D. Macdonald 
27 
occupying an intermediate position as regards infection ; the light-eyed child 
seems to be more susceptible to diphtheria and whooping cough than to scarlet 
fever and measles. 
(4) The Recuperative Power of the various pigmentation Types in the Diseases 
considered. Throughout this section no attempt has been made to separate boys 
and girls or Belvidere and Ruchill cases. 
To determine the recuperative power of the various pigmentation types in the 
diseases considered, the number of patients, the percentage of severe cases and the 
percentage of deaths in each type have been tabulated. The number of patients 
includes the severe cases and deaths. The percentage of severe cases includes the 
percentage of deaths. What have been termed the severe cases will require 
further definition. In scarlet fever, measles and whooping cough, severity is indi- 
cated by the incidence of complications. The complications are chiefly represented 
in scarlet fever by nephritis, arthritis, adenitis and otitis media, in measles by 
laryngitis, broncho-pneumonia, subsequent tuberculosis and otitis media, and in 
whooping cough by convulsions, broncho-pneumonia and subsequent tuberculosis. 
These complications indicate the severity of the attack. In diphtheria, however, 
there are so many cases with a toxaemia considerably above the average, which 
yet develop no actual complications, that it has been thought more accurate to 
consider the degree of toxaemia without reference to complications. In diphtheria, 
therefore, any case with marked toxaemia, that is, with a toxaemia more intense 
than the average, has been tabulated as severe. 
1. Recuperative Power and Pigmentation of the Hair. During a two years' 
experience of children in fever hospitals and before any attempt had been made to 
arrive at any statistical proof on the subject, I had formed, more or less uncon- 
sciously, the opinion that the fair-haired child tended to be more severely attacked 
by and to succumb more readily to the acute fevers, and that the dark-haired child 
tended to be less severely attacked and offered more resistance to the disease. 
How far this impression is confirmed by fact will be seen from the tables below. 
It appears that in each of the diseases considered the fair-haired children show 
the greatest percentage of severe cases and of deaths, and not only is this so, but 
the greater severity and higher mortality in fair-haired children is marked and 
constant. The only exception is the slightly greater percentage of severe cases of 
diphtheria in red and medium-haired children. Next, but not so pronounced, in 
order of severity and mortality comes the red-haired class. Only in the percentage 
of deaths in diphtheria, which is remarkably small, and of severe cases in whooping 
cough is this order changed. But the low death rate in diphtheria is fully made 
up by the large number of severe cases, and the small number of red-haired 
children with whooping cough renders the observation of little value. The severity 
and mortality in medium-haired children occupies a mean between the high 
severity and death rates among the fair-haired and, in a less degree, the red- 
haired children and the comparatively low severity and death rates among the 
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