144 NUNNELEY, ON THE CRYSTALLINE LENS. 
FISH (7 lenses). 
1. Cod . : . Lotte 
2. Ditto : : . Lalye 
3. Haddock . ; oe bel toy 
4. Ditto ° , . 11684 
5. Ditto . 5 - Life 
6. Holibut , : , iise3 
7. Ditto . ‘ . 11645 
7y8°2817 
Average ; », d:188l 
In estimating the sp. gr. of the lens it 1s essential that the 
eye should be perfectly fresh. If the animal has been dead 
any length of time the size of the lens is increased, but its 
sp. gr. lessened. If it has been preserved in dilute spirit its 
sp. gr. is diminished, while it is increased if it has been kept 
in Goadby’s solution, which answers so well for many tissues. 
The action of water at and above 160° F. is very uncertain. 
In the hard lens of the fish it scarcely alters the sp. gr., but 
commonly that of the softer lenses of birds and mammalia is 
increased. I have therefore rejected all the calculations 
made from lens which were not fresh—they include the lion, 
several monkeys, many reptiles, many human, and other 
creatures. 
The same remark, as to the necessity of employing only 
the lens of animals very recently dead, holds good in taking 
the measurement of its curves. It soon becomes too convex 
by imbibition of fluid; when preserved in spirit it also swells 
out; if kept in Goadby’s solution it shrinks in size and be- 
comes too flat. 
Reagents act upon the lens almost as they do upon 
albumen, yet not entirely, for though by boiling the lens its 
outer portion at once becomes opaque, the inner does not, as 
is best seen in the solid lens of a large fish, the centre of 
which becomes like transparent horn, while the outer is like 
coagulated white of egg. 
The composition of the lens is given by Berzelius as— 
Water . j ‘ ; . 58:0 
Peculiar matter (protein compounds) . ¢ oor" 
Hydrochlorates, lactates, and alcoholic extracts . 2-4 
Phosphates and watery extracts : Bi tegen 
Insoluble membranous residue : i yee 
100°0 
Simon (‘ Animal Chemistry,’ vol. ii) says, besides albumen 
there is in the lens a peculiar substance resembling casein. 
