284 EXPERIMENT STATION RECORD. 



With the advance of lactation, the specific gravity, solids, fats, 

 protein, and ash increase more or less regularly, while the milk sugar 

 decreases. There is no regular variation between morning's and 

 night's milk when the interval between milkings is the same. Stall 

 feeding is not good for the sheep. The claims made for the East 

 Friesian milk sheep should be regarded with caution when the sheep 

 are to be taken to another locality. In the opinion of the author, the 

 use of the milk sheep as "the poor man's cow" is not to be recom- 

 mended in general over the goat. 



Studies on the souring of milk, H. Hoft (Milch Ztg., 26 (1897), 

 No. 14, pp. 211, 212). — The author made experiments on the restraining 

 influence of acetic, citric, oxalic, and lactic acid. Acetic acid restrained 

 fermentation noticeably, in proportion to the amount added to the milk. 

 Citric and oxalic acids both had a slight effect when added in consider- 

 able quantity; and lactic acid also restrained the fermentation. 



In souring milk in vessels of different shape it was found that the 

 souring went on most rapidly in a tall, narrow vessel, presenting a 

 small surface of milk. 



When equal quantities of cream and skim milk from the same sepa- 

 rator were taken, the cream almost invariably soured more rapidly 

 than the skim milk. 



Milk and cleanliness, F. H. Werenskiold (Norsk Landmansblad, 

 15 (1896), pp. 501-504). — The author examined for microscopic impurities 

 46 samples of new milk, 3 of cream, 3 of centrifugal skim milk, and 12 

 of gravity skim milk. The samples were taken at milk depots or from 

 the cans of milkmen in Christiania, Norway, and were examined accord- 

 ing to Renck's method, wiih the following results: 



Impurities hi milk. 



The 25 samples of milk or cream from milk depots contained from 0.0 

 to 4.2 mg. of impurities, an average of 1.9 mg. ; while the 39 samples 

 from milkmen contained from 0.1 to 11 mg. per liter, an average of 

 2.6 mg. 



For comparison the amount of impurities in a few other common 

 articles of food was determined, and it was found that 1 kg. of common 

 sugar contained 65.8 mg. of impurities; another sample of white granu- 

 lated sugar contained 242.5 mg. per kilogram, and 1 kg. of table salt 

 contained 366.0 mg. of impurities. 



In case of 59 of the samples of dairy products examined, the impuri- 

 ties were subjected to microscopic examination ; the author distinguishes 



