30 THE AMERICAN MONTHLY [Feb 
posterior layers of the cornea, the lymphatic spaces are 
clearly exhibited when tangential sections are to be made 
from the back of the cornea and mounted. 
Calcareous materials are so often deposited in the eye 
that a process of decalcification has been worked out. 
Slight calcification is destroyed by Muller’s fluid during 
the process of hardening. Greater calcification is re- 
solved by a month’s immersion in Muller’s fluid. Action 
is hastened by the addition of nitric acid and a weekly 
change of the liquid. But for quick and effective de- 
struction of the lime salts, Haug prescribes nitric acid 
(15) absolute alcohol (300) salt (1) and pure water (150) 
as a solvent. 
Pigment epithelium of the retina can be bleached out 
by means of euchlorine, in which the tissue is soaked 48 
hours, first having been hardened in Muller’s fluid and 
washed for 24 hours. Euchlorine is made from chlorate 
of potash and strong hydrochloric acid and must be kept 
in the dark to avoid the passing off of chlorine gas which 
would render the euchlorine inert. There is also a way 
of bleaching the sections individually after cutting. This 
is by Leopold Muller’s method (1895). It depends upon 
exposure to sunlight in peroxide of hydrogen or in 
chlorine water. Or, it may be done by E. Fick’s method 
with bichromate of potash and dilute sulphuric acid. Al- 
fieri bleaches in a solution of permanganate of potash 
exposed to sunlight followed by oxalic acid. Bleaching 
renders all sections very fragile so that they must be 
handled with a section lifter and not with needles. After 
bleaching away the pigment stain with Heidenhain’s 
Iron-hamatoxylin, beautiful slides may be made. 
Greeff has not failed to present three methods of pre- 
serving eyeballs for museum specimens or for future use. 
There are (1) the gelatine method, (2) the dry method, 
and (3) the formalin method. Medical or general muse- 
ums can now exhibit a great number and variety of pre- 
