112 
Brain -weight and Head-size 
An extreme case of this disease is seen in Figa. E and F in Plate III., which are 
photographs of specimen 3878 in the Hunterian Museum of the Royal College of 
Surgeons, England. It is described in the catalogue as " The skeleton of a man 
who died with hydrocephalus at the age of 25 years. Its greatest horizontal 
circumference is 914 cms. ! Besides the enlargement of the frontal and parietal 
bones by which the greater part of the enlarged cranial cavity is formed rows of 
Wormian bones from 2"5 to 3"8 cms. in breadth are placed in the whole course of 
the lambdoid and sagittal sutures, and in great part of the length of the squamous 
sutures." 
Fig. 3. 
The enlargement of the head in hydrocephalus is associated with an increase in 
the amount of the cerebro-spinal fluid, which is found either in the space between 
the arachnoid and pia mater, outside the brain, within the cerebral ventricles, or in 
both these situations. In the case of James Cardinal, the skeleton of whom is 
preserved in the Museum of Guy's Hospital, seven pints of cerebro-spinal fluid 
were found between the membranes, whereas the ventricles contained one pint. 
In this case " it appeared that the fluid had been originally contained within the 
ventricles, but had burst through an opening in the corpus callosum *." 
It is obvious that both in the case of osteitis deformavs, and hydrocephalus the 
size of the brain cannot be gauged by the size of the head. 
The enlai'gement of the head in hydrocephalus is also of interest, as it indicates 
one means by which the size of the cranium is increased in the course of normal 
growth, namely by an expanding force acting from within. In the early stages 
of development the foetal brain has a smooth even surface, at a later stage from 
the 8th week of intrauterine life to the 4th month, what are called the ' transitory 
fissures ' make their appearance ; these are infoldings of the thin walls of the 
* See description of case in Tumours, Innocent and Maluinant, p. 448, J. Bland Sutton. 
