166 PREPARATION AND MOUNTING 
under water with a fine camel-hair brush very gently, so as 
to remove the precipitates of the gold salt. Sections of a 
cornea so prepared may be made on the finger by a sharp 
razor, and must be examined and kept in glycerine. 
Liver, Kinney, Spiteen, Lune, &c.—Some parts which 
are too soft to be cut into sections in their ordinary state, 
are usually hardened by being steeped in a solution of 
chromic acid, about two grains to an ounce of water. This 
will take some weeks according to the substance, and the 
solution should be changed now and then. Dr. Bastian, for 
mounting, uses Canada balsam partially dried to dispel the 
turpentine, and then diluted to necessary consistence with 
benzole. The section being cut from the hardened organ is 
washed in spirits of wine for some minutes, then a drop of 
liquid carbolic acid is placed on the slide where the speci- 
men is to be mounted. Take the specimen and let its edge 
touch’ a piece of blotting-paper, and place it upon the 
carbolic acid, which will render a thin section transparent 
in about a minute. Remove the superfluous acid with 
blotting-paper, when two or three drops of chloroform must 
be poured upon the section and remain one minute. Drain 
off and place upon the object the solution of Canada balsam 
in benzole, and apply the thin glass cover. Or place the 
object in ordinary spirits of wine for about a minute to wash 
it, then remove into absolute alcohol for five minutes. Lay 
it upon the slide and drain, cover with one or two drops of 
benzole for about a minute, tilt to drain off, and proceed as 
above. 
Both these methods are good, but the first does not 
always answer for sections of liver, as they generally are 
acted upon by carbolic acid; but few other tissues are thus 
affected. Tinted specimens seem equally safe when mounted 
in this way. 
Sections oF Brain anp Sprnan Corp.—Dr. Bastian 
gives his experience of these tissues as follows :—I immerse 
the section for about ten minutes in absolute alcohol diluted 
with eight per cent. of water, then place upon the glass 
