498 Dr Duckworth , Report on the brain of a 
left, not the right as in the present instance. And judging from 
the appended histological report, the minute structure of the 
cortex was definitely altered in Dr Wigglesworth’s example. 
The condition in the present case is complex. In the first 
place, an arrest of the normal capacity of the encephalon for 
development has occurred, for, as we have seen, the brain is 
microcephalic. And again, the quality of the tissue has been 
defective, so that in the course of time a cortical vessel has given 
way, and the escaping blood has destroyed portions of the cerebral 
surface. 
As regards the first factor, that of deficient power of growth, 
the present example is not an extreme case. The literature of 
microcephalus abounds with instances of a more exaggerated kind. 
The asymmetry between the two hemispheres, and certain other 
parts of the central nervous system, notably the pyramidal tracts 
from the mid-brain downwards, is perhaps worthy of special remark, 
and the comparison of the sections of the mid-brain and bulb with 
control examples, shews that the arrest of development has affected 
all parts of the central nervous system which were accessible to 
observation. Such a condition is to be clearly distinguished from 
a type of microcephaly in which the arrest affects little or nothing 
beyond the cerebrum. And of this contrasted condition the 
microcephalous pig described in the preceding paper ( Gainb . Phil. 
Soc. Proceedings, xiv. Part v., p. 447), offers a striking example. 
In the cerebrum, the neopallium has been chiefly affected and 
the rhinencephalon differs (macroscopically at least) but little 
from that of the normal individual. The difficulty in identifying 
the central sulcus in the right hemisphere demands special 
mention, but is by no means uncommon in the more pronounced 
cases of microcephaly. 
As regards the haemorrhage and its sequels, I may repeat 
that it appears to me indicative of the poor quality of the blood- 
vessels. The left internal carotid artery presents features which 
support this view : indeed upon inspection with the naked eye, 
one would hesitate to pronounce the section that of an artery, 
for it resembles a vein. 
The haemorrhage formed a tumour upon the right parieto- 
occipital area, but probably did not encroach upon the motor area 
of that side. The clinical evidence does not refer to the state of 
the limbs, nor with the comparison of the two sides, so that further 
comment is valueless. In view of the much smaller sectional area 
of the right motor tract, one would expect that there would have 
been at least some paresis of the left side. But no degenerating 
bundles have been discovered in this tract. Probably the usual 
number of fibres never developed. 
The locality of the haemorrhage and its encroachment upon 
