STUDY OF BRAINS OF SIX EMINENT SCIENTISTS AND SCHOLARS. 209 



beginning atrophy. The brain of the ethnologist and geologist J. W. Powell showed 

 distinct signs of atrophy, and those of Whewell, C. BischofF, and Fallmerayer are 

 similar examples. That of the Hon. B. G. Ferris, an active lawyer and politician who 

 lived to be 89 years old, is doubtless another instance of such senile atrophy. 



Aside from these atrophic changes there occur the inevitable errors due to varia- 

 tions in the amount of fluid afld blood contained in the cavities and the brain sub^ 

 stance itself, and in the thickness of the pia-arachnoid. These recur so frequently 

 in brain-weighings that in the absence of special data they may be neglected, since 

 relativity of the weights is not much impaired. So far as the writer knows, all of the 

 brains here tabulated were weighed with the pia-arachnoid. As those of BischofF's 

 and Marchand's tables, used here for comparison, were weighed under like conditions, 

 no further allowance need be made. 



Other factors known to affect brain-weight, such as stature, nationality, body- 

 weight and build, etc., cannot well be considered in these cases ; the necessary data 

 are insufficient for the purposes of a critical estimate of these influences. Marshall 

 has essayed to do this with the brain-weights of Thackeray, Grote, Grant, Babbage 

 and DeMorgan. 



In my table no attempt at correction for the various deteriorating influences above 

 mentioned has been made, and all further discussion is based upon these figures ex- 

 clusively. 



