CHANGES IN HUMAN CEREBELLUM WITH AGE 



19 



THE MOLECULAR LAYER AND THE INTERNAL GRANULAR LAYER 



We are indebted to Roncoroni ('05) for a careful and exten- 

 sive series of measurements on the molecular and internal gran- 

 ular layers of the cerebellum in normal and pathological human 

 cases and in a number of lower animals. 



He finds that in general the molecular layer decreases in rela- 

 tive thickness and the submolecular layers increase relatively 

 during the course of evolution. 



TABLE 9 



The thickness in n of the molecular and submolecular layers in the human cerebellar 

 cortex (Roncoroni). The sex of the idiots is not stated, but probably four out of 

 the five are males 



Normal men aged about 30 years. 



Idiot, age 20 years 



Idiot, age 9 j'-ears 



Idiot, age 20 years 



Idiot, age 25 j^ears 



Idiot, age 34 years 



Women, aged about 45 years 



Woman, age 104 years 



» m 



a w 



o o 



6. < 



131 



180 

 167 

 213 

 207 

 154 

 150 

 106 



In table 9 I have condensed those of Roncoroni's results which 

 apply most directly to the present discussion. In his paper he 

 gives the minimum, average, and maximum widths of the molecu- 

 lar and internal granular layers, magnified 80 diameters. He 

 has also given a series of the percentage values obtained by di- 

 viding the value for the molecular layer by that for the internal 

 granular layer. From this series I have taken, for the sake of 

 brevity, the minimum, mean, and maximum percentages, and have 

 added in a fourth column the percentage obtained from his aver- 

 age measurements of the two layers. 



