ON THE BRAINS OE TWO IDIOTS OF EUROPEAN DESCENT. 
523 
externally ; the upper posterior lobes are also narrower and less curved than in the ordi- 
nary European brain ; the superior vermiform process is long, but relatively narrow. On 
the under surface, the amygdalae are not more than half the usual size, and are narrow 
and oblong, not broad and pyramidal in shape ; the biventral lobes are, on the contrary, 
large, and, owing to the small size of the amygdalae, are placed nearer to the middle 
line and have their laminae more vertical ; the slender lobes are also large and broad ; 
lastly, the lower posterior lobes, separated from the upper posterior by the usual deep 
horizontal fissure, are likewise very broad. In the vallecula, the pyramid, uvule, and 
nodule are clearly defined, but somewhat narrow ; the posterior velum is very well 
developed. The floccules, or subpeduncular lobes, are small, being both short and com- 
pressed. On the whole, therefore, the median parts of the cerebellum are relatively 
small, whilst its hemispheres are relatively large. 
The transverse commissural, or middle peduncular fibres appear, even to the eye, pro- 
portionally more abundant than in the European, and likewise more so than in the 
Chimpanzee. A comparison of the sectional area occupied by these fibres in the pons, 
with the weight of the cerebellum, confirms this observation. The oval surface (Plate 
XXIII. fig. 23,^), which includes the ends of these transverse fibres, as divided in the 
median plane of the pons, is in the European '95 inch long by - 65 inch wide, giving 
a sectional area of - 6175 square inch, which, as the total weight of the cerebellum is 
4-68 oz., gives about T3 square inch of surface to each ounce of cerebellum. In the 
Bushwoman, the corresponding’ oval surface (fig. 24, p) measures 1 inch by ’6 inch; its 
area equals therefore '6 square inch, which, divided by the weight of the cerebellum, 
3’45 oz., gives T73 square inch of surface to each ounce of cerebellum. In the Chim- 
panzee the equivalent measurements are ‘55 by ’4 inch ; the area is - 22 square inch ; 
the weight of the cerebellum is 2 - 02 oz., and the ratio of cut surface to each ounce of 
cerebellum is nearly T1 square inch. This is an important point in which the brain of 
the Bushwoman does not stand intermediately between the European and the Ape, but 
surpasses even the European brain. The inferior peduncles, and also the superior 
peduncles of the cerebellum, appear relatively small ; but no precise method of measure- 
ment could be adopted in regard to them. 
It is difficult also to devise any satisfactory mode of determining the number of 
lamina; in any given cerebellum. If the superficial laminae be counted, they are found 
to vary so in length, that, whilst some pass round the whole surface or border of the 
cerebellum, others disappear between adjoining laminae at various points, so that no 
single line can be drawn over the surface which will cross the edges of all the super- 
ficial laminae. On the other hand, if the deep as well as the superficial laminae be 
counted, then it is difficult to determine how small or short a fold shall be considered a 
distinct lamina, some of them being very short. Furthermore, the larger ones are 
often slightly grooved along their edge, and might be reckoned or not as consisting of 
two. Malacarne *, who gives the number of laminae in the healthy cerebellum at as 
* Neuro-encefalotomia. Pavia, 1791, p. 7. 
