ACTION OP SALTS. 183 



the presence of 1 : 300,000 in a culture medium, and Geppert has re- 

 cently shown that even so small an amount as 1 : 2,000,000 will pre- 

 vent the development of spores the vitality of which has been reduced 

 by the action of a strong solution (1 : 1,000). When this restraining 

 action is entirely neutralized by washing the spores in a solution con- 

 taining ammonium sulphide it requires, according to Geppert, a solu- 

 tion of 1:1,000 acting for one hour to completely destroy the vitality 

 of anthrax spores. Frankel found that a solution of 1 : 1,000 was 

 effective in half an hour. The typhoid bacillus, the bacillus of mouse 

 septicaemia, and the cholera spirillum, in bouillon cultures and in 

 cultures in flesh-peptone-gelatin, are destroyed in two hours by 

 1 : 10,000 ; but in a bouillon culture to which ten per cent of dried 

 egg albumin was added a oiie-per-cent solution was required to de- 

 stroy the typhoid bacillus in the same time (Bolton). According to 

 Van Ermengem, cultures of the cholera spirillum in bouillon are steril- 

 ized in half an hour by 1 : GO, 000, but cultures in blood serum require 

 1 : 800 to 1 : 1,000. In experiments upon tuberculous sputum Schill 

 and Fischer found that exposure of fresh sputum to an equal amount 

 of a 1 : 2,000 solution for twenty-four hours failed to disinfect it, as 

 shown by inoculation experiments in guinea-pigs. The antiseptic 

 power of mercuric chloride is given by Miquel as 1 : 14,300. In the 

 writer's" experiments 1 : 33,000 was found to prevent the development 

 of putrefactive bacteria in bouillon, but a minute bacillus contained in 

 broken-down beef infusion multiplied, after several days, in 1 : 20,000. 

 The pus cocci were restrained in their development by 1 : 30,000. 



In Behring's experiments the anthrax bacillus and cholera spiril- 

 lum were killed in one hour by 1 : 100,000 when the temperature 

 was 36 C., but at a temperature of 3 C. the proportion required 

 was 1 : 25,000. The same author states that at 22 C. Staphylo- 

 coccus aureus in bouillon is not always killed in twenty-five minutes 

 by 1 : 1,000. 



In a recent series (1891) of experiments Abbott has shown that a 

 1 : 1,000 solution does not always destroy Staphylococcus pyogenes 

 aureus in five minutes. He says: "Frequently all the organisms 

 would be destroyed after five minutes' exposure, but almost as often 

 a certain few would resist for that length of time, and even longer, 

 going in some cases to ten, twenty, and even thirty minutes." 



According to Yersin, a solution of 1 : 1,000 kills the tubercle bacil- 

 lus in one minute. 



We might add considerably to the experimental data given, but 

 the results already recorded are sufficient to show the value of this 

 agent as an antiseptic and germicide, and justify its use for general 

 purposes of disinfection in the proportion of 1 : 500 or 1 : 1,000 for 

 material containing spores, and in the proportion of 1 : 2,000 to 



