PROTEINS OF THE LENS. 619 



taining cysteine, disappears in part from the lens and is partly transformed 

 into albumoid. The relation between albumoid and crystallins is changed 

 with increasing age, so that the albumoid increases. In normal lens 

 the relation of the crystallins to the albumoid changes correspondingly 

 from 82:18 in youth to 41:59 in old age; in senile cataract the relation 

 can be changed to 25 : 75. The amount of fat, cholesterin and lecithin 

 is on the contrary not changed. 



The average results of four analyses made by LAPTSCHINSKY 1 of the 

 lens of oxen are here given, calculated in parts per 1000: 



Proteins 349.3 



Lecithin 2.3 



Cholesterin 2.2 



Fat 2.9 



Soluble salts 5.3 



Insoluble salts 2.4 



In cataract the amount of proteins is diminished and the amount of 

 cholesterin increased. This statement requires further substantiation. 2 



The quantity of the different proteins in the fresh moist lens of oxen 

 is, as follows, according to MORNER: 



Albumoid (lens fibers) 170 p. m. 



/3-Crystallin 110 " 



a-Crystallin *. 68 " 



Albumin 2 " 



The corneal tissue has been previously considered (page 550). The 

 sclerotic has not been closely investigated, and the choroid coat is princi- 

 pally of interest because of the coloring-matter (melanin) it contains 

 (see Chapter XV). 



Tears consist of a water-clear, alkaline fluid of a salty taste. Accord- 

 ing to the analyses of LERCH S they contain 982 p. m. water, 18 p. m. solids 

 with 5 p. m. albumin and 13 p. m. NaCl. 



THE FLUIDS OF THE INNER EAR. 



The perilymph and endolymph are alkaline fluids, which, besides 

 salts, contain in the same amounts as in transudates traces of protein, 

 and in certain animals (codfish) also mucin. The quantity of mucin 

 is greater in the perilymph than in the endolymph. 



Otoliths contain 745-795 p. m. inorganic substance, which consists 

 chiefly of crystallized calcium carbonate. The organic substance is very 

 similar to mucin. 



1 Pfliiger's Arch., 13. 



2 See Gross, Arch. f. Augenheilk., 55 and 58. 



3 Cited from v. Gorup-Besanez, Lehrbuch d. physiol. Chem., 4 Aufl., 401. 



