236 THE POPULAR SCIENCE MONTHLY
"When the evidence of vital statistics indicates the presence of an nnsanitary condition through an excessive prevalence of some com- municable disease;, investigations are commonly made to determine the nature of the difficulty. This is often a troublesome and uncertain task. But when the difficulty is once discovered it is usually a simple matter to prescribe the remedy.
In very recent years sanitary investigations have been made much more definite and effective by the applications of bacteriology, chem- istry and pathology, and a new class of professional men has been devel- oped for laboratory and field work of the highest and best order. These persons we may call sanitarians or, better, hygienists.
The second main branch of public health work is the suppression of communicable diseases. Suppressive measures include the establish- ment of quarantine, the isolation of patients, disinfection, vaccination and the management of epidemics. Contrary to the custom of twenty years ago, all the best work in these directions to-day is based upon a scientific knowledge of what we may call the natural history of disease. In all these matters of control the dictum of the health authority is supreme. It can be resisted only through intervention by the courts.
The third main branch of public health work is the abatement of nuisances. The practical work of suppressing unsanitary conditions is done by health authorities by recourse to special statutes and local regu- lations made by the authorities themselves and termed " sanitary ordi- nances " or " sanitary codes." Offenders against these laws and regula- tions are brought before proper magistrates and fined. A board of health exercises the imique function of both making and enforcing the law.
It may be extremely difficult to determine what does and what does not constitute a nuisance. For practical purposes it is often considered that anything which is detrimental to health or which threatens danger to persons or property may be considered and dealt with as a nuisance.
Interesting work for the suppression of disease lies in educating the public, the medical profession and the health authorities as to the causes of and means of preventing the transmission of disease germs. This is one of the newest and most successful branches of public health work which has been undertaken for many years. It is based on the fact that people are not careless in sanitary matters because of a wilful or vicious design against the public welfare ; they err through ignorance. By educating the less fortunate concerning the ways in which diseases are transmitted and showing how they can be prevented, substantial benefit results.
This educational work is carried on by the daily papers, the medical papers, special bulletins and magazines, by lectures, by clinics, by con- gresses and, to some extent, by schools. Sanitary societies and public