ON THE BRAINS OF TWO IDIOTS OF EUROPEAN DESCENT. 
549 
In the idiot woman the hemispheres are proportionally large and well shaped, whilst 
the median portion is not quite so well developed. In the idiot boy the hemispheres 
are relatively larger, projecting laterally, and preponderating still more over the median 
portion. 
In the idiot woman the square lobe is normal in shape and proportions, the posterior 
superior lobe is narrow and shallow, the amygdala and biventral lobe are strikingly 
large ; the slender lobe is very small, the posterior superior lobe is, on the contrary, well 
developed ; the pyramid and uvula are prominent, but narrow ; the nodule is small ; the 
posterior velum is exceedingly thick ; the floccule is very small. In the idiot boy the 
square lobe is of ordinary shape and proportions, the posterior superior lobe is wide and 
deep ; the amygdala, contrary to its condition in the idiot woman, is small, and partly 
concealed beneath the biventral lobe, which is large ; the slender lobe is of moderate 
size, and the posterior inferior lobe again large ; the pyramid, uvula, and nodule are 
small ; the posterior velum, as in the idiot woman, is exceedingly thick, suggesting the 
idea that it usually becomes attenuated as development advances; the floccules are 
small, but not so small as in the female idiot. 
The middle peduncular (or transverse commissural) fibres are defective, not merely in 
comparison with the perfect organ, but also in relation to the size of the idiots’ cere- 
bella, especially considering the great development of their hemispheres. The oval 
surface occupied by the divided ends of these fibres, as seen on a median section through 
the pons, is shorter and much smaller than usual. In the idiot woman (Plate XXIII. 
fig. 25, p) it measures -6 of an inch long by -325 inch wide, its sectional area being 
therefore T95 square inch, whilst in the idiot boy (fig. 26, p) the dimensions of the same 
part are *45 inch by - 28 inch, and the sectional area T26 square inch. The idiot woman’s 
recent cerebellum having weighed 1*95 oz., and the idiot boy’s 2 - 25 oz., there would be 
to each ounce weight of that organ T square inch of commissure in the woman, and only 
•05 square inch in the idiot boy. The healthy proportion, as shown at a previous page, 
is T3 square inch. In this point of view, then, the cerebellum is very defective in both 
idiots, but especially in the idiot boy ; which is remarkable anatomically, since in him 
this organ is so much larger than in the woman. The imperfect gait and feeble power 
of control over the muscles generally, always associated with true idiocy, were noticeable 
in the case of both idiots ; and this might appear to be in part explicable, on the ordinary 
hypothesis that the cerebellum is concerned in coordinating the voluntary muscular move- 
ments, by the obvious deficiency in the bulk of that organ in both these cases ; but, on 
the other hand, the fact that the cerebellum is larger in the idiot boy, though his powers 
of locomotion were altogether absent, and though he could not handle anything, nor 
articulate any words, seems contradictory and inexplicable. Under these circumstances 
it is at least interesting to find that one of the cerebellar commissural systems of fibres 
is so much more deficient in him than in the idiot woman ; and whether we adopt the 
view that the office of the cerebellum is directly to coordinate the muscular movements, 
or that it indirectly aids in this coordination, by registering the various muscular sensa- 
mdccclxiv. 4 D 
