CHEMICAL DISINFECTANTS 121 



Pieces of thread sterilized, and then put in fluid cultures may 

 be used in experiments; they are dipped into solutions of chemicals 

 for varying lengths of time and then placed in culture media and 

 growth noted. 



Bichloride of mercury is a highly efficient germicide in watery 

 solutions; if, however, albuminous matter is present its action is 

 inhibited very much. 



CHEMICAL DISINFECTANTS. 



Mercury Salts. Bichloride of mercury in highly dilute solution 

 is a very valuable antiseptic. It dissolves in 16 parts of hot water. 

 It requires an acid reaction for most favorable action and the 

 tablets now on the market are made up with some acid having no 

 effect upon the mercury salt. In i-ioo watery solution this salt 

 will kill anthrax spores in twenty minutes. In blood, the anthrax 

 bacillus is killed by a 1-2,000 solution in a few minutes. In bouillon 

 the same organism is killed in a dilution of 1-40,000; in water, 

 1-500,000; all in the same interval of time. The presence of the 

 albumins in the blood or bouillon, no doubt acts as a protecting 

 envelope about the bodies of the bacteria. Bichloride is then more 

 efficient outside the body than in it. It is also more useful and 

 powerful when it is acidulated with a . 5 percent of HC1, or when it 

 is mixed with common salt or ammonium chloride. In culture 

 1-1,000,000 solution prevents the growth of most pathogenic bac- 

 teria. Biniodide of mercury is said by some observers to be more 

 powerful than the bichloride. It is certainly less likely to be inter- 

 fered with by albumins. 



Sulphate of copper in water is a powerful germicide. It is more 

 potent in watery solution than in bouillon. It has a remarkable 

 affinity for algae and for moulds. The author found that if moulds 

 are put into alkaline solution of copper sulphate and heated, the 

 copper enters into chemical union with the protoplasm of the 

 mycelia, hyphae, and the spores; 1-400,000 of copper sulphate in 



