THE LENS. 
yield gelatin, [ts chief constituent is mucin, or mucinogen (Young), 
called mucoid by * '. T. Morner. According to the latter, this mucoid con- 
tains 12*27 nitrogen, and L*l 9 sulphur, per cent. There are also small 
quantities of proteid. References to the papers of Young and Morner, 
the most recenl workers on this subject, will be found on p. 62. 
The lens. — The following are the results of Laptschinsky's 1 
analyses : — 
Water . 
63*50 per cent. 
Cholesterin 2 . 
- 22 per cent 
Solids . 
. 36-50 „ 
Fats 
0-29 „ 
Proteids 
. 34-93 „ 
Salts 
0-82 
Lecithin 
. 0-23 „ 
Fig. "20. — Absorption spectra of retinal pigments. — 1, of visual purple : 2. of visual yellow ; 
3, of xanthophane in ether; 4, of rhodophane in turpentine; 5, of chlorophane in 
ether. This diagrammatic way of representing absorption spectra indicates the thick- 
Dess of the absorption-bauds in solutions of different strengths : the top of each 
spectrum shows the thickness of the bands in a dilute solution : as the concentra- 
tion of the solution increases, the bands become wider, as in the lower part of eaeli 
diagram. — After Kiihne. 
The proteid matter is thus very abundant; it is chiefly a globulin, to 
which Berzelius gave the name of crystallin. It has also been the 
subject of researches by Hoppe-Seyler, Laptschinsky, Kiihne, and C. T. 
Morner. 3 According to the last-named investigator, aboul 52 per cent. 
of the proteid matter of the lens is insoluble in water and saline 
solutions. The insoluble proteid residue is an albuminoid, and it is 
1 Arch. f. d. ges. Physiol., Bonn, Bd. xiii. S. 631. 
- The cholesterin increases greatly in cataract (Calm, Hoppe-Seyler's "Physiol. Chera.," 
S. 692). 
3 Ztschr. /. physiol. Chem., Strassburg. Bd. xviii. S. 61. 
