On the Structure of the Brain in Man and Monkeys. 193 



As regards the application of the brain structure to zoologic 

 classification, which I believe Leuret first,* and more recently 

 Agassiz m regard to the turtles, suggested, the attempt of Owen 

 among naammals shows its failure to be that of any other single 

 anatomical character so used. As with the classification of 

 fishes proposed by Miiller and that by Agassiz, every application 

 of a single organic character fails when carried out, leaving gaps 

 that destroy the uniformity of the whole. It is the sum of 

 the mutual relation of the individual parts of the structure that 

 measures affinities, rather than individual marks of structure 

 through the highest. The very objections, which Miiller urges 

 against Agassiz's classification by scales, may be applied with 

 equal force to Miiller's classification, baaed on the valves of the 



, There is much that suggests thought in Owen's application of 

 the brain structure to classification. The importance of the organ 

 ieads one to expect beforehand that it should, better than any 

 other individual character, mark the scale of the being. But the 

 distinctions between morphologic and physiologic equivalents 

 (analogies, homolgies, &c.), are still so indefinite and disputable 

 as to demand the greatest caution; and though I accept, I must 

 still regard them as obscure conceptions rather than as scientific 



In regard to the gyrations of the brain it seems surprising that 

 ^0 large, highly organized, and physically elevated an animal as 

 Jje ostrich has smooth hemispheres like the lower mammals. 

 ^or in man do the gyrations seem to hold a constant relation to 

 tbe mind. The brain of the mineralogist, Hausmann, who had 

 a body of more than ordinary size, appears to me similar to that 

 01 the Hottentot Venus or of a seventh month embryo. We do 

 ^ot know what relation the terminal gray substance of the sur- 

 face may hold to the white fibres or to the nerve origins of the 

 ^^Wi and spinal cord, nor their special p.^ychical significance. 



yn the other hand the typical arrangement of the gyrations 

 and the formation of the lobes of the cerebrum are certainly in 

 intimate relation to the systematic division of the groups, orders 

 and families. The ruminants, carnivores and quadrumanes give 

 evidence of this, and the genera even may be known by their 

 ^''''angetnent. But it is only the individuals o^ one order or 

 £^uy, and especially those of a marked natural group, that may 

 °^ justly compared as to the relative development and arrange- 

 °^eiit, and in the number and details, of their gyrations. 



