No. I.] HARDENING REAGENTS. 147 
TABLE 18. 
Determination of solids extracted. 
Six encephala after 55 days in 95% alcohol showed a per- 
centage of solids based on the fresh weight, as follows :— 
SERIAL NuMBER. PERCENTAGE OF SOLIDS. 
76 15.4 
77 15.8 
78 L5e1 
79 15.6 
80 Gt 
81 13.8 
AVEFABE- jae) ter “a Packed 2 Gd 
Six hemiencephala after 60 days in 95.7% alcohol. 
SERIAL NuMBER. PERCENTAGE OF SOLIDS. 
64 13.4 
65 ihtces 
66 12.9 
67 13.9 
68 13.6 
69 14.9 
ANEYASE Oe: oa Pie st a) sre kis 
We have no observations on the power of the several 
percentages of alcohol to extract solids, nor on the time 
relations of this power, but it would appear from the above 
figures that the extraction is still going on between the 55th 
and 60th days, when the decrease in volume has reached 
nearly a maximum. 
Recovery of Solids. — The loss of the solids due to the action 
of alcohol was controlled, by weighing the solids after evaporat- 
ing known quantities of the alcohol in which the specimens had 
been hardened. The control was satisfactory. These facts 
show that nervous tissues are damaged by the action of strong 
alcohol through the extraction of solids. 
To return now to the conditions which control the change 
in weight. Since specimens from different animals treated in 
the same manner did not change weight to the same degree, 
it might be supposed that either the specimens differed as 
