Reginald J. Gladstone 
111 
17 Females from 20 — 46 years of age. 
mm. 
Height of hecad minus height of skull = 3'82. 
Length „ „ length „ =7-52. 
Breadth „ „ breadth „ =7-88. 
27 Females from 40 years upward. 
mm. 
Height of head minus height of skull = 3 50. 
Length „ „ length „ =7'12. 
Breadth „ „ breadth „ =6-98. 
It will be observed that the scalp is thinner in female subjects than in males 
and that there is a diminution in the thickness of the scalp, which amounts to : 
: 0 26 mm. % : 0"32 mm. at the vertex. 
122 mm. 0 40 mm. at the glabella and occipital point together. 
0"87 mm. 0'90 mm. on the two sides. 
There is thus a diminution in the length of the principal diameters of the 
head, attributable to the atrophy attendant on old age, which amounts if the 
mean of both sexes be taken to : 
0'29 mm. in the vertical diameter. 
0"81 mm. „ longitudinal „ 
0 885 mm. „ transverse „ 
The thickness of the skull also varies with age, as will be noted on comparing 
the cut surface of the vault of a skull shown in Plate II. Fig. D, which is a 
photograph of the vault of the skull of a child about four years old, with that 
in Fig. C, which is the photograph of the vault of a normal adult skull. 
The difference in thickness of the skull of a child, and that of an adult will also 
be seen on comparing Fig. A, Plate II. with Fig. B on the same plate. Fig. A 
represents the right half of the skull of a child about five or six years of age; 
Fig. B the right half of a thick, adult skull. Note also the absence of frontal 
sinuses in Figs. A and C. 
The extent to which the thickness of the skull may be affected by di.sease, may 
be seen in Fig. 3, which represents part of the vault of a skull, from a case of 
' osteitis deformans *,' the walls of which averaged about one inch in thickness. 
The increase in thickness of the skull in these cases takes place partly on the outer 
and partly on the inner surface of the skull, so that although the size of the head 
is enlarged the capacity of the skull is diminished, and compression exerted on its 
contents. 
The reverse condition is met with in cases of chronic hydrocephalus in which 
the size of the head is increased b}' an augmentation in the volume of its contents. 
* Specimen 1239. Museum of the Royal College of Surgeons, England. 
