No. 1.] HARDENING REAGENTS. 137 
Table 10 left hemiencephala after hardening in a 2% solution 
of bichromate of potash for 35 days :— 
TABLE I0. 
SERIAL NuMBER. PERCENTAGE OF SOLIDS AVERAGE. 
96 22.0 
97 20.8 —— 21.4) 
Table 11 left hemiencephala hardened 35 days in a 2% solu- 
tion of bichromate of potash at ordinary temperature, then 
heated in an oven at 37° C. for 30 days :— 
‘PABLE: LY: 
SERIAL NuMBER. PERCENTAGE OF SOLIDS. AVERAGE, 
5! 23-9 
52 22.6 
53 22.6 
54 24.5 
55 227 232 
This shows very nicely the effect of the higher temperature 
on the percentage of solids. 
The percentage of solids found in Table 11 is above that 
which would come from mere saturation of the fluid within the 
specimen ; hence, at 37° C., under the above conditions, we 
must have some deposit of salts in addition. 
As a result of these observations, we have determined that 
in the bichromate of potash solutions the specimen takes up 
both water and salts as it becomes hardened in the histological 
sense. 
Variation.—In this connection, it needs but a glance at 
some of the foregoing tables to show that although the 
attempt has been made to have the conditions similar in 
different series, the results may vary by as much as 8%. 
In search of an explanation for this, we have made the 
observations which immediately follow. 
