NOs.) HARDENING REAGENTS. 129 
an initial loss of 2.3%, and a permanent loss of 1.3%. The 
third specimen hardened in 93% alcohol showed after similar 
treatment an initial loss of 2%, which proved permanent. 
It appears from these observations that a comparatively small 
loss of fluid from the specimen may cause a permanent diminu- 
tion in weight, and that drainage must not be continued for 
too long a time. 
Modifying Conditions.—In pursuance of our plan we may 
now consider a number of questions concerning possible 
changes in the specimen, Table 1, under slightly different con- 
ditions. We shall first indicate those conditions which have 
been varied and found to be insignificant. 
The combination of tap water or distilled water with either 
common bichromate of potash or that chemically pure (C. P.) 
does not influence the result. 
The point was tested on 6 brains, giving 12 specimens. 
Each of these was put in 800 c.c. of 2% bichromate of 
potash in the dark for 60 days. The specimens were all re- 
moved from the skull and weighed within two hours. The 
results are exhibited in Table 3, in the order of the removal of 
the brains, —the two halves of the same brain being indicated 
by a serial number and its prime. 
TABLE 3. 
BICHROMATE PERCENTAGE DIFFERENCE 
SERIAL NuMBER. oF PoTasn, WATER. OF INCREASE IN BETWEEN 
2 PER CENT. | WEIGHT. HALVEs. 
15 Common. Tap. 30.2 a 
1G G@3.P: 2 32.6 1.4 
16 Common. te 36.5 0.5 
16’ Cae u: 36.0 — 
17 Common. Distilled. 33-6 0.8 
17a CoP: i 32.8 — 
18 (G5 ter i 36.5 _ 
18’ Common. ke 36.9 0.4 
19 (CREE Tap. 35-1 — 
19’ Common. Distilled. 35-6 0.5 
