506 EXPEEIMENT STATION EECOED. 



lesser refined methods wliich have been used in the older investigations. With 

 the Bechhold method it is not necessary to dilute the milk and consequently any 

 <?hange in the conditions of dissociation which might occur as a result of adding 

 water are prevented. It also allows working with compressed nitrogen for the 

 purpose of preventing decomposition, and, furthermore, a concentrated filtrate 

 is obtained. 



It was found that boiling produces no depression of the freezing point in 

 either cow's or human milk. The nitrogen and phosphoric acid content were 

 practically not affected in cow's milk, but in human milk an appreciable reduc- 

 tion in nitrogen and phosphoric acid was produced. The calcium content in 

 the ultrafiltrate of both milks is diminished by long boiling, especially in cow's 

 milk. No changes were noted when buttermilk was boiled. 



From the data obtained with unboiled milk it can be seen that in human milk 

 the amount of noncolloidal rest nitrogen (nitrogen not precipitated by phospho- 

 tungstic acid) is greater than in cow's milk, and, furthermore, that a larger 

 percentage of phosphoric acid and calcium is present in the free state in human 

 milk than in cow's milk. Buttermilk, so far as calcium and phosphoric acid 

 are concerned, has a greater resemblance to human milk than to cow's milk. 

 The acid fermentation which has taken place in buttermilk results in a scission 

 of phosphoric acid from calcium. 



The biologic differentiation of railk proteins, H. Kleinschmidt (Monats- 

 schr. Krnderhcilk., JO {1911), pp. 402-419; ahs. in Ztschr. Immunitdtsf. u. Expt. 

 TJier., II, Rcf., 6 (1913), Ko. 15, p. iiOO).— Corresponding to the results obtained 

 with the complement fixation and precipitation reactions, it was also found 

 possible to differentiate milk proteins with the anaphylactic test and guinea 

 pigs; thus serum and milk proteins could be differentiated. The albumin and 

 globulin of whey seem to be the same substance. Casein is markedly differen- 

 tiated by the reaction. 



Animals sensitized with cows' milk albumin were not affected b.y injections 

 of casein. By a second injection of the homologous antigen, antianaphylactic 

 phenomena were observed. Animals sensitized to globulin became sick on 

 receiving the amount of casein which is lethal to animals sensitized with casein. 



Biological method for judging the quality of milk, S. Paraschtschuk 

 (Milchw. Zenfbl., 42 (1913), Xo. 3, pp. 05-69, figs. S).— In investigations on the 

 biological properties and peculiarities of various strains of lactic acid bacteria 

 it was observed that not every strain gave a good coagulum with milk, and that 

 the souring of milk at times went on very slowly. It often occurred that cul- 

 tures of equal strength and kind kept under the same conditions would not 

 coagulate certain kinds of milk at all. It was later found that certain strains 

 would not develop in poor milk, and consequently the use of lactic acid bacteria 

 for judging the quality of milk suggested itself. 



The milk under examination was poured into a flask and sterilized, and then 

 inoculated with the appropriate strains (1 to 2 per cent) of lactic acid bacteria 

 and incubated at 32 to 36°. Good milk after the lapse of from 5 to 6 hours is 

 coagulated. If the inoculation has been made with a loopful of bacteria, the 

 time required for coagulation is about 12 hours. 



For inoculation five separate strains of bacteria were used, as follows: (1) 

 A Danish streptococcus previously used for preparing dry lactic acid cultures 

 and which only grows on fresh milk; (2) a small diplococcus obtained from 

 Jaroslaw, which gives a marked coagulation and is characterized by the fact 

 that it remains virulent for eight months, or twice as long as any other culture; 

 (3) Giinther's lactic acid diplococcus, which yields a pleasant sweetish co- 

 agulum of not an especially thick consistency (the last two-named strains of 

 organisms require a milk of good quality for development, although they will 



