113 
housed, or so overcrowded in their dwellings, that this has to be 
counted as causing disease. In another case, some particular 
collective occupation, injurious to the adults and adolescents who 
follow it, may be creating disease additional to that which the 
filth produces. Another case may be cited, where swarms of 
young children, whose mothers are engaged away from home, or 
who are given to drunken, idle habits, may be suffering from 
disease induced by neglect and mismanagement. In filthy urban 
districts, where the foul air incarcerated in courts, and alleys, and 
narrow streets, can act with most force in regard to masses of 
population, the population always shows increased mortality, under 
several titles of disease. This miscellaneous increase of mortality 
affects probably all ages, more or less; but a distinctively large 
proportion of it attaches to the children. Apparently the mere 
influence of the filth (apart from other influences), will be causing 
the infants and young children to die at twice, or thrice, or even 
four times their standard rate of mortality ; and this disproportion, 
which becomes more striking, when the chief epidemics of ordinary 
childhood, such as measles, whooping-cough, and scarlatina, are 
left out of the comparison, seems to mark the young and tender 
lives as finer tests of foul air, than are the elder, and what I might 
call acclimatised population. 
Besides nuisances being produced by the presence of putres- 
cent refuse-matter, there are also diseases which are abundantly 
caused by air which is fouled ix other ways. Overcrowding, for 
instance, is a fruitful source of evil. In dwellings which are 
inhabited beyond their means of ventilation, the foulness of the air 
due to the non-removal of the volatile refuse thrown off by the 
human body, becomes strictly a nuisance, and comes within’ the 
scope of sanitary law, quite as much as the non-removal of solid 
or liquid refuse. In filthy districts, one special class of diseases 
seems to stand in relief, viz. diarrhoeal. These diseases, in relation 
to filth, deserve very special attention, first, on their own account, 
as they are extremely large causes of death; and, secondly, because 
an exact knowledge of their method of production is likely to throw 
comparative light upon the pathology of obscure filth diseases, 
9 
