52 SHINKISHI HATAI 
dogfish they take place in utero.’”’ He, however, has not de- 
termined the water content in the brain of the dogfish in utero. 
From the foregoing it is clearly important to determine the 
water content in the brain of the fish at very early stages in 
order to discover the period of rapid reduction which must take 
place in consequence of the appearance of myelin in the brain. 
It is the hope of the writer to do this in the near future. 
CHEMICAL ANALYSIS OF THE BRAIN (GRAY SNAPPER) 
Utilizing the materials which were employed for the deter- 
mination of the percentage of water, I have determined the 
nitrogen in the total solids, as well as the amount in the ether- 
alcohol soluble fraction extracted from the total solids. The 
results of these determinations are shown in table 5. 
TABLE 5 
Showing the amount of the ether-alcohol soluble and insoluble fractions in the brain 
of the gray snapper; also the amount of nitrogen in the total solids, as well as the 
nitrogen in the ether alcohol fraction 
BRAINS WEIGHT OF NITROGEN IN 
TOTAL 5; 
SERIES = 8 SOLIDS | WATER | NITRO- Alcohols Alcohols 
¢ 2 aE Residue ether Residue ether 
D = Extract Extract 
a & 
weight per cent | mgms. gms. gms. mgms. mgms. 
1 28 |27.303) 5.665) 79.14 | 462 2107 2.958 364 98 
8.15%| 47.79% | 52.21% | 78.79% | 21.21% 
2 19 |20.013) 4.588) 77.07 | 334 1.938 2.650 269 65 
7.28%| 42.24% | 57.75% | 80.54% | 19.46% 
IAWVCTAZO hte ceRe assess 78.11 | 7.72%| 45.02% | 54.98% | 79.67% | 20.38% 
To carry out the determinations presented in table 5, I have 
divided the entire materials into two groups in which group 1 
gives for the brain a percentage of water which ranges between 
78 per cent and 80 per cent, while in group 2 the percentage of 
water ranges between 76 per cent and 77 per cent. All the other 
brains which gave percentages of water beyond these limits were 
excluded. Since all these data for the fish may be discussed 
conveniently by comparing them with similar data obtained 
