170 BACTERIOLOGY. 



small value, but continued high temperatures not as 

 great as that of fire will destroy all forms of life; thus, 

 boiling or steaming in closed vessels for one-half hour 

 will absolutely destroy all disease germs. 



4. Carbolic Acid Solution. Dissolve six ounces of 

 carbolic acid in one gallon of hot water. This makes 

 approximately a 5 per cent, solution of carbolic acid, 

 which, for many purposes, may be diluted with an 

 equal quantity of water. The commercial " crude car- 

 bolic acid" should not be used, as it does not readily 

 enter into solution. Care must be taken that the pure 

 acid does not come in contact with the skin. 



5. Bichloride Solution (bichloride of mercury or cor- 

 rosive sublimate). Dissolve sixty grains of pulverized 

 corrosive sublimate and two tablespoonfuls of common 

 salt in one gallon of hot water. This solution must be 

 kept in glass, earthen, or wooden vessels (not in metal 

 vessels). For safety it is well to cover the solution. 



The carbolic and bichloride solutions are very pois- 

 onous when taken by the mouth, but are harmless when 

 used externally. 



6. Milk of Lime. This mixture is made by adding 

 one quart of dry, freshly slaked lime to four or five 

 quarts of water. (Lime is slaked by pouring a small 

 quantity of water on a lump of quicklime. The lime 

 becomes hot, crumbles, and as the slaking is completed 

 a white powder results. The powder is used to make 

 milk of lime.) Air-slaked lime (the carbonate) has no 

 value as a disinfectant. 



7. Dry Chloride of Lime. This must be fresh and 

 kept in closed vessels or packages. It should have 

 the strong, pungent odor of chlorine. 



8. Formalin. Add one part of formalin to ten of 



