152 PROTECTION OF THE CONSUMER. 



obtain a higher price for their milk. Nevertheless, although 

 these various rules are incapable of absolute enforcement they 

 become much more forcible when they are a part of the public 

 statute, as they are in many European cities, than when they 

 are only a matter of advice on the part of a few private per- 

 sons. In America, where such rules are only suggested, they 

 are not so likely to be followed, as they would be if they were 

 a part of the public statute, and were put in printed form in 

 the hands of every milk producer. The general conditions 

 under which milk is produced are doubtless improved by the 

 numerous regulations in regard to the details of milk produc- 

 tion which are adopted by the European cities. 



PURIFICATION OF MILK. 



Although it is impractical to avoid the entrance of bacteria 

 in milk and difficult to prevent their growth, it is possible to 

 get rid of them later. The problem of how to purify milk 

 from its bacterial contamination has occupied a large amount 

 of attention, and resulted in a large number of devices and 

 special forms of apparatus. None of the methods suggested 

 is thoroughly satisfactory. Most of them are only partially 

 successful in reaching the desired end, and even these have 

 manifest disadvantages. 



The Use of Disinfectants. A simple means of accomplish- 

 ing this end is to add to the milk some material which will 

 prevent the bacteria from growing. There are a number of 

 chemicals that can be used for the purpose. It is, of course, 

 necessary to use such as are comparatively harmless to man, 

 and which do not give a noticeable taste to the milk. To be 

 of any use a disinfectant or preservative must be of a nature 

 such that a quantity insufficient to give any taste must have a 

 decided effect in reducing bacteria growth. Only a few of 

 the known disinfectants are feasible for use in milk and those 

 most commonly used are the following (177, 178) : 



Boric acid, which may be used in proportion of I gm. per quart milk. 

 Borax, which may be used in proportion of 5 gm. per quart milk. 



