UPON THE SERIES OF PREHISTORIC CRANIA. 275 



fissures therefore deeper, and their aggregate square area of gray 

 matter much more extensive than those of the Australian brain ; 

 the Europeans specified being dolichocephali latiores, and the 

 Australians dolichocephali angustiores. But the dolichocephalic 

 'Silurian' type which characterised the inhabitants of Great 

 Britain and Ireland, and of a very great part of Europe also, in the 

 stone age, included crania resembling the Australian in the points 

 of which we are speaking, for the long-barrow-builders were not 

 rarely ' dolichocephali angustiores V 



1 If Schroder van der Kolk's calculation as to the extent of that difficultly measure- 

 able area made up by the surface of the convolutions within and without the fissures 

 from the fissure of Rolando to the front of the brain in men of various degrees of 

 intelligence had been accepted and confirmed by other anatomists, another argument 

 would have been available under this head. According to these calculations ('Pathology 

 and Therapeutics of Mental Diseases,' Australian translation by J. T. Rudall, 1869, 

 preface, p. vi), based upon measurements of the figures given by Rudolph Wagner in 

 the first part of his * Vorstudien zu einer wissenschaftlichen Morphologie und Physio- 

 logic des menschlichen Gehirns als Seelenorgan,' 1 860, the ■ lobus anterior before the 

 gyrus centralis ' held to the ' lobus anterior behind the gyrus ' the relation, 



in the mathematician Gauss . . of 88-5 : 100. 



in the mathematician Lejeune Dirichlet of 100 : 100. 



in the philologist Hermann . . of 75 : 100. 



in the artisan Krebs . . . . of 69 : 100. 

 Schroder van der Kolk in writing to this effect, Nov. 21, 186 1, to Dr. Theile of Weimar, 

 1. c, remarks that ' it will be understood that this gives only a relative value and a 

 relative accuracy, for I measure the plane and not the arched surface, but after all 

 that occurs in a tolerably equal degree in all the measured brains. I am convinced it 

 would lead to good results if comparisons were made in this way between the brains 

 of persons of talent and those of less mental capacity.' But Rudolph Wagner, to 

 whom the actual brains were available, whilst Schroder van der Kolk's estimate was 

 based merely upon Wagner's figures of them given in his 'Vorstudien' of 1862, 

 repudiated ('Vorstudien,' 1862, ii. p. 21) the Dutch anatomist's conclusions. And 

 Hermann Wagner, following up mathematically his father's researches in his ' Maas- 

 bestimmungen der Oberflache des grossen Gehirns,' 1864, p. 36, averred that the only 

 difference which his more exact method of measurement, as applied to the difficultly 

 measureable area in question, in four brains examined by him, including those of Gauss 

 and Krebs, had enabled him to discover was that with the increase of intelligence the 

 complexity of the convolutions increased in the frontal, but not demonstrably in the 

 other lobes of the brain : « Em Bevorzugen eines einzelnen Lappens und zwar des 

 Stirnlappens gegeniiber dem ganzen Gehirn hat sich fur die intelligenten Gehirne aber 

 doch durch diese Messungen herausgestellt ; die Oberflache des Stirnlappens derselben 

 besetzt eine starkere Zerkltiftung als die iibrigen Lappen.' It is obvious, I may 

 remark, that any argument which could be based upon mere mensuration of the 

 square area made up by the convolutionary sheet of gray matter in various segments 

 of the brain would be more amenable than any of the lines of argument given in the 

 text to objections on the ground that such measurements took no account of possible 

 variations in the thickness firstly, and in the quality secondly, of the sheet of gray 

 -matter. 



T % 



