Milk Fermentations. 73 



In case it becomes necessary to employ chemical sub- 

 stances as disinfecting agents, their use should always be 

 preceded by a thorough cleansing with hot water so that 

 the germicide may come in direct contact with the surface 

 to be disinfected. 



It must be borne in mind that many chemicals act as 

 deodorants, i. e., destroy the offensive odor, without de- 

 stroying the cause of the trouble. 



Sulfur is often recommended as a disinfecting agent, 

 but its use should be carefully controlled, otherwise the 

 vapors have but little germicidal power. The common 

 practice of burning a small quantity in a room or any closed 

 space for a few moments, has little or no effect upon germ 

 life. The effect of sulfur vapor (802) alone, upon germ 

 life is relatively slight, but if this gas is produced in the 

 presence of moisture, sulfurous acid (H 2 S0 3 ) is formed, 

 which is very much more efficient. To use this agent 

 effectively, it must be burned in large quantities in a 

 moist atmosphere (three Ibs. to every 1,000 cubic feet of 

 space) for at least twelve hours. After this operation, 

 the space should be thoroughly aired. 



Formalin, a watery solution of a gas known as form- 

 aldehyde is a new disinfectant that recent experience has 

 demonstrated to be very useful. It may be used as a 

 gas where rooms are to be disinfected, or applied as a 

 liquid where desired. It is much more powerful in its 

 action than sulfur, and it has a great advantage over 

 mercury and other strong disinfectants, as it is not so 

 poisonous to man as it is to the lower forms of life. 



Bleaching powder or chloride of lime (Ca01 2 ) is often 

 recommended where a chemical can be advantageously 

 used. This substance is a good disinfectant as well as a 

 deodorant, and if applied as a wash, in the proportion of 

 four to six ounces of the powder to one gallon of water, 



