THE PHYSICAL BASIS OF MIND. 45 



kind, it is not a constant relation. Even within the limits of 

 the human species this relation is not so precise as is usually 

 supposed ; for, neglecting particular cases that might be 

 quoted of men of genius not having particularly large or 

 heavy brains, the converse cases are perhaps in this connec- 

 tion more remarkable — viz., those of feeble-minded persons 

 having large and apparently well-formed brains. I am 

 indebted to Dr. Frederick Bateman of the Eastern Counties' 

 Asylum for directing my attention to the observations of 

 Dr. Mierzejewskis, which were published at the international 

 congress of psychologists held in Paris in 1878. These 

 observations, which appear to have been carefully made, 

 seeing that casts of the brains were exhibited, went to show 

 that idiotcy is compatible with large and apparently well- 

 developed brains — the amount of grey matter in one instance 

 being " enormous." 



And, if we turn to the animal kingdom, w^e find in a still 

 larger measure that the mere amount of cerebral substance 

 furnishes but a very uncertain index of the level of intelli- 

 gence which is attained by the animal. This is the case 

 even when w^e eliminate the element of complexity that is 

 introduced by the differences which obtain in different 

 animals between the bulk of the brain and the bulk of the 

 body — small animals requiring a greater proportional bulk of 

 brains than large ones, because the nervous machinery wiiich 

 ministers to muscular movement and co-ordination has in 

 both cases to be accommodated. But this element of com- 

 plexity may be removed by considering the cases in which 

 small animals exhibit remarkable intelligence ; and in this 

 respect no animals are so remarkable as the more intellioent 

 species of ants alluded to in my former work. As Mr. Darwin 

 has observed, the brain of such an insect deserves to be 

 regarded as perhaps the most wonderful piece of matter in 

 the world. 



But if this whole question touching the relation between 

 the mass of brain and degree of intelligence is felt to lie as 

 a difficulty in the way of evolutionary theory, I should reply 

 to it by the following considerations. 



In the first place, that there is a general relation between 

 size of brain and degree of intelligence, both in the case of 

 man and in that of animals, is unquestionable. It is, there- 

 fore, only with the more special exceptions that we have to 



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