630 EXPERIMENT STATION RKCORD. 



"It will be seen that in the case of these animals, when the production of fat was 



approximately at its best, the digested fat of their food was nearly sufficient to meet 



the demand. ... As the result of 4 years' experiment with our seven Ijreeds of 



cattle, we have as follows : 



Poiiuds. 



Crude fat in food fed 24,358 



Pure fat iu food fed (82.6 per cent) 20,119 



Pure fat iu food between lactation jieriods 631 



Fat in milk 17,754 



"From which it Avill appear that there was cousumed by these various animals 

 16.9 per cent more fat than was produced by them in their milk." 



A preliminary bulletin on the pasteurization of milk, C. D. 



Smith {Michigan 8ta. Bui. 13L pp. 15-43, Jigs. (J). — This is a popular 

 bulletin on the pasteurization of milk, treating" briefly of the micro- 

 organisms in milk, the sources of infection, iiathogenic bacteria, dis- 

 eases traced to infection through milk, prevalence of tuberculosis among 

 cows, the need of regular official insi)ection of dair}^ herds, and milk 

 preservation. Under the latter head the pasteurization of milk is 

 described iu considerable detail, the requisites to pasteurizing being 

 enumerated, and illustrated descriptions given of several simple meth- 

 ods for household use and of the De Laval and Ivussell apparatus for 

 sterilizing milk on a commercial scale. The description of the latter is 

 reprinted from Wisconsin Station Bulletin 44 (E. S. R., 7, p. 987). 



Jt is explained that "the chief object of ])asteurizing milk at home is 

 to kill the germs of disease, and this is accomplished in one form of 

 apparatus as well as another if the entire mass of milk is kept at 155^ F. 

 for the requisite time.-' The author has found an ordinary wash boiler 

 filled with water up to the level of the milk in the tin cans entirely 

 satisfactory. Perforated tin pie plates are placed in the bottom of the 

 boiler and the cans set upon these. The water is heated to IGO'^ F. and 

 the cans of milk then placed in it without covers and stirred at frequent 

 intervals until the temperature of the milk reaches 155°. The covers 

 are then put on the cans and the boiler, and the latter set on the back 

 part of the stove. After the milk has been kept at 155° for 20 minutes 

 the cans are removed and placed iu ice water. Repeated experiments 

 have shown that with straight-sided tin cans 3 in. in diameter and 7 in. 

 deep the milk was cooled to below 50° in less than 15 minutes. 



"For hotels and large boarding houses Ave have no a2)paratus that gives more 

 promise of cheapness, ease of management aud efficiency than simple shotgun cans 

 and a boiler made to order as high as the cans are deep and long enougli to hold at 

 least three of the cans. These cans are 8 in. in diameter and 22 iu. deep, aud hold 

 conveniently 37 lbs. of milk." 



Two trials are reported on the keeping quality of milk sterilized 

 commercially by the De Laval apparatus. 



The testing of rennet preparations, and the curdling of milk 

 ■with cheese rennet, A. Deyaeda {Landic. Vers. Stat., 47 {1S96), iV"o. 

 0, pp. 401-447). — The following method is given for determining the 

 efficiency of rennet preparations, which is a modification of Soxhlet's 



