40 



NOBUHARU SUITSU 



growth, represented by a curve, and, 2) the period of later slow 

 growth, represented by the straight line. 



The body weight of about 125 grams (75 days) corresponds 

 to the transition point of the two periods. Figure 1 gives a 



TABLE 2 



Giving the mean observed and calculated area of the brain and of the corpus callosum 



on observed body weight in the albino rat. In columns G to II the 



relations of the callosal area to the total brain area are given 



series of outlines of the callosum at six ages, showing the increase 

 in area and the change in shape. At seventy-five days the out- 

 line of the callosum is a little smaller than that shown at E. 



