MICROBES AS FACTORS IN SOCIETY. 109 



To these special causes of infectious disorders invasion by- 

 microbes and their intra-organic evolution hygiene is able to 

 oppose a number of means of protection or defense ; this is the 

 part of prophylaxis. The physician can, besides, assist the organ- 

 ism to make a victorious struggle against the microbe ; this is the 

 part of therapeutics. On these two points, also, social influences 

 have an extremely active effect. These interventions may be 

 greatly modified by the position of the subject in society, and 

 rendered, according to circumstances, insufficient and illusory, or 

 more efficacious and even potent. 



The facts thus far glanced at in this rapid review relate only 

 to isolated cases, or to diseases which reach and kill only a few 

 subjects. Suppose, however, these pathogenic influences raging 

 at their extreme height ; we shall then be dealing with epidemics 

 carrying men off by thousands, by hundreds of thousands, as actu- 

 ally takes place with cholera, yellow fever, and the plague. Un- 

 der such circumstances the microbe performs destructive work, 

 carries death abroad, and decimates populations. 



So we are brought back to the beginning of this discussion ; 

 and, examining philosophically this phase of the complex ques- 

 tion of the office of the microbe in society, we are able to answer 

 Broca's question, quoted at first, " What will take place in future 

 generations when they shall have exhausted the temporary re- 

 sources of emigration ? " We say : Then the microbe will inter- 

 vene, as it does periodically ; it will decimate populations and will 

 sow death ; but it will be to renew life by enabling new existences 

 to take the place of those which have become extinct, and by fur- 

 nishing them, under an assimilable form, the organic matter 

 which they will require for their life and healthy growth. 



We thus see, even from this rudimentary sketch, that the 

 function of microbes in society is very important. Good or evil, 

 useful or injurious, they all have a part which is indispensable to 

 the regular evolution of social bodies. Moreover, paradoxical 

 as the assertion may at first sight appear, I believe the fact has 

 been rigorously demonstrated, and may be formulated in the 

 words, that society can not exist, live, or subsist except with the 

 aid of the constant intervention of microbes, the great purveyors 

 of death, but also the dispensers of matter, and therefore all- 

 potent purveyors of life. Translated for The Popular Science 

 Monthly from the Revue Scientifique. 



The mass of the asteroids has been computed by B. M. Roszell, of Johns Hop- 

 kins University, and found including the whole three hundred and eleven bodies 

 whose elements had been calculated at the time to be '026 of the mass of the 

 moon. 



vol xlvii. 9 



