A Study of Cerebral Anthropology 21 



ical influences do not fail to present themselves in every subject, 

 but they determine only individual, not constant variation. These 

 conclusions are in accord with the opinion of Turner, who believes 

 that the production of a convoluted surface may be regarded, in 

 the main, as a physical problem. Smith also uses the argument of 

 mechanical forces to explain the arrangement of the fissure pat- 

 tern in the occipital region of man. Sergi (1910) has expressed 

 the factors very clearly as " a mechanico-functional " condition, 

 because that complexity of causes, to which is due the origin of 

 a sulcus, is represented by a fundimental factor which is the 

 functional necessity of enlargement of the cortex within a deter- 

 mined zone ; enlargement which, in its own time, ought to sustain 

 a whole series of mechanical necessities, thence a form and rela- 

 tion which can be reduced to a scheme. 



Eberstaller (1884) says of the formation of the convolutions, 

 " Die Bildung der Hirnwindungen nicht aus aiisseren Grunden, 

 und durch mechanische Einfliisse der Umgebung, zum Beispiel, 

 Schadelgehaiise, Blutgefasse und der gleich, erfolgt, sondern aus 

 inneren Bedingungen und dass die relative Grosse eines Rinden- 

 bezirkes Hand in Hand geht mit seiner functionellen in-aus-pruch- 

 nahme. Vom anatomischen Standpunkte kann man das mit gutem 

 gewissen des Korpers entnommen sein konnen, belegen nur liber 

 die physiologische Dignitat der Theile in Sinne der Localisations- 

 theorie sind wir annoch zu wenig unterrechtet," which in the 

 light of Smith's work coincides with Chiarugi. 



Smith (1904c) in his memoir takes up the question of the sig- 

 nificance of embryological evidence which Cunningham had so 

 extensively employed in interpreting the morphology of the cere- 

 bral fissures, and says, " Experience teaches . . . that embryo- 

 logical data relating to sulci need to be constantly checked by the 

 more certain evidence yielded by the examination of large num- 

 bers of adult brains and by comparative and histological studies, 

 because the latter are a much surer and more fruitful source of 

 unequivocal information." 



Of more importance than the embryological is the comparative 

 study which here, as in other fields, has been very helpful in 

 clearing up the obscure questions which have pervaded the sub- 



365 



