486 
Dr Duckworth , Report on the brain of a 
The parietal region. 
The absolutely small size of this part of the brain is. shewn 
by a study of the following dimensions of this hemisphere. 
Marginal circumferential measurements of the left hemisphere 
along the supero-mesial border: 
from anterior to posterior pole of the hemisphere, 
183 mm. 
from anterior pole to upper end of central sulcus, 
120 mm. 
the same expressed as a percentage of (a), 65'57 mm. 
from the upper end of the central sulcus to the upper 
end of the paracalcarine sulcus, 40 mm. 
the same expressed as a percentage of (a), 21 '86 mm. 
the remaining portion of the arc (a) (by difference), 
23 mm. 
; the same expressed as a percentage of (a), 12‘57 mm. 
The following table exhibits these values together with those 
provided by Cunningham and Telford-Smith 1 for normal and for 
microcephalic human cerebra. 
(a) 
(b) 
(o) 
(d) 
(e) 
(/) 
(g) 
Length of the supero-mesial border of the hemisphere = 100 
Frontal Parietal 
index index 
Occipital 
index 
Normal human brains 1 53-3 
Brain of microcephalic 1 idiot Fred (left hemisphere) ...65'5 
Brain of microcephalic idiot here described (left hem.) 65-57 
25-5 
21-5 
21-86 
21-2 
13-0 
12-57 
From this, the close resemblance between the two micro- 
cephalic cerebra, and the contrast they provide with the normal 
human cerebrum, will be evident. 
The two postcentral components of the sulcus intraparietalis 
are- conjoined. Halfway along this sulcus a branch springs off to 
be directed backwards and divides into three portions, all of which 
are continued 1 Jaack wards, the uppermost being inclined directly 
upwards rather than ^backwards. The posterior limb .of the 
Sylvian fissure just fails to end^r tbi 0 complex at the point of 
divergence of the three terminal branches. The parietal lobe 
thus possesses a posterior ascending gyrus ; while the notorious 
“pli de passage” is not recognisable. The anterior or ascending 
part of the supramarginal gyrus is very broad below, but is 
quickly reduced in width on turning backwards. 
The occipital region. 
The extreme posterior end of the well-marked retrocalcarine 
sulcus is received within the concavity of a small lunate sulcus 
1 From D. J. Cunningham and T. Telford-Smith, Scient. Trans. Royal Dublin 
Society, Vol. v. Series ii. p. 299. 
