24 



ROBERT S. ELLIS 



accordingly eliminated these two questions of race and mental 

 grade from my discussion. The three conditions remaining, age, 

 sex, and variations between the right and left sides, will be dis- 

 cussed in turn. 



Age. The results of the counts for all the cases were tabulated 

 and plotted according to age. But as cell losses are frequently 

 due to disease, I have eliminated those cases for each age which 

 showed the greatest losses, and have retained as the basis for 



X- 



-X, males; 



Chart 6 Loss of the Purkinje cells on age (man). 

 O, females. Based on tables 11 and 12. 



the chart only those cases which showed the greatest number of 

 cells and the least indiction of cell degeneration for a given age. 

 By this rnethod I have eliminated forty-three cases, which left 

 a balance of twenty-seven males and thirteen females. To 

 these, for the sake of greater completeness, I have added three 

 cases, all males, reported in my earlier paper. The process of 

 selection described does not materially affect the form of the 

 curve in the chart, although of course it makes it higher. This, 

 however, instead of being a defect, should give us more nearly 

 the true result for the normal biological loss of cells with age. 

 The results are shown in tables 11 and 12, and in chart 6. 



