CHANGES IN HUMAN CEREBELLUM WITH AGE 13 



The relative weight of the cerebellum according to the grade 

 of the intelhgence has been studied by Spitzka ('07), who gives 

 a table showing the ratio of the weights of the cerebellum to the 

 weights of the cerebrum in ten ordinary and eleven eminent men, 

 and from this he concludes : 



''A glance at the list shows that while in ordinary men the 

 ratios cluster around 1 :7.5, among eminent men it is fully a unit 

 higher ; that is to say, the cerebrum, or essential-thought apparatus, 

 is relatively more massive, while the somatic organ of motor co- 

 ordination (cerebellum) remains relatively reduced" (p. 300). 

 This sounds very plausible, but let us examine the matter more 

 closely. According to the weights given by Boj'd for English 

 males, the average weight of the cerebellum is about 148 grams 

 and the average weight of the cerebrum is close to 1200 grams. 

 Bischoff reports approximately the same figures for German and 

 for French males. On this basis, then, the ratio for ordinary 

 men should be 1:8 instead of 1:7.5, as Spitzka has it; so the su- 

 periority of the eminent men is reduced by half. To clear the 

 matter up still further, I tabulated all the cases of eminent men 

 reported by Spitzka, in which the percentage weight of the cere- 

 bellum could be determined. These are nineteen in number. 

 I then weighed the parts of the encephalon of eighteen idiots and 

 imbeciles, these, with one exception (table 4), being all of the 

 brains of this class that were available in The Wistar Institute 

 Museum. The results are presented in table 8 and in chart 3. 



A glance at the chart and a comparison of the distribution of 

 the percentage values in the different types of cases shows clearly 

 that the number of cases is too small to show exactly the normal 

 probability curve; at the same time, it leaves little room for 

 doubt that the relative weights of the parts of the encephalon do 

 not show significant variations corresponding to different levels of 

 intelligence. 



The foregoing conclusion is another reason for doubting the 

 existence of a sex difference in relative cerebellar weight, a differ- 

 ence which has been often connected with a supposed difference 

 in intelligence between males and females. 



