86 HENRY H. DONALDSON 
Sample table, to illustrate the procedure for obtaining a correction factor for the 
percentage of water as modified by the brain weight. Albinoralt. Male. Brain. 
Age growp 210-215 days. 
DIFFERENCE IN PER CENT OF 
OBSERVED TABLE 74 DIFFERENCE, GRAMS TABLE VALUE 
VALUES 
BRAIN tt it ais? 
aa Brain Weight | W=!GHT = ce = ae 
grams grams grams 
160 iL gala 1.807 0.096 DES 
171 ike aU 1.824 0.117 6.5 
216 1.982 1.886 0.096 HO) 
224 1.765 1.895 0.130 6.9 
251 1.911 1.925 0.014 0.7 
273 Pale 1.947 0.250 12.8 
276 2.215 1.948 0.267 13SEC 
Ave. 1.890 
ARRANGEMENT OF PERCENTAGE DIFFERENCES IN CORRESPONDING PERCENTAGES OF WATER 
BRAIN WEIGHT FROM MINUS TO PLUS OBSERVED 
~ - ~ + 
£ 6.9 77.9 
ra | 6:5 78.7 
[5.3 79.1 
Ave. 6.2 Ave. 78.57 
13).0) 78.1 
rene 12.8 78.0 
: 130, 78.4 
Ave. 10.5 Ave. 78.17 
served. Similarly the three plus cases give an excess of brain 
weight of 10.5 per cent and show 78.17 per cent of water ob- 
served. The relatively heavier brain group has, therefore, the 
less percentage of water and the relation is ‘accordant.’ 
If we use the mean of the table values for brain weight— 
1.890—as the standard and calculate the absolute difference 
for the brain weights, between the minus group (= —6.2 per 
cent) and the plus group (= +10.5 per cent) we find this to be 
315 mgm. This difference 315 mgm. corresponds to a difference 
in the percentage of water of (78.57 per cent —78 17) =0.40 
