GROWTH OF THE CEREBRAL CORTEX 



503 



Chart 1 Giving for each brain weight group, in millimeters, on brain weight 

 in grams, the values for the several diameters. W .B. and W .D., width; L.F . 

 and L.G., length; Et., height. 



• — • — • = W.B. 



• •= W.D. 



X-- 



° — ° — ° = L.G. 



o o ^ Li.h . 



X = Ht. 



(volume) (see also table 4, column C). The approximate value 

 of W. B can be estimated by formula (1) as follows: 



W . B. (mm.) = Cw ^ vBrain weight (grams) (1) 



grains 



where C^ will be 13.5 for a brain weighing 0.3-0.5 

 13.2 for a brain weighing 0.5-1.0 

 12.9 for a brain weighing 1.0-1.3 

 12.5 for a brain weighing 1.3-1.6 

 12.2 for a brain weighing 1.6-2.1 



The value for the measurement W. D stands in an almost 

 fixed relation to that for W. B. The latter averages through its 

 course 0.6 to 1.0 mm. below the former, the average difference 

 being 0.76 mm. Thus in chart 1 both graphs run nearly parallel 

 to each other. 



