PRESENT PROBLEMS 81 



is to be opposed on medical and humanitarian grounds. Neither is 

 there any reason, but the inertia of their owners, for the maintenance 

 of manufacturing plants in the midst of cities, and their establish- 

 ment should be vigorously opposed by the sanitary authorities. 



The so-called dangerous trades offer a field thus far little worked 

 by the sanitarian in this country, although the subject has had much 

 attention abroad. Here we have hardly any legislation under which 

 the sanitary authorities can take radical action to safeguard the life 

 and health of persons employed in those trades, and therefore they 

 may hardly be said to be under official control. There are many 

 trades, however, in which the ordinary processes of manufacture 

 induce disease, and others also which offer means for the spread of 

 infection. All will repay study by the sanitarian, with a view to 

 remedial legislation. 



Jurisdiction of boards of health over public supplies, such as water 

 and milk, is already well developed in some states and cities, and 

 much valuable work has been done in respect to the sanitary purity 

 of these necessaries of life. Negligence by the public authorities, 

 however, is still resulting, year by year, in outbreaks of typhoid and 

 other enteric troubles communicated in impure water or milk. For 

 evidence of this we have recent typhoid epidemics in Ithaca and 

 Watertown, New York, and Butler, Pennsylvania. 



The very rapid growth of our cities and towns and the improper 

 disposal of their sewage are causing general pollution of many water- 

 sources, and making it more difficult either to find pure water-sup- 

 plies or to keep existing supplies safe from infection. The only remedy 

 for this increasing menace is filtration, and that on a large scale and 

 under constant supervision by sanitarians and bacteriologists. This 

 work is very costly, but its maintenance after the installation is com- 

 plete will amply repay the expense, in the saving of life and the 

 preservation of health. Equally important are precautions for the 

 treatment of sewage. Bacterial purification of the liquid refuse of 

 cities and towns is now coming into use, with salutary effect; but 

 too often municipalities which have installed such systems imagine 

 that their work is done, when in fact such methods of sewage dis- 

 posal require constant expert attention in order to insure their maxi- 

 mum efficiency. 



Thorough sanitary control of watersheds involves not only the 

 removal therefrom of all possible sources of infection and the prepara- 

 tion of reservoirs by the elimination of all decaying vegetable mat- 

 ter; there is also demanded an efficient, unremitting inspection of all 

 sources of water-supply, with frequent chemical and bacteriological 

 examination of the water itself. Statistics gathered in the course of 

 such investigations are all-important in tracing the nature and sources 

 of pollution. The extension of existing watersheds and the taking 



