242 MUCOUS SYSTEM. 



*fl. The dried membrane coagulates it. 



Q. In what is the peculiar sensibility of the mucous 

 texture seated ? 



#. In the papillae of the mucous chorion. 



Q. In what part of the mucous tissue does functional 

 power, such for example as the secretion of gastric juice, 

 reside ? 



t#. In the vascular net-work at the base of the villi, 

 not in the villi themselves, as has been supposed. The 

 villi are adapted to sensibility, not to secretion. 



Q. What experiment decided the function of the villi ? 



#. Irritate the villi after removing the epidermis, and 

 great pain is felt; introduce an instrument so as to irritate 

 the internal surface of the chorion, and no pain is felt. 

 The base of the papillae is nervous, and the papillae receive 

 the impression of foreign bodies. 



Q. Are these papillae susceptible of erection? 



#. Certain portions, as the tongue and nose, are sup- 

 posed to have an erectile capacity, somewhat resembling 

 the corpus cavernosum penis. 



Q. Whence proceeds the mucus which lines this texture? 



*ft. From the glands called mucous. They are found un- 

 der the chorion; they are largest in the velum palati and 

 mouth, and they are rounded in form. 



Q. What difference is observable in the serous and 

 mucous fluids? 



*#. The mucus is secreted; the serum exhaled. 



Q. If the glands are seated beneath the chorion, how 

 are they excited to secretion by foreign bodies? 



*#. These bodies irritate the extremities of the ducts 

 which convey the mucus, and thus the glands are irri- 

 tated. 



