DAIRY FARMING DAIRYING. 783 



cake or peanut oil, in certain amounts, has an important inftuonce on the fat content 

 of the luilk. In a ration witli a luitritive ratio of 1:3.6 and a fat content equal to 

 about 1 gm. to 1 kg. of live weight, the addition of more fat in lieu of carbohydrates 

 tended to a diminution in the yield of milk fat; a decrease in the fat in the food, if 

 below a certain limit, caused a decrease in the fat content of the milk and an increase 

 in the sugar, ash, and nitrogen. Again, the fat in the food may cause an increase in 

 the fat content of the milk, but not of the other comi:)onents. The fat in the food 

 in increased amounts produces an increased fat content of the milk, up to a certain 

 limit. Beyond that it varies with the individuality of the animal, and in an unusual 

 amount may even cause a lessening of the fat content. 



Investigations concerning' the germicidal action in cow's milk, (). F. Hun- 

 ziKER {Ncir York (\rnidl Sta. Bid. 197, pp. G1-'j1, dgniM. .>). — The source of bacteria in 

 milk is briefly discussed and investigations to determine the presence and degree of 

 germicidal ([ualities in milk and the conditions most favorable for their action are 

 reported in detail. The cause of the germicidal action in milk, according to the 

 author, is unexplained. The data for the experiments are tabulated, and 3 diagrams 

 are given showing graphically the germicidal action in milk as affected by tempera- 

 tures ranging from 40 to 70° F. by heating to 149-212° F., and by the acidity of the 

 milk. From the results of the experiments, which are discussed at some length, the 

 following c(mclusions are drawn: ^ 



"(1) Freshly <lrawn milk of most cows contains varying germicidal qualities. 



"(2) The degree of the germicidal action varies greatly in milk of different animals 

 and sometimes in milk of the same animal taken at different milkings. 



"(3) The bactericidal influence behaves differently at different temperatures. It 

 appears to be greatest, while it lasts, at 70° F. ; at lower temperatures it is less pro- 

 nounced but of longer duration. At 70° F. the maximum duration of the germicidal 

 action was 12 hours, the average duration 3 to 6 hours. 



"(4) Heat is detrimental to the germicidal agent. Milk subjected to a tempera- 

 ture of 149° F. for 40 minutes had lost its bactericidal qualities. 



"(5) The acidity in milk did not increase appreciably while the germicidal action 

 lasted. A decided and continuous increase of acidity occurred only about 15 to 20 

 hours before the milk curdled. 



"(6) Owing to the lack of control over the germicidal power, the latter can at 

 present be of little value in practical dairying. 



"(7) So far as investigations up to the present time have shown, the best means 

 of improving the keeping quality of milk, without the use of chemical preservatives, 

 seems to be scrupulous cleanliness and low temperatures." 



Studies in dairy bacteriology and dairy science, E. Petersson ( A". LamU. AJcad. 

 Jldiidl. TIdsli:, .J!) (JHOO), No. r,-0, /i/i. 27'>--U7). — A report of the following German, 

 Swiss, or Danish dairy in.stitutes or schools: Gottingen, Ilameln, Fulda, Kiel, Star- 

 gard, Kleiniu)f-Tai»ian, Bern(% and Copenhagen, and of the dairy experiment stations 

 connected with the larger of these institutions. A detailed outline of a short bacteri- 

 ological laboratory and lecture course given by Professor Salomonsen, Copenhagen, is 

 presented, as are also the results of work on the occurrence of lactic-acid bacteria, 

 their general morphological and biological characteristics, done by the author in the 

 dairy liacteriological lal)oratory at Gottingen Agricultural Institute. — p. w. woll. 



Milk bacteria investigation, V. A. Mooke {Neiv York Prod nee Rev. and Amer. 

 Crnniirrii, 190./, .fun. ./.-', ]i. ..^9). — The following deductions are drawn from a study 

 of bacteria in milk: 



" (1 ) Milk as it is drawn from the; udder contains a variable, but rarely an exces- 

 sive, number of bacteria. 



" (2) Ordinarily the dirt and finer jiarticles of dust that fall into the pail during 

 the process of milking carry a large number of bacteria with them into the milk. 



