130 DONALDSON. iVion. xe 
It is evident from this table, that although treated in slightly 
different ways, the two halves of the same brain react in a 
similar manner. The comparison between the two halves of 
the same encephalon is much more reliable than between two 
encephala, as we shall see, so that a study of the small differ- 
ences between specimens in different mixtures justifies the con- 
clusion that neither chemically pure bichromate of potash nor 
distilled water effect any significant variations in the increase 
in weight. , 
Amount of Air, etc.—It was further determined that the 
amount of air enclosed in the jar holding the specimen was 
without significance. 
The substance extractable by 2% bichromate of potash from 
the small cork sometimes used to suspend the specimen in the 
jar has no influence on the weight, nor did the point in the 
fluid column at which the specimen was suspended, affect 
the result, that is, the specimen reacted in the same way 
whether it was hung near the top of the jar or near the bottom. 
The variations due to the quantity of fluid employed are 
slight, and appear to be easily explicable. 
A series of four encephala were taken for this test. In each 
case one hemiencephalon was put into a small quantity of a 
2% solution of bichromate of potash and the other into a 
large quantity, in which they remained for 27 days. As in 
Table 3, the number and its prime indicate the two halves of 
the same brain. 
The following table shows the results obtained: — 
TABLE 4. 
SERIAL NUMBER. QUANTITY OF FLUID. FRESH WEIGHT. PERCENTAGE (GAIN 
AFTER 27 DAYS. 
6 200) CIC. 49.71 grms. 41.0 
6’ 2500 “ 49.61 “ AI.I 
8 ZO0Ns* Alc OO fms 35-6 
8’ 2500) % 49.00 “ 34.7 
10 4oo “ A760. s 37.0 
10’ 2500.8 50:7 2s 35:2 
12 400 “ 47.48 *“ 33-1 
Te 2,500. “ 47250. is 32-4 
