260 MICRO-ORGANISMS AND DISEASE. [CHAP. 



of antiseptics on micro-organisms, both putrefactive and 

 pathogenic, and I have found that many assertions hitherto 

 made on this subject, treated in the above light, are abso- 

 lutely untrustworthy 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 i in 

 i, 600; but if the same organisms are exposed to these 

 substances in much stronger solutions, i in 800, i in 400, 

 or even i 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 i in 200 for 

 forty-eight hours and longer, and then inoculated guinea-pigs 

 with them, and I found that the animals died of typical an- 

 thrax 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 1 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 i in 

 600,000 is capable of impeding, one of i in 300,000 of com- 

 pletely checking, the germinating power of the spores. To 

 regard these substances, from these observations, in any way 

 as germicides for the spores of bacillus anthracis would be 

 1 MitthdL aus. d. k. Gesundheitsamte, Berlin, 1881, 



