New YorK AGRICULTURAL EXPHRIMENT STATION. 187 
TasBLe VIJ.— Resuuts or FREUDENREICH CALCULATED ON BASIS 
oF TotaL NITROGEN IN MILK. 
Soluble Amide 



nitrogen, | nitrogen, 
expressed | expressed 
AGE OF MILK WHEN fas percent- as percent- Organism used. 
ANALYZED. age of total age of total 
nitrogen in|nitrogen in 
milk. | milk. 
Beginning of experiment. Ostrene S.C poaes .  e  c s tere ee 
Sie oy ah ek MIR died, Sle iii 47.0 | 34.6 Milk culture Bac. ¢ from rennet. 
RVRIREEREIUINS So? ese 4, 5.00 oes 44.4 30.2 Milk culture Bac. ¢ from cheese. 
LEaOU LOB Es ede 4 AO G2 ANE A A Milk culture Bac. ¢ from cheese. 
Pamanuiss... ot... 2s 42.8 | 28.0 Bac. a and Bae. ¢. 
POH; oo ote Ue es, 18.8 | 10.6 Bac. a. 
The amounts of soluble nitrogen reported by Freudenreich as 
being formed by the action of different lactic-acid-producing 
organisms are considerable. Moreover, it is to be noticed that 
quite large amounts of amide nitrogen are formed. While there 
were in the flasks used solutions of calcium carbonate and of 
calcium lactate, we can not explain the relatively large amounts 
of soluble nitrogen by the solubility of either the saturated or 
unsaturated lactates of casein in solution of calcium carbonate 
or lactate. Whether his explanation is correct or another is to 
be found, Freudenreich’s results clearly represent actual pro- 
teolytic changes of casein. 
Nicholson’ repeated Freudenreich’s work, using the common 
lactic acid bacterium found in cheese, but failed to find any pro- 
teolysis of casein. Nicholson says: ‘“ In some cases, the table 
shows a slight increase in soluble nitrogen, where the calcium 
carbonate has been added; in others, there is no increase. In the 
uncarbonated milk there is absolutely no increase in any case.” 
The slight increase reported by Nicholson in the case of the miJk 
containing calcium carbonate can readily be explained on the 
basis of the slight solubility of the lactic-acid salts of casein in 
solution of calcium carbonate or calcium lactate. 
We have recalculated a portion of Nicholson’s results on the 
same basis as that used with AES ss figures, and give 
them in the table following. 
14¢Thesis for Master’s Degree—Univ. of Wis. 1902. 
