174 EXPEPJMENT STATION RECORD. [Vol.36 



respectively, making the feed cost per gallon of milk 6.8 cts. and 6.9 cts. for tlie 

 two goats. 



Further studies of the relation of the quality of proteins to milk produc- 

 tion, E. B. Habt, G. C. Humphrey, and A. A. Schaal (Jour. Biol. Chcm., 26 

 (1916), No. 2, pp. 457-4^1, fios- 4)- — Continuing tha study previously noted 

 (E. S. R., 33, p. 275), data on the comparative value for milk production of the 

 proteins of gluten feed, oil meal, distillers' grains, casein, and skim-milk powder 

 are reported. Fifty per cent of the total digestible proteins of the ration was 

 furnished by these concentrates, which were used to supplement a basal ration 

 of corn stover, corn silage, and corn meal. The total protein intake constituted 

 about 10 per cent of the dry matter of the ration, and the nutritive ratio was 

 approximately 1 : 8. 



" With a daily production of 40 to 45 lbs. of milk carrying 10 to 12 per cent 

 of total solids, negative nitrogen balance ijersisted throughoiit the experiment 

 of 16 weeks' duration. Only during the period of skim-milk powder feeding 

 was one of the animals storing nitrogen. In spite of this long negative balance 

 milk secretion continued at the expense of catabolizing tissue. The total yield 

 and total solids of the milk declined .slightly after two months of continuous 

 negative nitrogen balance." 



A marked dilference in the utilization of the concentrates Avas observed, 

 gluten feed showing a percentage efficiency of 45, oil meal 61, distillers' grains 

 00, casein 59, and skim-milk pov\'der GO. These data I'epresent the efficiency in 

 the mixture used. 



" Possible errors in calculation may arise from the supplementing effect of the 

 catabolizing tissue, thereby raising the figures above their true value, but 

 nevertheless they do have comparative worth. Other roughages will be, used in 

 a further study of this problem. 



" These studies furnish additional evidence that the nutritive ratio or plane 

 of protein intake for milk production may vary according to the nature of the 

 concentrates and basal ration used." 



Cooling hot-bottled pasteurized milk by forced air, S. H. Ayeks, J. T. 

 BowEN, and W. T. Johnson, Jr. (U. S. Dcpt. Agr. Bui. 420 (1916), pp. 38, figs. 

 20). — In continuation of investigations previously noted (E. S. R., 31, p. 275), 

 experiments are reported the object of which was to ascertain whether hot- 

 bottled pasteurized milk can be successfully cooled by forced air under com- 

 mercial conditions. Data are also given on the heating cf cold-bottled milk 

 by means of circulated hot air. 



The cooling experiments were conducted on a 30-crate basis, 15 for quart 

 bottles and 15 for pints, with a specially designed experimental apparatus which 

 is illustrated and described. A description is also given of the instruments and 

 method of recording data. On account of the small variation in the relative rate 

 of the cooling of water and milk, water was mainly used in these experiments. 

 Bottles of milk were distributed throughout the crates, however, for bacterio- 

 logical studies as well as for temperature readings. Temperature readings were 

 also taken in the bottles of watei'. 



To compare the rate of cooling bottles and cans containing milk when exposed 

 to still air and to moving air, pint and quart bottles and 10-gallon cans of milk 

 were place<l in a refrigerated room, the temperature of which was held at about 

 40° F. In still air it required 4J hours to reduce the temperature of milk in 

 pint bottles from 142 to 50°, while in circulating air, where the air was forced 

 in a horizontal direction over the containers at a velocity of 1,250 ft. per minute 

 and at a temperature of about 40°, the corresponding time required was 1 hour 

 and 27 minutes. "With quart bottles of milk under the same conditions the 



