452 AQUEOUS HUMOR. CRYSTALLINE LENS. [BOOK I. 



Aqueous Humor. 



This liquid which fills the anterior chamber of the eye is free from 

 all formed elements. Although the anterior chamber must be looked 

 upon as essentially a lymph space, and the secretion of the aqueous 

 humor like that of lymph is essentially dependent upon the arterial 

 pressure 1 , yet it possesses a very different chemical composition. 



Aqueous humor is a perfect transparent liquid of 

 roSe? specific gravity 10031009, possessed of alkaline 

 reaction. 



Aqueous humor contains a trace of a proteid matter 

 wtic1 } is stated by Ktihne to be fibrinoplastic, it also 

 contains about 4 parts per 1000 of extractive matters, 

 amongst which is urea, and from 7 to 8 parts per 1000 of mineral 

 matters. 



The following are the results of an analysis by Lohmeyer 2 of the 

 aqueous humor of a calf. 



Water per 1000 .... 986*87 



Proteids 1'22 



Extractive matters . . . . 4'21 



Sodium chloride . . . . 6 '89 



Other mineral matters . . . 0'81 



1000-00 



Crystalline Lens. 



The crystalline lens is composed of concentric layers of fibres, 

 which are essentially elongated cells, and which usually present more 

 or less marked serrated edges. The structure is bounded externally 

 by a capsule composed of a structureless membrane which appears to 



Eossess physical and chemical characters similar to those of the sarco- 

 jmma of muscle. 



The crystalline lens is not homogeneous, as its refractive index 

 increases as we pass from the more external to the more internal layers 

 an optical property which probably bears a relation to the fact 

 that the specific gravity of the central portion of the lens is, according 

 to Chevenix 3 , greater than that of the superficial layers, in the propor- 

 tion of 1194 to 1076. 



Chemical The lens contains about two-thirds of its weight of 



constituents water; its solid matters consist chiefly of a globulin 

 of the Lens. (about 24'6 p.c.) besides some serum albumin; in addi- 

 tion they contain small quantities of fat, traces of cholesterin and salts. 



1 Chawas, " Secretion des Humor aqueus im Bezug auf die Frage nach den Ursachen 

 der Lymphbildung." Pfliiger's Archiv, Yol. xvi. p. 143. 



2 See Gorup-Besanez, Lelirbuch d. phys. Chemie, 4to. ed. (1878), p. 401. 



3 Chevenix, quoted by Kuhne, Lehrbuch, p. 404. 



