DAIRY FARMING DAIRYING. 



387 



the acid form salts that are easily eliiiiinatcil from tlie product in Imtter making, 

 passing into tlie l)uttermilk and leaving no undesirable taste in the butter. Further- 

 more, they do not form jiroducts any mure harmful than tlie ordinary salt employed. 

 In neutralizing sueh milk certain undesirable Havers are eliminated. Neutralized 

 milk may be pasteurized, therel)}' destroying many bacteria that have an undesirable 

 influence, and the cream inoculated with pure cultures. The neutralized milk is 

 easily and thoroughly creamed after heating to 45° C. When the milk contains free 

 acid, much foam is formed m separating. This is obviated by the neutralizing. The 

 curds from neutralized milk may be made into cheese and ripened in the ordinarv 

 manner. 



Influence of the addition of boric acid, borax, and sodium sulphite upon 

 the coagulation of milk, L. Lange {Arrli. Ifi/<j., 40 (luoi), No. 2, pp. 1S1-1S6). — 

 The author made a study of the spontaneous coagulation and the coagulation by 

 rennet of milk to wliich had been added l)oric acid, borax, and sodium sulphite. 

 The varying amounts of the preservatives were added to 10 cc. of the milk and the 

 coagulation carried out in sterilized tubes at room temperature. 



The addition of boric acid to the milk gave the following results with spontaneous 

 coagulation : 



Days. 



Control coagulated in 2\ 



With \ per cent boric acid in 3 



With \ per cent boric acid in ^ 4 



With J per cent boric acid in o\ 



With 1 per cent boric acid in 7 



With 2 per cent boric acid Did not coagulate. 



AVith 4 per cent boric acid Did not coagulate. 



The time required for coagulating the milk after the addition of 0.1 cc. of a 1 per 

 cent rennet solution is shown in the following table. The first column shows the 

 result soon after the addition of the boric acid, and the second column 2 days later. 



Coagulaiion of preserved milk by rennet. 



Strength of preservative. 



No preservative 



i per cent boric acid . 

 i per cent boric acid . 

 \ per cent boric acid . 



1 per cent boric acid . 



2 per cent boric acid . 

 4 per cent boric acid . 



Fresh ; ^Ii^k pre- 

 *7,r served 

 °'''^- twodavs. 



Seconds. 

 165 

 125 

 100 

 70 

 45 

 30 



Seconds. 

 80 

 345 

 255 

 240 

 150 

 125 



a Did not coagulate. 



It will be observed that in spontaneous coagulation the process was hindered, and 

 with above 2 per cent of boric acid no coagulation took place. With the rennet 

 extract the time of coagulation was shortened by the use of up to 2 per cent, while 

 with 4 per cent, as with si>ontaueous coagulation, no action of the rennet w'as possi- 

 ble. It would appear that the boric acid in small amounts had a deterrent effect 

 upon the bacteria concerned in the natural coagulation of milk, while up to 2 per 

 cent it had no unfavorable effect upon the unorganized ferment of the rennet. 



With borax the results were not so striking. There was with the increased addi- 

 tion of this substance a slight retardation of the rennet coagulation. 



The addition of from i to 1 per cent of sodium sulphite exercised no essential 

 influence upon the coagulation of rennet; nor was the natural coagulation apparently 

 affected by it. 



The action of certain proteolytic enzyms in the ripening of cheese, 0. Jen- 

 sen {Ann. Agr. Suisse, 2 {1901) , No. 3, pp. 95-100). — In the conthiuation of his work 



