TRANSACTIONS OF SECTION H. 703 
resistant to the evil influences of a city life than those of the next generation born 
and bred amidst urban surroundings. 
A comparison of the relative proportions of the different classes of Londoners 
among the general populace, as shown by the census, and among hospital patients, 
shows an increase of morbidity with increasing length of city residence. 
III. Distribution of Pigmentation in Children among the General Population of 
London and among Hospital Patients. 
It is found that in all parts of London the children are much fairer than the 
adults, and that the children attending the medical casualty rooms of the various 
hospitals are much fairer than those, presumably healthy, observed at school or in 
the streets in the sphere of attraction of each hospital; while the average of the 
general child population and of those attending accident-receiving rooms of the 
hospital is practically identical. 
Hence it may be concluded that disease during childhood falls more heavily on 
the fair element. It would also appear that in the different districts of London 
the difference between the pigmentation of children and adults and the degree of 
infant mortality vary in the same direction, if allowance be made for the presence, 
in certain areas, of a large alien population. 
So far, then, it would appear— 
i. That certain diseases show special affinities for certain types of the popula~ 
tion. 
ii, That adult hospital patients, as a whole, are slightly fairer than the popula- 
tion in the sphere of attraction of each hospital. 
ili. That among adults immigrating from the country the fair element sends an 
undue proportion of its members to the hospitals. 
iv. That child patients are markedly fairer than the children in the districts 
around the hospitals. 
y. That there are some indications of a relation between the difference in pig- 
mentation of adults and children in any area and the degree of mortality in child- 
hood of such an area. 
IV. Possible Influences of the above Factors in Changing the Distribution of 
Physical Characters in Successive Generations, 
In the earliest years of life the fair element is certainly at its maximum. 
During the first ten years of life the chief causes of death are disorders of the 
alimentary and respiratory systems, coming on either directly or as sequelze of some 
of the infectious disorders common in childhood. These, as we have seen, even in 
adult lite, show (as far as case incidence is concerned) a certain degree uf greater 
frequency among the fairer class of the community. The diseases associated with 
brunet traits are at this period at their minimum. The quinquennial period 10-15 
is characterised by a very low mortality, which seems very evenly spread over the 
different disorders, but falling least on the ‘ brunet’ group. 
The special incidence of illness and probably of mortality on the lighter class of 
the community continues until the period 20-25, when, owing to the sudden rise 
both of case incidence and mortality from pulmonary tuberculosis, the darker 
element begins to suffer severely. During this period, 20-25, it seems certain 
that the darker individuals are at their maximum degree of frequency among the 
general population. This age, however, is that at which most marriages occur, so 
that assuming that the marriage rate is uniform among the different types—which 
is, however, susceptible of proof—the parents of the next generation should have 
maximum of pigmentation. Supposing the difference to be slight, yet it might in 
time produce the effects now everywhere visible of a greater pigmentation in urban 
areas, Tables show that most marriages occur between 21 and 25, next in fre- 
quency between 25 and 30, and the majority of offspring are born in the early 
years of married life. 
However, as will be seen from any diagram of death-rates bet seen 20 and 40, 
