82 



SCIENCE. 



[Vol. XI. No. 26; 



no further than the cuxulatory system, it would throw a flood of 

 light on the significance of otherwise obscure if not absolutely in- 

 explicable phenomena. But it is to the nervous system that we 

 must look for evidence which places the doctrine beyond cavil to a 

 degree perhaps not equally clear in other parts of the economy. 



When a mammal is poisoned by curare, by which the nervous 

 influences normally reaching the tissues and regulating heat-pro- 

 duction (and, as I believe, nutrition) are wholly or partially cut off, 

 the mammal becomes virtually a cold-blooded animal. Its tem- 

 perature rises and falls with that of the ambient air. This is one 

 clear example of physiological reversion experimentally produced. 

 It is, however, only one of many that might be instanced. It is 

 well-known, and can be shown in the simplest manner, that when 

 the head of a frog is removed, reflex action is more readily excited : 

 the same applies to the removal of the cerebral lobes of the mam- 

 mal. As Goltz has pointed out, one of the most remarkable results 

 following removal of large portions of the cerebral lobes in the 

 dogs which this experimenter kept under observation, is, as I can 

 myself testify, the increase of reflex action. The animal becomes 

 a sort of machine, which one may manipulate at will. A similar 

 result follows in man when the higher centres of the cerebrum are 

 rendered functionally inactive by disease or injury. 



Now, in all these cases the animal loses its own peculiar charac- 

 ter, and sinks to the level of some form lower in the scale. All will 

 agree that the higher forms of true automatic (spontaneous) action 

 in the physiological sense are dependent on the existence of the 

 cerebrum. It follows, therefore, that the lower we pass in the scale 

 of life, the more machine-like animals become. 



Pathological reversion is most plainly illustrated by the results 

 of hemorrhage into the cerebrum. Dr. Hughlings-Jackson has so 

 well described the order and relation of the various events, that I 

 shall here quote his own words in describing lesions of the cerebrum 

 {corpus siriaitcm), from hemorrhage : — 



"It will be found that those parts suffer most and suffer longest 

 which have the more voluntary uses. This is notorious of the arm 

 and leg : the arm nearly always suffers more, and recovers later, 

 than the leg. Of course, the distinction into complete and incom- 

 plete hemiplegia is artificial. There are all degrees of paralysis 

 according to degrees of gravity of the lesion. But there is an order 

 in which paralysis increases in increasing gravity of lesions. We 

 observe that the graver the lesion, not only are the more voluntary 

 parts (arm and leg) 7nore paralyzed, but that the further spread in 

 range is the paralysis, and the method of its spreading is from the 

 more voluntary to the more automatic parts. Thus, neglecting 

 very small clots, a considerable lesion paralyzes only the most vol- 

 untary movements of one side of the body, those of the face, arm, 

 and leg, and these parts in degree according to their degree of vol- 

 untary use. A larger lesion not only causes a deeper and more 

 permanent palsy of these three parts, but it leads also to implica- 

 tion of more automatic parts. In still larger lesions the palsy 

 spreads to the most automatic parts of the body, even to parts sup- 

 plied by ganglionic nerves. It produces stertor from palsy of the 

 palate and palsy of the respiratory muscles and of the heart, — the 

 palsy of respiration and of the heart showing itself chiefly in slow- 

 ness of movement. There is also abasement of temperature." 

 — Reynolds's System of Medici7ie, vol. i. 



I have intentionally quoted the exact words of this eminent in- 

 vestigator of the abnormalities of the nervous system constituting 

 disease, so that their interpretation alone may rest with me. 



It being granted that the lower we pass in the scale of animal 

 life the more machine-like or automatic does the organism be- 

 come, it will be clear, that, taking the various degrees or grades of 

 paralysis as described above, we have likewise degrees of resem- 

 blance to lower forms ; i.e., the graver the paralysis, the lowerin the 

 scale must we seek to find an animal comparable to man in this 

 condition. The slowing of the heart and the lowering of the tem- 

 perature are both modes of approach to the normal functional con- 

 dition in cold-blooded animals. 



When we add to this, or take by itself, paralysis of the muscles 

 of the face, by which the expression peculiar to man is lost, we 

 have a condition plainly like that in lower mammals, and, in 

 extreme cases, even like that of the lower vertebrates, in which facial 

 expression as determined by muscular action is minimal. 



It must be conceded that the uneducated deaf-mute is in a con- 

 dition mentally much nearer that of the higher mammals than is 

 his uneducated fellow-man in possession of all his senses. But in 

 aphasia, the result of disease or shock, there is in man plainly a 

 marked reversion to a condition mentally resembling that in the 

 ' dumb-brutes ' about him. 



In the case of the idiot we have an example of man in many re- 

 spects inferior to the higher mammals. 



But it is not my intention to treat the subject of psychological 

 reversion in this paper. The subject is at once large, tempting, 

 and, to my mind, furnishes evidence the most conclusive for the doc- 

 trine of descent with modification from lower forms as an expla- 

 nation of man's nature. 



One naturally looks about for an explanation of such remarkable 

 facts as the order of muscular failure or paralysis as indicated in 

 the paragraph quoted above. The entire brain may be separated 

 from the medulla in a rabbit, and respiration still continue. The 

 lower we descend in the animal scale, the more do we find the 

 brain reduced to a mere repository for mechanisms adapted to 

 regulate those processes constituting the so-called vegetative func- 

 tions ; but the question again and again recurs, ' Why in mammals, 

 why in man, should the functions first to fail be those peculiar to 

 them or to him, and not the reverse ? ' 



The longer even in the lifetime of a single individual a certain 

 form of muscular action has been practised, the less attention is 

 required for its performance, the less voluntary, the more auto- 

 matic it becomes. But would the duration of man's existence on 

 this planet suffice to explain, on any system of gradual progression 

 or functional improvement, the wonderful automatic action of all 

 of those mechanisms essential to the maintenance of life ? 



The doctrine of descent renders the whole plain enough ; and 

 unless we adopt the view that man appeared suddenly and inde- 

 pendently upon the scene, fully equipped for the battle of life, it 

 seems but rational to assume that with all his departures, both by 

 way of progress and retrogression, his functions are what they are 

 by reason of such relationship as we are indicating. The morphol- 

 ogists have done much to account for the affinities of form or 

 structure in the animal series : it remains for the physiologists to 

 do their part in showing how the functions of the higher animals 

 are related to the functions of the lower. 



But once accepting this position, it is possible to explain phenom- 

 ena following experiments on animals, and growing out of the ex- 

 periments disease is producing, or, as I would prefer to say, the 

 phenomena which are the deviations from the normal that consti- 

 tute disease. Disease is no entity in itself, though we often use 

 language which might lead to the belief that we so conceived of it. 



When the normal adaptations to environment on which the very 

 existence of an animal depends are disturbed, what more natural 

 than that there should be a return to a functional condition preva- 

 lent in some ancestral group, or common to a host of such groups, 

 as the case may be ? T. Wesley Mills. 



BOOK -REVIEWS. 

 Animal Magnetism. By Alfred Binet and Charles Fere. 

 (Internat. Sclent. Series.) New York, Appleton. 12". 

 The nation that brought forth JVIesmer, . with his glittering dis- 

 play of charlatanry, has well atoned for this injury by bringing the 

 study of hypnotism into general scientific recognition, and develop- 

 ing with a remarkable activity our knowledge of this obscure re- 

 gion of the human mind. Nowhere are so many men of science 

 practically engaged in the study of hypnotic phenomena in all their 

 various manifestations, nowhere are subjects so plentiful or so in- 

 teresting, nowhere do we find so vast or so sound and constantly 

 increasing a literature devoted to this field, nowhere else a journal 

 devoted exclusively to the study of hypnotism, as in France. Al- 

 though much that has been developed there is doubtless destined 

 to be revised or rejected, yet the work is eminently scientific, and 

 with few exceptions the workers have never deserted the field of 

 painstaking, methodic study for the temptation of enlarging upon 

 remarkable facts, liable to attract the popular imagination. The 

 admission of a work on this subject into the International Scientific 

 Series is therefore eminently fitting, and it is also right that the 

 work thus honored should come from Paris, and more particularly 



