26 Pigmentation, Susceptibility and Race Selection 
In whooping cough medium hair is considerably and fair hair slightly in excess, 
red hair is considerably, and dark and jet black hair markedly, deficient, as com- 
pared to their proportional representation in the general population. This would 
indicate that the medium-haired child and, to a much less extent, the fair-haired 
child, is more susceptible to whooping cough than the red-haired child and 
much more so, than the dark and jet black-haired child. 
TABLE X. Eye Colour. Showing the Percentages and Numbers of the 
various Eye Colours of Children suffering from Whooping Cough, as 
compared tvith the General Population. 
Dark 
Medium 
Light 
Blue 
Totals 
Belvidere and Ruchill : 
Actual numbers 
47 
118 
111 
34 
310 
Theoretical numbers 
76 
105 
94 
35 
310 
Actual percentage ... 
15-2 
38-1 
35-8 
iro 
100 
Theoretical percentage 
24-5 
34-0 
30-3 
11-2 
100 
In whooping cough the light eye and the medium eye are in excess but not 
to any marked extent, the blue eye is equal and the dark eye deficient when 
compared to their proportional representation in the general population. This 
would indicate that the light-eyed child and the medium-eyed child are more 
susceptible to whooping cough than the blue-eyed child and considerably more 
so than the dark-eyed child. 
Thus a striking similarity is maintained throughout in these four fevers as 
regards the susceptibility of the various hair and eye colours. 
Hair Colour. In every case there is a marked excess of medium hair and 
a marked deficiency of dark and jet black hair. In measles there is a con- 
siderable, and in diphtheria and whooping cough a slight excess of fair hair. In 
scarlet fever there is a slight deficiency of fair hair. Red hair is deficient except 
in scarlet fever, where it equals its proportional representation in the general 
population. 
The conclusion would seem to be that in scarlet fever, diphtheria, measles 
and whooping cough, the medium-haired child is more liable to become infected 
than the red-haired and much more so than the dark and jet black-haired child, 
the fair-haired child occupying an intermediate position as regards infection. 
Eye Colour. In every case there is an excess of medium eyes, not so marked 
in whooping cough, and a considerable deficiency in blue and dark eyes, except in 
whooping cough, where blue eyes are equal to their proportional representation in 
the general population. The light eye occupies an intermediate position, being in 
excess in whooping cough and diphtheria and deficient in scarlet fever and measles. 
The conclusion would seem to be that in scarlet fever, diphtheria, measles and 
whooping cough the medium-eyed child is more liable to become infected than the 
dark-eyed child and, even more so, than the blue-eyed child, the light-eyed child 
