260 EXPERIMENT STATION RECORD. 



Oxygen was not necessary to the fermentation. The effect of diifer- 

 ent temperatures was studied in detail. Although at lower and middle 

 temperatures the bacillus behaved like spontaneously souring milk, at 

 higher temperatures (above 4'5o C.) it diifered perceptibly. It was 

 found that the spontaneous souring between 44 and 50° C. was a lactic 

 fermentation, but was caused by a difterent organism from the one cans 

 ing the ordinary spontaneous souring. The author concludes that there 

 are two well-characterized mocroorganisms concerned. Sometimes one 

 of these predominates and sometiuies the other. The most common of 

 these is a micrococcus, the other a bacillus. Both thrive only at a high 

 temperature, but are very different on agar plates. In other respects 

 they appear to be alike. They cause exactly the same curdling of steril- 

 ized milk as the bacteria causing the common spontaneous souring, 

 although they act only at higher temperatures — at 33 to 35° C, rela- 

 tively slowly, but rapidly at 40 to 48°. The product of their action is 

 the same as the common form, except that the micrococcus produces 

 right-handedlactic acid, while the bacillus produces theleft-handed acid. 



With regard to the occurrence of the ordinary bacillus of the spon- 

 taneous souring of milk, the author found it regularly in dust, provided 

 this had not laid too long in a dry j^lace. It was frequently found on 

 hay and straw, but not in cow dung or tap water. It was found to be 

 an active element in the pure cultures purchased at the Kiel Station 

 for souring cream and in Hansen's preparation. 



Creaming experiments, F. B. Lini< ield ( Utah Sta. Bui. 43, pp. 15). — 

 In these experiments, which covered nearly a year, comparisons were 

 made between separating the cream with a hand separator and cream- 

 ing in shallow pans and in deep cans of the Boyd Cooley, Shotgun, 

 Common Sense, and Vermont Cooley patterns. The Common Sense 

 can is like the Shotgun, except that the skim milk is drawn from the 

 bottom of the can. The results with each method of creaming are 

 tabulated and summarized. Taking the averages for the whole year, 

 the percentages of fat in the skim milk with the different methods 

 were as follows: Shallow pan 0.35, Boyd Cooley deep can 0.70, Shotgun 

 pail O.Go, Common Sense pail 0.70, Vermont Cooley can 0.70, and 

 separator 0.10. 



A number of tests of the skim milk from fiirms where deep and 

 shallow pans were used for skijnming indicated that the above results 

 "are not exceptional, but rather better than many peojjle are doing." 



Six tests were made during the fall and winter months of setting the 

 milk in deep cans in ice water or in the air. In September setting in 

 ice water gave much the best results, but in the winter months there 

 was naturally less difference. 



The author makes the following practical deductions from his experi- 

 ments : 



" (1) As regards thoroughness of skimming, the efl'ectiveness of the methods of 

 creaming milk, according to our work, stands in the following order: 1st, separator; 

 2d, shallow pans ; 3d, deej) pails. 



