1004 



EXPERIMENT STATION RECORD. 



the inethixls of analy.'^is mid tlic it.<uIIs <il)l:iiiicil, aixl sumiiunizcs llic data in the 

 tal)le given Ix'low: 



Couslaiilx of liulti-r flit. 



In general the specific gravity increased with the Reichert number, and the sapon- 

 ification and refractonieter nunibens decreased. A low proportion of volatile acid 

 was associated with a high percentage of oleic acid. Twenty samples showed an 

 average Reichert nnmljer of 24.2 and an iodin number of 40, and 30 sami)les an aver- 

 age Reichert iiuml)er of 30.S and an iodin nnml)er of 32.4. 



Sodium fluorid for the preservation of butter, F. Je.vx ( Tml. Ar/r. Pro;/. [ ]"a- 

 kneiennes], 1903, No. 293; ahs. in Rev. Gen. Lait, 8 {1903), Xo. .',, ],. .9/).— While 

 condemning the use of antiseptics in food products the author would make an 

 exception of sodium fluorid as a means of preserving butter, arguing that when 

 properly used for this purpose the daily consumption of 60 gm. of butter Avould 

 mean the ingestion of 6 mg. of the fluorid^ an amount considered entirely unoffen- 

 sive, and which would moreover be rendered inert by the lime in the food and 

 digestive secretions. 



Chemical changes in the souring- of milk and their relations to cottage 

 cheese, L. L. V.\n Slyke and E. B. Hart (Xeiv York Slate Ski. Bnl. 245, pp. 30). — 

 The authors have studied the formation of casein monolactate and casein dilactate 

 in the ordinary souring of milk, and have considered the results obtained in their 

 relation to the manufacture and digestibility of cottage or Dutch chee.se. 



To study the relation existing between the disappearance of milk sugar and the 

 formation of lactic acid, with the subsequent formation of casein monolactate and 

 casein dilactate, fresh separator skim milk, with and without pasteurization and the 

 addition of a starter, was kept at room temperatures and examined at frequent 

 intervals. In all cases the milk sugar was found to decrease rapidly during the first 

 32 hours, after which the change was slow, ceasing entirely at the end of 72 to 96 

 hours. On an average 11 per cent of the milk sugar disappeared in 8 hours, 21 per 

 cent in 24 hours, 25.5 per cent in 32 hours, 26 per cent in 48 hours, 27 jier cent in 

 72 hours, and 27.6 per cent in 96 hours. 



The maximum amount of acid calculated as lactic, was al)out 0.9 per cent, which 

 was equivalent to only about 62 per cent of the milk sugar that disappeared. The 

 equation Ci2H220ii-t-H20=4C3HB03, while expressing the most prominent chemical 

 action which occurs, is therefore not believed to give anything like a complete or 

 accurate statement of the entire chemical action. Under the conditions of the 

 experiment the milk coagulated in from 24 to 29^ hours, the ac-id content of the 

 milk at the time of coagulation varying from 0.6 to 0.7 per cent. At the beginning 

 of coagulation the amount of casein in the form of monolactate was 13 to 14 per 

 cent, and in the form of dilactate, 86 to 87 per cent. Later the monolactate was 



