DISINFECTANTS IN MILK. 153 



Salicylic acid, which may be used in proportion of .3~.2 gm. per quart 



milk. 

 Formalin, which may be used in proportion of .O2-.OI grrt. per quart 



milk. 



Hydrogen peroxide, which may be used in proportion of 5-6 c.c. per 

 - quart milk.^ 



There are some other substances occasionally employed, 

 but these are the basis of most of the products sold for the 

 purpose of preserving milk and going under various com- 

 mercial names. The use of all such disinfectants is open to 

 several objections. 



1. They are all adulterants and, therefore, all are forbidden 

 by legal statutes. 



2. To be really efficient they must commonly be used in 

 quantities large enough to produce a noticeable taste in the 

 milk. 



3. The effect of these adulterants upon the health of the 

 consumer is an important consideration. They are all drugs 

 of a more or less poisonous nature, and it is certainly not 

 desirable to consume them constantly in considerable quan- 

 tity. That it is undesirable to consume them in large amount 

 is certain, but whether, in such small quantities, they are liable 

 to produce any appreciable injury in the consumer has been 

 vigorously disputed. It is claimed that the presence of 

 boracic acid in milk is responsible for a considerable amount 

 of the digestive derangements and malnutrition which can be 

 found in countries where boracic acid is used quite freely, but 

 it is difficult to prove this fact and it is still under dispute. 

 Whether any of these materials can be used without any dan- 

 ger we do not yet know. The quantity of formalin required 

 to protect milk from souring is extremely minute, and it is 

 doubtful whether this extremely minute quantity of formalin 

 is sufficient to render the milk any less wholesome. Hydro- 

 gen peroxid appears also to be harmless and capable of being 

 used without interfering with the wholesomeness of the milk, 



