TO RELATIVE CAPACITY OF RACES. 181 



development of surface. But the two elements were not in uniform 

 ratio. Some of the lighter brains presented a much greater degree of 

 convolution and consequent extent of convex superficies than others 

 which ranked above them in weight. It is thus apparent that in 

 estimating the comparative characteristics of brains, various elements 

 are necessary for an exhaustive comparison. Besides the functional 

 differences of the cerebrum, cerebellum, and pons varolii, they have 

 different specific gravities, so that brains of equal weight may differ 

 widely in quality. Dr. Peacock, taking distilled water as 1000, 

 gives the vakies of the subdivisions of the brain thus : cerebrum, 

 1034; cerebellum, 1041; pons varolii, 1040. Again, Dr. Sankey 

 states the mean specific gravity of the gray matter of the brain in 

 either sex as 1"0346, and of the white matter as 1*041 2. The varia- 

 tions from these results, as given by Bastian, Thurnam, and others, 

 are trifling. But it is" significant to note that recent researches shew 

 that where greater specific gravity of brain occurs in the insane, it 

 appears to be limited to the gray matter.* Professor Goodsir main- 

 tained that symmetry of brain has more to do with the higher faculties 

 than bulk or form. It is, at any rate, apparent that two brains of 

 equal weight may differ widely in qiiality. 



Nevertheless, the popular estimate embodied in such expressions as 

 "a good head," "a long-headed fellow," and "a poor head," like 

 many other popular inductions, has truth for its basis. Up to a cer- 

 tain stage the growth of the brain determines the capacity of the 

 skull. Then it seems as though moi"e complex convolutions accom- 

 panied the packing of the elaborated cerebral mass within the fixed 

 limits of its osseous chamber. 



A comparison of races, based on minute investigation of an 

 adequate number of brains of fair typical examples, may be expected 

 to yield important results ; but in the absence of such direct evidence, 

 the chief data available for this purpose are derived from measure- 

 ments of the mternal capacity of their skulls. Among English ob- 

 servers who have devoted themselves to this class of observations, the 

 foremost place is due to Dr. J. Barnard Davis, who, in 1867, summed 

 up the results of his extensive researches in a contribution to the 

 Royal Society, entitled, " Contributions towards determining the 

 weight of the brain in different races of man."t Inferior as such 



* "Journal of Mental Science," Vol. XII., p. 23. 



t " Pbilosophical Transactions," Vol. CLVIII, p. 505. 



