METABOLIC ACTIVITY OF NERVOUS SYSTEM DO 
TABLE 7 
Showing the comparison of the gray snapper with the albino rat in regard to the chemi- 
cal composition of their brains 
a hee 
ENTIRE | ENcEPHA- | ENTIRE 
BRAIN LON SN 
Water Insbrain percents... o arcceta ec sae 78.11 75.16 77.96 
Total nitrogen in fresh tissue, per cent............ 1.69 1.89 1.95 
Totalini¢rozenm:solids, per cent! 3645 sesenie - Gate leat 8.98 
Alcohol-ether extract in solids, per cent........... 54.98 55.03 47-14 
Nitrogen in alcohol-ether soluble fraction, per cent| 20.60 19.90 18.20 
Percentage of water in lipoid-free tissue, per cent. 88.80 87.06 87 .00 
Milligrams of non- protein nitrogen per 100 grams 
of fresh tissue, milligrams See RR TI re dice pes RN 225 150 159 
Partition of nitrogen in milligrams of nitrogen per 
gram of solids 
INON=PROLEIN=IN Nath sees tale cee was nse xe ees 9.6 6.0 7.6 
AMIN O-aclds=Nieraasscrce cas sa edo Oo ee eee 5.3 2.9 3.5 
Wire tae nme Nereis cere, ates oclemes WU AT SS Go's ORG 0.7 Ond 
FAMITMLON IAIN Geant ances cite om eine he tere wrtaeh i ormieate. 5 0.8 0.6 ORG 
Partition of non-protein nitrogen in percent of pro- 
tein nitrogen 
INU OMS JOT OG EMTS tray seeps r rte R rn) meats ear ima eats sep ty oar 13.04 9.72 10.37 
PATVIM OP ACLU Steere NEA Ore TES RE (220 4.68 4.60 
(ORR SERS cons OG tact acts PAST ORES Si tr cicieae one ea 0.97 1.05 0.95 
AITO NE. obo permcoe Op elo eee De a obo polbo Gee 510i] 1.04 1.01 
cerebrum and cerebellum compared with the size of the stem 
in which the myelinated nerve fibers are abundant. Conse- 
quently we should expect a higher value of the total nitrogen 
in the rat brain than in the fish brain, since the former possesses 
relatively a much greater number of cell bodies in those two 
well developed parts, the cerebrum and cerebellum. At the 
same time the rat brain ought to give relatively a less amount | 
of lipoids, owing to the greater abundance of the gray matter 
in the predominant parts. In the fish brain the insignificant 
growth of the cerebrum and cerebellum makes the stem of the 
brain relatively predominant in the quantitative relations, and 
since the stem is the portion of the brain in which the myelinated 
fibers are mostly found, we should expect the percentage value 
of the lipoid fraction in the fish brain to be relatively higher 
than in the rat. 
