668 THE POPULAR SCIENCE MONTHLY. 



community must be made, one and all, experts in its knowledge and in 

 its applications. 



This last consideration should lead educators to bestow a preemi- 

 nent importance to a thorough course of instruction in hygiene. It is 

 all well enough for the young to learn more or less about the philoso- 

 phy of electricity and magnetism, but, as the great majority of them 

 in after-life will make very little, if any, use of this knowledge, its 

 importance practically dwindles to very small proportions. Wholly 

 different is it in the case of sanitary science. Every one can make of 

 it in after-life most important, and ultimately momentous uses, not 

 occasionally, but during every day and hour of life. And, if thus 

 applied, its benefits would transcend those of any other branch of 

 knowledge ; it would tend to make man a master of himself, of his 

 pains, deformities, and mortal afflictions. 



"We have said that the applications of sanitary science must be 

 made mainly by the individual members of society. This is true of 

 the kind of air breathed, of the food and drinks partaken, of the 

 clothing worn, etc., etc. But where human beings are clustered to- 

 gether, their sanitary relations are so intimate that it becomes ab- 

 solutely necessary for the general good to define and regulate some 

 sanitary matters by law, which each member of a community cannot, 

 as an individual, regulate for himself. It is not possible, for example, 

 for one in a densely-populated place, to enforce regulations for a sup- 

 ply of wholesome water, for carrying off to a safe distance all the ref- 

 use and noxious matters of a great city, or to protect himself from the 

 presence of persons suffering from infectious diseases. It is here 

 plainly the duty of the State to exercise supervision for the general 

 good, and to protect all, as far as may be possible, against evils which 

 a few persons may fight against in vain. There is absolutely no dif- 

 ference, except in the matter of will, between the danger of allowing 

 a person who has a mania for putting poison into the drinking-water 

 of a city, by which many perish, and one who puts the poison of small- 

 pox into the air of a city by which hundreds are slain. In the former 

 case, even if it were the work of an idiot, or of an irresponsible person, 

 and if he were known to be travelling over the country, liable at any 

 moment to enter a city, would not the officers of the law be considered 

 exceedingly derelict in duty if they did not carefully guard against 

 his entrance ? And, if such a class of persons were in a city infecting 

 others with their mania, would not all applaud the law and the efforts 

 of its officers in securely confining them where they could do no harm, 

 taking from them the means by which they injured and destroyed the 

 lives of others ? This is precisely what ought to be done with every 

 one in a densely-populated place laboring under an infectious or con- 

 tagious disease. When out of a city, such dangerously-affected per- 

 sons should be watchfully excluded until cured of their disorder ; and, 

 when in, a cordon should be placed around them, so that the com- 



