536 
PROFESSOR MARSHALL ON THE BRAIN OF A BHSHWOMAN ; AND 
fully tortuous and complex character in the perfect brain. In comparison even with the 
Orang’s (Plate XXIII. fig. 20) or Chimpanzee’s brain, they are far more simple. They 
are rather better developed in the idiot woman than in the boy. 
The two ascending parietal convolutions (Plates XXI. & XXII. figs. 10, 12, 14 & 16, 
4 - 4 i & 5 - 5 ) commence, in both idiots, very far forward on the cerebrum, just above the 
entrance to the Sylvian fissure, instead of, as in the perfect human brain and in the 
higher Apes, a little in front of the middle of that fissure ; they thus resemble the con- 
dition found in Cercopithecus and other similar Quadrumana. In the perfect human 
brain these ascending convolutions, as pointed out by Gratiolet, are interposed between 
an anterior and a posterior set of longitudinal ones, which occupy the rest of the cere- 
brum — the portions in front and behind the slanting line of the ascending convolu- 
tions being nearly equal, the occipital region preponderating slightly. On the other 
hand, in the idiots’ brains the portion in front of these ascending convolutions, as seen 
either laterally or from above, is by far the smaller; indeed it is not a fourth as large 
as that behind. In the Orang and Chimpanzee it is about one-third. (Compare Plates 
XX. & XXIII. figs. 7, 18, 19 & 20.) 
As usual, these ascending parietal convolutions arise from the supramarginal convo- 
lution, which unites them below the outer end of the fissure of Rolando. In the idiot 
woman, on the right side, where the fissure of Rolando is a simple sulcus, the two 
ascending parietal convolutions are also simple, forming two oblique ridges instead of 
the zigzag bands seen in the perfect human brain. On the left side, the anterior con- 
volution is represented partly by the intrusive triangular mass ( 4 /) before spoken of, as if 
by an arrest of development. In the idiot boy it is curious that the same condition exists 
on the same side of the cerebrum, whilst on the right side the anterior ascending con- 
volution is developing itself, as it were, into its more perfect but still simple form of an 
even oblique ridge. The symmetry between the two sides is thus again effectually de- 
stroyed in both brains. In both the idiots’ brains, as usual, the anterior ascending pari- 
etal convolution (4-4 i) joins, or would have joined, at its upper end, the upper frontal row, 
whilst the posterior convolution (5-5) expands into its so-called lobule ( 51 - 51 ), which is pro- 
portionally large, has its customary lozenge-shape, and extends backwards to the exter- 
nal perpendicular fissure (h). In the idiot woman (Plate XXI. fig. 10), on the left side, 
this lobule is notched by a single deep sulcus running from the longitudinal fissure ; on 
the right side it has this sulcus placed further forwards, and another slight triradiate one 
besides, but its surface is remarkably smooth in comparison with its complex form in the 
perfect brain, or even in the Orang (Plate XXIII. fig. 20) or Chimpanzee. In the idiot 
boy’s brain (Plate XXII. fig. 14) the lobule of the posterior ascending parietal convo- 
lution is on both sides proportionally larger, and slightly more complex in form, in 
accordance with the greater development of the parietal region in the idiot boy. In both 
the idiots’ brains the outer border and angles of the lobule are distinctly defined on the 
left hemisphere, whilst on the right hemisphere it blends at the outer border with the 
neighbouring convolutions — that is to say, with the lobule of the supramarginal convo- 
