267 



quadruped, and becomes perhaps the principle of their sociability. The 

 books of travellers and naturalists swarm with facts, attesting the won- 

 derful sagacity of the elephant. Some Indian philosophers have gone the 

 length of allowing him an immortal soul. If birds, notwithstanding the 

 prodigious activity of their life of nutrition, are yet of such confined in- 

 telligence, so little susceptible of durable attachment, so restive to educa- 

 tion, is not the cause to be assigned to their imperfection of touch ? In vain 

 the heart sends towards all their organs, with more force and velocity 

 than any other animal, a warmer blood, and endued, more remarkably, 

 with all the qualities which characterize arterial blood. In vain is their 

 digestion rapid, their muscular power lively, and capable of long continu- 

 ed motion; certain of their senses, as those of sight and hearing, happi- 

 ly disposed; touch being almost nothing with them, as also the greater 

 number of impressions belonging to this sense, which informs us of the 

 greater part of the properties of bodies; the circle of their ideas must 

 be extremely narrow, and their habits, and manners, much more remote 

 than those of quadrupeds, from the habits and manners of man. 



CXXXVI. Of all the senses, the touch is the most generally diffused 

 among animals. All possess it. from man, who, in the perfection of this 

 sense, excels all the vertebral animals, to the polypus, who, confined to 

 the sense of touch only, has it, in such delicacy, that he appears, to use 

 a happy expression of M. Dumeril, to feel even light. The skin of man 

 is more delicate, fuller of nerves than that of the other mammiferas: its 

 surface is covered only by the epidermis, insensible indeed, but so thin 

 that it does not intercept sensation, whilst the hairs which cover so thick- 

 ly the bodies of quadrupeds, the feathers which* clothe that of birds, quite 

 deaden it. The hand of man, that admirable instrument of his intelli- 

 gence, of which the structure has appeared to some philosophers* to ex- 

 plain sufficiently his superiority over all living species: the hand of man, 

 naked, and divided into many moveable parts, capable of changing, 

 every moment, its form, of exactly embracing the surface of bodies, is 

 much fitter for ascertaining their tangible qualities, than the foot of the 

 quadruped enclosed in a horny substance, or than that of the bird, covered 

 with scales too thick not to blunt all sensation. 



CXXXVII. Of the nerves. These whitish cords, which arise from the 

 base of the brain, and from the medulla oblongata, are distributed to all 

 parts of the body; and give them, at once, the power of moving and feel- 

 ing. In this analysis of the functions of the i>ervous system, the most 

 natural order is to consider them merely as conductors of the power of 

 sensation. We shall then see, in what manner tfiey transmit the princi- 

 ple of motion to the organs by which it is performed. The nerves arisef 

 from the sentient parts, by the extremities that are, in general, soft and 



* See the work of Galen, de usu partium, cap. 4, 5, 6, and BuflTon, Histoii". C\'ulureUe 

 torn. IV. etV. 12mo. 



y In considering the nerves as conductors of sensation, it is correct to say, that they 

 arise from sentient parts, since it is the extremity rnost distant from the brain, \vhich 

 experiences the sensitive imjnvssion, that it is propagated to the organ itself, along- the 

 course of the nerve. In attending, on the contrary, to tue phenomena of motion, the 

 nerves are considered to arise from the brain ; for] it is> from the centre of the circum- 

 ference, thst the principle of motion is transmitted to the muscles called, by Cullen, 

 moving extremities of the nerves. Some anatomists have considered it as a doubtful point', 

 whether the nerves arise from the brain and spinal marrow, or whether these parts are 

 formed by the union of the nerves. Authors Note. 



