594 



TPIE TISSUES. 



medullary portion is plfysiologically distinct from the former, and 

 must be regarded as an apparatus pertaining to the nervous system, 

 as Bergmann suggested. And Leydig's recent investigations in 

 regard to the structure of these organs in fishes and reptiles, have 

 led him to conclude that they have the same relation to the gan- 

 glia of the sympathetic nerves, that the pituitary body bears to the 

 brain (p. 465). 



CHAPTER XVIII. 



THE OKGANS OF THE SENSES. 



THE histological elements of the organs of the senses have already 

 been mostly described. 



I. The organ of touch the skin in Chap. XL (pp. 476494.) 



II. The organ of taste the mucous membrane of the tongue 

 pp. 515-18, and Figs. 344 to 347. 



Pi* 421. 



General view of the external, internal, au,l middle ear, as seen in a prepared section through o, 

 the auditory canal ; b, the tympanum or middle ear ; c, Eustachian tube, leading to the pharynx ; 

 d, cochlea ; e, semicircular canals, and vestibule, seen on their exterior as brought into view by 

 dissecting away the surrounding petrous bone. The styloid process projects below; and the inner 

 surface of the carotid canal is seen above the Eustachian tube. (From Scarpa.) 



