62 LABORATORY MANUAL OF ANTHROPOMETRY 



Where the cranial capacity is between 1200-1300, take for each 



With a cranial capacity of Take for each 100 cc. a brain weight of 



1200-1300 91 grams 



1300-1400 92 grams 



1400-1500 93 grams 



1500-1600 94 grams 



1600-1700 95 grams 



Bolk (1904) gave the following table of the percentage of brain weight 

 to cranial capacity at the different ages of life. It will be noticed that 

 this is the greatest at 50, after which, through senile changes, the weight 

 of the brain decreases, while the cranial capacity naturally remains the 

 same. 



Age, years Percentage of brain weight to cranial capacity 



30 73.7-94.0 



40 90.0-96.5 



50 90.0-95.2 



60 89.2-93.4 



70 88.1-93.8 



80 85.2-90.1 



90 84.1-88.4 

 over 90 81.5 



Earlier Manouvrier, without considering the matter as to the age of 

 life, gave, as a general average of the percentage of brain weight to cranial 

 capacity, 87 %. No author has found any notable sexual difference. 



Indices 



Indices of Cranium and Face, with Classification of Values. — The 



following list of Indices includes the most of those which have been found 

 of value in craniological comparisons thus far. As they are merely a 

 simple numerical method of expressing the relationship of definite parts 

 and have been devised to express more precisely certain differences to 

 which the attention of the observer has been called, it is to be expected 

 that, with the inauguration of new comparisons, there will appear from 

 time to time new indices to express them. Indices of the skull involving 

 direct measurements, may be conveniently grouped as those of the 

 Cranium, those of the Face, and those which express Comparisons be- 

 tween the two. These are followed by those derived from the 

 craniogram. 



I. INDICES OF THE CRANIUM 



, , , 7 , , . , maximum cranial breadth [2] X 100 



1. Lennth-breaath index - — -. — — -~r-\ , u M i — 



maximum cranial length [1J 



