THE AMERICAN 



MONTHLY 



MICROSCOPICAL JOURNAL 



Vol. it. 



New York, April, 1881. 



No. 4. 



Charljon and the Germ Theory 

 of Disease. 



BY D. E. SALMON, D. V. M. 



The Study of contagious diseases is 

 to-day the most important work at- 

 tracting the attention of scientific 

 men ; for not only is the loss of hu- 

 man life from them enormous, but 

 the loss of property by their ravages 

 among our live-stock, and the neces- 

 sary obstructions to commerce is be- 

 coming a matter for the most serious 

 consideration. 



Until the last few years the con- 

 tagious plagues of men and animals 

 have been shrouded with the most 

 impenetrable mystery, to be ex- 

 plained only as punishments sent or 

 allowed by an angry God ; and when 

 the black plague destroyed twenty- 

 five millions of people in Europe at a 

 single invasion, or when it devastated 

 such great cities as London, there 

 were few, if any, who imagined it 

 possible for medical science to com- 

 bat these terrible scourges with any 

 hope of siiccess. But quarantines 

 have already done much, and it is 

 only in exceptional instances that the 

 advance of exotic pests, like cholera, 

 yellow fever or the plague, causes 

 any serious alarm. 



Notwithstanding this, however, we 

 have among us a number of conta- 

 gious diseases, from which the coun- 

 try is never entirely free, which 

 cause far greater loesses of human and 

 animal life than the majority of peo- 

 ple ever imagine. There is small 

 pox, now robbed of many of its ter- 

 rors by a general system of vaccina- 



tion ; scarlatina, which is often re- 

 sponsible for ten per cent, of the 

 annual deaths in entire States ; diph- 

 theria, which causes an equal mor- 

 tality ; typhoid and puerperal fevers, 

 measles, whooping-cough, syphilis, 

 pyaemia and septicaemia, all of which 

 help to swell the mortality lists. 

 Then as affecting animals, and com- 

 municable from them to man, there 

 are such horrible and fatal maladies 

 as charbon, rabies, glanders, and, 

 overshadowing all other plagues in 

 importance, tuberculosis. Finally, as 

 affecting and causing immense losses 

 among animals, we have pleuro- 

 pneumonia (bovine), rinderpest, Tex- 

 an fever, swine-plague and fowl- 

 cholera. Not less than one-seventh 

 of our people die from tuberculosis 

 alone, or, in the United States, one 

 hundred and twenty-five thousand 

 annually ; and if we add the 

 losses from other zymotic diseases 

 we will double this number, and have 

 in all a mortality approaching that 

 caused by our late civil war. 



With this introduction to indicate 

 the importance of the most thorough 

 knowledge of these diseases, I shall 

 enter upon a discussion of the germ 

 theory as applied to charbon, in the 

 hope of keeping my readers inter- 

 ested by the magnitude of the sub- 

 ject, even if I fail to present my 

 views in an attractive style. 



Before 1876, we were totally with- 

 out satisfactory evidence in regard to 

 the nature of the virus of any zymo- 

 tic disease, but Koch's investigation 

 of charbon, published in that year, 

 made it so clear that this malady was 

 due to a bacterium, called the Bacil- 



