Proceedings of the Association of American Anatomists IX 
THE ANATOMY OF THE HUMAN INSULA IN ITS RELATION TO THE 
SPEECH-CENTERS; ACCORDING TO RACE AND INDIVIDUALITY. 
By Epwarp ANTHONY SPITZKA. Anatomical Laboratory, Columbia 
University. 
The insula, probably the purest association area in the brain, seems 
to be most intimately concerned with the speech-faculties. The pur- 
pose of these investigations was to ascertain the form, size and surface- 
markings of the insula in the brains of various races and in those of 
known or distinguished men. ‘hus far, the race-brains in the series 
were those of 4 Eskimos, 2 Papuans, and 1 Japanese. The distin- 
euished or known individuals were Dr. Edouard Seguin, his son Dr. E. 
C. Seguin, W A , a New York Assemblyman, an Anatomist, a 
Palaeontologist, General Morphologist, a Physician and a Cerebral Mor- 
phologist. ‘The brief descriptions by Waldschmidt of the insulae of 
two Freiburg professors, by Riidinger of those of H. V. Schmid and 
Wulfert; and by Wilder of the exposed insulae of Chauncey Wright, 
seem to be the only references in the literature. 
The author’s investigations included the making of drawings, wax 
and plaster models or casts, and careful measurements, for purposes of 
comparison. The number of specimens is far too small for generaliza- 
tion, yet the following may be tentatively proposed: a. The insula 
is, on the whole, somewhat of an index of the degree of development 
of the general cerebral surface, particularly of those parts which are 
more or less in juxtaposition with it. This is especially demonstrable 
in the redundancy of the preinsula in persons noted for their powers 
of speech. (The significance of this redundancy of the pre- or post-insu- 
lar region, as the case may be, in its relation to the greater or lesser 
development of neighboring somaesthetic and sense-areas, seems strongly 
emphasized in the form of the insulae of the cetacea and proboscidea. ) 
b. The two insulae in the same brain usually exhibit a common type; 
and there seems to be a difference of type according to race. When 
there is any notable difference between the two sides, it is practically 
always in favor of the left insula, so far as size, massiveness and com- 
plexitv of configuration are concerned. 
ec. The exposure of the insula has already been noted by the author 
in the two Seguin brains, and Wilder has observed it in the brain of 
Chauncey Wright. This feature has been explained elsewhere. In the 
race-brain series, the insula is exposed on both sides of two Eskimos 
(Atana and Avia) more so on the left than on the right side. 
The author would urge the necessity of obtaining for further study 
the brains of men notable for their oratorical powers, as well as of 
