OF ANIMALS. 



167 



them. Vaillant, wishing to preserve a locust of the Cape of Good Hope, 

 took out the intestines, and filled the abdomen with cotton, and then fixed it 

 down by a pin through the chest ; yet after five months the animal still moved 

 its feet and antennas. 



In the beginning of November, Redi opened the skull of a land-tortoise, and 

 excavated it of the whole brain. He expressly tells us that the tortoise did 

 not seem to suffer : it moved about as before, but groped for its path, for the 

 eyes closed soon after losing the brain, and never opened again. A fleshy 

 integument was produced, which covered the opening of the skull, but the in- 

 stinctive power of the living principle was incompetent to renew the brain, 

 and in the ensuing May, six months afterward, the animal died.* 



Spallanzani has incontestibly proved that the snail has a power of repro- 

 ducing a new head when decapitated : but it should be remarked that the 

 brain of the snail does not exist in its head. 



I will not pursue this argument any farther ; it is in many respects painful 

 and abhorrent ; and consists of experiments in which I never have been, and 

 trust I never shall be, a participant. But I avail myself of the facts them- 

 selves in order to establish an important conclusion in physiology, which I 

 could not so well have established without them. 



Let us turn to a more cheerful subject, and examine a few of those pecu- 

 liarities in the external sense-s which characterize the different classes and 

 orders of animals, so far as we are acquainted with such distinctions ; and 

 admire the wisdom which they display. 



The only sense which seems common to animals, and which pervades 

 almost the whole surface of their bodies, is that of general touch or feeling; 

 whence M. Cuvier supposes that the material of touch is the sensorial power 

 in its simplest and uncompounded state ; and that the other senses are only 

 modifications of this material, though peculiarly elaborated by peculiar 

 organs, which are also capable of receiving more delicate impressions. f 

 Touch, however, has its peculiar local organ, as well as the other senses, for 

 particular purposes, and purposes in which unusual delicacy and precision 

 are required ; in man this peculiar power of touch is well known to be seated 

 in the nervous papillae of the tongue, lips, and extremities of the fingers. Its 

 situation in other animals I shall advert to presently. 



The differences in the external senses of the different orders and kinds 

 of animals, consists in their number and degree of pnorgy. 



All the classes of vertebral animals possess cne same number of senses as 

 man. Sight is wanted in zoophytes, in various kinds of moluscous and articu- 

 lated worms, and in the larves of several species of insects. Hearing does not 

 exist, or at least has not been traced to exist, in many molluscous worms, 

 and several insects in a perfect state. Taste and smell, like the general and 

 simple sense of touch, seem seldom to be wanting in any animal. 



The local sense of Tour^, however, or that which is of a more elaborate 

 character, and capable of being exercised in a higher degree, appears to be 

 confined to the three classes of mammals, birds, and insects : and even in the 

 last two it is by no means common to all of them, and less so among insects 

 than among birds. 



In apes and macaucoes, constituting the quadrumana of Blumenbach, it 

 resides partly in the tongue, and tips of the fingers, as in man, but equally, 

 and in some species even in a superior degree, in their toes. In the racoon 

 (ursus loior) it exists chiefly in the under surf^ace of the front toes. In the 

 horse and cattle orders, it is supposed by most naturalists to exist conjointly 

 in the tongue and shout, and in the pig and mole to be confined to the snout 

 alone ; this, however, is uncertain ; as it is also, though there seems to be 

 more reason for such a belief, that in the elephant it is seated in the proboscis. 

 Some physiologists have supposed the bristly hairs of the tiger, lion, and 

 cat, to be an organ of the same kind ; but there seems little ground for such 

 an opinion. In the opossum (and especially the Cayenne opossum) it exists 



* Dalzeirslntrod. to his Transl. of Spallanzani, p. xlv. 



t Anatom. Comparat. i. 25, 



