VARIATIONS IN BRAIN-WEIGHT. 139 



In the forms of mania are found the greatest ence- 

 phalic weights, while the lowest occur in the forms of 

 general paralysis and dementia. The pathological pro- 

 cesses which in the latter groups account for decrease in 

 weight are generally recognised, whereas in the manias 

 the overfilling of the encephalon with blood may in part 

 account for the larger figures obtained. Whether there 

 is any significance to be attached to the weights given 

 for melancholia and epilepsy cannot be determined, and 

 it would also be unwise to draw inferences from the 

 relative weights of the subdivisions of the encephalon 

 in the different forms, since if these were really signi- 

 ficant the two sexes would be expected to give similar 

 figures ; but such is not the case. Since here, as else- 

 where, there appears in encephalic weight the character- 

 istic difference between the two sexes, it might be 

 inferred that the smaller weight for both sexes in the 

 diseases which are associated most clearly with the loss 

 of mental power, is an expression of the breaking down 

 of those structures in the brain on which the mental life 

 anatomically depends, and there is some pathological 

 evidence to support such a view. The original records 

 from which this table has been condensed give the cases 

 under each division, arranged according to age, but not 

 grouped according to stature ; and hence the figures in 

 these partial tables do not exhibit the same regularity 

 as those in the tables for the sane, but the number of 

 cases entered in each decennial period is not large 

 enough to warrant the expectation that the law of age 

 would come out clearly, especially as the classification 

 according to stature is lacking. Taking, then, the insane 

 altogether, we find them, as far as their encephalic 

 weight is concerned, very similar to sane persons, and 

 the differences which appear in this table may be 

 looked upon in a large measure as the result of disease, 



