XXL] ANTISEPTICS. 189 



In order to pronounce a certain substance an antiseptic in 

 the strict sense of the word, it is necessary to place the organisms 

 in this substance for a definite time, then to remove them 

 thence, and to place them in a suitable nourishing medium ; if 

 they then refuse to grow the conclusion is justified that the 

 exposure has injured or destroyed the life of the organisms. 

 In the case of pathogenic organisms a substance to be pro- 

 nounced a germicide must be shown to have this power, that 

 when the organism is exposed to the substance and then 

 introduced into a suitable artificial medium it refuses to grow ; 

 and it must also be shown that when introduced into a suitable 

 animal it is incapable of producing the disease which the 

 same organism, unexposed to the substance in question, does 

 produce. 



I have made a good many observations on the influence of 

 antiseptics on micro-organisms, both putrefactive and patho- 

 genic, and I have found that many assertions hitherto made on 

 this subject, treated in the above light, are absolutely untrust- 

 worthy and erroneous. 



Various species of putrefactive micrococci, bacterium termo, 

 bacillus subtilis, various pathogenic micro-organisms, as 

 bacillus anthracis, bacillus of swine fever, absolutely refuse to 

 grow in media to which is added phenyl-propionic acid, or 

 phenyl-acetic acid, to an amount so small as 1 in 1,600 ; but if 

 the same organisms are exposed to these substances in much 

 stronger solutions, 1 in 800, 1 in 400, or even 1 in 200, and 

 then transferred to a suitable nourishing material, it is found 

 that they have completely retained their vitality, they multiply 

 as if nothing had been done to them. I have exposed the 

 spores of bacillus anthracis to the above acids of the strength 

 of 1 in 200 for forty-eight hours and longer, and then ino- 

 culated guinea-pigs with them, and I found that the animals 

 died of typical anthrax in exactly the same way as if they 

 had been inoculated with pure spores of the bacillus anthracis. 



Koch has published a large series of systematic and most 

 valuable observations l made in testing the influence on spores 

 of bacillus anthracis of a large number of antiseptics (thymol, 

 arsenate of potassium, turpentine, clove-oil, iodine, hydrochloric 

 acid, permanganate of potassium, eucalyptol, camphor, quinine, 

 salicylic acid, benzoic acid, and many others), and amongst 

 them he found perchloride of mercury to be the most powerful, 

 since even a solution of 1 in 600,000 is capable of impeding, 

 one of 1 in 300,000 of completely checking, the germinating 



1 Mitiheil. am d. k. Gesundlieitsamte, Berlin, 1881. 



