144° F. 

 131° F. 

 140° F. 

 167° F. 

 176° F. 

 131° F. 



ANTISEPTIC AND ASEPTIC METHODS. 7l 



the dry temperature required for the same result varies from 290° 

 to 330° F. Moisture considerably enhances the destructive action 

 of high temperatures and of antiseptics. Few pathogenic microbes 

 resist steam heat for more than a few minutes. Many die at 175°, 

 160°, and even 150° F., but the spores of the tetanus bacillus and of 

 some septic organisms endure higher temperatures than 212° F. without 

 destruction. The following table shows the temperatures at which 

 the organisms of chief surgical interest are destroyed : 



Staphylococcus pyogenes aureus is destroyed in ten minutes by a temperature of 137° F. 



>> " albus ,, ,, fj ^ 144° F 



,, ,, citreus ,, „ 



Streptococcus of erysipelas 



,. strangles 



The bacillus of tetanus ., ,, 



,, ,, tuberculosis ,, 



„ ,, glanders 



Anthrax spores are destroyed in ten minutes by a temperature of . . 212° F. 



Tetanus spores ,, ,. ., ,, . . 220° F 



Tetanus spores are destroyed in fifteen minutes by a temperature 

 of 212° F. and in five minutes by a temperature of 240° F. At 

 ordinary temperatures they resist 5 per cent, carbolic solution 

 for more than ten hours. The organism of black-quarter is 

 destroyed in ten minutes by immersion in boiling water. When dry 

 it resists a temperature of 250° F. for ten minutes. Moist anthrax 

 spores are destroyed in a few minutes by a temperature of 212° to 

 220° F. When dry they are only killed after ten minutes' exposure 

 to a temperature of 240° F. 



Bacteriological researches and some clinical investigations show 

 that disinfection by chemical agents is not always complete even 

 when concentrated solutions are used. Organic substances, even 

 in thin layers, are not always readily penetrated by liquid antiseptics, 

 and the deeper strata may retain virulent organisms in spite of the 

 prolonged action of such liquids. Chemical disinfectants are there- 

 fore reserved for the seat of operation, and the hands ; instruments, 

 ligatures, drainage-tubes, and other materials used for dressing are 

 subjected to the action of boiling water, glycerine, heated oil, or 

 simply to a high degree of dry heat. The simplest and most practical 

 method is that of boiling in water containing one per cent, of sodium 

 carbonate. Although it does not give absolute security — certain 

 spores resisting even a temperature of 212° F. — it is almost always 

 sufficient. 



