey (Macacus Rhesus). Adapted from Mott, and 
 reduced. 
 
 From the resume of the work of the different histologists it 
 will be seen that the occipital cortex can be roughly divided into 
 two areas, of somewhat different structure, and that one of these 
 areas is very definite. The anatomo-pathological studies indicate 
 a close connection between the occipital lobes and the eyes and 
 this connection is admitted for the calcarine type of cortex more 
 generally than for the surrounding regions. In the next section 
 of this article, we shall see there is little warrant for the assump- 
 tion that the cortex surrounding the calcarine type of cortex has 
 visuo-psychic functions, although most workers in this field be- 
 lieve that the calcarine cortex is concerned with visual sensations. 
 
 The occipital lobe is in connection with the external geniculate 
 bodies, the pulvinar and the anterior corpora quadrigemina. 4 
 
 8 No special effort was made to mark the limits of the other areas of the 
 occipital cortex and a definite statement of their extent in the Rhesus 
 monkey can not be made at present. 
 
 4 For the description of the relations and the connections between the 
 occipital lobes and the retinae, see especially von Monakow (45, 47 and 48),. 
 Dimmer (13), Knies (38), Moeli (44), and Mott (49).
 
 HISTORICAL 9 
 
 THE LOCALIZATION OF FUNCTION IN THE OCCIPITAL LOBE 
 
 Movement. Electrical stimulation of the occipital cortex re- 
 sults in movements of the eyeballs and of the intrinsic eye mus- / 
 cles. The eyeball movements are associated movements. Differ- 
 ent observers have located in this region centers for a number 'of 
 movements, and have demonstrated a functional connection be- 
 tween this region and the precentral cortex. It has been found 
 that the eye movements occur upon stimulation of the occipital 
 lobes even after the frontal cortex has been destroyed, and that 
 they also occur upon stimulation of the frontal cortex 
 after the occipital lobes have been extirpated. This has been taken 
 to mean that there are independent centers for the movements of 
 the eyes; one in the occipital lobe, the other in the cortex an- 
 terior to the central fissure. 
 
 Ferrier (14) reported that in monkeys stimulation of points 
 on the angular gyrus produced movements of the eyes "to the 
 opposite side, with an upward and downward deviation, accord- 
 ing as the electrodes are placed" anterior or posterior to the paral- 
 lel fissure. He has also noted the contraction of the pupils and 
 the tendency to closure of the eyelids, and occasionally an asso- 
 ciated movement of the head to the opposite side. Ferrier's ob- 
 servations have not been confirmed by other observers, and 
 Schafer (62, 64) and others assign to the occipital lobes this 
 motor function. Schafer reports : "If the electrodes are applied 
 directly to the upper surface of the occipital lobe, conjugate devia- 
 tion to the opposite side with downward direction of the visual 
 axes is extremely well marked, and it is also produced by excita- 
 tion of the upper part of the mesial surface of that lobe, and 
 of the quadrate lobule immediately in front of the internal par- 
 ieto-occipital fissure. If, on the other hand, the posterior ex- 
 tremity of the occipital lobe, its lower or tentorial surface, and 
 the posterior and lowermost part of its mesial surface be stimu- 
 lated, the lateral deviation is combined with an upward move- 
 ment. In both cases the downward or upward movement may 
 be almost uncomplicated by lateral deviation; this depends upon 
 the position of the electrodes. On the other hand, there is an 
 intermediate zone, narrow on the mesial surface of the lobe, and 
 broader upon the outer or convex surface, excitation of which
 
 io SHEPHERD IVORY FRANZ 
 
 is productive of simple lateral deviation. All the effects are 
 strongest upon the mesial surface, especially toward the anterior 
 limit of the lobe ; it is here that the local point for the movements 
 is located." On the assumption that the eye movements resulting 
 from stimulation of the occipital lobes are due to something akin 
 to sensations Schafer (64, p. 5) was led to conclude that the 
 occipital lobe has the following physiological connections : "The 
 whole of the visual area of one hemisphere is connected with 
 corresponding lateral half of both retinae. The upper zone of 
 the visual area of one hemisphere is connected with the upper 
 part of the corresponding lateral half of both retinae. The inter- 
 mediate zone of the visual area is connected with the middle part 
 of the corresponding lateral half of both retinae." Von Bech- 
 terew (2) has located only three centers for movement of the 
 extrinsic eye muscles, and he has reported that eye movements 
 may be obtained from stimulation of the parietal lobe as well as 
 from the stimulation of the occipital. It is worthy of note that 
 Steiner (70) has found the occipital lobe unresponsive at birth, 
 although at this time the stimulation of the frontal (pre-Rolan- 
 dic) cortex results in eye movements. This has been confirmed 
 by Berger. 5 
 
 Many observers have recorded movements of the iris, i. e., 
 pupillary changes, following the stimulation of the occipital lobes. 
 Von Bechterew has located in the occipital lobes two centers for 
 pupillary movements, a contraction center in the middle part of 
 the occipital lobe, and a dilating center slightly inwards from 
 the contraction center. These results or similar ones have been 
 found by other observers, and they are partly confirmed by the 
 observations on man when there is disease or destruction of the 
 occipital cortex. 6 
 
 The observation of Schafer (66, p. 750) on the latent periods 
 of the movements from stimulation of the occipital lobe and of 
 the precentral cortex are of primary importance, and have often 
 
 "See also Schafer (62), Gerwer (22), Mott and Schafer (51) and 
 Obregia (57). 
 
 6 On the pupillary changes see also the following articles : v. Bechterew 
 (2, 3) ; Parsons (59) ; Mislawsky (43) ; and also Alamagny (i) ; zur Verth 
 (72); Bernheimer (6); Leyden (39).
 
 HISTORICAL ii 
 
 been overlooked by other investigators. He has carefully timed 
 the movements and finds that the latent period for movements 
 from occipital lobe stimulation is much longer than that from 
 the stimulation of the Rolandic area. That this lengthening of 
 the time is not due to the passage of the impulse to the frontal 
 lobe, i. e., to the motor cortex, and thence to the muscles is shown 
 by the fact that the movements from stimulation of the occipitals 
 may be obtained after the frontal lobes have been excised. We 
 are, therefore, compelled to conclude that the cells in the occipital 
 lobes have a more direct connection than that through the motor 
 cortex, although it is apparent from the results of Schafer's work 
 that there are more intercalated cells in the chain from the occipi- 
 tal lobes to the eye than from the pre-Rolandic cortex to the same 
 muscles. 
 
 Sensation. It was known for a long time that destruction or 
 injury of parts of the cerebrum caused visual defects or disturb- 
 ances, but the recognition of a localized center or centers for 
 visual sensation and perception has been largely due to the results 
 of experiments on animals. In the hands of different observers 
 the method of extirpation has led to somewhat discordant re- 
 sults, and to opposing conclusions. The controversies regarding 
 the functions of the occipital lobes will not detain us here, but 
 although they apparently did not change the opinions of those 
 who took leading parts therein they have left us many observa- 
 tions of value. 
 
 Extirpation of certain cortical areas in the dog's brain led 
 Munk to the conclusion that in this animal there is a center (des- 
 ignated by him as Ai) for visual perception and that the sur- 
 rounding more extensive region was a subsidiary visual center 
 which could be used when the primary center was injured or des- 
 troyed. Munk (52-56) furthermore attempted a more careful 
 localization and attributed to parts of the center more definite 
 functions. The conclusions of Munk were strongly combatted 
 by Goltz who at first denied there was any localization in the 
 cortex of the brain, but who later admitted that a certain amount 
 of localization was possible, and in fact was indicated by the 
 results of the experimental investigations. The position taken
 
 12 SHEPHERD IVORY FRANZ 
 
 by Goltz (23-25) in regard to localization of vision was that 
 although a visual defect, which he did not deny, might be pro- 
 duced by the ablation of part of the cerebral cortex, the defect 
 was not due to the extirpation of the cortical cells concerned with 
 the visual processes, but to a general effect and might be pro- 
 duced by the extirpation of parts of the brain other than that 
 assigned the visual function by Munk. Regarding this he has 
 written : (23) "Indem ich also auf Grund meiner neureren Erfah- 
 rungen einen grosseren Einfluss des Hinterhirns auf das Sehver- 
 mogen fur festgestellt erachte, kommt es mir dabei nicht in den 
 Sinn, etwa eine begrenzte Sehsphare zuzugeben, wie sie Ferrier, 
 Munk und Luciani konstruiert haben." This admission of the 
 possibility of localization is much the same as that of Loeb 
 (40-42) who investigated the so-called visual cortex at a later 
 date, and who has taken a stand much like that of Goltz. Loeb 
 asserts that the visual disturbance following operations upon 
 the occipital lobes which is temporary in character is due to a 
 lowering of the irritability of the retina-cerebral cortex mechan- 
 ism. The differences between the Munk and Goltz school does 
 not, however, disappear even if we consider that the Goltz and 
 Loeb explanation of the latter be correct for the symptoms that 
 are temporary. Part of the difference between the explanations 
 of Munk and Goltz rests, as von Monakow has shown, upon 
 different standpoints in the collection of the data. Goltz has 
 used as evidences of the presence of visual sensations the move- 
 ments of the eyes and of the related parts when the eyes are 
 stimulated by light, but there is no reason to believe that these 
 reactions are more than reflex in character, and there is good 
 reason to believe that they do not depend entirely upon the activi- 
 ty of the cerebral cortex. It would be equally correct to say 
 that there was no localization of movement or of the skin sensa- 
 tions because it is possible to get reflexes of the leg after there 
 has been complete separation of the spinal cord from the cere- 
 brum. Loeb does admit,' however, that the destruction of the 
 occipital lobe in man is followed by a blindness, which he believes 
 is due to a loss of irritability on one side of each retina, but he 
 explains the results in dogs to be not a loss but only a decrease
 
 HISTORICAL 13 
 
 in irritability in that organ. 7 He furthermore asserts that, 
 with Goltz, he believes the associative memory of animals de- 
 prived of their occipital lobes does not differ from that they had 
 previous to the operation. The main difference between Goltz 
 and Loeb and the followers of Munk, Hitzig, and others, is in 
 the conception of the relation of the brain to mental processes. 
 The former object to the interpretation that extirpations of or 
 injury to parts of the brain cause psychical disturbances, while 
 Ferrier, Munk, Hitzig, and other investigators interpret the de- 
 fects to be psychical. From the standpoint of localization, which 
 apparently all admit in some form, the important question is not 
 concerning the presence or absence of certain psychical disturb- 
 ances but the definite or indefinite restriction of certain functions 
 to certain areas. There can be no doubt that in man certain 
 cerebral destructions produce certain effects of the nature of loss 
 of associations, e. g., those of speech, and the clinicians still debate 
 whether or not these losses mean mental deterioration. Whether 
 or not the disturbances are to be interpreted as psychical will 
 depend upon the connotation of the word psychical. 
 
 The conclusions of Munk were supported by von Monakow 
 (46) both from the results of personal experiments and from 
 the examination of the brains of animals upon which Munk had 
 operated, von Monakow, however, believes the visual area is not 
 as small as it was pictured by Munk, and considers that, in dogs 
 at least, it extends anteriorly beyond the limits assigned by Munk. 
 
 The conditions reported by Hitzig (30-34) following removal 
 of parts of the occipital lobes in dogs was that of crossed am- 
 blyopia. This is unlike the results of other investigators, who 
 have reported a condition of hemianopia (for the opposite visual 
 field) following the extirpation of cortical regions in both dogs 
 and monkeys. Hitzig had also been led to conclude that a similar 
 condition may follow lesions of the anterior part of the brain, 
 but these results have not been confirmed by independent investi- 
 gators. As an explanation of Hitzig's conclusions it has been 
 pointed out that the visual defect in the dog following the extir- 
 
 7 Why he has selected the eye in this connection is not made clear, for it 
 would seem that the explanation should be made in regard to the central 
 nervous structures.
 
 I 4 SHEPHERD IVORY FRANZ 
 
 pation of one occipital lobe is blindness, not for the opposite eye, 
 but for objects in the opposite field of vision, which on account 
 of the large number of the optic fibers crossing at the chiasm is 
 more marked (i. e., includes more than half of the visual field) 
 in the opposite eye in the dog. Perimetric examinations of ani- 
 mals have shown that from two-thirds to three-quarters of one 
 retina in the dog is connected with the homonymous occipital 
 lobe. The conclusions of Hitzig are, therefore, taken to indicate 
 that on account of the involvement of such a proportion of the 
 retina of the one eye by an unilateral occipital lesion the exact 
 nature of the defect was not discovered, i. e., there was retention 
 of vision for only about one-quarter of the field and the appear- 
 ance was that of a complete blindness for the whole field of that 
 eye. 
 
 Using monkeys as subjects, Ferrier localized the visual area 
 at first in the angular gyrus, but later concluded that the occipital 
 lobe was used in connection with the angular gyrus, and called 
 the area the "occipito-angular" area. The later conclusions of 
 Ferrier were due to the criticism of his early work by Schafer 
 and others, and to the fact that he repeated the work using some- 
 what different methods. His early experiments were performed 
 without aseptic precautions, and it is this condition and its result- 
 ant consequences (e. g., the secondary extension of the injury by 
 infection, etc.,) which Ferrier uses to explain his first results 
 and conclusions. In the later localization work by Ferrier (14, 
 p. 268-305) the angular gyrus is given a prominent place and 
 he reports that the occipital lobes may be cut away alone without l 
 appreciable impairment of vision. The visual defect reported by 
 Ferrier ( 14, p. 273) was that of amblyopia. Many of the animals 
 operated upon by Ferrier showed a blindness which persisted 
 for only a few hours. This has been urged by others as a criti- 
 cism of Ferrier's work and conclusions, for it has been said that 
 the observations taken so soon after the completion of the opera- 
 tion do not warrant the conclusion of blindness. Although Fer- 
 rier rightly retorts that the "period of reliable observation is not 
 to be measured by the mere time that has elapsed since the opera- 
 tion, for the period of recovery is most variable, many animals 
 being up and active almost before their wounds have been
 
 HISTORICAL 15 
 
 dressed," it does appear to stretch a point to conclude that the 
 blindness may remain for only a few hours and then entirely 
 disappear. In reply to Schafer, the citation of cases from his 
 work in 1884 is not convincing in regard to the part played by 
 the angular gyrus in visual perception or sensations (15). 
 
 Following are abstracts of several cases cited by him in the 
 discussion with Schafer : In one monkey the left angular gyrus 
 was cauterized. The left eye was secured so that the animal 
 could not use it for vision. A half hour after the operation the 
 animal was apparently "wide awake but would not move unless 
 touched"; it sprawled on the floor and knocked against obstacles; 
 an hour later it bounded away when it was touched and ran 
 against the leg of a table, but did not show signs of perception 
 when it was approached cautiously without noise ; on the follow- 
 ing day "no 'defect of vision, amblyopic or hemiopic, could be 
 detected." In regard to the effects of similar lesions on other 
 animals he says : "Similar results were obtained in many other 
 instances, and if in some they were even more transient, this 
 may have been due to less extensive destruction or perhaps dif- 
 ferences in animals as to the relative importance of this region 
 in the ordinary exercise of their visual function." Three cases 
 cited by him are to be compared with the results in the present 
 work. In these three animals the occipital lobes were destroyed 
 or severed with great care so that the angular gyri were not in- 
 jured. In one the occipital lobes were exposed and the surfaces 
 were "destroyed by cautery, which was also passed deeply into 
 the interior of the lobes so as to cause as much disorganization 
 as possible. Care was taken not to injure the angular gyrus." 
 About forty minutes after the operation the animal began to 
 move but staggered a good deal ; its eyes were open and the pupils 
 were dilated. An hour and a half later there was "emphatic 
 evidence of sight ; ran away as I approached it, carefully avoiding 
 obstacles" ; it entered its cage, and avoided a cat that had taken up 
 its quarters there; "tried to escape my hand when I offered to 
 lay hold of it, but picked up a raisin which I had left on the 
 perch." In a second animal the occipital lobes were severed "by 
 a perpendicular section with hot wires about a quarter of an inch 
 posterior to the parieto-occipital fissure, so as to avoid all inter-
 
 16 SHEPHERD IVORY FRANZ 
 
 ference with the angular gyrus;" in twenty-five minutes, it was 
 observed that the animal "can see quite as well, as it avoids ob- 
 stacles, and when removed, regains its position by the fire." In 
 a third animal "both occipital lobes were severed with a galvanic 
 cautery and scooped out bodily; the line of incision in both cases 
 passed between the anterior extremity of the first occipital and 
 the parieto-occipital sulcus;" in half an hour the animal sat up 
 and wanted to move about ; for two hours there were no definite 
 tests of vision, but at the end of that time "a piece of apple was 
 thrown into the cage, and though it fell a full arm's length away, 
 the animal, without the slightest hesitation or want of precision, 
 put forth its left hand, picked it up and ate." 
 
 Ferrier explains the results of Schafer and of Munk on the 
 ground that both of these investigators cut away more than the 
 occipital lobes and that in their experiments the angular gyri were 
 injured. The greatest difference, however, between the conclu- 
 sions of Ferrier and Schafer is that the latter believes the blind- 
 ness is of the nature of an hemianopsia. The results obtained by 
 Schafer, especially those in conjunction with Sanger Brown, are 
 apparently convincing not only in regard to the participation of 
 the occipitals in vision, but also in regard to the character of the 
 defect following lesions in these regions (67). Schafer (63, 65) 
 not only obtained results on the occipitals opposed to those of 
 Ferrier but has failed to obtain the positive results on the angular 
 gyri reported by Ferrier to be constant. In fact, Schafer has 
 shown that the angular gyri may be removed without interfering 
 with vision in the least, but that when these parts are removed 
 and the underlying fibers (going to the occipital lobes) are in- 
 jured, some visual disturbances are to be noticed. Some of 
 Schafer's results are particularly instructive. One animal upon 
 which he operated, extirpating the angular gyri on both sides, 
 showed no loss of vision, no defect of movement of the eyes, and 
 no anesthesia of the conjunctiva or the cornea, and although this 
 animal was kept alive for several months, no disturbance of the 
 eyes, visual or otherwise, was found. In this connection Schafer 
 concludes : "A single well marked negative case like this is con- 
 clusive against the idea that in the monkey cerebral visual per- 
 ceptions are localized in the angular gyri" (63, p. 365). On the
 
 HISTORICAL 17 
 
 other hand the positive results following extirpations of the 
 occipital lobes are worthy of note. One animal, the left occipital 
 of which was completely removed showed a bilateral homonymous 
 hemianopsia, persisting for the whole time the animal remained 
 alive (eight months) (63, p. 367). Another monkey from 
 which both occipitals were removed showed a "total and persis- 
 tent blindness. The animal could only find food by groping and 
 smelling. Brought into a strange place, it ran against every 
 obstacle. Placed in a dark room and with a light flashed upon 
 it, no signs of perception were given. Hearing was very acute 
 and all other senses besides vision were unimpaired" (63, p. 
 368-9). This animal was clinically in the same condition as a 
 monkey observed by Ferrier and Yeo, from the brain of which 
 they removed both occipitals and both angular gyri. Other cases 
 were cited which confirm this general conclusion of the non-par- 
 ticipation of the angular gyri in the same sensory processes. In 
 conclusion Schafer says that for complete blindness the "removal 
 of the lobe must be complete and when a small portion of one of 
 the lobes is left, although blindness is not complete, yet the limit 
 of the visual field of the retinae may be greatly restricted" (63, p. 
 
 370). 
 
 Schafer sums up the differences between him and Ferrier as 
 f ollow, c ; "The chief points at issue are ( I ) the connection of 
 the angular gyrus with central vision of the opposite eye; (2) 
 the relative importance of the occipital lobe. According to Dr. 
 Ferriers experiments, decorticisation of the angular gyrus of 
 one side produces blindness of the opposite eye (amblyopia) ; of 
 both sides produces blindness of both eyes. According to our 
 experiments, decorticisation of the angular gyrus of one or both 
 sides is not necessarily followed by any visual defects perceptible 
 to our means of investigation in animals; but complete eradica- 
 tion of the gyrus produces hemiqpia (not amblyopia), which is 
 temporary only. According to Dr. Ferrier's experiments, de- 
 struction of one or both occipital lobes alone produces no appre- 
 ciable effect whatever on vision. According to our experiments 
 which are merely confirmatory of those of Munk removal of 
 the occipital lobe only, without the angular gyrus, produces per- 
 manent hemiopia; of both occipital lobes, blindness of both eyes
 
 i8 SHEPHERD IVORY FRANZ 
 
 which is also permanent and, x so far as we were able to judge, 
 complete" (65, pp. 158-9). Schafer admits the possibility that 
 the visual area does extend beyond the limits of the occipital lobe 
 and asserts that the cortex undoubtedly extends somewhat anter- 
 iorly beyond what is regarded the limits of the occipital lobe, es- 
 pecially on the under surface (and perhaps also the mesial 
 surface). 
 
 The conclusions of Munk, Goltz and Hitzig, which were drawn 
 from observation of dogs deprived of parts of the cerebrum, can 
 not be applied directly to man, whose brain it has been the object 
 to understand by the experiments upon animals. On the other 
 hand, the results of Ferrier and of Schafer are almost directly 
 applicable to the brain of man, but in addition to the experimental 
 results on animals there are numerous clinical observations on 
 man of the visual and other sensory conditions following de- 
 struction of parts of the brain, and the results of these observa- 
 tions are of primary importance. Chief among the results that 
 have been reported are those of Henschen (27, 28). This 
 author examined all the available accounts of reported cases of 
 blindness following lesions of the brain, and contributed observa- 
 tions of personal cases. From the consideration of the clinical 
 accounts and of the patholbgico-anatomical examinations he con- 
 cludes that the visual center is limited to the cortex of the calcar- 
 ine fissure, and that the centers for light and color coincide. He 
 furthermore defined an area, in the anterior part of the calcarine 
 fissure, to which he assigned a connection with the macula lutea, 
 and disputed the conclusions of others who located the macular 
 center in the cuneus. Regarding the lateral surface of the occipi- 
 tal lobes and the cortex of the angular gyrus, he says "I have not 
 found documents which prove there exists a projection in this 
 part, and a lesion of this part does not cause blindness" (28). 
 This part of the cortex is, however, admitted by him to have 
 something to do with vision and this fact leads to the conclusion 
 that there are two areas : one restricted, in which there is a "pro- 
 jection of impressions," while the other, extracalcarine area, does 
 not receive the impulses directly, and is more extensive. The 
 calcarine area is conceived to be a sort of brain retina while the 
 extra-calcarine area is supposed to have perceptive functions.
 
 HISTORICAL 19 
 
 Vialet (73) using similar material concluded that the visual 
 center extended beyond the calcarine fissure, including the cuneus, 
 the lingual and the fusiform lobules, and part of the occipital 
 pole. He concluded that lesions of these parts separately ma\ 
 be accompanied by hemianopsia, but Henschen has analyzed the 
 cases of Vialet and has assured himself that the results obtained 
 by the latter are in harmony with his own hypothesis. Against 
 the hypothesis of Henschen, von Monakow has brought forth the 
 fact that in cases of early blindness with total destruction of the 
 optic nerve, where we expect to find the cortex wasted in the 
 corresponding brain areas, the principal atrophy is to be observed 
 over the convexity of the occipital lobes as well as along the cal- 
 carine fissure. The conclusion of von Monakow has recently 
 been supported by Wehrli (77) who has examined histologicallv 
 the brains in cases of blindness. He supports the view that the 
 fibers from the macula lutea spread over a wide area at the 
 occipital pole, and that the visual area is widely distributed and 
 not to be limited to the area surrounding the calcarine fissure, not 
 even to the part of the cortex with the cell lamination known as 
 the calcarine type. He claims, furthermore, that purely cortical 
 lesions causing hemianopsia have never been observed. 
 
 There aie many cases reported clinically which seem to indi- 
 cate that the localization of visual processes is not as limited as 
 Henschen believes, but it must be said that the observations have 
 often been poorly made, not only clinically but also pathologically, 
 and it is difficult to estimate the value of the individual contribu- 
 tions. Of the negative results with the experimental method, tht 
 work of Vitzou (74-76) is of interest. He extirpated parts of 
 the occipital lobes and of the angular gyri and found the animals 
 lost their visual ability immediately after the operation, but recov- 
 ered it to a great extent during the time they lived. In one animal 
 he extirpated the occipital lobes but preserved the angular gyri. 
 Although this animal was blind after the operation, this condition 
 ameliorated in a month and a half, and after twenty-one months 
 the animal was able to recognize its cage and people. 'A second 
 monkey, in (which both angular gyri and both occipitals were ex- 
 tirpated, was completely blind for about two months but follow- 
 ing this period it began to recognize objects and persons. In a
 
 20 SHEPHERD IVORY FRANZ 
 
 third monkey, both occipitals and parts of both angular gyri were 
 extirpated. This operation resulted in complete blindness for 
 about two months, but at the time the report was made, about one 
 year and three quarters after the operation, the monkey recog- 
 nized objects and people. This animal is reported to have been 
 able to see better than either of the two previously described ani- 
 mals. In a fourth monkey both occipitals and the posterior parts 
 of both angular gyri were removed, causing complete blindness, 
 which was much improved at the time of the report, twenty-one 
 months after the operation. 
 
 Somewhat similar negative results have been reported by 
 Panici (58) from the laboratory of Luciani. The conditions of 
 three monkeys are reported, in which various operations were 
 performed. In one animal the decortication of the posterior 
 segment of the right calcarine fissure produced a bilateral 
 homonymous psychical hemianopsia which persisted for only two 
 days. In a second monkey Panici first extirpated the posterior 
 part of the left cuneus. This resulted in no defect of vision, but 
 following a second operation, in which additional cortex of the 
 left occipital lobe was extirpated, there was found a condition 
 similar to that in monkey I, but which lasted only three days. 
 Seven days after the second operation, Panici extirpated the 
 whole left occipital lobe, and found a bilateral homonymous psy- 
 chical blindness for about a month, which condition gave place 
 to an amblyopia. A month later he extirpated the whole of the 
 right occipital lobe, and found this to result in a right psychical 
 hemianopsia for about a month, after which time the animal 
 began to react to food, but remained indifferent to gestures and 
 to a mirror, but with a corresponding amblyopia. At the first 
 operation on a third monkey the internal portions of the right 
 and left cuneate lobes were extirpated, and a week later this was 
 followed by a more extensive extirpation. Neither of these oper- 
 ations appeared to have any effect upon the visual ability of the 
 animal, but after the third operation, three weeks after the second, 
 the complete excision of the left occipital was accompanied by a 
 bilateral homonymous psychical hemianopsia, which continued 
 for about a year. Twelve days after this operation the right 
 occipital lobe was completely severed, which produced a complete
 
 HISTORICAL 21 
 
 psychical blindness for one year. Thirteen months later a final 
 operation on the left produced complete blindness in the right 
 visual field, and three and a half months subsequent to the opera- 
 tion on the left the right hemisphere was destroyed up to the fis- 
 sure of Rolando. After the extensive destruction just noted the 
 animal became blind in both eyes, over the whole field. 
 
 These results of Panici are of very great interest for they 
 show how much of the brain must be destroyed to produce a 
 complete blindness, and also because they show how transient 
 some of the visual defects may be. It will be seen in the experi- 
 mental part of this article how closely some of the results of 
 Panici resemble those observed by me. 
 
 By the method of recording electromotor changes in the brain, 
 Danielewski (12) and Gotch and Horsley (26) found the occipi- 
 tal lobes responded to stimulation of the retina and the optic 
 nerve. 
 
 After considering the various facts Schafer (66) has summed 
 up regarding the occipital lobes in man as follows: "There is 
 abundant clinical evidence to show : That lesions of the occipital 
 lobe produce disturbances of vision which are invariably of a 
 hemiopic character. That lesions of the mesial surface of the 
 lobe in the immediate neighborhood of the calcarine fissure are 
 those which for their size produce the most serious visual disturb- 
 ances. On the other hand, lesions of parts near to but not involv- 
 ing these parts of the occipital lobe have not infrequently been 
 associated with defective appreciation of visual objects and par- 
 ticularly with word blindness. Perimetric observations in man 
 show that in cases of hemiopia, produced by lesions of the cor- 
 tex (of one hemisphere), the line of demarcation between the 
 blind and functional parts of the retina usually passes, not 
 through the middle of the fovea, but on the homonymous side, 
 in other words, the fovea is not involved in the hemiopic condi- 
 tion." These, and the observations of animals following experi- 
 mental lesions have led him to the following conclusions: "The 
 whole of the visual area of one hemisphere is connected with the 
 corresponding lateral half of both retinae. The upper zone of 
 the visual area of one hemisphere is connected with the upper 
 zone of the corresponding lateral half of both retinae. The lower
 
 22 SHEPHERD IVORY FRANZ 
 
 zone of the visual area of one hemisphere is connected with the 
 lower zone of the corresponding lateral half of both retinae. The 
 intermediate zone of the visual area is connected with the middle 
 zone of the corresponding lateral half of both retinae. The 
 focal point of the visual area, which is placed on the anterior part 
 of the mesial surface of the occipital lobe, is connected with 
 rather more than the corresponding half of the macula lutea of 
 each retinae." With these conclusions von Monakow (47) is 
 not in complete accord, although he considers the visual areas to 
 be rather widely spread, and not be located in a small area. 8 
 He believes the visual area for sensations extends beyond the 
 calcarine area, and includes the lateral part of the occipital lobes, 
 the cuneus, the lingual lobule and the gyrus descendens. More 
 than this, von Monakow admits that the subcortical parts may 
 have something to do with visual sensations (as mental phe- 
 nomena), and if this be so, it would explain many of the appar- 
 ently discordant observations and conclusions of experimenters 
 and clinicians. 
 
 Throughout the previous discussion the psychological conclu- 
 sions regarding the experiments upon animals and the observa- 
 tions of man have been reported as if they were of about the 
 same character. This is not so, for we find the results have been 
 interpreted to mean that the occipital lobes are the sensory receiv- 
 ing stations, or, on the other hand, that these portions of the 
 brain are the places in which the visual associations (physiologi- 
 cal and psychological) take place. From the first point of view 
 the visual disturbances are considered to be inabilities to see, 
 from the second they are conceived to be inabilities to perceive. 
 This is the main point of difference between the adherents of 
 Goltz and those of Munk. With the methods used by these inves- 
 tigators a solution of the problem is not possible, and the results 
 -which have been reported to us may be interpreted in either way. 
 
 Perceptions, etc. Regarding the psychic or higher intellectual 
 functions of the occipital lobes little need be said. In an area 
 close to the occipitals some have located the visual speech func- 
 
 8 "Diese und andere Beobachtungen batten mich zu der Annahme gefiihrt, 
 dass die Stelle des deutlichsten Sehens iiberhaupt nicht in einer engen cor- 
 ticalen Zone reprasentiart sein konne.' J
 
 HISTORICAL 23 
 
 tion, but others have placed this same function in the angular 
 gyms, to which it will be remembered Ferrier assigned such im- 
 portant visual functions. Optical agnosia, alexia and agraphia 
 have all been located in the occipital lobes, but usually the loca- 
 tion has been so indefinite that the individual localizations can 
 not be discussed here. It may, however, be said that the more 
 definite localizations are localizations in areas of the cortex and 
 of the underlying white matter which can not be considered part 
 of the visuo-sensory or of the visuo-psychic types of cortex. An 
 examination of the diagrams of von Monakow and of Moutier in 
 comparison with the cortical differentiation of Brodmann, of 
 Campbell, of Bolton and of Elliott Smith will make this clear.
 
 EXPERIMENTAL. 
 
 INTRODUCTION 
 
 On account of the lack of information in regard to the func- 
 tions of the areas (visuo-psychic) believed by histologists to be 
 closely connected with the visual center (calcarine area), it ap- 
 peared advisable to attempt to determine the functions of this 
 so-called psychic area, and it was this problem which originated 
 the present work. Subsequent developments directed the inquiry 
 into other channels, and eventually it became imperative to rein- 
 vestigate the whole occipital lobe. Only part of the work has 
 been finished but sufficient has been accomplished to indicate that 
 the histological differentiation has not the physiological import 
 which the histologists impute to it. The present work deals main- 
 ly with the relations of the lateral aspect of the occipital lobes in 
 the monkey to certain sensory and perceptual states. 
 
 In this work eight monkeys were used, each of which was 
 trained in visual discrimination previous to the extirpation or 
 the destruction of parts of the occipital cortex. These animals 
 were purchased from a New York dealer, and, as far as could be 
 ascertained, had not been used for experimental purposes or for 
 pets before the time of purchase. All the animals were reported 
 to be about six to nine months old at the time they were receiv rl, 
 although in size there was a considerable variation. During the 
 nine months following their purchase they were utilized by Dr. 
 W. T. Shepherd in psychological investigation, and after that 
 period they were entirely in my charge. During the time they 
 were under my observation they were fed mainly by me, but at 
 other times by three other people. The animals were, therefore, 
 well acquainted with the experimenter and they acted in as normal 
 a manner as could be expected from animals kept in captivity. 
 The observations of the animals continued for about fifteen 
 months, at the end of which time all had been operated upon and 
 killed. The animals lived, therefore, approximately two years, 
 during which time they were under almost constant observation,
 
 MONKEYS 25 
 
 although the experiments to be reported in the present paper were 
 not being conducted throughout all this period. 
 
 Two of the animals upon which operations were performed 
 were shown at meetings of scientific associations, monkey 7 at 
 the meeting of experimental psychologists in April, 1910, and 
 monkey i at a meeting of the Georgetown University Clinical 
 Society in February, 1910. 
 
 During the time the animals were under my observation they 
 were kept in pairs or by threes in cages, 114 cm. high, 90 cm. 
 wide, and 58 cm. deep. The front and right hand ends of the 
 cages were covered with chicken wire, of one and one-half inch 
 mesh. The top, the bottom, the back and the left side were 
 boarded. Within the cage there was a shelf 30 cm. wide jutting 
 from the back of the cage at a height of about 45 cm. This shelf 
 extended the width of the cage. From the front of this shelf to 
 the floor of the cage was a sliding door. When an experiment 
 was to be conducted one of the animals (the one not working) 
 was induced to get below the shelf, the sliding door was closed 
 behind it and the monkey confined beneath, leaving the second 
 animal free so that the experiments might be conducted without 
 interruption and without disturbances. 
 
 The sliding door was kept open except at the time of the ex- 
 periments, and the animals, which lived in these cages during 
 the progress of the experiments, ran in and out of this space 
 as they wished. There was, therefore, no cause for alarm 
 on the part of the animal which was confined. The animals 
 were not handled and the environment, except for the presence 
 of the experimenter, was kept fairly constant throughout the 
 day. Food and water, other than that used in the experiments, 
 were pushed through or under the wire front of the cage and 
 the animals took as much food as they wished. 
 
 Notwithstanding the animals were not handled, all became fair- 
 ly tame, they would hang upon the wire netting of the cage and 
 take fruit, nuts, bread, etc., directly into the mouth, and at no 
 time did they appear to be disturbed by the presence of the ex- 
 perimenter. 
 
 In the accounts of the work which will be found in the section 
 dealing with the observations of the animals before and after the
 
 26 SHEPHERD IVORY FRANZ 
 
 operations, it will be found that there are many expressions simi- 
 lar to those used in describing the actions of man. It must not 
 be understood, however, that these expressions are used in the 
 same way they are used for man, but solely for convenience and 
 for brevity. It would, perhaps, have been advisable to describe 
 the actions of the animals, but such descriptions to be intelligible 
 must be accompanied by equally minute descriptions of the situa- 
 tions, and from the visual side can best or accurately be shown 
 only by means of motion pictures. It must be understood, how- 
 ever, that the anthropomorphic method of describing animal 
 activity is not to be taken as an indication that the animal had the 
 same sort of mental process which a man would have under simi- 
 lar circumstances, but even the most careful of the animal psy- 
 chologists have found it impossible to dispense with terms des- 
 criptive or indicative of mental processes in man. It would, for 
 example, have been better to say "the animal turned its head and 
 its eyes in different directions" rather than "the animal peered 
 around the cage" but, on the other hand, with the warning that 
 has been given, no one should interpret the animal activity in a 
 way other than in terms of movement. 
 
 METHODS 
 
 Training. To one who is familiar with the studies on the 
 functions of the cerebrum, it is evident that many of the differ- 
 ences in opinions and in conclusions have been due to the fact 
 that the tests of animals upon which experiments have been made 
 have been of such a character that they permit of more than one 
 interpretation. It is certain that simple observation of animals 
 following extirpation of parts of the cortex or following the 
 injury to other parts of the nervous system is an inadequate 
 method. For the reason that both the description of results of 
 previous physiological work on the association areas were lacking 
 in exactness and defmiteness, about ten years ago, the writer 
 (16-20) devised a method to determine more accurately the sen- 
 sory and associative functions of parts of the nervous system, 
 especially of the cerebrum. The first investigation to be per- 
 formed by this method was one on the association functions of 
 the frontal lobes (16, 17), but the method has been applied to
 
 TRAINING METHODS 27 
 
 sensory functions both in the present work and in work published 
 by others. This method has previously been described in various 
 places and at present it may be said that it depends upon the 
 formation of definite associations in an animal and the determin- 
 ation of the presence or absence of the associations after lesions 
 of the nervous system. It will be readily appreciated that by this J 
 method there is an approach to the method the clinicians use in 
 the examination of their human cases, and there is afforded the 
 possibility of obtaining very exact information regarding the 
 sensory or associative processes of animals even though in animal 
 experimentation we are hampered, as compared with the investi- 
 gations on man, by the lack of the definite means of communica- 
 tion by speech. 9 
 
 Before an animal is operated upon we must become acquainted 
 with its mental character, we must know the animal well before 
 we operate so that we shall be better able to notice deviations 
 from its normal mental character, following, let us say, the loss 
 or the destruction of a certain amount of a certain part of the 
 brain or the spinal cord. Usually it is not possible to keep a 
 laboratory animal for a period of months or years in order to 
 
 ' This method was used to a limited extent by a number of investigators 
 before it was applied by me to the investigation of the frontal lobes, but all 
 who had previously used it had employed it in much the same way as they 
 made their regular observations. From the account given by Kalischer (36) 
 of an investigation of the functions of the temporal lobes by this method, 
 it might appear to one unacquainted with the situation that he were the 
 originator of it. He calls it "meine Dressurmethode." To an impartial 
 observer it appears a mere hair splitting matter to differentiate Kalischer's 
 method of testing hearing in dogs from that of Thorndike (71), but through- 
 out all of Kalischer's work there is evidence of total ignorance of the work 
 which has been performed in America on animal psychology. It is of interest 
 to note that following a critical note by me (20) Kalischer (37) relinquishes 
 claim to the method as a whole, but makes a claim that he has used the most 
 simple movement as an indication of the presence of sensation in the animal. 
 This claim, in the way it is made, I am sure no comparative psychologist will 
 admit, for the movement of the paw, or the movement of walking, is just 
 as simple physiologically as the movement which Kalischer has used, viz., 
 that of the snapping up of food, which must have associated with it other 
 movements of the head. It is also of interest to note that Kalischer admits 
 in his second article (37) some acquaintance with the training method that 
 had been used by others (e. g., Gaule, 21), although no mention is made of 
 this in his first article.
 
 28 SHEPHERD IVORY FRANZ 
 
 get acquainted with its mental make-up, and to facilitate matters 
 we have at our command the training method devised by Lloyd 
 Morgan and so ably followed out by Thorndike (71) and many 
 others. By the use of this method we may have animals, which 
 are to be operated upon, form certain associations, the presence 
 or absence of which can be later determined by the experimenter 
 in a few minutes. The associations always involve two elements, 
 the sensory or afferent, and the motor or efferent. It is believed 
 that in most, if not all, cases a third element is present, viz., the 
 associational. By proper combinations and by the formation of 
 more than one habit at a time it is possible to differentiate these 
 three elements, and to infer without question which of the ele- 
 ments is lacking and which has been interfered with. 
 
 Comparative psychologists have investigated the visual dis- 
 crimination ability of monkeys, but some have not been satisfied 
 from the results and the methods of the experiments that mon- 
 keys discriminate colors as such. The methods of other investi- 
 gators and the results obtained by them indicate that monkeys 
 have good visual discrimination, although a few are unwilling to 
 admit the conclusiveness of the experiments on color. It seemed 
 advisable to have the animals acquire a habit indicative of color 
 discrimination but none of the methods previously employed ap- 
 peared to be sufficiently well accepted and none appeared to place 
 the animal in a position similar to that it might normally be in. 
 In the present work an attempt was made to have the animal test- 
 ed in as normal a way as possible, and to form the habit or to 
 produce the discrimination quickly as well as naturally. 
 
 In the present work it was necessary to have the animals form 
 habits of a definite visuo-motor character. For this reason the 
 sensory part was made as simple as possible, viz., foods of dif- 
 ferent colors, which had to be discriminated. In a series of 
 experiments on the color discrimination of monkeys, conducted 
 by Dr. W. T. Shepherd (68), under my direction it was found 
 that the animal rapidly learned to discriminate colored objects 
 if the stimuli were of a character to attract and to hold the atten- 
 tion. In most animal experimentation it has been found difficult 
 to get stimuli which will attract the attention of the animal, 
 stimuli which are appreciated by the animal and which will lead
 
 TRAINING METHODS 29 
 
 to definite reactions. In color experiments it has been customary 
 to use the box method of feeding, the box being covered with 
 colored paper or lights being exposed near the box. The employ- 
 ment of this method has certain advantages and certain disadvan- 
 tages that are apparent to all who have used it. On the one hand 
 the colors may be changed to a considerable degree both in inten- 
 sity and in hue, but on the other hand the use of papers, filters, 
 or other similar means of giving stimuli introduces an element 
 foreign to the animal mind and must have less effect than the 
 exhibition of colors in direct connection with the object to be 
 obtained. Moreover, in order to determine discrimination ability 
 many investigators have found it necessary to punish the animal 
 for a wrong selection and to reward it by means of food for a 
 correct selection. In most of the work which has been reported 
 the punishment has also been something foreign to the animal 
 mind, and the use of electric shocks and other similar methods 
 to inhibit the activities of an animal have led at times to disturb- 
 ances in activity which are not conducive to proper experimenta- 
 tion. 
 
 Because of the difficulties and disadvantages of the methods 
 which have been previously employed, colored food was used in 
 the experiments of Dr. Shepherd, and in these experiments it 
 could not be doubted that the attention of the animal was directed 
 toward the stimuli. In the early work bread or rice was mixed 
 with appropriate colors, two or more differently colored pieces 
 of food were simultaneously displayed before the animal and the 
 animal learned to select one or more of the colored pieces. The 
 artificial method of punishment was discarded in these experi- 
 ments and a more natural method was employed. In the method 
 the punishment and the cause of the inhibition of the wrong re- 
 actions were contained in the stimuli and were not extraneous. 
 Certain of the colored foods were soaked with a solution of qui- 
 nine and others had added to them a certain amount of saccharine. 
 On the assumption that the monkey likes sweet and dislikes bitter 
 tasting foods, we should find that the animal would learn to de- 
 cline the bitter food and to take only those which were sweet or 
 at least not bitter. As a matter of fact, this assumption wa^ 
 found to hold in almost all the animals tested. With only one
 
 SHEPHERD IVORY FRANZ 
 
 monkey was there any difficulty in the establishment of the habit 
 to take the properly colored and sweetened food and to leave the 
 food which had been made bitter. This animal seemed to have 
 little objection to the bitter taste and for a relatively long time 
 ate both the sweet and the bitter foods. This animal died before 
 the effects of the operation were determined and the records are 
 not included in the accounts of the experimental work. Eight 
 other monkeys, however, had a decided dislike for bitter food, or 
 to express this in terms of reaction, these animals soon learned to 
 permit the bitter foods to remain on the plate, and although hun- 
 gry, did not touch them. In the formation of the habit and in 
 the subsequent tests following the operation the monkeys were 
 not kept in a state of absolute hunger, for it was found by pre- 
 vious work that this factor would interfere with the normal work- 
 ing of a monkey. 
 
 In performing the experiments to be described here the animal 
 was in its usual cage. The cage has already been described. The 
 animal sat upon the shelf, sometimes near the wire netting on the 
 right hand side and sometimes farthest away from the netting. 
 A glass plate, 12.5 by 18 cm., was arranged on a platform with 
 cup hooks to catch the wire of the cage so that it could be at- 
 
 9 
 
 FIG. 9. Glass plate and holder for the presentation of food to the monkeys, 
 A, glass plate; B-B, cup hooks to catch upon the wire netting of the cage.
 
 TRAINING METHODS 31 
 
 tached to any part of the front or side of the cage. The arrange- 
 ment was such that the glass plate was kept horizontal. Fig. 9 
 illustrates the glass plate and the holder. All this part of the 
 apparatus was colored black. The food was placed upon the 
 glass plate, the holder was arranged on the cage and the experi- 
 menter moved away from the cage about a meter's distance. The 
 animal, which usually sat at the farthest end of the platform, 
 moved forwards and took the food which was presented to it on 
 the plate. In performing the experiment in this manner the 
 greatest possible freedom was accorded the animal, and the move- 
 ment to be performed was as simple as possible and one which 
 would give the right to conclude that discrimination did or did not 
 take place, i. e., the taking or leaving of the food. The arrange- 
 ments at a later date were made more simple, as far as the ad- 
 justments are concerned, in that the glass. plate holder was at- 
 tached to the cage at the beginning of the series of tests and kept 
 there throughout the series on that day. When this was done the 
 food was placed upon the plate in the same manner as has been 
 described. In all the series of tests the arrangements of the breads 
 were constantly changed, the bitter being at times on the right, at 
 times on the left, and if three or four pieces were simultaneously 
 displayed the bitter pieces were between the sweet, or at both 
 f.nds. In most of the experiments, all of those in which the 
 animal was being trained, the two or more pieces of food were 
 placed upon the plate at approximately the same distance from 
 the cage netting. In later tests at times the foods were arranged 
 indiscriminately on the plate, the sweet being farther from or 
 nearer the cage, etc. Most of the animals were trained on the 
 discrimination of colored foods, and one on the discrimination of 
 foods of different sizes. 
 
 The colored food. After a number of tests it was found 
 that white bread was most suitable both for coloring and for 
 food. The bread was usually 24 to 48 hours old at the time 
 it was received. The crust was removed and the bread was cut 
 into thin slices about 5 mm. thick, then into strips of about the 
 same width, and finally into shorter lengths making hexahedrons, 
 approximately cubes, 5 mm. on each edge. A large number of 
 these were cut at one time and from 30 to 100, depending upon
 
 32 SHEPHERD IVORY FRANZ 
 
 the number of animals under the test, were colored ; the remain- 
 der were used on succeeding days. If kept uncovered the small 
 cubes dried, but it was found that the immersion into the solu- 
 tions brought them back to their original size. The cubes were 
 dipped into watery solutions of different colors, and thoroughly 
 saturated. The resultant colors were fairly homonymous, but 
 did not have the smoothness of colored papers or of other similar 
 material on account of the small bubble holes in the bread. The 
 colored moist breads were placed in small crystallizing dishes and 
 covered with watch glasses to prevent the entrance of dust and 
 to limit evaporation. In this way it was found possible to make 
 up fairly large quantities of the different colors and to keep them 
 fresh and moist for several days. 
 
 In the general experiments on color four differently colored 
 breads were prepared : red, blue, green, and yellow. The color 
 solutions, formulae for which follow, were made up in large 
 quantities, and to each solution a proportionate quantity of alco- 
 holic solution (5%) of thymol was added. The thymol was 
 added for two reasons ; first to prevent the formation of mold in 
 the solution and, secondly, to overcome any special odor of the 
 solution and to substitute for the special odor that of thymol. In 
 this way an attempt was made to equalize the odors of all the 
 stimuli, in order that the discrimination might not take place be- 
 cause of the differences in odor. Particular attention is cal : ed 
 to this factor, for although we have no right to say that by this 
 introduction of a foreign odor (distinctly perceptible to man) 
 the odors of all the pieces of bread were the same, I believe the 
 strength of the solution was sufficient to overcome any odor of 
 the individual solutions. None of the individuals (men) who 
 were tested could detect the least difference in the odors of the 
 solutions, and the tentative conclusion was drawn that the indi- 
 vidual odors of the solutions were overcome, and that all the 
 breads smelled alike. 
 
 The formulae used in making the solutions were as follows : 
 
 Red : Congo red i.o gram. 
 
 Water 300.0 cc. 
 
 Saccharine 3-O grams.
 
 33 
 
 Blue : Toluidin blue 0.5 gram. 
 
 Water 400.0 cc. 
 
 Saccharine 4.0 grams. 
 
 Yellow : Methyl orange 0.5 gram. 
 
 Water 250.0 cc. 
 
 Quinine bisulphate (0.5% solution) 25.0 cc. 
 
 Green : Methyl orange 0.2 gram. 
 
 Smaragd grim o.i gram. 
 
 Water 250.0 cc. 
 
 Quinine bisulphate (0.5% solution) 25.0 cc. 
 
 When they were intended for use, i. e., for the dipping of the 
 bread, the solutions were diluted to one-half strength by the 
 addition of water. 
 
 Immediately after dipping the breads the colors of the breads 
 were compared with the colored papers in the Milton-Bradley 
 series. On this comparison it was found that the yellow bread 
 was approximately half-way between the yellow orange and the 
 orange yellow of that scale, but after slightly drying the color 
 was more nearly like the latter. 10 The red bread was approximate- 
 ly like the red of the scale, although on account of the chemical 
 properties of the Congo red this color varied to a greater extent 
 than did any of the others. When the bread was dipped into the 
 blue solution it took a color most like that of the Engine colored 
 paper 5b of the scale, being close to the regular blue shades nos. 
 
 1 and 2. When the solution was diluted to half strength, as 
 usual, the bread became nearly like Engine colored paper 5, or 
 like the blue of the regular scale, although the latter was a trifle 
 darker. The bread, after having been dipped into the green solu- 
 tion almost exactly matched green yellow shade i, but on stand- 
 ing this color changed to yellow green shade 2, and eventually 
 became almost like yellow green. The change in this case was 
 probably due to some combination with the air, probably oxida- 
 tion. 
 
 No special examination of the colored solutions by means of 
 
 10 The colors of the breads are given in terms of the nearest color in the 
 Milton-Bradley scale, but the comparison is rough, and in the case of green 
 2, the color scale showed nothing to correspond closely. The color of green 
 
 2 was much darker than the M-B green shade no. 2, but there is nothing irr 
 that scale to give a better idea of the color and shade. The difference in 
 the colors, is, however, the main fact to be remembered.
 
 34 SHEPHERD IVORY FRANZ 
 
 the spectroscope or by the photometer was made, because all the 
 colors are standard colors, and can readily be made by anyone, 
 and because this examination was not deemed of importance in 
 the present work. 
 
 Color Vision of the Monkey. It has been said above that the 
 animals soon learned to discriminate the colored breads, leaving 
 the bitter ones and taking the sweet. At first this may be taken 
 as sufficient evidence that the discrimination was made on the 
 basis of the color quality, but to this conclusion many animal 
 psychologists will take exception. On account of the doubt on 
 this point a supplementary series of tests were made with several 
 monkeys to determine whether the hue or the difference in inten- 
 sity (or brightness) was the factor which was discriminated. The 
 tests of one animal will suffice to make this matter clear. 
 
 With this animal breads colored red and green were employed. 
 After the animal had learned to discriminate the two kinds of 
 bread, the colors were changed in intensity or in saturation and 
 additional tests were then made. In the original tests (before 
 the changes in the intensity, etc., of the colors) in making up 
 different lots of colored, breads the pieces showed slight differ- 
 ences in intensity and in saturation, and to a greater extent in 
 moisture. These variations were not of sufficient amount to be 
 particularly noticeable by me or by others, and were determined 
 only when the breads colored at different times were placed side 
 by side and examined in very bright light. There was also a 
 very slight difference in the colors of the individual pieces of 
 bread, but under the most favorable conditions these differences 
 -could not be detected at a distance of about a meter. In per- 
 forming the experiments the colors were placed on the plate sim- 
 ultaneously but in an irregular position ; half of the time the reel 
 was to the right of the animal and half to the left. Sometimes the 
 red and sometimes the green was nearer the animal. In this way 
 no association could be formed between positions and the tastes. 
 
 Experiments in color (beyond these performed by Dr. Shep- 
 herd, to whose work reference has been made) began with mon- 
 key 6 on November 30. On that day in the first test the animal 
 took both pieces of bread, red and green, and immediately placed 
 them in her mouth and ate them. She did not appear to enjoy the
 
 COLOR VISION OF THE MONKEY 35 
 
 taste of one of the pieces and became more cautious after two 
 trials, and on the third trial she partly rejected the green (bitter). 
 On seven other trials on this day the animal took only the .red 
 bread (sweet). On the following day she took only the red. 
 Three days later she took both the red and the green in the first 
 seven trials, and only the red the other three trials. A rest of 
 two days was given, and, following this, on twelve successive 
 days, ten trials each day, there were only three mistakes. At the 
 end of this time it was concluded the habit was firmly established. 
 The animal would not take the green bread, no matter what posi- 
 tion it occupied on the plate. At times the red bread was placed 
 as far away as possible, and at other times to the extreme right or 
 to the extreme left while the green was in the most prominent 
 place, viz., the center of the glass. 
 
 On the following day the conditions of the experiment were 
 altered. Instead of presenting to the animal only the definite col- 
 ors with which it had become familiar and to which it had learned 
 to react in a definite way, marked variations of these colors were 
 presented. Each of the stock solutions for this experiment was 
 mixed with different quantities of water, and in this way there 
 was obtained solutions giving (to man) four distinct shades of 
 red and four of green. The mixtures which gave the different 
 colors and the color results on the bread (according to the Milton- 
 Bradley scale) of saturating the bread with these mixtures are 
 as follows : 
 
 Red I (red, shade no. 2) 16 cc. standard red solution, 40 cc. water, and 
 
 a piece of sodium carbonate the size of the head of a pin. 11 
 Red 2 (red) 16 cc. standard red solution, 40 cc. water, and sodium 
 
 carbonate until the solution began to clear. 
 Red 3 (orange red) 16 cc. standard red solution, 40 cc. water, and 
 
 sodium carbonate until the solution became clear. 
 Red 4 (red, tint no. 2) 10 cc. standard red solution, 50 cc. water, and 
 
 sodium carbonate until the solution became clear. 
 Green i (yellow green, shade no. 2) 20 cc. standard green solution and 
 
 50 cc. water. 
 
 11 The Congo red is an indicator for acids and alkalies, and the color ot 
 the solution depends upon the relative amounts of these opposing conditions. 
 The color of the solution was readily altered by the addition of small quanti- 
 ties of sodium carbonate and the greater or less quantity of this alkali gave 
 the various shades and tints of the red.
 
 36 SHEPHERD IVORY FRANZ 
 
 Green 2 (green, shade no. 2) 35 cc. standard green solution, and 20 cc. 
 
 water. 
 Green 3 (green, tint no. i) 15 cc. standard green solution, and 25 cc. 
 
 water. 
 Green 4 (yellow green, tint no. i) 10 cc. standard green solution and 
 
 50 cc. water. 
 
 Two of these colored pieces of bread were presented to the 
 monkey in the same manner as the breads to which it had learned 
 to react. The breads were selected and arranged in an irregular 
 order ; red i and green i ; red i and green 2 ; red 2 and green i ; 
 red 3 and green 3, etc. With these combinations twenty tests 
 were made and in every test the animal took the red bread and 
 disregarded the green. Twenty tests on each of two succeeding 
 days gave the same result; green of any shade or tint was not 
 taken, the red bread of any shade or tint was taken. Three days 
 later twenty-two tests with two of the colors gave almost the 
 same result, and two tests in which two pieces of green and two 
 pieces of red were presented simultaneously showed that the ani- 
 mal would take the red and disregard the green even when the 
 conditions of the test were changed in this particular. Follow- 
 ing is a record for this day : 
 
 December 23, 1909. Monkey 6, reactions to shades and tints of red and 
 green. Ri, R2, R3, R4, Gi, G2, G3, G4, are the different shades and tints 
 used. The color noted first in each test was placed at the left of the plate. 
 
 1. Ri, Gi. 9. G4, Ri. 17. G3, R3. 
 
 2. R2, G2. 10. G4, R2. 18. R4, 63. 
 
 3. R3, G3. ii. G2, Ri. 19. G4, Ri. 
 
 4. R4, G4. 12. G2, R2. 20. R2, G4. 
 
 5. Ri, G4. 13. R3, G2. 21. R3, G4. 
 
 6. G4, R4. 14. R4, G2. 22. R4, 64. 
 
 7. R2, G4. 15. Ri, G3. 23. Ri, Gi, G4, R4. 
 
 8. G4, R3. 1 6. G3, R2. 24. R2, G2, R3, 63. 
 
 In test 4 the monkey took the red piece first and after it the 
 green ; in all other tests only red was taken. Eighteen days later 
 the monkey made no mistakes in 13 trials with two pieces pre- 
 sented simultaneously. Following is the order of the tests : 
 
 1. Ri, G2. 6. G4, R3. ii. Gi, K4- 
 
 2. G2, R3. 7. G4, R2. 12. R2, Gi. 
 
 3. G2, R2. 8. R4, G4- 13. R4, G3. 
 
 4. R4, G2. 9. Ri, Gi. 
 
 5. Ri, G4. 10. Gi, R3.
 
 COLOR VISION OF THE MONKEY 37 
 
 Another monkey which was tested picked out the shades and 
 tints of red when the number presented simultaneously was more 
 than four, and two other animals made no mistakes on the differ- 
 ent shades at a later date although the colors were not so defined 
 as they were in these experiments. Even when other colored so- 
 lutions were used for the dipping of the bread the animal always 
 selected the red in preference to the green. In some of the later 
 tests the red bread was made by dipping the pieces into Carter's 
 crimson ink, and the green by dipping pieces into a mixture of 
 blue and yellow drawing inks (Columbia brand). These later 
 tests were made also without having the solution mixed with 
 thymol solution, and without the addition of saccharine and qui- 
 nine. It appears from these tests, therefore, that neither the 
 smell of the thymol nor the presence of the saccharine affected 
 the reaction after the habit was established and that the reaction 
 Avas one due to the color of the breads. 
 
 In further tests with monkey 6 in which some of the colored 
 pieces of bread were of a larger size, 10 to 12 mm. on each edge, 
 and some were of the smaller usual size, the combinations of the 
 small with the large did not affect the reaction to the color. The 
 following combinations were made: A, small red with a large 
 green ; B, small red with small green ; C, large red with large 
 green ; D, large red with small green ; tints and shades varying 
 as has been described. In these tests the red was selected re- 
 gardless of size, tint or shade ; the green was always disregarded. 
 
 The results of these experiments indicate plainly that the mon- 
 key which has been taught to react to a particular situation is 
 able in some way to transfer this practice to a situation, which 
 has certain elements of similarity, or, to put the matter in more 
 definite terms, the monkey which has learned to react to definite 
 colored objects in some manner extends this mode of reaction 
 to shades and tints of the same hues. Two explanations may be 
 offered for this result; that the animal has in each case reacted 
 to the hue of the object or that it has reacted to some other factor. 
 The experiments with the different sizes shows that the reaction 
 was not to size. The fact that the colored breads were placed on 
 the plate in irregular order indicated that the reaction was not 
 due to the position. Because the animal disregarded the differ- 
 
 > < t i ; 
 L A 1 1 ,)
 
 38 SHEPHERD IVORY FRANZ 
 
 ence in intensity of the colors and continued to react in an appro- 
 priate manner regardless of the intensity differences is an indica- 
 tion that the intensity relations of the breads was not the impor- 
 tant factor, and because other reds and greens (with presumably 
 different absorption spectra, although this was not determined) 
 were selected by the monkey in the same manner, the indication 
 appears plain that the reaction was due to the color or hue. From 
 the tests, especially when we compare them with other tests on 
 animals performed by others, it seems justified to conclude that 
 monkeys do discriminate colors, and that in the present work 
 the discrimination was one of color and not of other elements in 
 the stimuli. 
 
 Operation. Each monkey was caught in a bag and anesthetized 
 in it before being prepared for the operation. This was found 
 to be necessary on account of the struggles of the animal from 
 the anesthetic and binding, and after the anesthetic was begun it 
 was continued throughout the time the operation was in progress. 
 As an anesthetic I used the A. C. E. mixture. This I found was 
 well taken by the animals, it decreased the time of excitement, 
 and was much safer than when chloroform alone was given. The 
 recovery was rapid and attended by no adverse conditions. 
 
 After having been anesthetized the animal was placed upon an 
 operating board, and tied thereto. The hair over the head and 
 over the back of the neck was cut closely, and over the part where 
 the incision was to be made a depilatory solution or paste was 
 applied. This was found, as in my previous work, to be an ex- 
 cellent method of removing the hair, and was much easier than 
 the method of shaving. In shaving it has been found that the 
 skin is sometimes broken and this introduces an extra wound 
 which must be attended to or the chance of infection is increased. 
 Moreover the depilatory produced a "close shave" removing the 
 fine hairs as well as the coarse ones. The mixture employed by 
 me was made by combining equal parts of precipitated chalk and 
 barium sulphide, and adding sufficient sterile water to make a 
 paste. 12 This was applied to the head, as has been mentioned and 
 
 12 1 tried upon myself various mixtures, but found the most satisfactory 
 results to be obtained with the mixture of chalk and sodium sulphide, calcium 
 sulphide, and barium sulphide. The calcium and sodium sulphides did not 
 work as rapidly as the barium, and were apparently more irritating, so that 
 in all the experiments with the monkeys the barium sulphide was employed.
 
 OPERATIONS 39 
 
 in from three to five minutes the hair was removed by scraping 
 away the paste. The head was then washed with bichloride solu- 
 tion, i : looo, and a gauze sponge soaked in the solution of bi- 
 chloride was applied to the head, and left there until the operation 
 was begun, i. e., about 3 to 5 minutes. 
 
 The i-nstruments had been sterilized by boiling in a solution of 
 sodium carbonate, and the dressings had been sterilized in a 
 pressure steam sterilizer. After having carefully attended to the 
 matter of sterilization, the operation was begun. The apparently 
 great trouble taken for the production of asepsis was repaid by 
 the results of the operations, in only one of which were signs of 
 infection found, and this case was readily explained and will be 
 mentioned below. 
 
 A median incision was made in the scalp and a second one was 
 made at right angles to the original one, about at the place the 
 skull openings were to be made. The skull was opened by the 
 use of a half-inch trephine, and in most of the operations this 
 opening was enlarged by bone forceps to three or four times the 
 original size. In some of the operations the brain was incised 
 with a fine cataract knife, for the purpose of separating the 
 occipital lobe from the remainder of the brain, but in most of the 
 operations the cortex was cauterized by means of a galvano-cau- 
 tery. The depth of the burning varied in each case, in each hemi- 
 sphere and even in different parts of the hemisphere, but these 
 results will be mentioned in the appropriate experimental sections. 
 The trephine buttons were seldom inserted. Bleeding from the 
 cliploe was checked by the application of bone wax, and the bleed- 
 ing of the brain was usually controlled by the application of com- 
 presses wet with normal saline solution. At times it was neces- 
 sary to apply a small quantity of Suprarenalin, i : 1000, which 
 effectively checked the hemorrhage when it was used. 
 
 After the operative interference with the brain the dura was 
 drawn over the brain, but was not sutured. The scalp wound was 
 closed, and over the site of the scalp wound a layer of gauze 
 slightly thicker over the site of the removal of the bone, was 
 placed. A cotton bandage was then arranged around the head, 
 to include the jaw, but leaving out the ears. After sufficient lay- 
 ers of this had been applied it was sewn with strong thread to
 
 40 SHEPHERD IVORY FRANZ 
 
 prevent its removal by the animal. The bandage was picked at 
 by the animal but in no case in which the sewing was thoroughly 
 performed did the monkey cause it to fall off. The constant 
 picking frayed the edges and after a few weeks the bandage en- 
 tirely disappeared from the head, and was found encircling the 
 neck like a ruching. Long before this time, however, the wound 
 had healed and the removal of the bandage did not affect the 
 wound. After the bandage was removed it was usually found 
 that the hair had begun to grow. With one animal the bandage 
 was hurriedly sewed, on account of the rapid recovery from the 
 anesthetic, and the whole bandage was found to have been re- 
 moved within three hours after the operation. Even this animal 
 did not show signs of infection at the autopsy. In this case a 
 new bandage was applied after the head was thoroughly washed 
 with bichloride solution. 
 
 Post Mortem Examinations. One animal was killed with illu- 
 minating gas, and the others were given overdoses of chloroform. 
 In most cases the autopsy was performed immediately after 
 death, and in only one was there a delay of as much as two hours. 
 The brains were weighed as a whole, and no effort was made to 
 separate the cerebrum from the cerebellum and pons, etc., nor to 
 get the separate weights of the hemispheres. It was found incon- 
 venient at times to get the brains weighed at the time of the autop- 
 sy, and those which were not weighed at the time of the autopsy 
 were weighed after having been preserved in alcohol (95%) or 
 in formalin (10%) for 24 hours. 
 
 Some of the brains were photographed immediately after the 
 autopsy, but a few were photographed after having been in alco- 
 hol or in formalin. From the photographs tracings were made, 
 showing all the principal points, fissures, etc., and the illustra- 
 tions accompanying this article are reproductions of these trac- 
 ings. Whenever a brain was photographed it was placed on a 
 scale showing centimeter and half centimeter divisions, and these 
 divisions are marked in the illustrations. The surface diagrams 
 are, therefore, approximately accurate representations, and on 
 account of the presence of the scale the accurate sizes of the 
 brains may be determined. The illustrations are reductions from 
 the tracings, in some cases to one-half size, in others to two-thirds.
 
 POST MORTEM EXAMINATIONS 41 
 
 size of the originals. When the hemispheres were cut for the 
 purpose of rapid hardening and impregnation, sketches were 
 made of the appearance of each section, with the apparently ab- 
 normal parts distinctly marked. 
 
 After complete hardening, sectioning, staining and mounting 
 of the sections they were placed in the Edinger projection and 
 drawing apparatus and accurate sketches made of all appearances. 
 The magnification was usually about three to four diameters. On 
 each of these drawings the scale was drawn. Reductions of these 
 sketches are reproduced. 
 
 The sections were examined microscopically by Dr. G. R. La- 
 fora, and the results of his examination are noted on the dia- 
 grams. Wherever the cortex or pia or fibers were diseased marks 
 were made on the drawings (Edinger) and at the same time Dr. 
 Lafora marked the limits of the so-called visual (i. e., calcarine 
 type) cortex if these were determinable. At times it was found 
 that all distinctive marks of the calcarine cortex had disappeared 
 from the lateral aspect of the hemispheres, and at times it was 
 even difficult to note the limits along the calcarine fissure. In 
 estimating the amount of destruction and in drawing this on 
 the diagrams it was done conservatively, but on the other hand, 
 on account of the negative character of some of the results, there 
 was a liberality in defining the limits of the calcarine cortex. It 
 is possible that other observers would have judged these two 
 limits to be closer together than they are pictured in the accom- 
 panying illustrations. 
 
 Following is a summary of the histopathological findings by 
 Dr. Lafora : "The lesions of the pia may be summarized as fol- 
 lows : In places where the galvano-cautery acted directly upon 
 the pia (i. e., burned it) the pia was found to be completely des- 
 troyed. In certain cases and in certain places the following ef- 
 fects of partial destruction were found : hemorrhagic processes 
 with an accumulation of polymorphonuclear leucocytes and 
 Kornchenzellen (full of pigment and fat) and a hyperplasia of 
 the fibroblasts. These are reactive processes consequent to a 
 partial destruction or to an irritation of the pia a short time pre- 
 vious to the examination. A similar condition, though not so 
 marked, is found in the pia over a comparatively large area sur-
 
 42 SHEPHERD IVORY FRANZ 
 
 rounding the cauterized regions, but the pial alterations in the 
 latter cases are not accompanied by cortical changes as are those 
 in the cauterized area. In the cerebral cortex numerous patholog- 
 ical changes, especially different forms of degeneration, have 
 been found. When the pia was totally destroyed the cortex was 
 found to have disappeared, and to be replaced by an accumulation 
 of blood cells with polymorphonuclear leucocytes, around which 
 there were many Kornchenzellen and macrophages. Around the 
 necrotic zone, which sometimes extended to a considerable depth 
 into the white substance, was another zone of a reactive charac- 
 ter. In this secondary zone there were found marked hyperplasia 
 of the blood vessels, many fibroblasts showing a transformation 
 into macrophages, and hyperplasia of the glia cells. The nuclei of 
 the glia cells frequently showed karyorrhectic processes, and 
 these cells were charged with pigment, and apparently took the 
 functions of the Kornchenzellen. When the pia was only par- 
 tially affected there was produced a marked reactive process, in 
 which condition we found very different lesions. At times it was 
 found that the zone agranularis was destroyed and the other cor- 
 tical layers were only slightly affected by a neuroglia hyperplasia 
 and many ganglion cells showed tigrolysis and neurophagia. 
 At other times the process was more marked in the middle layers 
 of the cortex (granularis interna and ganglionaris of Brodmann) 
 while the zona agranularis (lamina zonalis of Brodmann) and the 
 lamina pyramidalis were not much affected. These conditions 
 are undoubtedly dependent upon the different vascular destruc- 
 tions. In the last described conditions in the vicinity of the 
 cortex in which the lesion was pronounced there were always 
 found indications of irritative changes (neurophagia, neurog- 
 lia hypertrophy and hyperplasia), the vessels showed many Korn- 
 chenzellen in the lymphatic spaces and there were also observed 
 neuroglic Stabchenzellen. We observed hemorrhagic, necrotic 
 and reactive processes. Where hemorrhages were produced a 
 reaction around these areas was always found. Sometimes the 
 obstruction of a vessel produced a necrotic process in the depth 
 of the white substance, with a preservation of the cortex. In 
 the brains of the animal operated upon by cutting, the degenerat- 
 ed elements (fat formation) were not well marked on account of
 
 POST MORTEM EXAMINATIONS 43 
 
 the short time intervening between the operation and the time 
 of the examination. In these cases, however, some fat spherules 
 were found, as the drawings indicate." 13 
 
 It may be said that the examinations of the brains were made 
 after staining by the methods of Nissl and Marchi. 
 
 One point mentioned in Dr. Lafora's account of the lesions is 
 worthy of special attention, viz., the fact that in certain places 
 it was found that destruction of the pia was not accompanied 
 by destruction of all of the underlying cortex. In selecting the 
 cautery method of extirpation it was believed that the burning 
 of the cortex with the consequent obliteration of the vessels would 
 produce an anemia of the cortex, and a consequent destruction. 
 By the use of injection methods Beevor (4) concluded that the 
 cortex is supplied by the arteries passing through from the pia. 1 * 
 The results of the histological examinations in these cases appear 
 to indicate that not all parts of the cortex are supplied by the 
 pial vessels, and that some parts of the underlying white substance 
 may be supplied. Some of the more interesting, but finer obser- 
 vations on this point have not been mentioned in the account of 
 Dr. Lafora, but it appears true that contrary to Beevor's view 
 the cortex is not entirely supplied by the pial arteries. In some 
 cases, as has been mentioned in the above account, there has 
 been a selection even in the different layers of the cortex, and it 
 is neither true that all the cortex is destroyed nor that it may be 
 preserved entirely. 
 
 13 In all the figures (except 93 to 96) indicating the conditions found by 
 microscopical examination, dots are made to indicate the location of hem- 
 morhagic processes and crosses to indicate the destructions of pia, cortex, 
 fibers, etc. In figs. 93 to 96, the degeneration of masses of fibers could not 
 be well shown by crosses and the degenerated bundles are shown by dots 
 and lines. The following abbreviations are used in the figures: R, right; L, 
 left ; calc. or calc. fiss., calcarine fissure ; cent., central or Rolandic fissure ; 
 Sylv., Sylvian fissure ; par., parallel fissure ; occ., occipital fissure ; thai., 
 thalamus; lent, nucl., lenticular nucleus; vent., ventricle; posterior (in figs. 
 3-3S) indicates the posterior portions of the sections; c indicates the limits 
 of the calcarine type of cortex. 
 
 * "I hold with Duret that the arteries which penetrate and supply the 
 cortex are end arteries, and do not anastomose with their contiguous 
 branches; and I have found that, if the pia matter be carefully removed, or 
 a circular cut be made in it, the subadjacent cortex is not injected by the 
 vessels in the surrounding cortex."
 
 44 SHEPHERD IVORY FRANZ 
 
 RESULTS 
 
 Eight monkeys were used as the subjects in this work. 
 These, as has been said, had been previously used in an 
 investigation on animal intelligence by Dr. W. T. Shepherd, and 
 in the early work they were given numerical designations instead 
 cf names. These numbers were adhered to in the present work, 
 although they do not conform with the order in which the obser- 
 vations or the operations were made. The following accounts of 
 the experiments are, however, given in accordance with the ser- 
 ial numbers for the purpose of convenience. 
 
 An examination of the case records reveals a variety of opera- 
 tions, and a variety of observations on different aspects of mon- 
 key intelligence, some of which can, and some of which can not, 
 be correlated with the brain conditions. 
 
 Monkey i. This animal was trained to discriminate yellow 
 (bitter) from red (sweet) bread. The experiments for the pro- 
 duction of the habit were begun September 23, and continued 
 over a period of more than two months before an operation was 
 performed. In the training, tests were made on 29 days of the 
 whole period. Following is an abbreviated account of the process 
 of learning: Sept. 23, 10 tests; took yellow bread twice and the 
 other eight trials left it, but always took the red bread. Sept. 
 24, 10 tests; similar result, except that the monkey did not place 
 the yellow in its mouth the second time it picked it up. On the 
 two succeeding days there was a similar result, although on the 
 fourth day the animal more often picked up the yellow bread. On 
 the two succeeding days the monkey always picked up and ate the 
 yellow bread. On the two succeeding days the monkey always 
 picked up and ate the yellow bread, and did this apparently from 
 hunger, although he did not seem to like the taste. On Sept. 30. 
 i o tests ; the animal first showed perfect discrimination, for it al- 
 ways took the red bread and left the yellow. Two days later a 
 similar result was obtained, but on Oct. 4, after one day's rest, the 
 animal once more took both the red and the yellow. From this 
 time there was a gradual curve of learning, with only slight varia- 
 tions, to Oct. 19, after which time the monkey made very few. 
 mistakes. On November 3, the animal performed the ten tests 
 satisfactorily, and a rest of fifteen days was given, at the end of
 
 EXPERIMENTAL RESULTS 45 
 
 which time a "memory test" was made. This latter showed per- 
 fect retention. After five days another series was made, showing 
 perfect retention, and again three days later, Nov. 27, with the 
 same result. 
 
 Operation: November 27, n a. m. The occipital lobes were 
 severed by a cut posterior to the parieto-occipital fissure. During 
 the operation there was little loss of blood from the scalp, bone 
 and brain, except on the right side where there was considerable 
 hemorrhage when the incision was made into the brain substance. 
 This part of the brain was compressed for about ten minutes, and 
 at that time the blood flow ceased. The trephine buttons were 
 inserted, the head was bandaged, and the animal was taken from 
 the operating table at 1 1 130. 
 
 Immediately after the operation the eyes were widely dilated, 
 and the animal appeared to be only semi-conscious. 
 
 Two and one-half hours later the animal was found sitting up 
 in the cage in which it had been placed, but it was in a huddled 
 attitude. When a lump of sugar was handed to it, it took the* 
 sugar but threw it upon the floor of the cage. It took a piece 
 of cotton wool, which had been rolled into a swab, and threw it 
 upon the floor of the cage. Its attention could be attracted easily 
 when noises were made, and it started when touched and when 
 the door of the cage was shaken. When the hand of the observer 
 was placed near the cage netting the animal put one of its hands 
 in that direction, and at times took hold of the finger. The 
 movements that were made were slow and indecisive, and the 
 errors made in putting its hands through the wire netting were 
 from 2.5 to 5 cm., i. e., one to two meshes of the netting. When 
 the gaze was attracted to an object held in the hand and a lump 
 of sugar was exposed in the other hand of the observer, but peri- 
 pherally to the fovea, the animal would sometimes turn to the 
 sugar, but most, if not all the movements of attention appeared 
 to be due to the sound stimuli rather than to visual sensations. In 
 one visual respect the animal was quite unlike a normal animal ; 
 it kept its gaze fixed on one point for comparatively long periods, 
 and the quick shifting gaze of the normal animal was entirely 
 lacking. When no sound was made, and movements of the ob- 
 server were at a minimum the animal remained absolutely quiet,
 
 46 SHEPHERD IVORY FRANZ 
 
 the eyes became staring, the eyelids gradually lowered, until the 
 eyes were covered almost completely. Slight noises or move- 
 ments (which very likely produced noises although they could not 
 be seen) waked the animal immediately, and there was a return 
 to the sleepy condition immediately when quiet again reigned. 
 The pupils were medium in size. 
 
 Thirteen hours after the operation, the animal was looked at; 
 when the light was turned on the animal came from behind the 
 door of its cage, looked at the observer, and appeared to be 
 bright. No special observations were made at this time. 
 
 Thirty-two hours after the operation, the animal was with some 
 difficulty removed from its sleeping box to the observation cage. 
 Sticks introduced into the sleeping box to persuade it to change 
 its quarters were taken hold of and twisted away from its body. 
 When it went into the observation box, it was presented with a 
 lump of sugar, which it took with a rather awkward movement, 
 and immediately placed in its mouth. Several times it took the 
 sugar from its mouth, held it in its hand and looked at it, and 
 returned it to its mouth again. When the end of a stick or the 
 finger was put a short distance through the wire netting of the 
 cage the animal made movements to take hold of these things. 
 The movements were not the quick lightning-like movements that 
 a normal monkey makes, but slowly executed and inaccurate. 
 The arm moved toward the goal, or rather, in the direction of 
 the goal, but when the hand of the animal was about 5 to 8 
 cm. away from the object an additional adjustment was made so 
 that the ringer or the stick could be grasped. It was apparent 
 that the initial adjustment was very inaccurate, that the distance 
 was not properly sensed, but that the discrepancy was appre- 
 ciated, and that the secondary or later adjustment was con- 
 sidered necessary. The actions of the animal during these 
 tests could be compared best to those of a child or even of 
 an adult who tries to make a new or unaccustomed movement, 
 of a rather complex character, and who attends to the movement 
 with the eyes as a guide. 
 
 The indefmiteness or impairment of the movement may have 
 been due to one or more of several factors: (i) the loss of 
 rather definite visual sensations which are normally present and
 
 EXPERIMENTAL RESULTS 47 
 
 important in the adjustment of movements; (2) to a motor dis- " 
 turbance; or (3) to a loss of kinesthetic sensations from the 
 eye. That there was no motor disturbance was apparent from 
 the movements of a reflex character made by the animal. The 
 bandage was apparently disagreeable, and caused some irrita- 
 tion. At times the animal put its hand and plucked at the 
 bandage near the ear, pulled at it and endeavored to get rid 
 of the irritation. These movements were performed accurately, 
 quickly, and without the second adjustment which was noted 
 in the case of the movements of taking hold of the finger or 
 of the stick. 
 
 The following day the animal gradually improved, and it was 
 impossible for me to determine any visual defect. The move- J 
 ments continued to be a trifle uncertain, but this was all that 
 was observed to be different from a normal monkey. 
 
 Two days after the operation the animal was tested with the 
 colored breads. In these tests, the animal made no mistakes, 
 although at first the animal was not as quick as normal, and 
 it was usually necessary to wait a longer time for the animal to 
 select the bread. In the tests there was no memory or association ^/ 
 loss, and, as far as could be determined, the animal reacted 
 to the colors just as it had done previous to the operation. 
 After an interval of a day the animal was again tested and 
 found to retain the ability to discriminate the colored breads, 
 and from this time there was no appreciable disturbance in the 
 behavior of the animal. This animal could, therefore, see, and 
 there was neither a visual disturbance similar to the permanent 
 blindness noted by many observers, nor to the temporary blind- 
 ness recorded by Ferrier. Objects in all parts of the field were 
 accurately seized and apparently discriminated, and no defect of 
 the nature of restriction of the field of vision or of a segmental 
 blindness was found. 
 
 Four months later a second operation was performed. In 
 the intervening period the animal was not practiced much on the 
 color discrimination, but sufficient tests were made with him 
 so that this habit was not forgotten. No other visual dis- 
 criminations were taught to the animal. During part of this 
 time the discrimination tests on the red and yellow showed that
 
 48 SHEPHERD IVORY FRANZ 
 
 at times the animal took occasionally the yellow piece of bread, 
 smelled it, or tasted it and sometimes even ate it. In a series 
 of ten tests this was found to occur but once, and to be as often 
 in the middle of a series as at the beginning. The animal was 
 well fed during this period, and at times refused to work with 
 the colored breads, so that only three to five tests were made 
 on certain days. Following are accounts of the color tests 
 immediately previous to the second operation: 
 
 March 29, 10 tests: in the second test the monkey took the 
 yellow and the red at one time and placed both in the mouth 
 and ate them ; the tenth test the animal did not take either of the 
 pieces, although I waited five minutes; in the other eight tests 
 the animal took only the red bread and this was taken imme- 
 diately and without hesitation. March 30: the first seven tests 
 were made in the usual manner, the animal taking the red bread 
 as soon as the breads were presented; in the eighth test the 
 animal took the yellow with the left hand (in all other tests the 
 animal had been taking the bread with the right hand) and 
 tasted it, but threw it away without eating; the results of the 
 ninth test were correct, but the monkey did not take the red 
 bread on the tenth test until after thirty seconds. March 31, 
 5 tests : in the first test the animal took the yellow bread as 
 well as the red, but threw it away after having tasted it; the 
 other four tests were correct. April i : on the first test the 
 animal took the red bread and left the yellow, but did not take 
 either piece on the second test and the tests 'had to be discon- 
 tinued. 
 
 Second operation, April i. The trephine openings were made 
 farther back in the skull so as to expose the tip of the occipitals. 
 The buttons which had been inserted at the time of the first 
 operation were found to be present, but softened and adherent 
 to the dura. When they were taken away there was consider- 
 able bleeding. Both openings (including the two trephine open- 
 ings on both sides) were enlarged with bone forceps. The dura 
 was cut to expose the surface of the occipital areas. The cortex 
 was then burned with the electric thermo-cautery at a red heat. 
 The cautery was passed over the lateral aspect of the lobes,
 
 EXPERIMENTAL RESULTS 49 
 
 and inserted into the mesial part. The operation was finished 
 in an hour (12 130 p. m.). 
 
 An hour and a half after the end of the operation the animal 
 was inactive and appeared to be sleepy. The eyes appeared to be 
 turned from their normal positions, the left especially being 
 turned inwards and upwards. When a finger was put through 
 the wire netting the monkey crouched back into the corner of 
 the cage. When a piece of bread was held in front of the cage 
 the monkey put its hand awkwardly towards the bread, took 
 it and conveyed it to the mouth. Other pieces of bread presented 
 through the wire netting were not taken. A small piece of bread 
 dropped on the floor of the cage was apparently seen, for it was 
 picked up immediately and without hesitation. A piece of banana 
 was presented through the wire netting about 30 cm. from the 
 animal. The left hand was put forward, although the left side 
 was farther from the food, and the banana was grasped in an 
 awkward manner. Other pieces of food were presented and 
 were sometimes taken and sometimes not taken. When they 
 were taken the movements were slow and inaccurate. A short 
 stick thrust through the netting did not cause the animal to make 
 the usual defense movements of grasping and shoving, but the 
 left hand was put forward to take the object. When the stick 
 was quietly inserted into the cage in any direction the eyes of 
 the animal were directed toward it when it came sufficiently 
 near (about 15 cm.), and although the animal did not fight 
 against it as a normal animal did, the eye movements were 
 exactly like those of a normal animal. A white dish containing 
 water was placed in the cage, and the animal soon placed its 
 head in the dish and drank. A second attempt to drink was 
 more quickly made. It was noted as peculiar that the monkey 
 did not use the right hand for grasping, but used the left which 
 performed the movements in an uncertain manner. Previous to 
 the operation this animal usually used the right hand. At the 
 time the notes were made the following question was inserted : 
 How much of the inaccuracy in movement is due to the hetero- 
 phoria? This question has not been answered and even at pres- 
 ent I have no indication of the part this may have played in the 
 motor inaccuracy. Throughout these observations the animal
 
 50 SHEPHERD IVORY FRANZ 
 
 appeared to be under the influence of the anesthetic, to be sleepy, 
 with lack of energy, little attention and a "don't care" attitude. 
 
 Twenty-seven hours after the operation the animal seemed 
 perfectly normal, except that his movements were slow and de- 
 liberate, and quite unlike the quick sharp movements of a nor- 
 mal animal. Pieces of raw sweet potato were given to him ; these 
 he took slowly and put into his mouth only after having smelled 
 them. He ate them in a normal manner. Once a piece of potato 
 was dropped on the floor of his cage, he looked at the food, then 
 at me and reached for the food which he obtained although all 
 the time he kept looking at me. Apparently, the animal had 
 made a judgment of the location of the food, and acted upon 
 this judgment even when the eyes were turned from the food. 
 He drank water from a dish apparently without difficulty, and 
 picked up particles of food from the floor of the cage. When 
 a stick was presented to him he slowly reached out his hand 
 and took hold of it. His attention was attracted by someone 
 in front of the cage and a stick was placed in the back of the 
 cage, care being taken to make no noise, and when the stick 
 came within the field of vision he immediately turned and often 
 seized it. This reaction was the same whether the stick was to 
 the right or to the left. The angle of the stimulus was not 
 accurately determinable, but it appeared that the animal could 
 see objects in the outer portion of each field, i. e., with the 
 nasal portions of the retinae, at least as far away as 70 to 80 
 degrees. The angle of vision above the head was apparently 
 normal. There was a decided preference for the use of the left 
 hand, but it did not appear that the right hand was in any way 
 paralyzed, although from his continued use of the left it would 
 appear that there was a paresis or some similar change from the 
 normal. 
 
 Three days after the operation the animal appeared the same 
 as that just noted. On this day, five tests with the colored 
 breads were made. On the first, second and fifth the monkey 
 took only the red bread, but on the third and fourth tests took 
 both yellow and red. Two days later, five tests were correct. 
 The animal was exhibited before the Georgetown Clinical So- 
 ciety on April 4, and at that meeting the members were unable
 
 EXPERIMENTAL RESULTS 51 
 
 to note any difference from the normal. From the results of 
 the bread tests it was apparent that the animal retained the 
 ability to discriminate colors, and although the tests on the third 
 day after the operation were not entirely successful, they were 
 quite as successful as they had been immediately previous to 
 the operation. 
 
 Nine days after the operation (April 10), it was noted that 
 the animal was not inclined to work. It did not eat. During the 
 night of the Qth the animal tore the bandage from the head, 
 and opened the scalp wound slightly. On the following day 
 the scalp was swollen, and the brain appeared to be bulging 
 through the trephine openings. The animal did not work on 
 the tests, and, as it refused to eat, no observations of vision or of 
 movement were possible. At 8 p. m. of this day the animal was 
 found to be quite stupid and dull. It took a long time and a 
 violent stimulus to arouse him. At one time the eyes were 
 rolled upwards and showed a slight nystagmic movement. At 
 another time there were twitchings of the hand. The animal 
 
 FIGS. 10, ii, 12 and 13. Monkey i. Lateral and mesial aspects of the cere- 
 bral hemispheres, showing the parts destroyed by the operation. The latter 
 is a reconstruction. Slightly reduced (cf. scale). Traced from photograph. 
 The small size numerals are the sections from which other figures (14-23) 
 were drawn.
 
 SHEPHERD IVORY FRANZ 
 
 was killed with chloroform at 9:30, and the autopsy was per- 
 formed immediately. 
 
 At the autopsy the scalp in the neighborhood of the operative 
 
 tent 
 
 FIGS. 14 and 15. Monkey I. Gross sections of the hemispheres, showing 
 the parts affected by the operations. About natural size. Drawn at time of 
 autopsy, free hand. The illustrations are taken from the lower surfaces of 
 the sections indicated by lines in figs. 10-13.
 
 EXPERIMENTAL RESULTS 
 
 53 
 
 cuts was found to be swollen, the cellular tissue was rilled with 
 a watery fluid which could be squeezed from it. The scalp at 
 this place was about a half centimeter thick. The brain bulged 
 through the trephine openings. The dura was adherent to the 
 brain and the scalp was adherent to the dura. The brain was 
 removed from the skull with difficulty. The posterior surfaces 
 of the hemispheres were much reddened and soft to the touch; 
 there was no appearance of pus. The brain was placed in toto 
 in 95 per cent alcohol. The photographs were made thirty- 
 six hours after the autopsy. 
 
 Figures 10 to 23 show the brain with the effects of the two 
 operations. In figs. 10, n, 12 and 13 are given diagrams 
 of the lateral and mesial aspects of the hemispheres, with the 
 parts of the cortex destroyed at the time of the second opera- 
 
 FIGS. 16, 17, 18, 19, 20, 21, 22 and 23. Monkey I. Horizontal sections 
 through the occipital parts of the cerebral hemispheres, showing effects on 
 cortex, and underlying fibers of the second operation. About 3/2 natural 
 size. Edinger drawing apparatus. 
 
 tion. Figs. 14 and 15 show the gross appearance of the sections 
 made for the purpose of microscopical study, with the parts 
 marked thereon where the cortex had been destroyed. The cor-
 
 54 SHEPHERD IVORY FRANZ 
 
 tical effects of the first operation are not indicated, and it was 
 impossible to differentiate these from the results of the second 
 operation. Figs. 16, 17, 18, 19, 20, 21, 22 and 23 give the appear- 
 ance of the microscopical sections, which were stained by the 
 Nissl method, and which show the hemorrhagic and cortical ef- 
 fects of the second operation. It will be noted that the sections 
 numbered in figures 10 to 15 correspond with the sections 
 marked with the same numbers in figures 16 to 23. The areas 
 of cortical destruction (marked black) in figs. 10-15 have been 
 drawn from the examinations of the microscopical sections. 
 
 The results of the examinations of the microscopical sections 
 are given by Dr. Laf ora as follows : "Monkey i , cauterization 
 of the brain, Nissl method, horizontal sections. On the right 
 side the occipital lobe lateral aspect is almost entirely de- 
 stroyed, the lesion involving the whole depth of this part of 
 the cortex. A part of the periphery of the calcarine type of cor- 
 tex escaped destruction, and the calcarine fissure is affected only 
 in its posterior ramification, especially the superior part. On 
 the left side the lesion is more extensive than on the right, the 
 calcarine type of cortex being more affected especially in the 
 superior part of the occipital pole. The vessel lesions have pro- 
 duced softenings in the white matter which interfered with the 
 fibers coming to the visual cortex. The anterior part of the 
 calcarine fissure, and some parts of the posterior are well pre- 
 served." 
 
 Monkey 2. This animal was trained to discriminate the four 
 colors. Red and blue were sweet and green and yellow were 
 bitter. The training experiments began October 20. There was 
 a gradual acquisition of the habit of taking the red and blue 
 and of leaving the green and yellow, which became perfected 
 ^after this date there were no wrong reactions as long as the 
 animal was in a normal condition) after six days. The tests were 
 continued, however, a month longer, with intervals in which the 
 memory was tested. The final tests were made on December i, 
 the day of the operation, and on this day the animal made no 
 mistakes in ten trials. 
 
 Operation, December i. The usual preliminary parts of the 
 operation were performed in the manner described. On account
 
 EXPERIMENTAL RESULTS 55 
 
 of the fact that previous sections of the brains of other animals 
 had not been followed by visual disturbances of sufficient amount 
 to be noticeable, if they were present, I made the incision in the 
 brain much anterior to the so-called visual cortex, so that as 
 much of the occipital pole as possible should be included in the 
 effects of the operation. It was intended to separate completely 
 the occipital lobes from the frontal parts of the hemispheres, 
 but on account of the depth of the brain at the point the knife 
 was inserted, all was not cut away, as was later learned at the 
 time of the autopsy and at the time of the microscopical examina- 
 tion. 
 
 About fifteen minutes after the operation was completed the 
 animal staggered drunkenly against the sides of the cage in which 
 he had been placed. When a sudden noise was made he did not 
 jump. The pupils were widely dilated, and there were slight 
 tremors of the eyelids. 
 
 Twenty-four hours after the operation, the animal was fourrd 
 to be fairly active, engaged chiefly in pawing at the floor of 
 the cage and scratching at the bandage on his head. A ringer of 
 the experimenter poked through the wire of the cage elicited "&t 
 times a slapping of the floor, at other times it appeared that no at- 
 tention was paid to it, activity at least not being directed toward 
 the finger. A piece of rubber tubing hung through the top of 
 the cage elicited no reaction until the animal was touched, when 
 he made a slap in that direction. Water was presented in a 
 saucer. The animal put out his paw to investigate, got it in the 
 water, then leaned over and drank. A prune was held outside 
 but near the wire of the cage. The monkey started to put out 
 his hand to grasp it, but struck the wire and did not persist. 
 Later the prune was held in this position again and the paw 
 was put out and grasped the prune accurately. A prune was 
 thrown upon the floor; three grabs were made in the general 
 direction of the prune and each time the monkey missed it by 
 about 7 cm. It desisted. On the following day he groped about 
 the cage, especially on the floor when any noise was made, and 
 did not 'reach for objects held in front of him, but gave some 
 reactions to things that were held above the eyes. It seemed 
 at times that he saw things held in the upper part of the visual
 
 56 SHEPHERD IVORY FRANZ 
 
 field. This was not clear, however, for at times he would not pay 
 any attention to the food. When a stick was held close to him, he 
 paid no attention to it as he had previously done, and there were 
 no defense movements to push away the stick. Only when the 
 food was placed near the nose or mouth did he make definite at- 
 tempts to grasp it, and at times it appeared that his reactions were 
 due more to smell stimuli than to visual ones. 
 
 Three days after the operation he was placed in the large 
 observation cage into which he went from the small living box, 
 almost as soon as the door of the latter was opened. A peanut 
 held at the netting of the cage, about 25 cm. away from his 
 head was well grasped and the movement was quickly executed. 
 No hesitation was observed at this time. A dish of water was 
 placed on the floor of the cage about 54 cm. from where he 
 was sitting; the animal immediately went to it, drank from it 
 in an apparently normal manner, and went back to his old sitting 
 position. Other food was placed outside of the cage but within 
 reach of his extended paw, and these pieces he took and ate. 
 Small pieces of food on the floor of the cage were taken in an 
 apparently normal manner, and the sawdust on the floor of the 
 cage was picked over for particles of food. A stick inserted 
 in the cage was promptly seized, and warded off. The animal 
 moved its eyes in an apparently normal manner, and the eyes 
 followed a moving person. The animal turned its eyes toward 
 anyone entering the room. It moved from the large cage to- 
 the small one and reversely without mistakes regarding doors, 
 etc., and in this respect also appeared to be able to differentiate 
 visual stimuli. 
 
 Four hours later the animal seemed visually like a normal 
 animal. It took food, drank water, and put its hand through 
 the cage to get materials outside. At times its movements were 
 not as accurately coordinated as in a normal animal but the 
 errors of movement were not large and on this point it was im- 
 possible to make any accurate judgment. The animal scratched 
 the bandage almost continually and it was thought that perhaps 
 there was some pus formation at the wound. For this reason 
 the animal was lightly anesthetized, the old bandage taken off, 
 and a new one adjusted. The wound seemed to be in a perfectly
 
 EXPERIMENTAL RESULTS 57 
 
 healthy condition, and to be uniting by first intention. A wet 
 compress of 2 per cent carbolic acid was placed on the head 
 over the wound. The animal recovered from the anesthetic in 
 about an hour. The animal moved from the small cage to the 
 burlap bag without any difficulty and apparently knew what it 
 was doing. 
 
 On this day and on the succeeding days, the animal appeared 
 to have perfect vision and to be able to coordinate the visual im- 
 pressions with the proper movements. At no time after the 
 first days was I able to determine any defect of vision, and this 
 was also shown in the tests with the colored breads. Two days 
 after the operation the animal made some mistakes with the 
 colors. In all of the ten tests made on that day the animal took 
 the yellow bread and smelled of it. Once a piece of green bread 
 was taken in the same grab with a red, and this was apparently 
 due to the fact that they were very close to each other on the 
 plate. On the following day, the monkey made no mistakes in 
 the color tests, and it seemed most likely that the mistakes made 
 on the previous day were not due to a lack of discrimination. 
 It is particularly worthy of notice that in one of the tests the 
 piece of blue bread fell from his hand and that he immediately 
 picked it up, rather than take one of the other (yellow and green) 
 pieces remaining on the plate. The observations, and also the 
 tests, indicated that if there had been any visual defect, it was 
 of a nature similar to those observed by Ferrier. The general 
 reactions of the animal were, however, so abnormal for a day 
 following the operation, that I think we are not justified in 
 concluding that the defect is visual and is of any special char- 
 acter, but I believe we should conclude that the disturbance was 
 a general one, and is to be compared with the shock effects of 
 operations such as are exhibited by man, especially after opera- 
 tions on the nervous system. 
 
 The animal was killed with chloroform, December 5. The 
 autopsy was performed immediately after death. The brain ap- 
 peared to be normal except at the points where the knife had 
 been inserted, and there was no oedema apparent to the eye. 
 The brain was placed in alcohol and photographed and weighed
 
 58 SHEPHERD IVORY FRANZ 
 
 twenty-four hours after the autopsy. The brain weighed 85 
 grams. 
 
 Figures 24 to 35 show the conditions that were found post 
 mortem. In figs. 24, 25, 26 and 27, the tracings from the photo- 
 graphs, there are shown the points of insertion of the knife, and 
 the sections made for the purpose of examination by histological 
 methods. At the time the gross sections were made, drawings 
 were made of the appearances of the sections and these are 
 
 FIGS. 24, 25, 26 and 27. Monkey 2. Lateral and mesial aspects of the cere- 
 bral hemispheres, showing the course of the knife cuts into the brain x jr t 
 and y y t and the location of the parts of the brain examined histologically. 
 Slightly reduced (cf. scale). Traced from photographs. 
 
 given in figs. 28 and 29. From these drawings and from a care- 
 ful comparison of the brain as a whole and in the sections, a 
 reconstruction of the course of the knife cuts has been made 
 and these are indicated in figs. 24-27, by the heavily dotted lines. 
 It will be seen that the knife was inserted just posterior to the 
 central fissure and that in its course it cut away a large part of 
 the occipitals from the anterior part of the hemispheres, but 
 that the lower, especially the temporal, portions of the brain
 
 EXPERIMENTAL RESULTS 
 
 59 
 
 escaped. The microscopical examinations of the sections are 
 illustrated in figs. 30-35. 
 
 The account of the histological examination by Dr. Lafora is 
 
 Cenh 
 
 FIGS. 28 and 29. Monkey 2. Sections of the cerebral hemispheres showing 
 the hemorrhages due to the sections of the brain, and the parts probably 
 affected by the operation. About natural size. Drawn free hand at time of 
 autopsy. The illustrations are the appearances of the lower surfaces of the 
 sections indicated in figs. 24-27.
 
 6o 
 
 SHEPHERD IVORY FRANZ 
 
 as follows: "The sections were prepared by the method of 
 Nissl by Dr. Achucarro. On both sides of the brain the sections 
 show the lesions produced by the knife, which seem to be very 
 extensive in its transverse directions. Although we are unable 
 to judge of the amount of the fibers which were cut by the 
 operation on account of the histological method used in the ex- 
 amination, it is sure that most of the optic fibers, except those 
 lying low in the cerebrum, were destroyed or at least affected 
 by the section. The cortex shows some reactive processes of 
 the neuroglia and of the ganglion cells some of which later 
 show a slight degree of tigrolysis. In the inferior part of the 
 white matter the lesion is not as extensive as in the middle part. 
 The drawings indicate the general extent of the lesions." 
 
 post 
 
 FIGS. 30, 31, 32, 33, 34 and 35. Monkey 2. Horizontal sections through the 
 lesions indicated in figures 24-27. About 3/2 size. Edinger drawing 
 apparatus. 
 
 Monkey 5. This animal had been trained on the discrimination 
 of the large and small pieces of bread. The experiments for the 
 production of this habit were sporadically done, but the sys- 
 tematic training for the present paper was not undertaken until 
 about two weeks before the operation. Following is an account 
 of the process of learning at that time : 
 
 September 5, 10 tests: only once ate both large and small
 
 EXPERIMENTAL RESULTS 61 
 
 pieces, viz., first trial; on the first, second, third and fifth trials, 
 she took the large before the small, and on the ninth and tenth the 
 large after the small. After the first trial, however, the animal 
 did not eat the large piece, but smelled or tasted it and threw it 
 away. September 6, 10 tests: took the large piece on the first, 
 sixth and on the eighth trials, but ate the large piece only the 
 first two times. September 9, 20 tests : took the large piece only 
 the first two times. September 10, 5 tests: took both pieces the 
 first three trials, but the smaller piece only on the fourth and 
 fifth trials. September n, 20 tests: first, took both pieces but 
 did not eat larger; from second to twentieth only smaller. Sep- 
 tember 14, 20 tests: on the first and second trials she took only 
 the small pieces, but from the third to the fifth the larger ones 
 were also taken, although they were only tasted, not eaten. Sep- 
 tember 15, 10 tests: only the small were taken. September i6 ? 
 10 tests: only the small were taken. September 17, 5 tests: only 
 the small were taken. These tests were the final ones before 
 the operation which was begun an hour later. 
 
 Operation, September 17, 10 a. m. Occipital lobes were cau- 
 terized. There was considerable hemorrhage which was checke 1 
 by hot compresses to the brain. Immediately after the comple- 
 tion of the operation the face of the animal was cyanotic, the 
 eyelids closed, and the facial muscles were contracted into a 
 grimace (Schnauzkrampf). The left pupil was about one and 
 one half times larger than the right, and neither reacted to light. 
 The head was turned backwards and towards the left; the right 
 arm was flexed at the elbow and the left arm was extended ; 
 both legs were extended. There was hypertonia, more marked 
 on the left. 
 
 About three minutes later the left arm became flexed at both 
 shoulder and elbow and the left leg at the thigh; the flexion 
 of the left arm at this time was greater than the flexion of the 
 right arm noted immediately after the operation and which had 
 continued. When the animal was placed on its back or on the 
 right side there was a tendency to turn to the left, and the trunk 
 of the animal described an arc with the concavity towards tht 
 left (emprosthotonus). The tongue was protruded, and devi- 
 ated to the left ; when it was pushed into the mouth and towards
 
 62 SHEPHERD IVORY FRANZ 
 
 the right, it gradually returned to the protruded left position. 
 Ten minutes after the operation was finished it was found that 
 both sides of the animal were approximately equally flexed, and 
 the tail was turned under the body but in the median line. The 
 animal was tremulous; it was placed close to the fire and the 
 tremor (shivering) ceased in about two minutes. 
 
 About half an hour after the operation the animal attempted 
 to sit up, but immediately fell down, and remained in a rather 
 unnatural attitude. Two hours after the operation it was found 
 sitting up, and when I moved about the room it followed with 
 its head and eyes all my movements ; part of this may have been 
 due to the noise made by me in walking, but the movements 
 of the animal appeared to be rather those associated with vision. 
 
 Eight hours after the operation, the animal was sitting in its 
 cage in a perfectly normal attitude. The contractions of the 
 groups of muscles had entirely disappeared, and, so far as could 
 be determined, the movements were normal in character, but 
 rather slow. Four pieces of bread were placed approximately 
 5 cm. apart on the floor of the cage in the form of an arc, 
 30 cm. away from the eyes; for about ten seconds the animal 
 took no notice of the food (it had not been fed on this day 
 except at the time of making the final five tests on the dis- 
 crimination of large and small) but finally accurately reached 
 for and obtained one of the pieces in the middle; after it had 
 eaten this piece it took the second middle piece, but during ten 
 minutes it disregarded the other two pieces which were at the 
 ends. Some pieces of apple were dropped into the cage; some 
 of these the animal picked up with a great degree of accuracy, 
 but the movements were slow and it did not immediately try to 
 secure the food. At times the food was disregarded until 
 some part of the animal, a hand or a foot, touched one of the 
 pieces, whereupon she reached to the appropriate spot, secured 
 the piece and inserted it in the mouth. A fresh fig was placed in 
 the cage about 45 cm. distant from the eyes of the animal. This 
 it disregarded until it was shoved near enough to the animal to 
 be touched by it, whereupon the animal took the fig and ate half 
 of it. After this she wandered around the cage picking up pieces 
 here and there, but at other times her attention was attracted to
 
 EXPERIMENTAL RESULTS 63 
 
 the pieces of food solely by the sight, and at times it appeared 
 that the animal did not see but picked up the food only when it 
 was accidently touched by part of the body. Tests for deter- 
 mining the extent of the visual field were unsuccessful, for the 
 animal did not respond to the food when it was offered on 
 the wires. The latter observations were made at night in arti- 
 ficial, but good light, and it is possible that the shadows thrown 
 by the food on the wires and the shadow of the cage on the food 
 were distracting, although I lay no stress on this point. During 
 all the tests mentioned in this paragraph the right eye of the ani- 
 mal was much inflamed, probably due to the anesthetic. 
 
 Twenty-four hours after the operation the animal was ob- 
 served and tested by Dr. Lafora, who made the following notes : 
 "The right eyelid is much inflamed, but the eye is kept open, and 
 is used with the other; the pupils react equally to light. Objects 
 (food) at some distance (about 60 cm.) were at first not at- 
 tended to and it appeared that the animal could not see them; 
 only when pieces were brought near its face did it try to take 
 them. In a number of tests she continued to make movements 
 as if to take other pieces of food in the same place although 
 none were being presented ; at other times the animal would look 
 directly at the places and moved her head and eyes as if to 
 follow the movements of the (imaginary) particles of food. Is 
 this a perseveration phenomenon? Small objects, such as wires, 
 were not well discriminated, for the animal frequently made no 
 movement until the wires were close to, sometimes touching, 
 the face or the facial hairs; similarly with small pieces of apple. 
 The first experiments on the field of vision indicated that the 
 monkey did not have a normally fine perception in the macula, 
 for objects about 40 cm. away were peered at and the animal 
 moved the head closer as if to get a better view before attempt- 
 ing to take them. All objects held towards the periphery were 
 seen but the movements of grasping were not accurate. It is a 
 remarkable fact, however, that the animal looked at a fly at 
 the bottom of the cage and followed its movements with head 
 and eyes. A piece of an apple was afterwards held on a wire 
 in front of the animal and moved about far and near and to 
 the right and left. The animal apparently centered its attention
 
 64 SHEPHERD IVORY FRANZ 
 
 upon the object which it approached and obtained after some 
 unsuccessful attempts. After the monkey found it impossible to 
 obtain some moving pieces of food by grasping with the hand, 
 the animal moved the head towards the food and took it directly 
 into the mouth. Pieces of food held to the right or to the left 
 brought about approximately normal movements of the animal, 
 except when the food was held at the extreme right, where it 
 was found that movements were sometimes produced but only 
 after a much longer time than when the food was held in any 
 other part of the field. The hallucinatory tendency, noted above, 
 to take objects not presented was again shown in the later move- 
 ments ; at times when pieces of food had not been presented for a 
 minute or two, the animal grasped in the air or groped on the 
 floor in the location of previously obtained food; this would 
 indicate that the visual part of the reaction is not a perservation 
 but an hallucinatory phenomenon. Color discrimination ap- 
 peared to be preserved, at least to some degree, for the animal 
 selected tomato three times instead of apple, its normal prefer- 
 ence being for the former. In the later experiments the move- 
 ments of grasping were accurate, showing a complete associa- 
 tion between the movements of the hand and arm and the visuo- 
 kinetic representation of the movement. A piece of cotton soaked 
 in alcohol and then lighted was brought close to the animal and 
 this experiment many times repeated showed that there was an 
 ability on the part of the animal to see with all parts of the 
 retina, on the right as well as on the left, the movements in all 
 parts of the field being accurate and quick. When one piece of 
 lighted cotton was shown and held the attention of the animal, 
 and a second piece was brought inwards from the sides (right 
 and left) the animal turned towards the second piece, showing 
 that the extent of the field was approximately normal. Conclu- 
 sions : Diminution of visual acuity ; no diminution in extent of 
 the visual field, at least at the sides, although it is impossible on 
 account of the eye movements to determine whether or not there 
 is a central scotoma; ability to discriminate colors appears to be 
 preserved; and there is exact visuo-kinetic representation." 
 
 On the third day after the operation the animal was tested with 
 large and small pieces of bread ; on the first trial she selected the
 
 EXPERIMENTAL RESULTS 65 
 
 small piece and disregarded the large ; on the second trial she took 
 the large piece tasted it and .threw it away and then took the 
 small piece which she ate; the third trial was a repetition of the 
 second ; on the fourth trial she took only the small piece ; and on 
 the fifth trial she got both pieces in one grasp and ate the small. 
 The results of these experiments do not indicate plainly whether 
 or not the habit of discrimination of the large and small pieces 
 persisted, but the indications are that the habit remained, because 
 each of the two times that the animal obtained the smaller piece 
 she did not try to take the larger one which remained on the 
 glass plate, and each of the two times that she obtained the larger 
 piece first she returned to the plate and secured the smaller piece. 
 In these experiments she showed the condition noted in the other 
 tests on this day, viz., a certain amount of inaccuracy in motor 
 adjustment. The taking of the larger piece in the fifth trial was 
 awkwardly done, and the taking of both pieces in the second and 
 third trials may have been due to this motor derangement. A 
 piece of raw potato was dropped on the floor of the room close 
 to the cage, about 75 cm. from the animal; she moved to the 
 front of the cage, accurately reached under the bottom bar and 
 secured the piece of food. A piece of raw apple was held on a 
 wire about 20 cm. from the eyes of the animal, and midway be- 
 tween them; this she grasped on the second 'attempt after having 
 made at first an error of 2 cm. After having obtained the piece 
 of apple she grasped in the same direction (or place) although 
 there was no food being presented, and her actions at this time 
 gave me the same impression as they did Dr. Lafora on the pre- 
 ceding day, viz., that there was an hallucination or a persistence 
 of the impression. A piece of raw potato held in front of the 
 animal about 30 cm. away was reached for; in grasping for it 
 the animal made a movement error of about 7 cm. at first but 
 on the second attempt secured the food. A fly was walking over 
 the back of the cage about 60 cm. from the monkey and to the 
 left ; the animal moved cautiously toward the part of the cage 
 where the fly was and when near enough she grasped for it with 
 the left hand, hitting the spot where the fly had been (the fly 
 flying away when the hand approached ) . A piece of raw carrot 
 was dropped into the cage, but fell outside : the animal groped at
 
 66 SHEPHERD IVORY FRANZ 
 
 the place where the carrot fell, moved to the other end of the 
 cage, returned to its original position in about ten seconds, and 
 picked up a piece of raw potato; then it put its hand outside the 
 cage and picked up the carrot accurately and without hesitation. 
 A piece of apple and a piece of potato were placed on the floor 
 of the cage about 75 cm. away from the animal; by short steps 
 she moved in the direction of the food and when sufficiently near 
 reached accurately for and obtained the potato but disregarded 
 the apple which was on the right. Nine small pieces of food, 
 three each of raw carrot, apple and potato, were dropped into the 
 cage from .the top, a few rolling outside and the distribution in 
 the cage being irregular, the monkey took immediately two pieces 
 which were within reach, then took a step and secured two pieces 
 farther away ; after having secured a fifth piece she dropped it 
 before getting it to her mouth and it rolled away about 10 cm. 
 from its original position but she secured it immediately; then 
 she secured pieces of carrot and of apple which had fallen in the 
 shadow; finally she looked outside the cage and secured two 
 remaining pieces which had rolled outside the cage. Two small 
 wads of cotton were dropped in the cage; for a time she dis- 
 regarded these, but picked up similarly sized pieces of apple and 
 carrot, but finally she picked up one piece of cotton and placed 
 it in her mouth. A piece of sugar was silently placed on the floor 
 of the cage about 70 cm. away from the animal ; she stopped try- 
 ing to pick up the small particles of food near her, made three 
 steps and accurately grasped the sugar; another piece was 
 dropped into the cage and it rolled close to the body of the animal ; 
 she peered around but did not secure it, then moved away about 
 30 cm., turned around, immediately reached for and secured it; 
 a third piece was dropped in the cage in the shadow ; for about a 
 half minute this was unnoticed but then she made five steps and 
 with an accurate arm movement secured it. Quick movements 
 of the experimenter's hands and arms in any direction made the 
 animal start and crouch in a corner; fingers and sticks placed 
 through the wire netting were also startling. A piece of raw 
 potato was placed in and stuck by its moisture to the bottom of 
 a glass crystallizing dish, 5 cm. diam., the dish was then placed 
 in the cage bottom side upwards ; the monkey reached for the dish.
 
 EXPERIMENTAL RESULTS 67 
 
 made the proper adjustment, picked up the dish, turned it in the 
 proper position and tried to get the potato by putting the mouth 
 in the dish ; when she could not get the food in this way, she put 
 out her tongue, dislodged the food, secured it with the right hand 
 while the dish was held with the left. A fly on the cage 20 cm. 
 away and to the right was caught at but not secured although the 
 movement was accurate. A small piece of apple was wrapped in 
 a piece of paper and placed 75 cm. away, the package was secured 
 immediately and opened in the usual way by teeth and hands. 
 Similarly with other packages. 
 
 The animal was killed with chloroform at n 130 a. m. so that 
 the brain could be examined before there were any marked ex- 
 tensions of the lesions and before any repair could be brought 
 about. 
 
 37 
 
 39 
 
 FIGS. 36, 37, 38 and 39. Monkey 3. Lateral and mesial aspects of the 
 cerebral hemispheres, showing the amount of the cortex involved by the 
 operation. Slightly reduced. Traced from photographs. 
 
 The autopsy was performed fifteen minutes after death. The 
 wound was healthy in appearance. The brain showed a slight 
 hernia beneath the two skull openings and weighed 102 grams. 
 On account of the brief time between the operation and autopsy,
 
 68 
 
 SHEPHERD IVORY FRANZ 
 
 the brain was examined only for the destruction of cells and the 
 c-xtent of lesion. 
 
 Figures 36 to 45 show the amount of the destruction of the 
 cortex. An examination of the microscopical sections (figs. 40 
 to 45) shows that comparatively large amounts of the fibers were 
 destroyed as well as the cortex, and the cautery undoubtedly pene- 
 t rated the white substance as well as burning the cortex. It will 
 be seen that the cortex in the neighborhood of the calcarine fissure 
 has entirely escaped, and remained normal, while the greatest 
 amount of destruction took place over the convexity of the hemi- 
 spheres, being more marked over the superior portion. 
 
 FIGS. 40, 41, 42, 43, 44 and 45. Monkey 3. Microscopical findings after the 
 cauterization of the cortex. 
 
 The report of Dr. Lafora on this case is as follows : ''Monkey 
 3, Nissl method, frontal sections. On the right side the de- 
 struction of the calcarine type of cortex was fairly complete to- 
 wards the occipital pole except along the calcarine fissure. The 
 calcarine fissure is affected only in its profundity by a reactive 
 process which arose from the injury to the external part of the 
 hemisphere. On the left side the lesions are a trifle more exten-
 
 EXPERIMENTAL RESULTS 69 
 
 sive, but the calcarine fissure is affected only in its extreme depth. 
 The external part of the lobe is almost entirely destroyed." 
 
 From the accounts of the histological findings and of the clini- 
 cal appearances of the monkey following the operation, it is plain 
 that the visual defects are not in proportion to the amount of 
 destruction of the so-called visual cortex, and that the lack of 
 blindness can not be ascribed to the failure to destroy the part 
 of the brain which is supposed to have visual functions. This 
 case is to be compared with that of monkey 5, in which latter 
 the calcarine fissure was destroyed more than the remainder of 
 the visual cortex, and the clinical accounts of each of these mon- 
 keys differ to an extent to be paralleled by the microscopical 
 findings. 
 
 The animal retained its visual function to a very great degree 
 and the disturbance in function can be said to be almost exclusively 
 a dissociation between the sensations from the eyes and the 
 movements of the hand (and other parts). The observations do 
 not indicate a visual defect per se. 
 
 Monkey 4. This animal had been trained by Dr. Shepherd in 
 his experiments, and about eight months later for a period of 
 about nineteen days it was trained to discriminate blue (sweet) 
 from green (bitter) and yellow (bitter) breads. At this time 
 the habit of taking the blue and leaving the green and yellow 
 was firmly established. No further experiments were done for 
 about seven months at the end of which time the animal appeared 
 to have almost, perfect retention of the habit and reacted properly 
 to the conditions as is indicated in the accompanying account. 
 
 July 30, 5 tests; in the first test the monkey took the piece of 
 bine bread at first and then the piece of green, but threw the latter 
 away without eating it; the fifth test on this day was made with 
 two pieces each of the three colors arranged in an irregular order 
 and the animal took only the blue breads. July 31. 3 tests; in all 
 tests the animal took only the blue bread; but did not pay any 
 attention to the foods after the third test and the series could not 
 be continued on that day. August 7, 5 tests; in all these tests, 
 after the interval of seven days, the animal took only the blue 
 bread; at first it did not work rapidly but looked around and 
 paid no attention to the breads for several minutes after they
 
 70 SHEPHERD IVORY FRANZ 
 
 were placed before it; twelve pieces each of blue, yellow and 
 green were arranged on a board in an irregular order and pre- 
 sented to the animal which, after intervals, took ten of the blue 
 pieces and disregarded the yellow and green. August 16, 5 tests; 
 in all the tests the monkey took only the blue bread; in an addi- 
 tional test in which five pieces each of blue, yellow and green 
 were presented at one time the animal took only the blue; it is 
 worthy of note in connection with the discussion of color vision 
 that in the last experiment the yellow bread had been colored by 
 a solution of lead chromate instead of the usual methyl orange, 
 with which it had been previously tested. 
 
 Operation, August 1 7, 2 130 p. m. On the right side an at- 
 tempt was made to cut away the occipital pole from the rest of 
 the cerebrum by means of the cataract knife; on the left the 
 mesial aspect was cauterized and the cautery was thrust inwards 
 and forwards. The hemorrhage was considerable on the right 
 side, but it was checked by the application of I : 1000 suprarenal 
 solution and by hot sponges. The animal remained lethargic for 
 some time after the operation, but at 4 130 p. m. it was found sit- 
 ting up in its cage, apparently alert and bright. He appeared to 
 see a hand threatening him no matter from which direction the 
 hand was approached. At 7 p. m. I found the animal had torn 
 the bandage away ; after washing the head thoroughly with bi- 
 chloride, i : 500, I replaced the gauze dressing and bandages and 
 thoroughly sewed them together. An hour later the animal was 
 quiet but appeared to see a small stick thrust at him from right, 
 left, above and below for he moved away from the stimulus. 
 
 About twenty hours after the operation, the animal was found 
 quietly sitting in its cage. A piece of bread placed on the floor 
 of the cage was not noticed for about three minutes, but at the 
 end of that time the animal moved toward it, made an accurate 
 movement, picked it up and ate it. A dish of water was placed 
 in the cage, and he immediately moved near the dish, put his head 
 down and drank. Four small pieces of food, one each of bread, 
 cake, boiled potato, and cantaloupe, of about equal sizes were 
 placed on the floor of the cage ; the animal selected the cantaloupe 
 first, then took the cake and the potato and left the bread. In 
 four similar tests, the same result was obtained, but it was noticed
 
 EXPERIMENTAL RESULTS l\ 
 
 that at times the monkey took the bread but threw it away without 
 attempting to eat it. The movements of grasping were usually 
 made with an error of about 3 cm. In these experiments the 
 animal did not always take the food in its hand from the normal 
 sitting posture, but usually lowered its head toward the food 
 before reaching for it. It was concluded that this indicated an 
 impairment of vision, and the inaccuracies in hand adjustments 
 for the grasping of food were taken as confirmations of this 
 conclusion ; the impairment seemed to be not a blindness, but only 
 a dimness of vision. 
 
 Twenty-six hours after the operation. Two sticks were sim- 
 ultaneously introduced into the cage, one to the right and the 
 other to the left of the animal; that on the right attracted the 
 attention of the animal and was seized, that on the left was not 
 seized even when it was advanced to within a few inches of the 
 head of the animal. One of the sticks was held near the floor, 
 the other above the level of the eyes; the animal reached for 
 the upper stick and disregarded the lower one until it had been 
 moved so as to touch the body. The movements of grasping the 
 stick on the right were as accurate as before the operation, those 
 of grasping the stick above the level of the eyes and those near 
 the floor were very inaccurate. The colored breads, when pre- 
 sented to him, were disregarded and the test of this visual func- 
 tion was unsuccessful. The animal was able to see food and 
 other objects on the floor of the cage but it was not detern-ined 
 in what manner this was accomplished. From the peculiar move- 
 ments of the head, the lowering and the turning, it appeared to 
 be necessary for the animal to get the visual image on the lower 
 retinal segment, for, although an object lying on the floor was 
 approached, it was not taken until the head had been lowered a*.id 
 the eyes turned downwards. The direction of the errors (right 
 and left) in taking the food were not recorded. 
 
 Two days after the operation, the animal went into the small 
 observation cage as soon as the door was opened. At that tune 
 the animal was more lively than it had been and its actions were 
 apparently normal. It picked up food lying upon the floor of 
 the cage. When the hand was held above the cage the animal 
 showed signs of fright, shrinking into a corner, etc. A piece of
 
 72 SHEPHERD IVORY FRANZ 
 
 pear held above the level of the eyes was seized quite accurately. 
 Two pieces of pear were held simultaneously on a level with the 
 eyes, one to the right, the other to the left, each about 10 cm. in 
 front of and to the side of the median line; the animal always 
 took the piece on the left first, sometimes with the right hand, 
 sometimes with the left. A rod and a piece of pear were held 
 simultaneously in the upper part of the field; when the rod was 
 on the left it was seized and the pear was disregarded ; when the 
 pear was on the left it was seized and the rod disregarded. A rod 
 held about 15 cm. below the level of the eyes was disregarded until 
 the head was moved or until the rod touched the body or the 
 hair. The animal peered through the opening at the back of 
 the cage with all the appearance of the investigation of a normal 
 animal. 
 
 On the same day, four hours later, the animal was tested and 
 examined by Dr. Lafora, who reported as follows: "Pupils react 
 well to light. Held yellow and blue breads before the animal 
 twice, and each time the animal took the yellow bread first and 
 the blue afterwards. A piece of melon and blue bread, the latter 
 nearer the animal were presented simultaneously, and the monkey 
 reached beyond the blue bread and took the melon. Two pieces 
 of melon (one held in the visual axis and the other to the right, 
 left, superior or inferior) were presented simultaneously, and 
 each time the animal took both pieces, apparently seeing with all 
 parts of the visual field. For testing the ability to see in the lower 
 part of the visual field a board was placed near the bottom of 
 the cage so that food in the hand could be kept out of sight until 
 it was time to show it ; in the right hand a piece of food was held 
 in front of the animal in order to attract the attention, but just 
 beyond the reach so that the animal would need to exert himself 
 in his efforts to obtain the food, and a second piece was held in 
 the other hand behind the board ; the attention of the monkey was 
 gained by the exhibition of the piece of food in the right hand, 
 but when the second piece was exposed, the animal reached for 
 the latter. Two tests were made with pieces of green and white 
 breads after having performed many tests with melon and white 
 bread ; in the later tests the animal always reached for the green 
 bread; in tests with green and blue breads in which the green
 
 EXPERIMENTAL RESULTS 73 
 
 bread was held nearer the animal than the blue, the monkey always 
 reached beyond the green bread and selected the blue bread. 
 When, however, the blue bread was held in the inferior and the 
 green in the superior part of the field the green was always taken. 
 When a piece of melon and a piece of green bread were shown 
 simultaneously the animal always selected the green melon. Under 
 the following conditions the animal always selected the vegetable 
 or fruit instead of the bread; blue bread and tomato; blue bread 
 and melon; green bread and tomato; green bread and melon; 
 even when the bread was nearer or farther from the animal, to 
 the right or to the left, and when one or more pieces were pre- 
 sented simultaneously. Repeated tests to determine whether or 
 not both right and left visual fields were normal showed that the 
 animal made grasping movements for food regardless of the part 
 of the field in which the food was presented, but that the move- 
 ments for food on the right were not as quick as those on the 
 left. When pieces of melon or tomato were held in the hand 
 close to the cage the animal always took them, but did not take 
 the green, red or yellow breads." 
 
 Four days after the operation. When a plum was thrown into 
 the cage the animal moved toward it and tried to pick it up but 
 failed several times to locate the fruit. At first it grasped another 
 piece of food which it then smelled and rejected, and continued 
 to seek the plum until it was found. 
 
 Five days after the operation. A paralysis of both hands was 
 found, the fingers were shut into a fist and there was a wrist 
 drop. The movements of the arm appeared to be normal, and it 
 was found that when the arms were extended the fingers were 
 voluntarily moveable to a slight extent. When a pear was rolled 
 on the floor of the cage the animal moved toward it and attempted 
 to get it in his hands but on account of the flexion of the fingers 
 could not do this ; the pear was then eaten by the animal moving 
 its head close to the pear. The pear and other pieces of food 
 were held to a slight extent by the thumbs of both hands, which 
 appeared to be more moveable than the fingers. 
 
 On the following day (six days after the operation), the paral- 
 ysis of the hands disappeared; the movements of grasping and 
 of holding were normal in character, and, judging from the force
 
 74 SHEPHERD IVORY FRANZ 
 
 with which it held a rod inserted into a cage, of good force. The 
 monkey did not eat any bread presented to it, and the colored 
 breads were disregarded; on this account a test of the color dis- 
 crimination could not be made. All fruits and vegetables were 
 rapidly and unerringly selected from the food presented to him so 
 that it was evident the animal had considerable discrimination 
 ability. The animal was not fed at this time and in the afternoon 
 tests with the colored breads were made. In two tests the mon- 
 key selected the blue bread and disregarded the yellow and green, 
 but on the third test the animal picked up at one time both the 
 blue and the green, disregarding the yellow. 
 
 Two days later (eight days after operation). Tests with the 
 colored breads ; in three tests took blue bread and in the third took 
 yellow after having eaten the blue, but did not eat the yellow ; in a 
 fourth test in which two pieces each of yellow, red and blue 
 breads were presented simultaneously in irregular order, the 
 monkey took the blue pieces, brushed the red pieces off the plate 
 and disregarded the yellow bread. Tests with small pieces of 
 bread, cooked potato, raw apple, cooked green beans, and raw 
 tomato resulted in the selection of the vegetables and the dis- 
 regarding of the bread. 
 
 Ten days after operation. The animal was found in a convul- 
 sion with twitchings of arms, head, eyelids, etc. The fingers were 
 flexed as they had been five days previously, and there was in- 
 ability to grasp food ; the condition passed away by the following 
 day, and the animal caught with accuracy grapes rolled toward 
 him on either side and placed them in his mouth. Other foods 
 were selected from bread, their positions were accurately judged 
 (as evidenced in the accuracy of the movements) and they were 
 eafen. 
 
 Five days later (fifteen days after the operation). Color tests; 
 took only blue bread. The animal was killed on this day in order 
 that examinations of the brain might be made by the methods of 
 Marchi. 
 
 Figures 46 to 57 show the results of the post mortem examina- 
 tions. In figs. 46 to 49 are shown the results of the lesions. The 
 extent of the cortex destroyed by the cautery was accurately 
 determinable but on account of the character of the operation on
 
 EXPERIMENTAL RESULTS 
 
 75 
 
 47 
 
 51 
 
 SOI 
 
 49 
 
 FIGS. 46, 47, 48 and 49. Monkey 4. Lateral and mesial aspects of the 
 cerebral hemispheres, showing the extents of the lesion of the cortex on 
 the left side, and the approximate course of the knife cut on the right. 
 Slightly reduced. Traced from photographs. 
 
 JQlC* _ _ 
 f 153. 53 
 
 ol 
 
 FIGS. 50, 51 and 52. Monkey 4. Frontal sections of the left hemisphere in 
 the neighborhood of the cauterization, showing the amount of destruction. 
 Slightly enlarged. Drawn with Edinger projection apparatus.
 
 76 SHEPHERD IVORY FRANZ 
 
 the right side it was not possible to determine the amount of the 
 visual area involved by the operation. The approximate location 
 of the knife cut on the right side is shown in the figure. The 
 results shown in figs. 50, 51 and 52 are due to the cauterization 
 of the cortex, and have been investigated by the Nissl method. In 
 parts it will be noted that the depth of the cortical destruction 
 
 FIGS. 53. Monkey 4. Vertical section through the left hemisphere, anterior 
 to the cauterized area. Few fat drops are indicated in the diagram by 
 crosses. Slightly enlarged. Edinger drawing apparatus. 
 
 has not been great, a matter which has been considered in an 
 earlier portion of this article. The section of the left hemisphere 
 anterior to the parts examined by the Nissl method was examined 
 for fiber disintegration, or degeneration, and this showed, figure 
 53, a rather diffuse process, but with no marked evidences of 
 degeneration. The examination of the right hemisphere by the 
 Marchi method was unsatisfactory, for the only effects of the 
 lesion were those in the immediate neighborhood of the cut. 
 
 Regarding these preparations Dr. Lafora has written: "Mon- 
 key 4. Cauterization of the left hemisphere, cutting of the white 
 matter of the right hemisphere. Frontal sections. Nissl method 
 on the left, and Marchi method on the right. On the left the 
 calcarine fissure has almost entirely escaped destruction. The 
 outside of the brain (the calcarine type of cortex) is affected in 
 the external layers up to the granularis interna. (On account of
 
 EXPERIMENTAL RESULTS 
 
 77 
 
 the time of death so soon after the operation the cortex showed 
 only the primary effects of the operation and not the secondary 
 ones.) A large hemorrhage extends over the calcarine type of 
 cortex on the lateral aspect of the hemispheres and extends into 
 the white substance. Sections of the brain anterior to the cauter- 
 ized area were examined by the Marchi method, and these showed 
 some fat drops as are illustrated in the figures. The right side 
 was placed in toto by mistake into the Marchi fluid which pro- 
 
 FIGS. 54, 55, 56 and 57. Monkey 4. Frontal sections of right hemisphere, 
 showing destruction in the neighborhood of the knife cuts. For fuller 
 description, see text. Slightly enlarged. Edinger drawing apparatus. 
 
 cedure did not permit a proper impregnation, consequently tht 
 appearances found in the sections are only those near the surface. 
 Here are found many fat drops around the hemorrhagic areas, 
 which were produced by the cutting."
 
 ;8 SHEPHERD IVORY FRANZ 
 
 Clinically, it appeared at first as if this animal had a visual 
 defect but later observation failed to indicate this, and the con- 
 clusion is forced upon us that if there was a defect during the 
 first few days it was minor in character, and not of sufficient 
 amount to be called amblyopia, hemianopsia, or anything more 
 than what Loeb has called a "reduction in irritability." 
 
 Monkey 5. In the preliminary experiments this animal had 
 been trained to take red and blue breads and to disregard the 
 yellow and green. These early experiments were made on eight- 
 een days over a period of sixty-one days, the habit being estab- 
 lished after five days' experimentation. No further experiments 
 were made for eight months. 
 
 August 19, 4 tests; took red, blue and green the first test; red 
 and blue the second test, and only blue the third and fourth tests. 
 August 20, 5 tests were made with only red, yellow and blue, and 
 in all the tests the animal disregarded the yellow. August 23, 
 after an interval of three days, 10 tests were made with blue, yel- 
 low and green. In the first test the animal took the yellow as well 
 as the blue, but in the other nine tests took only the blue. August 
 25, 10 tests; took only the blue and disregarded the yellow and 
 green. On the last two days one test each was made in which 
 two or more pieces of each of the three kinds of bread were 
 presented simultaneously, and in these tests the animal selected 
 the blues from the other colored breads. 
 
 August 26. Operation. Both occipitals were cauterized, the 
 cautery being inserted into the brain substance as well as being 
 passed over the cortex. 
 
 Three hours after the operation the animal appeared to be 
 fairly normal. He picked up pieces of apple placed on the floor 
 of the cage, the color of which was quite similar to that of the 
 food. The movements were accurate when the food was placed 
 within 30 cm. of the animal, and in addition the animal made 
 accurate movements to secure food held at the top of the cage. 
 
 Four and a half hours after the operation, the animal was ob- 
 served by me in conjunction with Dr. I. W. Blackburn. At this 
 time the following notes were made : The pupils reacted to light 
 in a normal manner, and the general appearance of the animal was 
 normal. He peered around the cage and through the opening in
 
 EXPERIMENTAL RESULTS 79 
 
 the back, and examined all things placed in his way. In his usual 
 manner to strangers, he threatened Dr. Blackburn, but afterwards 
 remained huddled in a corner, but moved whenever the hand was 
 inserted into the cage or when food was presented. Grapes rolled 
 toward the animal were immediately and accurately seized ; grapes 
 held in the hand 30 cm. distant were reached for but not accurate- 
 ly grasped, for at times he took hold of the experimenter's finger. 
 A grape rolled to the other end of the cage (75 cm. distance from 
 the animal) was disregarded for ten or fifteen seconds, although 
 the animal was hungry and ate anything placed within its reach. 
 Grapes and pieces of apple placed near enough to be reached were 
 easily grasped, but at times with slight incoordination amounting 
 to about 4 cm. The grasping movements were sometimes to one 
 side, at other times to the other, and often nearer the animal than 
 they should have been. A mirror placed in the cage attracted the 
 attention, the animal moved toward it, peered into it and 
 examined the front and looked behind it repeatedly. He took a 
 piece of red colored blotting paper and inserted it into the mouth, 
 but then rejected it. A small piece of bread about 3 mm. in dia- 
 meter was picked up from the floor, but as he continued to fumble 
 for food and at times picked up grape skins which he had previ- 
 ously rejected it was impossible to decide whether the small piece 
 of bread had been seen or had been hit by the hand as the animal 
 moved the hand over the floor. The monkey repeatedly took the 
 grape skins which it had previously rejected, placed them in the 
 mouth and immediately spat them out again. A pair of eyeglasses 
 were held so that four images of the electric lights were thrown 
 on the floor of the cage; these attracted the attention of the 
 animal and he moved his head and eyes in accordance with the 
 movements of the images. 
 
 Four days after the operation. It was noted that when food 
 held on wires was presented to the animal, the food held in the 
 upper left visual field was always seized immediately, but that 
 the food held in other parts of the field was sometimes seized and 
 sometimes not seized. On this day an attempt was made to test 
 the memory for colors but the animal would not touch the breads 
 and the test could not be made. 
 
 On the following day, five days after the operation, the tests
 
 So SHEPHERD IVORY FRANZ 
 
 with colored breads on the glass plate were also unsuccessful, and 
 the breads were therefore presented in pairs on wires, viz., blue 
 and yellow, and blue and green. In ten tests with the yellow-blue 
 pair the monkey took the yellow once, the blue four times, and 
 both pieces five times. The latter result was obtained after the 
 other five. With the green-blue test, the monkey took the blue 
 five times, and did not take the green. On this day a lump of 
 sugar was placed at the bottom of the cage but it remained un- 
 noticed although before the operation the animal was very fond 
 of sugar. Other pieces of food on the floor of the cage were 
 also disregarded, although when food was placed close to the nose 
 it was seized and eaten with eagerness. A broom and a stick, of 
 which the animal was normally afraid, were introduced into 
 the cage without producing any reaction on the part of the 
 animal. 
 
 Six days after the operation the tests with colored breads were 
 more successful. Five tests were made with the following re- 
 sults : In the first test the animal reached in the direction of the 
 blue, but slowly drew its hand backwards and then put its head 
 down to the food plate and took the blue in the mouth. In the 
 second test, the animal fumbled about the plate, finally hit the 
 yellow bread, which it placed in its mouth but immediately spat 
 out. In the third test he grabbed for the bread, caught the green 
 piece, which was tasted and thrown away, and then he took 
 the blue which he ate. In the fourth test, he took the blue bread 
 immediately, ate it and disregarded the other two pieces. In 
 the fifth test he took the blue, but only tasted it ; the other pieces 
 were not touched. Following these experiments he was placed in 
 the cage with another animal. As soon as he got into the other 
 cage he walked half way across the cage and picked up a piece of 
 food lying on the floor, and then stood up and reached for a 
 piece of apple on the wire netting at the top. Small pieces of 
 apple were then placed at the top of the cage to the right or left 
 of the animal, and in every case he accurately reached for the 
 food. In one test in which two pieces were placed about 10 cm. 
 apart, he reached for one piece, but in taking hold of the netting 
 the apple dropped to the floor of the cage whereupon he immedi- 
 ately changed the direction of the movement and secured the sec-
 
 EXPERIMENTAL RESULTS 
 
 81 
 
 ond piece. After having secured the second piece he accurately 
 reached for and secured the first piece which had fallen to the 
 floor. 
 
 During the next three days the inaccuracies in reaching for 
 food increased, until the animal was able to get food only by 
 fumbling around on the bottom of the cage. Eventually his 
 movements became like those of a blind person. Ten days after 
 the operation it was noted that the animal had all the appearance 
 of being blind. He paid no attention to the movements of the 
 experimenter's hand and arm or to a small flag. Food held at 
 a distance of 30 cm. was unattended to except when held in the 
 upper left part of the visual field. He reached for food when 
 it was placed on the floor of the cage but the movements were 
 inaccurate and it appeared that the animal did not appreciate 
 
 6S 
 
 FIGS. 58, 59, 60 and 61. Monkey 5. Lateral and mesial aspects of the 
 cerebral hemispheres, showing the extent of the lesions produced at the 
 operation: Slightly reduced. Traced from photographs. 
 
 what he was reaching for. Once a small bright red tomato about 
 2 cm. in diameter was exhibited in the upper left part of the field ;
 
 82 SHEPHERD IVORY FRANZ 
 
 the monkey reached for it in a fumbling manner and knocked it 
 down so that it rolled to the left and behind him. He sought for 
 the food through the bars of the cage, although none was visible, 
 and groped hither and thither. When the tomato was shown a 
 second time in the upper left field, he reached for it, making an 
 initial error of about 10 cm., but finally managed to secure it. 
 Black and white grapes rolled on the floor of the cage were not 
 taken although the animal seemed eager for food. Grapes held 
 near his nose were taken hold of accurately. In the tests made 
 on this day it should be mentioned that there was an intention 
 tremor and part of, if not all, the inaccuracy of movement, may 
 have been due to this motor derangement. 
 
 Eleven days after the operation the animal was tested, and 
 found to be in almost the same condition as that noted in the 
 preceding paragraph, except that there was less ability to grasp 
 things presented to him. He was killed on this day. At the 
 
 FIGS. 62, 63, 64, 65, 66 and 67. Monkey 5. Frontal sections of the cerebral 
 hemispheres, showing the parts affected by the operation. In 64 no lesion 
 was found. Edinger drawing apparatus. Slightly enlarged. 
 
 autopsy the brain was found bulging above the level of the bone, 
 the hernia on the right side being more marked than that on the 
 left. There were adhesions between the brain and dura and 
 scalp. The brain weighed 92 grams.
 
 EXPER1 Ml- \T.\L RESULTS 83 
 
 The results of the post mortem examinations in this animal 
 showed much more extensive lesions than in any other animal 
 upon which I operated. The visual defect was noticeable only 
 after four or five days (although there was some incoordination 
 from the first) and in this case it is apparent that the end result, 
 the apparent blindness, must have been due to the extension of the 
 effects of the primary lesion. Only the anterior part of the cal 
 carine fissure on the right side was preserved (see figs. 59 and 64) 
 and the preservation of this, with the apparent lack of foveal 
 vision is against the hypothesis of Henschen. 
 
 The results of the histological examination by Dr. Lafora arc 
 as follows: "Monkey 5. Cauterization of the cortex. Frontal 
 sections, Nissl method. On the right side, with the exception of 
 the most anterior portion of the calcarine fissure, which is a very 
 small area, all of the calcarine type of cortex has been destroyed, 
 even the external part of the occipital pole, and large parts of 
 the white substance in the neighborhood of the calcarine fissure. 
 On the left side the lesion was apparently selective, for the effe:t 
 is localized along the calcarine fissure throughout its entire extent, 
 and into its depth. The occipital pole has only the outside part 
 of the cortex destroyed." 
 
 Monkey 6. This animal was trained to discriminate red and 
 green breads. The training results were as follows : 
 
 August 22, 5 tests; in all tests the animal took both kinds of 
 bread. August 24, 10 tests; after the first four tests the animal 
 did not eat the green, although on the sixth test she picked it 
 up but discarded it without smelling or tasting. August 26, 5 
 tests; in all of which the red was taken and the green was noi 
 taken. August 27 and 28, 5 tests each day; in all the green was 
 disregarded and the red taken. August 31, 5 tests; took only red 
 although in the last test on this .day four pieces of red and six 
 of green were presented simultaneously. September I, 5 tests: 
 in all of which the red was taken and no green. On this day the 
 operation was performed. 
 
 Operation, September I. After the trephine buttons were re 
 moved the openings of the skull were enlarged by means of bone 
 forceps so that all of the lateral parts of the occipital lobes were 
 exposed. At the time of the operation the hemispheres were
 
 84 SHEPHERD IVORY FRANZ 
 
 separated by a glass spatula and the internal aspects of both hemi- 
 spheres were cauterized as well as possible. The injury in this 
 animal was apparently more extensive than in animals 3, 4, and 
 5. A hemorrhage from one of the large occipital arteries was 
 checked by an application of suprarenal, I :iooo. 
 
 A half hour after the operation the animal was found sitting 
 in its cage, apparently looking at everything passing, for she fol- 
 lowed me with her head and eyes when moving around the room. 
 
 Two hours after the operation, she was found peering through 
 the opening at the back of the cage, and when I quietly moved 
 toward this part she retreated to the other side of the cage. When 
 I was seated in front of the cage and made movements with my 
 hands and arms, she followed with her eyes all the movements 
 in a perfectly normal manner. The reflexes of the pupils were 
 normal. Four pieces of white bread were put into the cage, the 
 animal appeared to look at these, and she touched some and 
 carried one to her mouth, but did not eat it. A grape rolled into 
 the cage among the pieces of bread was instantly seized and 
 placed in the mouth. Three grapes were placed among the bread 
 and all were selected and the bread disregarded; in these tests it 
 was noted that the error of movement was from one to three cm. 
 Pieces of muskmelon were selected unerringly from the bread of 
 the same sizes. Only two pieces of pear were taken although 
 six were placed in the cage. When pieces of melon, bread and 
 pear were presented the monkey took the pieces of melon and left 
 the bread and pear, and when grapes, melon, pear and bread were 
 presented she took only the grapes. 
 
 Five hours after the operation she was observed by Dr. Lafora, 
 who made the following observations : "Color vision was tested 
 by the ability of the animal to discriminate foods of different 
 colors ; red bread from a red grape, melon from green bread, and 
 combinations of different kinds of food. In these experiments 
 the monkey took the fruit in preference to the bread, but she did 
 not appear to be hungry and after about ten minutes would not 
 attempt to secure food. Tests of peripheral vision by means of 
 food placed at the ends of wires showed that when the food was 
 in any part of the visual field it attracted the attention of the 
 animal and there were no results that could be taken to indicate a
 
 EXPERIMENTAL RESULTS 85 
 
 contraction of the visual field, nor any difference in sensation 
 ability." 
 
 One day after the operation, when sitting quietly in front of 
 the cage observing the actions of the animal, there being no food 
 in the cage, I saw her make a quick movement in the air thereby 
 catching a fly on the wing. At this time, the monkey did not 
 work with colored breads, entirely disregarding them as they 
 were presented on the glass plate. Throughout the period of 
 observation on this day, the animal kept picking at the edges of 
 the bandage and when she had managed to get a small piece of 
 cotton she would hold it about 10 cm. in front of her eyes, as if 
 carefully examining it ; at times she placed the cotton in the 
 mouth and eventually threw it away. 
 
 During the next five days there were no new observations 
 worthy of note, the animal appearing to be in much the same 
 condition as was noted the day following the operation. On the 
 sixth day after the operation it was first noted that the animal did 
 not appear to see objects placed on the floor of the cage for she 
 left fruit and other kinds of food although she appeared to be 
 hungry and took all things presented to her in the hand or on 
 wires. On this day the visual defect was like that of many of 
 the animals, indicated by an inaccuracy in movements in grasping 
 the particles of food, for the errors in movement amounted to 
 from one to four cm. On this day, however, four tests with col- 
 ored breads were made, and in these tests she picked up the red 
 bread and disregarded the green three times ; and in the fourth 
 trial she moved in the direction of the red but managed to pick 
 tip the green which was only two cm. away from the red. 
 
 Two days later, eight days after the operation, three grapes 
 were dropped into the cage ; they rolled into positions forming an 
 irregular triangle with the apex about 50 cm. from the eyes of 
 the animal. The monkey made repeated efforts to obtain the 
 grapes but at first got its hand 15 cm. too close to its body and 
 then fumbled around until she by chance hit one of the grapes: 
 this grape rolled closer to the animal but the monkey continued 
 to feel around in the spot at which the grape had been felt and 
 at this time she did not manage to get this grape or the other 
 two which were presented. Afterwards with considerable fum-
 
 86 SHEPHERD IVORY FRANZ 
 
 bling she secured the two grapes the positions of which had not 
 been disturbed and finally the one which had been moved by her 
 fumbling, and which, as has been said, rolled closer to her body. 
 A second set of observations were made on this day with some- 
 what similar results. The defect of vision appeared to me to be 
 general and not of any particular retinal segment. When two 
 pieces of food were held on wires one to the right and the other 
 to the left, or one above and the other below the line of regard 
 both pieces were secured, but only after considerable fumbling 
 and after making numerous futile attempts to reach the food. 
 Grapes rolled into the cage were searched for and secured only 
 after they had been hit by one of the fumbling hands in their ap- 
 parently rambling movements. Seven lima beans were placed 
 on the glass plate in the form of a hexagon, and only after much 
 fumbling were these obtained. A small very bright red tomato, 
 placed 60 cm. from the animal, was not noticed for two or three 
 minutes, but after that time it appeared to me that the animal 
 had sensed its presence, whereupon she began a search for the 
 tomato finally securing it after about 40 seconds. Grapes and 
 beans lying outside the cage were secured with difficulty ; usually 
 the animal made a movement in the general direction of the food 
 and then, not finding it, swung the arm and hand until some- 
 thing was touched. In taking food presented at the ends of 
 wires and from the floor it was noted that the first movement was 
 in the general direction of the food, and when the food was not 
 secured by this first movement (as was usually the case) the 
 monkey drew the hand backwards, peered at the food for a second 
 or so and tried again. The errors of movement (i. e., the dis- 
 tance between the food and the tips of the searching fingers) 
 averaged about 2 cm., and the record of nine different attempts 
 show that these errors were in all possible directions, too far 
 from, too near, to the right of and to the left of the food. 
 
 On the succeeding days the inaccuracies in adjustment became 
 less noticeable, and thirteen days after the operation they were 
 to be discovered only by careful observation. On this day the 
 animal was examined by Dr. F. M. Barnes, Jr., who wrote the 
 following notes; "The animal is quite active, moving about the 
 cage and taking notice of all about it. She does not seem especial-
 
 EXPERIMENTAL RESULTS 87 
 
 ly frightened but moves quickly at very slight noises. It seems 
 impossible to make the slightest movement in front of the cage 
 without attracting the animal's attention. When a pencil is 
 pointed at her through the wires of the cage she strikes at it with 
 her right hand; the aim is true and sometimes she grasps the 
 pencil and pulls it. Vision for objects (wires and rods) on both 
 sides and from above and below is acute. A piece of potato was 
 placed under a watch glass and introduced into the cage. The 
 animal grabbed for it several successive times, then with both 
 hands found the edges of the watch glass and made an attempt 
 to turn it over. A piece of potato was placed in a small glass 
 crystallizing dish, which the animal seized, turned over quickly 
 but did not use the hand to secure the food but inserted the 
 mouth. Another trial under similar conditions, but the potato 
 dropped to the floor when the glass was introduced : the monkey 
 picked up the dish, held it to the mouth and tried to get food from 
 it leaving the food on the floor unnoticed. When the dish and the 
 watch glass were placed in the cage she took up both even though 
 no food was in them. Blocks of apple and carrot thrown into 
 the cage are generally picked up quickly and accurately. Often 
 she seems to look directly at a piece of food for some time before 
 taking it up. She frequently misses a piece of food by 5 to 8 
 cm., and on groping gets farther off. With several different 
 kinds of food thrown into the cage she does not appear to dis- 
 criminate but picks up ginger snap along with the apple and only 
 after having conveyed the ginger snap to the mouth does she re- 
 ject it. She often picked at a knot hole in the floor of the cage 
 and appeared to attempt to pick it up. Vision does not seem dis- 
 turbed when tested by rods approached from the four retinal 
 quadrants ; the upper segment may have some dimness, for there 
 is some inability to discriminate and to pick up food from the 
 bottom of the cage. There is some incoordination of movement 
 in prehension. It appears as if the animal does not discriminate 
 between the colors, white, red, and brown." The last conclusion 
 does not appear to me to follow from the results of the experi- 
 ments, for although the animal in its normal condition took fruit 
 in preference to bread and ginger snap both the latter kinds of 
 food were eaten with apparent enjoyment. It also appears that
 
 88 
 
 SHEPHERD IVORY FRANZ 
 
 the incoordination of movement in grasping the particles of food 
 may have given the impression that there is no ability to dis- 
 criminate, for in tests with other animals it was found that when 
 pieces of food were widely separated the movement was always 
 made in the proper direction, although the food was not imme- 
 diately secured, but that when the food pieces were close together 
 the animal at times managed to get the wrong piece and often to 
 take two pieces at once. It would perhaps be better to make 
 a statement of the action rather than to draw the conclusion : 
 the animal picked up indiscriminately pieces of white, brown 
 and red food, although when these pieces were conveyed to the 
 mouth only the red were usually eaten. 
 
 FIGS. 68, 69, 70 and 71. Monkey 6. Lateral and mesial aspects of the 
 hemispheres, showing the extent of the lesion produced by cauterization of 
 the pia and cortex. Slightly reduced. Traced from photographs. 
 
 The animal was killed two days later, without having shown 
 any further variations in vision or other sensory functions. At 
 the autopsy, the brain was found adherent to the dura and to the 
 scalp over the site of the trephine buttons, and it was with diffi-
 
 EXPERIMENTAL RESULTS 
 
 89 
 
 culty separated from the scalp. The brain weighed 94 grams. 
 The occipital lobes were placed in alcohol for examination by 
 the Nissl method and the remainder of the brain was hardened 
 in bichromate for examination by the method of Donnagio. 
 
 FIGS. 72, 73, 74, 75, 76 and 77. Monkey 6. Frontal sections of cerebral 
 hemispheres, with drawings of the histological examination. Slightly en- 
 larged. Edinger drawing apparatus. 
 
 The results of the operation are to be found represented in 
 figures 68 to 77. It will be seen that in this animal the cortex 
 surrounding the calcarine fissure has not been disturbed to any 
 extent and that the destruction of the visual cortex beyond the 
 calcarine region has been very extensive. Such a lesion should 
 have produced a very decided visual defect if this area were 
 concerned with perceptions or sensations of a visual character, 
 for with the exception of the cortex along the calcarine fissure 
 practically all the so-called visual cortex has been affected. 
 
 The report of Dr. Lafora on the examination of the micro- 
 scopical sections is as follows: "Monkey 6. Cauterization of 
 the brain, frontal sections, Nissl method. On the left side the 
 cortex along the calcarine fissure is not affected excepting the 
 oral side of the superior ramification, at the extreme end of the 
 occipital lobe. The lesion on the right closely corresponds with
 
 90 SHEPHERD IVORY FRANZ 
 
 that on the left, but there is a slight hemorrhage near the cal- 
 carine fissure." The examination by the method of Donnagio 
 has not yet been completed. 
 
 Monkey 7. This animal was trained to discriminate the four 
 colors. At first the animal did not seem to discriminate between 
 the bitter breads, and for the first eight days of the experiments 
 ate the bitter (green and yellow) breads, as well as the sweet 
 (red and blue), even though at times the green and yellow were 
 rolled in quinine and the animal had previously been thoroughly 
 fed and the cheek pouches were filled with food. Oct. 27, the 
 eighth day of the experiments, she refused the green and yellow 
 breads most of the time, and on the following three days did not 
 take the bitter breads once. On Nov. i and 3, she took the green 
 bread once each day, but in later tests (November 5, 20, 25, and 
 28), after intervals of one, fourteen, four and two days, re- 
 spectively, she made no mistakes. 
 
 The operation was performed Nov. 28. Both occipitals were 
 cut away by a frontal incision. On cutting the left occipital, 
 the right eye was observed to rotate slowly upwards and to the 
 right, and this movement appeared to be concomitant with the 
 slow drawing movement of the knife. The monkey reacted well 
 after the operation, and two hours after having been placed 
 in her cage was noticed to be busily engaged examining all parts 
 of it. Her movements were rather slow, but they seemed to 
 be executed well and precisely. No reaction to noises, loud or 
 soft, e. g., whistling, clapping hands, etc., was observed, but any- 
 thing moving about the cage attracted her attention. The ob- 
 servation cage had been placed in a room to which the animal 
 was not accustomed, and she repeatedly went to the 5 cm. open- 
 ing at the back and peered through it. Eight hours later the 
 animal was found asleep, but when awakened seemed to be in 
 the same state as that just described, curiously examining all 
 things, following with the head and eyes moving objects, etc. 
 
 One day after the operation, a few tests with colored breads 
 were made. In these the animal selected the red and blue and 
 disregarded the green and yellow, but in each test did not take 
 both sweet pieces. The movements were quick and accurate. 
 She picked up food from the floor of the cage, accurately reached
 
 EXPERIMENTAL RESULTS 91 
 
 up to the top of the cage and secured small pieces of sugar and 
 other food which were held there. She was tested with the 
 colored breads with the same result noted above. She was then 
 placed in the cage with the male Monkey 8, whom she picked 
 over for fleas, dandruff, etc., in a perfectly normal manner. Dur- 
 ing this procedure she was seen to stop, and make a quick move- 
 ment, thereby catching a fly. 
 
 Two days after the operation (Nov. 30), ten tests with the 
 colored breads showed perfect retention of the ability to discrim- 
 inate, and on the following day ( Dec. i ) the following results 
 were obtained: Tests 1-6, ate all four pieces; 7, ate the red, blue 
 and yellow, and disregarded the green; 8, ate red, blue and yel- 
 low, but did not pick up the green; 9, and 10, ate the red and 
 blue, but did not take the yellow and green. Two days later she 
 took red and blue in the first trial but refused to take more, and 
 on the following day (Dec. 4) refused to work. Two days 
 later in ten trials she ate all four pieces presented to her. 
 
 During the succeeding days no abnormality of vision was de- 
 tected; the movements of grasping objects presented in any part 
 of the visual field were accurate and quick, and there were no 
 observable errors in discrimination. A second operation was 
 determined upon but deferred for about four months and a half 
 (April 1 6). During the intervening period the monkey was re- 
 turned to the large cage with a normal monkey, and so far as it 
 was observed acted in a perfectly normal manner. At the end 
 of about four months the memory for the colored breads was 
 tested and found to be defective. On the first day after this 
 second series (March 29), she took all four pieces in the five 
 tests, but two days later made only two mistakes in ten trials. 
 During the next two weeks the monkey was given tests on three 
 days, with intervals of 5 and 7 days respectively, in all of which 
 the green and yellow were disregarded and the red and blue 
 were taken. On the day of the second operation (April 16) the 
 monkey took the yellow bread several times and the green once 
 in ten trials. 
 
 Second operation, April 16. At the operation the posterior 
 portions of the occipital cortex were cauterized. The site of 
 the trephine openings made at the time of the first operation
 
 92 SHEPHERD IVORY FRANZ 
 
 were distinctly visible, the button on the right side was soft, 
 that on the left was hard. New openings were made slightly 
 posterior to these, and the old buttons were removed. It was 
 found that the bridge of bone between the two original trephine 
 openings had disappeared, so that when the new trephine holes 
 were made, both occipitals were exposed and the bone opening 
 extended from one side to the other. The loss of blood at the 
 operation was slight and the animal recovered from the anesthetic 
 soon after being taken from the operating table. 
 
 Fifteen minutes after the operation the monkey sat up in the 
 
 79 
 
 FIGS. 78 and 79. Monkey 7. Lateral aspects of cerebral hemispheres, show- 
 ing the extent of lesions produced at the second operation, and the location 
 of parts examined by histological methods. Slightly reduced. Traced from 
 photographs. 
 
 cage, looked about in a dazed manner and moved about slowly. 
 An hour after the operation she was more nearly normal. She 
 took a piece of bread presented to her through the wire netting, 
 moving forward about 25 cm. and reached for the food with an 
 error of only about 3 cm. One hour later she was given a pea- 
 nut, which she reached for accurately. She conveyed the peanut 
 to her mouth, took the nut out of the shell and began to strip 
 the red skin from the nut in a normal manner. When the shell
 
 EXPERIMENTAL RESULTS 
 
 93 
 
 had been thrown away, the monkey took the nut from her mouth 
 from time to time when stripping the skin from it and examined 
 it until the skin had been removed. She was given water in 
 a saucer, but did not drink it for an hour. 
 
 The day following the operation, the animal appeared to be 
 normal, and two days after the operation in five tests with colored 
 breads she showed perfect discrimination. At no time was there 
 evidence of a visual disturbance as the result of this operation. 
 The monkey was taken to Baltimore, April 20, and exhibited at 
 the meeting of experimental psychologists, after which it was 
 killed. 
 
 80 
 
 cent 
 
 fcolc. 
 
 cole 
 
 FIGS. 80 and 81. Monkey 7. Tracings from photographs of lower parts 
 of sections 82, 83, 85, and 86, of rigs. 78 and 79, showing extent of lesions. 
 Slightly reduced. 
 
 At the autopsy the areas of softening of the cortex were dis- 
 tinctly noticeable apparently extending over the convexity of the
 
 94 
 
 SHEPHERD IVORY FRANZ 
 
 occipital lobes almost to the parieto-occipital fissure. The results 
 of the autopsy and histological examinations are shown in the 
 accompanying figures (78 to 87). In these it will be seen that 
 the occipital poles have been almost entirely destroyed, and that 
 the destruction of the so-called visuo-sensory cortex is extreme, 
 
 FIGS. 82, 83, 84, 85, 86 and 87. Monkey 7. Horizontal sections of cerebral 
 hemispheres, with results of histological examinations, showing the amount 
 of destruction by cauterization. Slightly enlarged. Edinger drawing appa- 
 ratus. 
 
 with the exception of that surrounding the calcarine fissure. 
 The report of Dr. Lafora on the brain is as follows : 
 "Monkey 7. Cauterization of the brain : Nissl method; hori- 
 zontal sections. On the right side the calcarine area is affected 
 only at the superior branch of the fissure, but the cortex at the 
 occipital pole is almost entirely destroyed. On the left side 
 there is a marked destruction of the most posterior part of the 
 occipital pole with an irritation lesion of the pia around this 
 lesion. In the superior branch of the calcarine fissure there are 
 some lesions." The effects of the first operation (section) were 
 not determined by the histological method employed, and at the 
 time of writing no examination of fibres had been made.
 
 EXPERIMENTAL RESULTS 95 
 
 Monkey 8. This animal was trained to discriminate red and 
 yellow breads. The training began Oct. 20 and continued until 
 Nov. 26, with intervals of 2, 6, and n days after the habit 
 had been formed. At the latter date, the animal had indicated 
 the ability to discriminate the red from the yellow, and to retain 
 this over a period of eleven days. 
 
 The operation of cutting both occipitals was performed Nov. 
 26. There was considerable hemorrhage which was controlled 
 by hot compresses. There was also considerable shock from the 
 operation, and the monkey did not recover from the general de- 
 fects for several hours. Immediately after the operation it was 
 noted that the pupils were slightly dilated, but were equal. A 
 slight nystagmus was suspected but at times this did not appear 
 to be present, and it was impossible to decide whether or not the 
 movement was partly voluntary. The eyes appeared to be rotated 
 toward the right. When placed in the observation cage the ani- 
 mal was laid on the left side but it kept its head raised from the 
 floor, and there was a slight tremor of the head. Three hours 
 after the operation the animal appeared lethargic, its general 
 movements were slow and apparently performed only with great 
 effort and without much force. When a stick was thrust through 
 the wire netting the monkey reached for it slowly but accurately. 
 It grasped the stick, carried it toward its mouth and bit it, making 
 these movements slowly and pulling and biting the stick without 
 any display of energy. The wound or the bandage was appa- 
 rently irritating, for the monkey continually scratched at the 
 bandage when its attention was not attracted by and directed 
 to objects held by the experimenter. The animal grasped food 
 accurately but slowly, and picked up food which was placed on 
 the floor of the cage, even when at the farther end (about 75 
 cm. distance). When a prune was held 10 cm. in front of the 
 cage, the monkey put its hand through the mesh of the wire 
 netting slowly but accurately, grasped the prune, drew it in, 
 and immediately ate it. 
 
 By the following day the dilation of pupils and the nystagmus 
 (suspected) had disappeared. The- general movements were 
 more quickly performed, and the accuracy was the same as that 
 following the operation. General tests with food were made, the
 
 g6 SHEPHERD IVORY FRANZ 
 
 animal reacting in a normal manner, selecting pieces of food 
 from a number placed on the floor of the cage, and rejecting 
 those things which were of no value, and also those which it 
 was known not to prefer, e. g., plain bread. No special tests of 
 color were made on this day. 
 
 Two days after the operation the animal appeared able to see 
 and to discriminate all kinds of food and other objects held in 
 any part of the visual field, but when tested with the colored 
 breads (which experiment was performed first on this day when 
 the animal was hungry), the animal reached for and took both 
 kinds of bread. It appeared at this time that the animal had 
 lost the ability to discriminate the colors red and yellow in the 
 bread test, although when tested with other foods of similar 
 color (carrot, tomato, yellow turnip), there was no hesitation 
 in selecting the red (tomato) and of selecting these vegetables 
 instead of the red and yellow breads. 
 
 No special tests were made on the following day the animal 
 appearing to be in the same condition as that just mentioned. 
 However, on the following day, four days after the operation, 
 the animal was first tested with foods placed in different parts 
 of the cage, with foods held in different visual segments and 
 with foods outside the cage, the animal reacting at all times fairly 
 quickly and accurately and at no time making errors in adjust- 
 ment of more than one cm. After these tests (the monkey 
 being not absolutely hungry) the tests with colored bread were 
 made, and in the ten trials the monkey did not select the yellow 
 bread once, and took only the red. It appears likely, therefore, 
 that the errors made on the second day following the operation 
 may have been due to hunger, any food being preferable to the 
 animal than no food. The results of this test are particularly 
 instructive, especially when they are considered in conjunction 
 with the results of the similar tests with Monkey 7. With 
 Monkey 7, it will be remembered (page 91), the animal dis- 
 criminated the colored breads perfectly on the second day after 
 the operation, but on the third day it appeared to have lost the 
 ability. The latter result, in my opinion, is to be explained as 
 due to the fact that these tests were performed at the beginning 
 of the series of observations on that day, when the monkey had
 
 EXPERIMENTAL RESULTS 
 
 97 
 
 not been fed for 24 hours, and when it was very hungry. A 
 similar conclusion was drawn by me in regard to the monkey now 
 under consideration. In the first tests of discrimination reten- 
 tion, the experiments were performed after a period of food 
 abstinence, and the conclusion is drawn that the taking of both 
 foods at this time was due to the extreme hunger of the animal. 
 That this conclusion (or a similar one) is correct is evidenced by 
 the fact that the discrimination of the breads on the fourth day 
 following the operation was perfect from the first trial, and there 
 was no mistake, not even that of touching the yellow pieces of 
 bread. On the succeeding days the discrimination was perfect. 
 The animal was killed eight days after the operation to determine 
 the pathological condition. 
 
 FIGS. 88, 89, 90 and 91. Monkey 8. Lateral and mesial aspects of the 
 hemispheres, showing the course of the knne cuts and indicating the ap- 
 proximate extents of the lesions. Made from photographs. Slightly reduced. 
 
 At the autopsy, the brain was found to be in a healthy condi- 
 tion. The positions of the insertion of the knife into the hemi- 
 spheres were visible, and it appeared that the knife had separated 
 most of the occipital (visuo-sensory) lobe from the anterior part 
 of the brain. The appearance of the brain is shown in figs. 88 to
 
 SHEPHERD IVORY FRANZ 
 
 FIG. 92. Monkey 8. Gross appearance through part of one section of the 
 left hemisphere. Free hand, slightly enlarged. 
 
 FIGS. 93, 94, 95 and 96. Monkey 8. Microscopical appearance of frontal 
 sections, showing degenerations as indicated by the method of Marchi. On 
 the right side only part of one section was preserved, which probably corre- 
 sponds with section 95 on the left. Edinger drawing apparatus, slightly en- 
 larged.
 
 EXPERIMENTAL RESULTS 99 
 
 91, in which are indicated the general courses of the knife cuts. 
 The brain weighed 107 grams. 
 
 The brain was prepared for examination by the Marchi method 
 to show the fiber degenerations, and at the time of the 
 autopsy a drawing was made of one of the gross sections on the 
 left side, in which there appeared to be an extensive hemorrhage. 
 This is shown in fig. 92. At the time of the autopsy the right side 
 was cut in the same way as the left, but none of the sections) 
 showed the appearance indicated on the left. After hardening, 
 however, each of the three sections on the right was again di- 
 vided and an appearance similar to that on the left was found 
 on this side. In gross section the hemorrhage on the right side 
 appeared to be more extensive than that on the left, including 
 practically all of the white matter. At this time no sketch was 
 made of the extent of the lesion on the right side, and this is 
 especially unfortunate on account of the later accidental de- 
 struction of most of the posterior portions of this hemisphere. 
 In the process of hardening and infiltration, all of the pieces ot 
 the right hemispheres, with the exception of part of one, dis- 
 integrated in the celloidin, leaving a muddy residue and this part 
 of the brain was, therefore, not examined histologically. The 
 part of the right side which did not disintegrate probably corre- 
 sponds with section 95 on the left side, although this is not certain 
 because so much has been lost. 
 
 Following is the report of Dr. Lafora on the microscopical 
 findings: "Monkey 8. Section of the white substance, Marchi 
 method by Dr. Achucarro. On the left side the degeneration is 
 not very well marked because of the short time the animal was 
 permitted to live after the operation (eight days). Many fat 
 drops, however, are observed in the sections, and they are more 
 abundant in the radiatio optica, and in the fasculus longitudinal is 
 inferior. In the white substance near the cortex many fat drops 
 were also observed. From the study of the degenerated fibers, 
 it is not certain that all the optical fibers on this side have been 
 destroyed, but that many, perhaps most, have been affected by 
 the degeneration, there can be no doubt. The section on the 
 right side shows about the same degree of degeneration as those 
 on the left, and although none of the parts can be accurately dis-
 
 ioo SHEPHERD IVORY FRANZ 
 
 tinguished, it appears that this section corresponds with 95 on the 
 left side." 
 
 The report of Dr. Lafora indicates a marked destruction of 
 fibers on the left side which corresponds closely with what is to 
 be expected from the extent of the hemorrhages indicated in 
 figure 92. It is especially unfortunate that in this case the 
 hemorrhagic appearance on the right side was not drawn and that 
 the pieces of this hemisphere disintegrated and prevented a care- 
 ful histological examination. Sufficient is shown in the part of 
 the right side to show the marked degree of degeneration and to 
 indicate an amount of destruction of fibers (fatty degeneration) 
 corresponding with that on the left. 
 
 DISCUSSION OF RESULTS 
 
 The observations recorded in the foregoing pages show that 
 destruction of parts of the so-called visuo-sensory cortex is ac- 
 companied by derangements of a varied character, but of minor 
 degree when compared with those recorded by most previous in- 
 vestigators. Only one animal showed the marked visual dis- 
 turbances which are comparable with those which have been 
 reported by Munk, by Ferrier, by Schafer and by others, and in 
 this case the amount of destruction was much greater than in any 
 other animal, and the disturbance did not become marked for 
 some days after the operation. 
 
 The effects of the operations on the animals may be grouped 
 into four general classes: the general appearance of the eyes 
 and the ability of the eyes to move, the fields of vision, the dis- 
 crimination of objects and of colors, and the ability of visual- 
 motor coordination. In no case were all of these elements af- 
 fected, and in most of the animals, as has been noted, the amount 
 of disturbance was slight and was often limited to one of the 
 elements just enumerated. 
 
 Some of the animals showed pupillary disturbances imme- 
 diately after the operation. Three (monkeys I, 2, and 8) had 
 dilated pupils, but it is not possible to say definitely whether this 
 condition was due to the effects of the operation as such or to 
 the anesthetic. It is well known that following operations on
 
 DISCUSSION OF RESULTS 101 
 
 other parts of the body there may be pupillary disturbances, and 
 these have been taken to indicate the effects of the anesthetic. 
 In these monkeys we are also justified in concluding that the 
 dilation is the effect of the anesthetic, although in one case it 
 must be remembered that the pupils were not equally dilated. 
 In the case just mentioned the left pupil was decidedly larger 
 than the right, and this may have been a sequel of the operation, 
 although it is not possible to determine this with exactitude. The 
 fact that the other four animals did not show pupillary dis- 
 turbances would lead me to suppose that in the cases of mon- 
 keys i, 2, and 8 we had to deal with a chance condition, not with 
 one intimately associated with the destruction of the occipital 
 cortex. 
 
 It may be different, however, with the other eye movements. 
 Immediately after the operation monkey 2 showed a tremor of 
 the eyelids, and this was not the effect of the anesthetic, but an 
 effect undoubtedly due to the operation on the occipitals. After 
 the second operation on monkey i, I observed that its eyes were 
 turned inwards and upwards, and after the operation on monkey 
 8 the eyes were directed toward the right. In addition, monkey 
 8 showed a nystagmus following the operation, this condition 
 persisting for some time. It was also observed that at the time 
 of the operation on monkey 7, the occipital lobe being cut in this 
 operation, the right eye slowly rotated upwards and turned 
 toward the right at the time the section was being made. 
 
 These oculomotor disturbances were noticeable in only four of 
 the animals upon which operations were performed, and it can not 
 be concluded that they have a direct bearing upon the problem 
 of the functions of this area. It is known that stimulation of the 
 occipital lobes produces movements of the eye balls and of the 
 intrinsic eye muscles, and it is possible that the motor defects 
 are due to the destruction of the mechanism which, by its activ- 
 ity, produces corresponding movements. That the defects per- 
 sisted for only a few hours or a few days indicates however, that 
 the phenomena are due to an irritation rather than to a paralyzing 
 effect, and it is pertinent to consider the slow upward rotation 
 of the eye in monkey 7 at the time of the section as evidence of 
 this. This condition corresponds with what has been found by
 
 102 SHEPHERD IVORY FRANZ 
 
 some investigators upon stimulation of the occipital cortex, and 
 since it corresponds also with the more lasting (although transi- 
 tory) effects in monkeys i and 8, it is at present justifiable to 
 conclude that it is an irritative effect. 
 
 The general statement may be made that the operations did 
 not produce any alteration in the ability of the animals to dis- 
 criminate objects, for in all cases the animals were able to select 
 food and to pick over the floor of the cage for objects which 
 were later conveyed to their mouths. In only one case was there 
 any difficulty, and this animal did not show this difficulty im- 
 mediately after the operation, but only after a week. That all the 
 animals which had previously been trained to discriminate colored 
 breads were able to discriminate them after the operation is 
 evident from the records of the individual cases. It was unfor- 
 tunate that the tests of color vision after the operation could 
 not be performed in exactly the same way as they were performed 
 before the operation, but the results which were obtained with 
 the new methods speak plainly for the retention of the color dis- 
 crimination. In most of the cases the color tests were delayed 
 ' for at least two days following the operation, so that any general 
 shock effects of the operation might pass away and so that the 
 animal should be in as normal a condition as possible for the 
 tests. Even with this amount of time it was sometimes found 
 that the animal would not take the colored breads, and the tests 
 had to be made on a succeeding day. Monkey I discrim- 
 inated the colored breads two days after the first operation, and 
 three days after the second operation. Monkey 2 discriminated 
 the colored breads three days after the operation. Monkey 4 
 discriminated the colored breads two days after the operation; 
 monkey 5 did not work well during the first few days after 
 the operation, but showed color discrimination ability on the sixth 
 day, and similarly with monkey 6. Monkey 8 discriminated the 
 colored breads on the fourth day, and monkey 7 was tested on 
 the same days as the operations (two of which were performed 
 on this animal) and both times was able to select the proper 
 colors. From these results it can not be doubted that the ability 
 to discriminate colors remained after the extensive operations 
 which were performed, and it appears plain that the parts of
 
 DISCUSSION OF RESULTS 103 
 
 the brain which were destroyed have not the function of color 
 perception or of color discrimination. 
 
 In addition to the special color tests, general tests were made 
 with each animal, and the results of these general tests are in 
 agreement with the special tests of color which were made with 
 the breads. Even immediately after the operation, if the animal 
 was sufficiently recovered from the effects of the anesthetic, 
 there remained a marked ability to discriminate colored foods, 
 and in most cases the judgment of the animal was unerring. 
 When cotton wool, rolled into balls, was introduced into the 
 cages, the animals at times picked up this material and placed it 
 in the mouth, but this is exactly what a normal monkey does, 
 and the fact is not evidence of a lack of color discrimination or 
 a lack of discrimination of different foods. The selection of the 
 pieces of melon which in color closely resembled some of the 
 green pieces of bread, but did not resemble them in texture 
 (the visual quality of which is uncertain), the selection of tomato 
 instead of the red bread, and the selection of different foods 
 from each other, as shown particularly in the accounts of the 
 actions of monkeys 3, 4, 6, and 8, all indicate that the visual 
 discrimination of these animals remained approximately normal. 
 That the discrimination ability was not alone that of color is 
 shown by the results with monkey 3, which had been trained to 
 discriminate different sizes. This animal, it will be recalled, re- 
 tained this ability after the operation, and it can not be taken 
 as evidence other than that for the retention of the general abil- 
 ity of visual discrimination. 
 
 It would have taken too long a time to detail for each animal 
 all the observations which indicated the normal amount of dis- 
 crimination ability, but in addition to the observations which have 
 been recorded above, and others which have been contained in 
 the individual case histories, it may be well to indicate a few 
 other facts which were observed. Whenever the door of the ob- 
 servation cage was opened the animal immediately walked out. 
 In only one case was this discrimination ability disturbed, in 
 monkey 5, and this animal showed at the same time an almost 
 total loss of visual ability. When the operated animal was in- 
 troduced into a cage with a normal animal it immediately walked
 
 104 SHEPHERD IVORY FRANZ 
 
 over to the second animal, picked him or her over for dandruff, 
 and acted exactly like a normal unoperated monkey. In some 
 cases when a male operated animal had been introduced into a 
 cage with a female normal animal, he immediately mounted the 
 female for sexual congress. It was found possible to fool an 
 animal once or twice with cotton wool, but not more than this 
 number of times, and this fact indicates either the retention of 
 the discrimination ability it previously had or the retention of 
 the general ability to learn very rapidly to discriminate particular 
 objects. Whichever conclusion is considered correct makes little 
 difference, for both indicate a high degree of discrimination 
 ability. When food wrapped in papers or small wads of paper 
 were introduced into the cages, the operated animals did not place 
 the covered food or the wads of paper into the mouth, but pulled 
 away the paper from the food, or pulled apart the wad of paper. 
 In both cases there was a discrimination of the paper from food, 
 for it was the habit of the animals to place food immediately into 
 the mouth. When water was placed in the cages, most of the ani- 
 mals immediately stooped down to the dish and drank. In this 
 experiment there must have been the retention of a visuo-motor 
 habit, comprised of visual discrimination of the dish and the 
 movements of the body, or there must have been a very great 
 ability to discriminate slight degrees of variation of visual in* 
 ^. tensities or qualities. The threatening of strangers, a common 
 trick with these monkeys, was shown in almost every case, a 
 fact which also leads to the conclusion that there was an ability 
 to discriminate me from the other observers who came to see them 
 after the operations. 
 
 Some of the facts which have been cited above may also be 
 explained in another way, viz., that the discrimination took place 
 not because of a visual discrimination ability, but because of a 
 smell discrimination ability. This might apply to the threatening 
 attitude and to the behavior with another animal, but it can not 
 be stretched to include all the observations which have been 
 recorded. On the other hand, it may be said that the smell 
 component in monkey life is not as great as in the carnivora,. 
 and that these animals depend much more upon vision and upon 
 hearing. Smell ability may be taken to explain the ability to-
 
 DISCUSSION OF RESULTS 105 
 
 perform a certain isolated act, but it can scarcely be taken to 
 explain the ability of the animal to select unerringly five pieces 
 of melon or of pear from among a large number of other pieces 
 of food, since the animal did not place its nose near the food 
 but selected the food apparently by eye and hand. 
 
 The observations regarding the visual fields are with the ex- 
 ception of those on monkey 5 consistent. No constriction of the 
 field was found immediately after the operation in monkeys i 
 (after two operations), 2, 3, 4, 6, 7 (two operations), and 8. 
 In some of these animals there was what might have been taken 
 by a casual observer to be a constriction of the field, but in the 
 two monkeys in which such a defect was noticed, it was shown by 
 careful tests to be something different from a constriction of the 
 field. Monkey 3 showed a condition which has been inter- 
 preted as a diminution in visual acuity, because the animal was 
 able to select things in all fields but selected those in some of the 
 fields more readily than those in others. Monkey 4 showed an 
 inaccuracy in reaching for things held above and below the direct 
 line, but here we are dealing with a complex condition rather than 
 with a simple inability to see with a certain part of the retina. It 
 will be remembered that monkey 6 showed a similar defect after 
 six days, but that on the first few days after the operation there 
 was nothing to indicate a variation in the field of vision. 
 
 The movement phenomena were similar in all the animals. 
 The variations in movement are of two kinds, the time and the 
 accuracy. After the first operation monkey i was slow and 
 indecisive, and in grasping movements made errors of about 2.5 
 to 5 cm. Immediately after the second operation the animal was 
 slow and awkward, the movements were deliberate and inaccu- 
 rate, and in all these ways they were quite unlike those of a nor- 
 mal animal. Twenty-two hours after the operation on monkey 
 2, it was noted that the movements were inaccurate, the inac- 
 curacy lasting for about three days. Monkey 3 made a number 
 of unsuccessful attempts to grasp food which was presented to it, 
 and for a number of days the adjustment was not like that of 
 a normal animal. Monkey 4 was also inaccurate in the taking 
 of food, and monkey 5 was more inaccurate than any of the 
 other animals. The last named animal at first could reach food
 
 io6 SHEPHERD IVORY FRANZ 
 
 within 30 cm. of its body with a fair degree of accuracy, but 
 outside of this area the movements were slow and inaccurate. 
 This animal eventually became blind, and the results must be con- 
 sidered apart from those of the other seven animals which re- 
 tained their visual ability. All the other animals showed inac- 
 curacies, slowings and apparent indecisions. 
 
 These movement disturbances were found only in the proc- 
 esses in which the eyes had to contribute. They were not found 
 with the movements which were of a reflex type, they were not 
 found for movements which did not require the cooperation of 
 the eyes, and no paralyses or pareses of the eyes or of any of 
 the body muscles could be determined. 
 
 At first glance it may appear that we are here dealing with a 
 visual disturbance which is evidenced by the lack of adjustment 
 between the visual sensations and the movements of the arms and 
 hands in grasping, but a few words may be said upon this point. 
 Simple movements, such as those of grasping for food, depend 
 upon a number of factors, which for simplicity we may reduce 
 to three the sensory, the motor, and the associational. It is by 
 the proper combination of these that movements are performed 
 accurately and quickly. If by any means the connection is in- 
 terfered with (in the diaschisis sense of von Monakow), the 
 end result of the afferent stimulation shows an abnormality, 
 which may vary from a slowness or an inaccuracy to an apparent 
 motor loss. All movements depend upon two primary factors, 
 the motor and the sensory. If one of the two primary factors 
 be disturbed, the movement as a whole is affected. It makes no 
 difference in a general way which of the two primary elements 
 be affected, except that if the motor element be destroyed there 
 results a total paralysis. With the incomplete destruction of the 
 motor element and with the complete or incomplete destruction 
 of the afferent or sensory element, the general effect may be the 
 same, viz., an inaccuracy, a paresis, or a slowing in movement. 
 In the case of the reflexes the elimination of the sensory element 
 may even produce a complete loss, just as well as the total elim- 
 ination of the motor element. In the present work, however, we 
 have to deal with a motor disturbance, not with a motor loss, 
 and it is apparent that the effects can not be considered off-hand
 
 DISCUSSION OF RESULTS 107 
 
 as purely motor, and on the other hand, we must not conclude too 
 rapidly that the effects are purely visuo-sensory. 
 
 That the disturbances are not of a motor type is well shown 
 by the fact that other movements of a similar character were not 
 affected at the time of the operation. The movements of con- 
 veying food to the mouth were accurate and quick. They were 
 exactly like those of a normal animal, as far as this could be 
 determined, and there was no motor defect in any of the move- 
 ments concerned with parts of the body other than those of the 
 hands and arms. The movements of the head, of the eyes, and 
 even those of the hands and arms, when the animal did not have 
 to deal with the taking of food, and with other movements in 
 which the visual apparatus was involved, were well executed, 
 and were as quick as those of a normal animal. It was apparent 
 that the motor disturbances were associated movement disturb- 
 ances, and were those in which the eyes were involved. 
 
 Since the movements which were affected were those in which 
 the eyes were concerned as one of the afferent factors, we must 
 look to see whether or not this element (the eye) has been dis- 
 turbed and has produced the motor derangement. We have, I 
 think, the right to conclude that the skeletal muscles or the direct 
 motor control of these muscles have not been disturbed, be- 
 cause movements which did not involve the visual element were 
 executed well. On the other hand we also know that for the 
 execution of an accurate movement the afferent elements are 
 most important. Coordination and the production of accurate 
 movements are brought about largely through the association 
 of afferent impulses with the efferent, and in the coordination 
 there are many afferent elements associated. In connection with 
 the movements under discussion, the more important (possibly 
 the sole) sensory elements are the visual (including the sensa- 
 tions or perception of eye movements) and the musculo-tactile. 
 Several times in the case histories it was mentioned that animals 
 which exhibited an incoordination showed this especially for 
 movements of grasping objects at a distance from the body. 
 When, for example, objects were rolled toward the animal or 
 when the objects touched any part of the body, the animal made 
 quick and accurate movements, with a degree of coordination
 
 io8 SHEPHERD IVORY FRANZ 
 
 apparently normal. When, however, such objects touched the 
 body and bounded away the objects were not accurately grasped, 
 but the animal fumbled in the place on the floor where the food 
 had been, and in many cases was not able to locate the object 
 without great difficulty. At times, also, a monkey would give 
 up trying to secure the food which in rolling had touched the 
 body and had then bounded away, and it was evident that the 
 actual coordination of movements which were made with the 
 musculo-tactile element alone was not impaired but that the im- 
 pairment was due to some other element. In the case of the ani- 
 mal which eventually became practically blind (monkey 5) al- 
 though food which was held at a distance of about 10 to 15 cm. 
 from the head of the animal was not accurately grasped, other 
 food which touched the body or the body hairs was taken im- 
 mediately and accurately. Observations similar to these were 
 repeatedly made with all the animals, and in every case in which 
 there was a marked degree of incoordination or of inaccuracy 
 in adjustment when the food was held at a distance from the 
 body, there was no inaccuracy and no incoordination when the 
 food was held close to the body or when it was touching the 
 body hairs. 
 
 We are justified in concluding, therefore, that the movement 
 disturbances were due neither to a disturbance of the motor 
 process (muscles and motor impulses) alone, nor to the lack of 
 or to the disturbance in physiological connection between the 
 motor impulses and the tactile and muscular sensations. In view 
 of this conclusion we are forced to conclude that the disturb- 
 ancesjwere due to a nervous factor connected with the visual 
 apparatus. Here there are two sensory elements which may have 
 a part in the disturbance the true visual and the movement. 
 The retention of the ability of visual discrimination speaks 
 against the view that the disturbance was due to a true visual 
 disturbance, for we are unable to say that there has been in 
 these cases any constant visual disturbance of the nature of an 
 amblyopia, nor even of the nature of a lessened irritability (in 
 the sense of Loeb). On the other hand, there is nothing distinc- 
 tive in the results which absolutely excludes this factor, except 
 that we have found none of the animals unable to distinguish dif-
 
 DISCUSSION OF RESULTS 109 
 
 ferent kinds of food which have had very similar color and light 
 qualities. If this element were the important one, I should 
 expect to find that the animals would not be able to distinguish 
 one kind of food from another which has a similar color and 
 a similar brightness. This discrimination of food was found to 
 be intact in all animals, and the only observations which may 
 be taken to negative this conclusion are those of Dr. Barnes 
 (p. 86). With these conclusions of Dr. Barnes I do not agree, 
 as I have indicated in the proper place. It appears to me unlikely 
 that a lessened irritability (which must be shown by a lessened 
 discrimination ability) should have been present in all the animals 
 which showed the movement disturbances, for, as has been said, 
 all the animals were able to distinguish one kind of food from 
 another, and each animal made a selection of food when dif- 
 ferent kinds were presented simultaneously. If this factor be 
 excluded, as I believe it should be from the evidence at hand, 
 there remain only two elements which might have contributed to 
 the disturbance. These elements are the sensations of the move- 
 ments of accommodation (i. e., of the lens, etc.) in the focussing 
 of the images on the retina, and the sensations arising from the 
 movements of the extrinsic eye muscles. We have very indirect 
 evidence of the part which the two afferent motor processes took 
 in the disturbances in the monkeys. Observations were made of 
 pupillary changes in some of the animals, and of pathological con- 
 ditions of the extrinsic eye muscles, but none of the conditions 
 was constant. We are unable to determine the sensory losses 
 in these fields in animals, on account of the lack of information 
 which the animal can give us, and on account of the inability to 
 judge of the focussing and of accommodation abilities of the 
 animal. The evidence is too general to exclude one of these fac- 
 tors and it appears to me that the only conclusion which, under 
 the circumstances, is warranted is that the motor disturbances 
 are due to the loss of or to defects in the sensational elements from 
 the oculo-motor apparatus. That the eye ball movements and the 
 movements of accommodation may remain normal even after the 
 destruction of the corresponding cortical center is not unlikely, 
 for we know that these movements are reflex, and are only affect- 
 ed in a general way by the activity of the cortex. If the corpora
 
 no SHEPHERD IVORY FRANZ 
 
 quadrigemina remain intact the eye movements may remain al- 
 most normal, and they may be produced in such a way that the 
 impression is obtained of complete and normal cortical control. 
 This, I believe was the condition in the monkeys which I studied. 
 
 It is unfortunate that the work of Vitzou and that of Panici 
 are not accompanied by illustrations of the extents of the lesions 
 in the animals upon which they operated, for their physiological 
 results have certain relations with the present work, which can 
 not be discussed fully without the accurate description of the 
 lesions. We do know enough, however, to be able to say that their 
 results resemble those recorded in the foregoing paper to an 
 extent unlike those of previous investigators with the possible 
 exception of those of Ferrier. The accounts of Ferrier's mon- 
 keys with occipital lesions (see pp. 14-16) read much like 
 those given by me and by the other observers who had an oppor- 
 tunity to study the animals carefully after the operations. It 
 will be remembered that Ferrier's animals could see although the 
 occipitals were extirpated, they ran away when they were ap- 
 proached, they avoided obstacles which were in their path, and 
 one animal was able to see sufficiently well two hours after the 
 operation to be able to pick up particles of food from the floor 
 of the cage. 
 
 In view of the possibility of the establishment of new paths, 
 possibly though lower centers, it is not surprising that Vitzou's 
 animals were able to recover to a larger extent their visual ability, 
 but it must not be understood that the recovery was complete, and 
 in fact there is nothing in Vitzou's work to indicate the possibility 
 of discrimination of a high degree. The fact that animals may 
 relearn habits after the frontal lobes have been extirpated was 
 interpreted by me to be due to the formation of new paths, and 
 it appears to me most likely that Vitzou's animals also formed 
 new paths for certain visuo-motor habits, even though the occipi- 
 tals were destroyed. 
 
 The results obtained by Panici are most nearly like those re- 
 corded in the foregoing paper, but from the accounts of the ani- 
 mal activities it is impossible to determine how much of the 
 visual functions, which he judged were retained, were retained 
 because of the lower reflex connections, and how much real dis-
 
 DISCUSSION OF RESULTS m 
 
 crimination ability was retained. The criticism of the work of 
 Goltz applies here as well as it did to the original work, and it 
 may be said again, as von Monakow has said, that the retention of 
 simple eye movements, or even of simple visual-motor habits, etc., 
 does not indicate whether or not there has been a retention of 
 vision in the sense in which this term is properly used. There is 
 undoubtedly a connection between the eyes and certain motor 
 centers, but we are not able to say that discrimination has taken 
 place, and without evidence of visual discrimination the interpre- 
 tation that visual functions per se remain will not stand. 
 
 The consideration of the results recorded by me, with those 
 which have been recorded by Ferrier, by Vitzou and by Panici, 
 lead directly to the conclusion that previous investigators who 
 have assigned to the occipitals a visual function have destroyed 
 large portions of the lobe, and have been content to assign a 
 visual function to its several parts as a whole without dividing 
 it into individual elements. The conclusion is forced upon us 
 that the lateral parts of the occipital lobes, which also have the 
 calcarine type of cortex, have not a true visual function but a 
 function in connection with the afferent impulses from the eye 
 muscles. This, it will be noted, is not inconsistent with the results 
 of previous investigators, although it is opposed to the conclusion 
 that the whole occipital portion of the cerebrum is visual in func- 
 tion, and although it is opposed to the conclusion that in this 
 portion there is a projection of the retina, such as Henschen be- 
 lieves.
 
 SHEPHERD IVORY FRANZ 
 
 SUMMARY AND CONCLUSIONS 
 
 The monkey readily learns to discriminate colors if the colors 
 are parts of objects to which the animal attends. 
 
 Extirpation of the lateral parts of the occipital lobes does not 
 interfere with color discrimination. 
 
 Extirpation of the lateral parts of the so-called visuo-sensory 
 cortex in the monkey does not produce disturbances of a true 
 visual character. 
 
 The destruction of the lateral parts of the occipital lobes is 
 followed by disturbances in coordination of movements which 
 are based upon the sensations from the eye and its appendages. 
 
 The disturbances in coordination are not due to a lack or to 
 a loss of the true visual element, but to a lack or to a loss of the 
 afferent motor elements, viz., those from the intrinsic or from 
 the extrinsic eye muscles. 
 
 One animal in which the cortex surrounding the calcarine fis- 
 sure was destroyed showed a true visual disturbance correspond- 
 ing with those described in man.
 
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