40 



Judging from the above, table salt can hardly be 

 called preserving, while boracic acid is considerably 

 so, and salicylic acid even more so. With the latter 

 it is quite noticeable that it prevents the curdling for 

 an extremely long period. 



In regard to the difference of taste produced by 

 these preservatives, the admixture of boracic acid and 

 of common salt are hardly to be detected, but that of 

 salicylic acid very plainly, as it gives milk a sweetish 

 taste. The preserving effects of these admixtures 

 was found lessened in proportion to the time which 

 elapsed between milking and that of adding the chem- 

 icals, a natural conclusion when we remember how 

 rapidly the germs multiply. 



A sample of a " trebly concentrated preserving 

 salt," manufactured at Stuttgart, Germany, was ascer- 

 tained to be composed of salt and boracic acid, and an 

 admixture of it in the strength of O.OOS per cent, 

 added to milk had a preserving effect of '24 hours. 

 So.rJiIct also investigated the preserving qualities of 

 boracic acid and found that curdling was protracted 

 for: 



:>"> hours by an admixture of 0.1 per cent. 

 r>5 u u " 0.1 T> 



147 " u u 0.2 " 



2:>1 " " " 0.4 " 



Temperature, as well, has a most important influence, 

 and milk with an admixture of boracic acid 

 (1 gramme to 1 liter) was kept from curdling for />() 



