CHAP. XX.] Otf THE HUMAN BRAIN. 361 



instance, ascertained by Dr. Thurnam, that the average 

 brain-weight of insane males belonging to the more 

 educated middle class in the York Ketreat was decidedly 

 above that of paupers who died in the county asylums of 

 Somerset and Wilts.* Broca has also made some inves- 

 tigations in order to ascertain the dimensions of the heads 

 of a number of students of the Ecole de Me'decine as 

 compared with those of a number of servants in the large 

 hospital of the Bicetre, with the result of showing a 

 distinct preponderance in favour of the students. This 

 latter statement is, however, not easy to understand, 

 unless we are to believe that the superior education of 

 the students has, during their own individual lives, given 

 rise to a distinctly increased size of Brain and of head. 

 Among the ancestors of the students and the servants it 

 is quite possible that, in many instances, the relative 

 degree of education and amount of habitual exercise of 

 brain may have been reversed. If Broca could measure 

 the heads of these two sets of persons again that is the 

 same individuals after an interval of ten years, the 

 relative difference between these two measurements of 

 the two classes might yield some interesting information. 

 But would any difference be observed in the two sets of 

 measurements after such an interval, and if so could it be 

 ascribed to the effects of superior brain exercise ? These 

 very doubtful questions remain to be solved.! 



* The difference was not nearly so well marked between the 

 brain-weights of the females of these two classes; a fact harmonious 

 with others already, and subsequently to be, cited, showing that 

 the range of variation in them under the influence of various con- 

 ditions is less than it is for the brain of men. 



f Le Bon has also given a table showing the prevailing circum- 

 ferential Head measurements (which ranged from 52 to 62*5 centi- 

 metres) of individuals belonging to different social classes, at 

 present living in Paris, and who, from their differences iu 



