PERCENTAGE OF WATER IN BRAIN AND CORD 97 
have the smaller percentage of water, and vice versa. ‘There 
were tested 50 male and 37 female age groups. Each of these 
groups has been treated as follows: The data were arranged ac- 
cording to the increasing spinal cord weights and after each 
cord weight the percentage of water found in it was set down. 
Then the averages of the spinal cord weights and of the cor- 
responding percentages of water for the first third or half of the 
groups were compared with respective averages for the last 
third or half. 
Where the lighter cord was associated with the greater per- 
centage of water, the data were considered as ‘accordant,’ but 
where the opposite relation was obtained as ‘reverse.’ When 
treated in this way it was found that of 50 male age groups, 84 
per cent, and of 37 female age groups, 70 per cent, were accord- 
ant. Thus in the cord a heavier weight was associated with a 
less percentage of water somewhat more frequently than in the 
case of the brain (p. 87). To obtain the correction factors the 
difference between the averages for the percentage of water was 
divided by the number of milligrams by which the correspond- 
ing average cord weights differed, and the value for one milli- 
gram of cord weight was thus obtained. This gave the cor- 
rection factor for a single age group. The correction factors to 
be applied at the different phases of growth were determined 
arbitrarily by taking the average of the accordant correction 
factor values in the several age groups within each phase. ‘Two 
such phases were recognized, as given in table 3. 
By the use of the factors thus obtained the corrected percent- 
ages of water in table 2 were determined. ‘To obtain these the 
observed weight of the cord in each age group was subtracted 
from the cord weights characteristic for that age and this dif- 
ference in milligrams multiplied by the appropriate correction 
factor. The observed percentage of water was then corrected 
by the amount of this product. — 
It is to be noted that in the case of the cord, in which the 
myelination process begins during the first or second day after 
birth, corrections can be applied as early as the tenth day of 
life. 
