210 BEAIN-WEiaHT AND SIZE IN RELATION 



Dr. Thurnam, in producing fifteen of tlie above examples, remarks : 

 "Altogether, they decidedly confirm the generally received view of 

 the connection between size of brain and mental power and intelli- 

 gence :" and he adds his conviction that if the examination of the 

 brain in the upper ranks of society, and in men whose mental endow- 

 ments are well known, were more generally available, further confir- 

 mation would be given to this conclusion. The converse, at least, is 

 certain, that no great intelligence or unwonted mental power is pos- 

 sible with a brain much below the average in mass and weight. But 

 there are unquestionable indications that a large, healthy brain may 

 exist without the manifestation of great mental power j while brains 

 inferior both in size and weight have been the organs of unwonted 

 intelligence and mental activity. 



In the "Philosophical Transactions" of 1861, Dr. Boyd published 

 an elaborate series of researches illustrative of the weight of various 

 organs of the human body, including the weights of 2,000 brains. 

 Most of the healthy brains are those of patients in the St. Maryle- 

 bone Infirmary, and have already been referred to as necessarily 

 representing the indigent and uneducated classes of London. Here, 

 therefore, if an unusually large brain, is the index of intellectual 

 power, every probability was against the occurrence of brains above 

 the average size or weight. But the results by no means confirm 

 this assumption. Among the patients in the Edinburgh Royal 

 Infirmary, in like manner, though including the better class of arti- 

 zans and others from country districts, we might still look for a con- 

 firmation of M. Broca's assumption, based on extensive observations 

 of French crania, "that, other things being equal, whether as the 

 result of education, or by hereditary transmission, the volume of the 

 skull, and consequently of the brain, is greater in the higher than ia 

 the lower classes." But Dr. Peacock's tables include four brain- 

 wei<yhts, three of them of a sailor, a printer, and a tailor, respectively, 

 ranging from 61 to 62*75 oz. ; and so surpassing all but two, or at 

 the most three, of the heaviest ascertained brain-weights of distin- 

 guished men. Tried by the posthumous test of internal capacity, 

 three skulls of nameless Frenchmen, derived from the common 

 cemeteries of Paris, in like manner showed brains equalling in size 

 that of Cuvier. The following are the maximum brain-weights 

 amonc the St. Marylebone patients apparently unaffected by cerebral 

 disease. 



