DAIRY FARMING — DAIRYING. 487 



The action of rennet on milk, Camus (La Semaine Medicate, 17 

 (1897), p. 275; abs. in Chem. Ztg., 21 (1897), No. 77, Repert., p. 215).— The 

 author found, with Gley, that rennet acts upon milk at 0° C. Milk 

 which had been kept for a long time with rennet at zero curdled almost 

 instantaneously when 3 or 4 drops of dilute lactic acid (1 to 10) was 

 added, while ordinarily, as is well known, a much larger quantity of 

 lactic acid is required to curdle milk at ordinary temperature. Rennet 

 previously dried could be heated to 100°, and even to 140°, without 

 losing its activity if treated with water after cooling. As milk is 

 readily sterilized, it was proposed to study the action of the sterilized 

 ferment on sterilized milk. But aqueous extracts of rennet, when pre- 

 viously neutralized, are rendered inactive by a medium low heat. For 

 example, distilled water has an unfavorable action on rennet at 40°, the 

 amount of the rennet rendered inactive at this temperature increasing 

 with the duration of the treatment and with the amount of water used. 



The cause of the curdling of milk when heated, B. Bardach 

 (Monatsh. Chem., 18 (1897), pp. 199-216; Chem. Ztg., 21 (1897), p. 290).— 

 The author made numerous experiments with milk and casein. As a 

 result of his studies he concludes that the curdling of milk by heating- 

 is a .complex process due to a change in the casein combined with the 

 action of small amounts of acid formed from the lactose when milk is 

 heated at high temperatures. The acid formed is unable to curdle the 

 original unchanged casein, and it is only after the casein has been 

 changed by heating that it is coagulated by the acid. 



The occurrence of alcohol in milk, H. Weller (Forsch. Lehensmtl. 

 Hyg., L (1897),p. 20; abs. in Chem. Ztg., 21 (1897), No. 77, Repert., p. 213).— 

 The examination of milk which had an irritating after-taste and which 

 was produced by a large herd of cows at a distillery showed the follow- 

 ing: Specific gravity at 15° 1.0335, solids 13.30, fat 3.89, alcohol 0.96 

 per cent. The concentrated food of the herd consisted of distillery 

 waste (slump). The material causing the irritating after-taste of the 

 milk could be expelled with steam, and could be obtained from the dis- 

 tillery waste in the same way. 



The evidence is regarded as conclusive that perfectly fresh and sweet 

 milk may contain alcohol when the cows receive food containing alcohol. 



Food and milk production, E. A. Shtjttleworth (Ontario Agr. 

 Col. and Expt. Farm Rpt. 1896, pp. 26-30). — An experiment was made 

 with 2 cows, an Ayrshire and a Holstein. The time, from April 2 to 

 •Inly 21, was divided into 5 periods, the cows being fed rations varying 

 in richness in alternating periods. In. the last period they were on 

 pasturage, the Ayrshire receiving about 2 lbs. each of oil cake and 

 chopped peas in addition, and the Holstein a little hay. The results, 

 including the average composition of the milk in different periods, are 

 tabulated. 



"The Ayrshire in the second period, when she was abundantly fed. gave an aver- 

 age daily yield of 25.48 lbs. of milk, being 12 lbs. more than in the first, and 10 lbs. 

 more than in the tbird periods, when she received insufficient nourishment. The 



