198 ANATOMY AND PHYSIOLOGY. 



TOUCH. 



The sense of touch is diffused over almost the whole external 

 surface of the body, but is possessed in greatest delicacy by certain 

 parts, such as the lips, and the ends of the fingers. When the 

 innermost layer of the skin is examined with a microscope, it pre- 

 sents numerous projecting points, or papilla, to each of which it is 

 probable a branch of a sensitive nerve is sent, as they are seen in 

 greatest numbers where the sense is most acute. To exercise this 

 sense in perfection, it is requisite that the organ should be so 

 constructed as to be capable of being readily applied to bodies, in 

 a variety of directions ; and it is in the human hand that this quality, 

 the distribution of the sensitive nervous filaments, and a thin cuticle 

 covering these,' are united in the highest degree. 



The late Dr. Thomas Brown, professor of moral philosophy in 

 Edinburgh, contended that touch gives us no, or at least very im- 

 perfect, ideas of extension or sp'ace, and of hardness or solidity. 

 Our ideas of these, he thought, are principally derived from what he 

 calls muscular sensations. Connected with this point, we may 

 remark, that Francisco Csesario, although entirely deprived of sensa- 

 tion on one side, so that even cutting it gave him no feeling, could 

 yet, with the same, judge of the weight and consistence of bodies. 



A similar conjecture, as to the feelings derived from temperature, 

 seems to be supported by such cases as the following : A physician 

 of Geneva, after an attack of palsy, could be pricked or scratched in 

 the right hand or arm, without giving him any sensation. When, 

 however, he took a cold body into his hand, he felt it, but it appeared 

 to him lukewarm. Here the feelings of touch seem to have been lost, 

 but a deranged perception of temperature existed. 



The soft bodies of the lowest classes of animals are well fitted for 

 the exercise of the sense of touch, and it is doubtful whether many 

 of them possess any other. The organs of touch in insects, if, in- 

 deed, they are not allotted to some higher sense, are especially their 

 antennae or feelers, which, though in themselves minute, are gene- 

 rally feathered or radiated, so as to include parts too small for human 

 vision, and the sensations of which must be of an exquisitely delicate 

 nature. Huber, in his interesting work on bees, states, that it is by 

 feeling with the antenna? that they seem to direct their various 

 works in the interior cff the hive. If an insect be deprived of its 

 antenna?, it either remains motionless, or, if it attempts to fly, 

 appears bewildered. A queen bee thus mutilated, ran about, 

 without apparent object, as if in a state of delirium. 



