CHANGES IX HUMAN' CEREBELLUM WITH AGE 6 



('92). Table 1 gives the weights of the cerebellum from birth to 

 twenty years of age together with the percentage which the cere- 

 bellum is of the encephalon. These are in ounces in the original 

 tables, but I have taken the liberty' of converting them into 

 grams for the sake of comparison with other results. 



The body weights listed by BoN'd show that the infants autop- 

 sied were much underdeveloped, and it is prol)able that the 

 brain weights for the period of infancy are below normal. 



A somewhat more satisfactory series of weights for the period 

 of growth has been made by Pfister, in Berlin ('07-'03). In- 

 stead of taking all the cases that came to hand, he has been 

 careful to reject all the brains that were underdeveloped, oedema- 

 tous, anaemic, or jiathological in any way that would appreciably 

 affect the gross weight. His results are presented with Boyd's 

 in table 1. 



As the weights given by Boyd and Pfister naturally show some 

 variation, I have attempted to determine the normal curve for 

 the growth in weight of the cerel)ellum and for the encephalon 

 as a whole during the first two years. This is shown in chart 

 1. The method used was as follows: The weights given by 

 Boyd, DanicUx^kof (not given in table 1), and Pfister were plotted, 

 and smooth graplis for the combined data were drawn so as to 

 represent as nearlj- as possible the recorded weights. The graphs 

 thus drawn are intended to show the normal relation between 

 the weights of the encephalon and the cerebellum in both sexes, 

 and from these grai)hs it is possible to determine the normal 

 weights for either sex at any age less than two years. A series 

 of values determined in tliis manner is given in table 2. 



In both the chart and table I have made the relative weights 

 of the cerebellum in males and females the same. It seems, how- 

 ever, not improbable that in females there may be some precocity 

 and that consequently during early growth the relative weight 

 of the female cerebellum maj' be somewhat higher than that of 

 the male. The results of Pfister especially, and of Danielbekof 

 also, would at least agree very well with this view, although they 

 do not prove it. 



