XI. 



ACTION OF COAL-TAR PRODUCTS, ESSENTIAL 

 OILS, ETC. 



IN the present section we shall consider the action upon bacteria 

 of a variety of organic products, and for convenience will arrange 

 them alphabetically. 



Acetone. Anthrax spores grow freely after two days' exposure 

 to the action of this agent; at the end of five days their development 

 is feeble (Koch). 



Alcohol. In the writer's experiments ninety-five-per-cent alco- 

 hol did not destroy the bacteria (spores) in broken-down beef tea in 

 forty-eight hours. Micrococcus Pasteuri was destroyed by two hours' 

 exposure in a twenty -four-per-cent solution ; pus cocci required a 

 forty-per-cent solution. Koch found that absolute alcohol had no 

 effect upon anthrax spores exposed to its action for one hundred and 

 ten days. Schill and Fischer found that when tuberculous sputum 

 was mixed with an equal amount of absolute alcohol its infecting 

 power was not destroyed in twenty-four hours, but that in the pro- 

 portion of five parts to one of sputum it was effective in destroying 

 the tubercle bacillus, as proved by inoculation experiments. Yersin 

 found that in pure cultures the tubercle bacillus is killed by five 

 minutes' exposure to the action of absolute alcohol. 



Aniline Dyes. Recent researches have shown that some of the 

 aniline colors possess very decided germicidal power. Stilling found 

 that solutions of methyl violet containing 1 : 30,000 exercise a re- 

 straining influence upon the development of putrefactive bacteria 

 and pus cocci, and that these microorganisms are destroyed by solu- 

 tions containing 1 : 2,000 to 1 : 1,000. Methyl violet has been placed 

 in the market by Merck under the name of pyoktanin. Janicke re- 

 ports the following results with pyoktanin : Staphylococcus pyogenes 

 aureus was restrained in its development by solutions containing 

 1 : 2,000,000, Bacillus anthracis by 1 : 1,000,000, Staphylococcus pyo- 

 genes by 1 : 333,300, Spirillum cholerae Asiaticse by 1 : 62,500, Bacil- 

 lus typhi abdominalis by 1 : 5,000. In blood serum stronger solutions 

 were required (1 : 500,000 for Staphylococcus pyogenes aureus). Sta- 

 phylococcus pyogenes aureus, Streptococcus pyogenes, and Bacillus 



