TBM ORGANS OF SENSE. 511 



§ 1393. The demonstration of the cranial nerves requires 

 much care and skill on account of the great number crowded into 

 small space, and also because they pass through various bony 

 canals and foramina or are concealed by bony processes. The 

 beginner can hardly hope to demonstrate all satisfactorily on one 

 specimen. It is especially necessary to employ a young lean ani- 

 mal, in order that fat may not oljscure the nerves and that the con- 

 nective tissue may not be so tough as to render the tracing of fine 

 nerves impossible. The general directions for dissecting nerves 

 given in §§ 1008, 1037, should be faithfully foUowed. Some of the 

 nerves may be traced on one side and some on the other. When- 

 ever a saw is employed, it is best to protect underlying parts if 

 possible by a cloth. In case a vessel or nerve is inadvertently sev- 

 ered, the two ends may be slightly lapped and tied with a thread. 

 The nippers employed should be sharp and narrow pointed (§ 146). 

 In using the nippers, remove Yevj small pieces, and use the tracer 

 often to make sure that all branches are pushed aside. Have at 

 hand for constant reference a prepared skull, the figures of the skull 

 (Pig. 56-62), and the Tables of foramina (§ 562) and nerves (§ 1392). 



THE OEGANS OP SENSE. 



§ 1394. The organs of sense are the specialized parts of animals 

 which, being acted upon by objects in the external world, are capa- 

 ble of transmitting the impressions so received to the central ner- 

 vous system by means of nervous connections. Huxley, S. 



The organs are five, corresponding to the five senses. 



(A) Cutis and mucosa. — The skin, and mucous membranes near 

 the exterior (Dalton, A, 510). These are the organs of Touch (tac- 

 tion, tactile sensibility). 



(B) Lingua (tongue). Soft Palate and Fauces, — These are the 

 organs of Taste (gustation, gustatory sensibility). 



(C) Nasus, nose.— Its mucous membrane, especially that of the 

 maxillo-turbinals, forms the organ of Smell (olfaction, olfactory 

 sensibility). 



(D) Oculus, eye.— The organ of Vision (sight or visual sensi- 

 bility). 



(E) Auris, ear. — The organ of Hearing (audition or auditory 



sensibility). 



(F) General Sensibility. — In addition to the special sensibilities 



