No. 1.] HARDENING REAGENTS. 141 
from the late arrival of the denser fluid, should often remain 
quite unhardened. 
Freshness.—It appears also that the time elapsing after 
death has a decided influence on the increase in weight. 
The series which we quote was tested with a 2% solution of 
bichromate of potash to which had been added one sixth of its 
volume of 94% alcohol. The reaction of this solution is 
similar to that of the simple bichromate of potash, but it causes 
a decidedly smaller increase in weight. 
This difference in treatment does not prevent the results 
from being applicable in this connection. Two control hemi- 
encephala were used. Three others were removed and allowed 
to remain in covered dishes at the room-temperature for the 
times indicated in the following table :— 
TABLE I3. 
eee MEAN TEMPERATURE 
STATE. INITIAL WEIGHTS. CHANGE IN , 8 ey 
WEIGHT 16 Days. a 
Fresh. 57-6 grms. + 20% 
63.38 9‘ + 21 14th, 20° C. 
Stale 1.3 days. 56.5 “ + 6 I5th, 24° C. 
“c 1.8 “6 54-7 “ — 2 
ce ZcOby <e op te ae Tily 16th, 26° C. 
The specimens did not harden after they had been allowed 
to become stale. Neither did they swell. These figures leave 
no doubt that shortly after death changes may take place in 
the nervous structures which prevent it from increasing in 
weight in the above solution. 
We have several other series which suggest the same thing. 
Table 4, given to illustrate the effects of using different 
quantities of the hardening solution, can be placed in evidence 
of this point, since nearly 7 hours elapsed between putting the 
first and the last pairs of specimens into the fluid, and the 
intervening pairs were put in at intervals of 2 hours, in the 
order in which they stand. 
It will require a special investigation to determine just the 
course of this loss in the power to increase in weight, and also 
