554 



NAOKI SUGITA 



The results of the measurement are given in chart 2. This 

 chart shows the curve of each measured diameter in milhmeters 

 given on the ordinates, the brain weight being entered on the 

 abscissa. Generally considered, at birth, the width W.B sur- 

 passes the length L.G, but after the third week, the length in- 

 creases more rapidly and finally surpasses the width at the end 

 of the seventh week, when the hemispheres appear somewhat 

 elongated and ovoid. 



Among these diameters, L.F is in the plane from which the 

 sagittal sections were taken and W.D in the plane from which the 



a g 



Fig. 12 a. Dorsal view of the albino rat brain weighing 1.5 grams, enlarged 

 1.8 diameters. To show the positions at which the two measurements for the 

 width and the two measurements for the length were taken. AB = Width W.B, 

 CD = Width W.D, EF = Length L.F and EG = Length L.G. 



b. Lateral view of the albino rat brain weighing 1.5 grams. Enlarged 1.8 diam- 

 eters.- To show the position at which the height was measured. HK = Height 

 Ht. 



frontal sections were taken. So I have used these values as those 

 from which to obtain a coefficient for correction. 



Assuming that, by fixation and when unfolded by heat on 

 slides, the section shrinks or extends uniformly, and, that the 

 white and the gray substancss suffer approximately the same 

 shrinkage or extension as the result of the treatment, I have 

 selected the following correction-coefficients for use in this series. 



In the sagittal section, the thickness of the cortex measured on 

 the sfide being represented by Ts and the thickness of the fresh 

 cortex by Tp. Then 



L.F (fresh) 



Tb X 



L.F (on slide) 



(1) 



