104 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



packages containing about one pound each are sold for thirty- 

 iive and thirty cents respectively. 



Boric acid is used at the present time largely by some milk 

 •dealers who furnish milk and cream to city customers. For 

 illustration I may call attention to some results taken from the 

 last report of the Ohio Dairy and Food Commissioner. Of the 

 four samples of cream suspected of adulteration, three contained 

 from o. 20 to 0.23 per cent, of boric acid. It must not 

 be taken for granted that this means that three of every 

 four samples of cream contain boric acid, but only that Of the 

 four samples suspected of being adulterated by the Ohio Com- 

 missioner, three were found to contain boric acid, as stated. 

 The same report contains results of the analyses of samples of 

 milk which were found to have about the same quantity of boric 

 acid as the samples of cream. 



Salicylic acid is almost. entirely used for the preservation of 

 foods other than dairy products. For the purpose of preserving 

 composite samples it is of little or no value. The copper and 

 mercury salts of salicylic acid, however, are probably equal 

 to corrosive sublimate and potassium dichromate as preservatives. 

 The ammonium, potassium, sodium, and zinc salts of this acid 

 have about the same value as the acid. The s alts of salicylic 

 acid are more expensive than those that are in common use and 

 therefore are not liable to come into general use for the composite 

 .samples. 



Formaldehyde, which was introduced some years ago, is, I 

 l3elieve, becoming more generally used as a preservative, not 

 only for dairy products but generally as a preservative. The 

 substance is one which is widely distributed throughout nature. 

 It is found in the leaves of plants, where it may be said to be 

 formed from water and the carbon dioxide of the air, and from 

 which the plant produces sugar. Formaldehyde is readily man- 

 ufactured from wood alcohol, and in its pure condition is a gas. 

 To produce this gas all that is necessary is to burn wood alcohol, 

 where there is a limited supply of oxygen or air. This result 

 may be produced by burning the alcohol in a lamp made for 

 this purpose, or the vapor of the alcohol mixed with air is 



