4:6 SECRETION. 



the proportions were 948*54: of water to 51*4:6 of solid matter. 

 In the latter the fluid was more viscid, and contained a 

 larger proportion of synovine with a smaller proportion of 

 salts. It was also more deeply colored, and contained a 

 larger number of leucocytes. 1 



Like the serous fluids, the synovial secretion is produced 

 by the general surface of the membrane and not by any 

 special organs. The folds and fringes which have been 

 described were supposed at one time to be most active in 

 secreting the organic matter, but there is no evidence that 

 they have any such office. 



The aqueous humor of the eye and the fluid found in the 

 labyrinth of the internal ear resemble the serous secretions 

 in many regards ; but these fluids, with the vitreous humor, 

 will be considered in connection with the physiological anat- 

 omy of the eye and the ear. 



Mucus. 



Mucous Membranes. The mucous membranes in dif- 

 ferent situations present important peculiarities in structure, 

 many of which have already been considered. We have 

 described, in detail, in the preceding volumes, the mucous 

 membrane of the air-passages and of the alimentary canal, in 

 connection with the subjects of respiration and digestion ; 

 and the membranes in other parts will necessarily be de- 

 scribed in treating of the physiology of the organs in which 

 they are found. It will be sufficient at present to take a 

 general view of the structure of these membranes and the 

 mechanism of the production of the various fluids known 

 under the name of mucus. 



A distinct anatomical division of the mucous membranes 

 may be made into two classes, as follows : First, those pro- 

 vided with pavement-epithelium ; and second, those provided 



1 FRERICHS, in WAGNER, Handworterbuch der Physiologic, Braunschweig, 1846, 

 Band iii., S. 467. 



