OF ANIMALS. 



177 



€ape 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 tor- 

 toise 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 instinctive power of the living principle was incompetent to 

 renew the brain, and in the ensuing May, six months afterwards, the ani- 

 mal died.'^ 



Spalanzani has incontestibly proved that the snail has the power of re- 

 producing 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 pain- 

 ful 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 themselves in order to estabhsh an important conclusion in physiology, 

 which f could not so well have established without them. 



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

 peculiarities in the external senses 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 feehng, 

 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 pecuHarly elaborated by 

 peculiar organs, which are also capable of receiving more delicate im- 

 pressions.! Touch, however, has its peculiar local organ, as well as the 

 other senses, for particular purposes, and purposes in which unusual deli- 

 cacy 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 ex- 

 tremities of the fingers. Its situation in other animals I shall advert to pre- 

 sently. 



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

 of animals consist in their number and degree of energy. 



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

 as man. Sight is wanting in zoophytes, in various kinds of molluscous and 

 arti'Tul ited worms, and in the larves of several species of insects. Hear- 

 ing does not exist, or at least has not been traced to exist, in many mollus- 

 cous worms and several insects in a perfect state. Taste and smell, like 

 the general ahd simple sense of touch, seem seldom to be wanting in any 

 animal. 



The local sense of touch, however, or that which is of a more elabo- 

 rate character Snd 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 tv^^o it is by no means common to all of them, and less so 

 among insects than among birds. 



Jn apes and macaucoes, constituting the quadrumana of Blumenbach, 



* Dalzell's Introd. to his Transl. of Spalanzani, p. xlv, 

 § Anatom* Comparat, i, 25. 



