Histology of the Island of Beil. By Herbert C. Major, M.D. 15 
the directions in which they point with irresistible force, as those 
in which research should be conducted, have, as I believe, been 
greatly overlooked, so that facts which ought ere this to have been 
elicited, and questions which ought to have been set at rest, have 
still to be worked out and brought to light. 
Since the time when Fr. German inaugurated the study of the 
cerebral cortex (1782), or even when Baillarger published his 
admirable memoir,* which ought to serve in all time as a model 
of accurate investigation and clear exposition, great additions have 
doubtless been made to our knowledge of the minute anatomy of the 
brain. But much remains to be done in many directions, and 
one of these, as before stated, is, I believe, the Island of Beil. 
The ordinary descriptive anatomy of the Insula, the manifold 
courses taken by the fibres which bring the lobe into relation with 
other parts of the cerebrum, have been carefully studied and de- 
scribed by Meynert, Buys, L. Clarke, Broadbent,t and others. 
With regard, however, to the minute anatomy of the cortex of the 
Insula, while it may be that unwittingly I do injustice to some 
whose labours have escaped my observation, I am not aware that 
the part has attracted heretofore special study, with the view of 
ascertaining its exact structure. 
The comparative anatomy of the lobe, again, is touched upon, in 
the briefest manner, by Gratiolet, who bestows merely a few vague 
sentences on its characters in the Orang and Chimpanzee ; J and I 
am not aware that any other author has extended our knowledge in 
this direction. 
And thus it is also with regard to the relative structure of the 
Insula in the foetus and young child as compared with the adult ; 
our knowledge is vague, uncertain, incomplete. And lastly, in the 
consideration of those atrophic changes which, under certain circum- 
stances, induce wasting and destruction of the nervous structure, 
the condition of the Insula, and the extent to which it is involved, 
are, I have reason to know, very generally passed over, and 
often, I cannot doubt, to the loss of important data. Now all these 
questions are well deserving of careful consideration, and it is to 
them I desire in this and subsequent papers to direct attention. 
And it seems natural and advisable that the opening paper should 
be devoted to a consideration of the histology of the Insula in the 
healthy human adult, an accurate knowledge of which is essential 
to a right judgment on the other points of the inquiry to which I 
have alluded. 
The questions, then, now proposed, and the answers to which 
* Baillarger, ‘ Structure de la Couche Corticale.’ Paris, 1840. 
t See more especially Broadbent, ‘ The Structure of the Cerebral Hemi- 
sphere.’ 
X Gratiolet, ‘ Memoire sur les Plis Ce're"braux de l’Hoinme et des Primates.’ 
VOL. XVIII. C 
