256 SECRETION. 



" The liquor amnii of pregnancy, and the urine, remarkable 

 for the peculiar nature and mixture of its proper constituents, 

 are generally enumerated among these. 



" The salivary fluids, concerned in mastication, digestion, and 

 chylification, appear more elaborated. 



" Next the mucous, which line the cavities of most of the 

 organs performing the natural and genital function s.and likewise 

 the tract of the nostrils, larynx, and trachea. 



" The mucus within the eye, and under the epidermis, is nearly 

 similar. 



" In the same class may be included the cerumen of the ears, 

 the unguent of the Meibomian glands and of the joints, and, 

 perhaps, the ambiguous and nameless fluid commonly poured 

 forth by the vagina during the venereal cestrum." Mucus 

 contains an abundance of hydrochlorate of soda, and differs in 

 different parts. That of the nostrils and bronchiae at first coagu- 

 lates in nitric acid, and at last dissolves ; that of the gall-bladder 

 coagulates by acids and alcohol ; that of the urine coagulates by 

 tannin, but not by acids, is very soluble in alkalies, and dries red. 



" The adipose are, besides the common fat, the medulla of the 

 bones and grease of the skin. 



" Related to these are the secretion of the corona glandis under 

 the praeputium, and of the external female genitals. 



" The truly serous, or albuminous, are the fluid of the ovarian 

 vesicle of De Graaf, and the liquor of the prostate. 



" The semen virile and the bile are each sui generis" b 



b Dr.Bostock arranges the productions of nutrition and secretion as the aqueous, 

 albuminous, mucous, gelatinous, Jibrinous, oleaginous, resinous, and saline. {An 

 Elementary System of Physiology, vol. ii. p. 329. sq.) 



The aqueous are the perspiration and pulmonary halitus, in which the propor- 

 tion of water is so great as to give the chief character. 



The albuminous, all the membranous or white parts of animals, the fluids of 

 serous membranes and of the cellular membrane, the former differing from the 

 albumen of the blood chiefly in being freed from extraneous matter and coagu- 

 lated ; the latter from serum, chiefly in containing much less albumen. 



The mucous are the mucus of all mucous membranes, the saliva, gastric juice, 

 tears, and semen. The animal matter which is their basis much resembles co- 

 agulated albumen, and their salts are neutral, while those of the albuminous 

 fluids are alkaline. 



The gelatinous are named from containing jelly, a substance not found in 

 the blood nor any of the fluids, but abundantly in membranes, and particularly 

 in the skin ; and as albumen may be converted into it by digestion in dilute 

 nitric acid, it appears to be the albumen of the blood with an addition of oxygen 



