374 EXPERIMENT STATION RECORD. [Vol. 41 



A physical and bacteriological inspection of 184 empty cans as returned to the 

 shippers during June and July is summarized. The odor of 14 was classified 

 as sour and of 83 as foul. Over 42 per cent, if used without further rinsing, 

 would have added from 500,000 to 4,332,000 bacteria to each cubic centimeter 

 of milk. It is pointed out that milk produced under very insanitary conditions 

 seldom has an initial bacterial content in excess of 20,000. Prompt drying of 

 the cans after washing is considered the most urgent reform. 



The proper methods of caring for milk cans are otttlined. 



Refrigeration on southern dairy farms, J. T. Bowen {Hoard's Dairyman, 57 

 (1919), No. 10, pp. 489-491, figs. 5).— This is a discussion by the author of Bul- 

 letin 98 of the U. S. Department of Agriculture (E. S. II., 31, p. 575), based 

 upon the section on cooling milk on the farm in that publication, but consider- 

 ably augmented. Data are furnished as to the cost of operating quarter-ton 

 and half-ton refrigerating machines under different precooling temperatures. 

 In the Southern States, where ice is scarce, it is held that refrigeration would 

 eliminate the principal hot-weather difficulties in the care of milk. By pre- 

 cooling the milk with spring or well water and by storing up refrigeration it is 

 possible to make a small machine provide refrigeration for a comparatively 

 large herd. 



A study of the alkali-forming bacteria found in milk, S. H. Ayees, P. Rxjpp, 

 and W, T. Johnson, jr. (U. S. Dept. Agr. Bui. 782 (1919), pp. 39, figs. 2).— The 

 authors, working in the laboratories of the Dairy Division, have investigated 

 the occurrence and activities of the group of alkali-forming bacteria, limiting 

 that term to nonpeptonizing types capable of rendering milk alkaline. An in- 

 tensive studj^ was made of 68 cultures isolated mostly from market milk, a 

 few being obtained from ice cream. Both bacilli and cocci were included. The 

 organisms grew best at temperatures between 20 and 30° C. and had thermal 

 death points ranging from 60 to 65.5° when heated in milk tubes for 30 minutes. 

 No spores were observed. 



Record is made of the ability of each culture to ferment ethyl, propyl, and 

 amyl alcohols, dextrose, 22 different organic acid salts, and urea, the results 

 being given in terms of pH values except in the case of the alcohols. State- 

 ments are also made with respect to several other substances. Synthetic 

 media were used, nitrogen being supplied by sodium ammonium phosphate with 

 the test substance furnishing the carbon. Dextrose and galactose were fer- 

 mented readily, lactose and saccharose by a few cultures, and raffinose not at 

 all. The monatomic alcohols were fermented by more cultures than were 

 raannite and glycerin. Study of the organic acid data indicates that the 

 carboxyl radical does not serve as a source of carbon for these organisms. 

 Cai'bon was most easily obtained from the methyl group. It is held that the 

 characteristic reaction produced by these bacteria in fresh milk is due to the 

 oxidation of the citric acid salts present to alkaline carbonates. 



The alkali-forming bacteria (as defined) are considered to be primarily soil 

 organisms. They were present in numerous samples of soil, in water, on the 

 hands of farm laborers, in unsterilized milk utensils, and in small numbers in 

 cow feces. An ar])itrary classification based on the substances fermented is 

 proposed. 



A comparison of bacteria counts in whole and skim milk, separator and 

 centrifug-e cream, R. W. Lamson (Jour. Dairy Sci., 1 (1918), No. 6, pp. 498- 

 507). — The author claims that many of the published statements as to the bac- 

 terial content of cream are based upon laboratory centrifuging of milk in 

 flasks, and records the results of 10 experiments conducted by the Bureau of 

 Chemistry of the U. S. Department of Agriculture in which it was possible 



