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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



is in the striated bodies, all those nervous acts 

 take their place which have to do with the elab- 

 oration of perceptions, with the extraction of the 

 ideas we draw from them, with the resolutions 

 which these impel ; that is to say, the intellect in 

 all it possesses, which is great, superior, " divine," 

 to use Plato's expression. The notion that the 

 soul might have an exact place in the brain does 

 not belong to materialists. Descartes decides 

 that it is lodged in the " pineal gland," a kind 

 of appendage resembling a tiny pineapple, sup- 

 ported on a slender stem. What is more sin- 

 gular is, that our philosopher never saw that or- 

 gan except in animals, particularly in calves, to 

 which he denies a soul, though in fact he places 

 a part of their memory in it. We find him, how- 

 ever, in 1647, at Leyden, assisting in the dissec- 

 tion of a woman. This is the only time, we be- 

 lieve, that he was actually in presence of a "sub- 

 ject," and that day he was unfortunate, in failing 

 to discover the pineal gland. An old professor, 

 named Vallcher, was equally unlucky, and he 

 must have been a very ignorant man, for he as- 

 sured the philosopher that he had never been 

 able to see that organ in a human brain ; but 

 Descartes, with some appearance of reason, at- 

 tributes the good man's ill-success to the ad- 

 vanced state of the subjects he used in his demon- 

 strations. It was of no consequence, at any rate ; 

 the philosopher had long had his ready-made 

 system as to the seat of the soul, as may be seen 

 from his correspondence, and he was not a man 

 to give it up so easily. The reason that decides 

 him is that the pineal gland occupies nearly the 

 centre of the brain. According to Chrysippus, 

 too, the soul must dwell in the heart, since that 

 is in the centre of the body, and Galen even rid- 

 icules the partisans of that doctrine by asking 

 them to observe that on that ground it ought to 

 be the navel, which is much more central than 

 the heart. The pineal gland is immovable in its 

 place, and confined as it were in a kind of fibrous 

 net, which envelops it in its meshes. " No mat- 

 ter," said Descartes, "the soul is mobile, the part 

 in which the soul dwells must be so, too ; " and 

 then he represents the pineal gland erecting itself, 

 bending to right or left, trembling on its stem, 

 " because this must be so." 



Descartes had made many dissections during 

 his life. We may say that he had a very strong 

 feeling that the secret of man's nature must be 

 inquired into through the conformation of the or- 

 gans ; but this feeling was. always led astray in 

 him by the magisterial presumption of the meta- 

 physician. The story of his house at Eymond is 



well known. A gentleman paying him a visit here, 

 asked to see his library, and begged him to tell 

 him what were the books on physics which he most 

 prized and habitually read. Descartes, to gratify 

 his visitor's curiosity, took him into a room which 

 he had had arranged for dissections, and, drawing 

 aside a curtain, showed him the foetus of a cow, 

 and his scalpels all prepared. " There," said he, 

 " this is my library, and this is the study which I 

 am now most devoted to." His biographer, Bail- 

 let, takes care to remark that this reply was not 

 at all " unworthy of Descartes's condition." It is 

 certain that it made much noise, some classing it 

 among the rarest apothegms, others only seeing 

 in it the proof of the blindest conceit. Yes, that 

 is, in truth, the book ; but one must know how 

 to read it, and in opening it Descartes shut his 

 eyes beforehand. When younger, he had studied 

 the eye very thoroughly, because he had no other 

 prepossession to prevent his seeing in it an instru- 

 ment in physics; he also studied the heart, the ma- 

 chine that impels the blood. Unfortunately, if the 

 camera of the eye and the heart with its valves 

 had a plain meaning for the geometrician, the 

 metaphysician talks nonsense in presence of the 

 brain to an amazing extent. The notes of Des- 

 cartes found among Leibnitz's papers show the 

 importance he attached to anatomical studies ; 

 but they show, too, a special impotence in this 

 genius, to whom, by a strange caprice of Nature, 

 biology necessarily remained a science absolutely 

 closed. His admirers say that he excelled in the 

 analysis of the passions ; they forget that this 

 study requires a solid basis which was not then 

 attained. There is no reason to fear that future 

 acquisitions will do more than has already been 

 done for the complete destruction of everything 

 on the works of that immortal geometrician that 

 relates to the science of life. 



The pineal gland is not even of a nervous 

 structure; it is a true gland, like those that se- 

 crete saliva or bile. It has nothing to do, there- 

 fore, directly, at least, with the purely nervous 

 phenomena of the brain. Physiologists are now 

 pretty generally agreed in lodging in the layer of 

 gray matter spread over the brain's surface the 

 seat of all those conscious acts which we cannot 

 define, and must designate, as well as may be, by 

 the names of thought, memory, imagination, rea- 

 son, will, -recollection, reverie, and dream. Physi- 

 cians are quite well aware that the mental de- 

 bility of old age, the imbecility consequent on 

 intemperance, and many cases of insanity, are 

 marked by deep changes in the inner structure of 

 this superficial gray layer. The results given by 



