CHANGES IN WEIGHT OF CENTRAL NERVOUS SYSTEM 673 
table 4 shows, there were but three series and the numbers, ex- 
cept in the last series are small. The treatment of these Minne- 
sota frogs was similar to that for the Chicago frogs, and need not 
be again described. 
As shown in table 5, there is a spring series, a summer series and 
a late autumn series (entered in two parts) and in these three 
series the relative weight of the central nervous system as shown 
by the values of C, undergoes a seasonal variation corresponding 
to that found in the Chicago frogs—although the absolute values 
for C are much higher. This variation is exhibited in chart 2. 
TABLE 4 
Data on frogs from Minnesota, 1908. Fundamental table giving the mean values 
for each series 
| NUMBER OF SPECIMENS | 
SERIES : BODY WEIGHT TOTAL LENGTH BODY LENGTH 
M. 12% 
gms. mm. mm. 
Hen Seb le weer eet 9: Dee ees (50S oltanerale 79.5 
ee fe ick bee OMe Ser 56-4 ees 84.2 
BNE Aah vc dose skiy 3 SP | 48258 Pca 78.4 
ener te AL 3 Qi) |e (64-98" | eaeeo see 85.4 
| 
Brain 
SERIES WEIGHT LENGTH | PERCENTAGE OF WATER 
| gms. mm. 
Pale antes es ee Mah ot | 0.1250 16.4 84.8 
hg Opal ooh te en Pe | 0.1475 17.5 85.6 
2 AAR Oui hae SRR a | 0.1245 | 16.6 85.0 
Sy Ney Rack einen aaeaes | 0.1334 | 17.5 84.6 
: CPUNSLRET te fi Kc 
Cord 
TRC Adeee sects 8.8 2 | 0.0577 18.5 79.9 
Tite ed ee Se | 0.0640 1807; 80.4 
oh ca ae | 0.0582 18.1 80.1 
| 
3) iS ids bin ee ae | 0.0665 19.3 | 79.9 
