392 'Journal of Comparative Neurology and Psychology. 



EXPLANATIOM OF PlATE III. 



Chart 3. In the upper curves, the continuous line (C), shows the weight of the brain according to 

 body weight as calculated by formula [i], the broken line (A/), the means of the observed brain weights. 



In the lower curves, the continuous line (C) shows the weight of the spinal cord according to body 

 weight as calculated by formula [3], the broken line (A/) the means of the observed spinal cord weights. 

 The same scale is used for both curves. 



Chart 5. On the base line representing age, one day of rat life is given the same value as 30 days 

 of human life (i.e., i day rat = 30 days man). The lower curves represent the weight of the brain 

 according to age (in days) for the rat. The solid line for the male, and the broken line for the female. 

 The upper curves represent the weight of the human brain (at yearly intervals) the actual values of 

 the ordinates being reduced to i-yooth in order to make the curves comparable with those of the 

 rat. Continuous line, male; broken line, female. 



