DAIRY FARMING DAIRYING. 387 



and pin-holey curds the test showed that the bad milk could be traced 

 to different sources where carelessness prevailed in caring for the 

 milk. The trouble was overcome when the fault was located. In 

 another factory, where brick cheese was made and the quality of the 

 product was so poor that the cheese had fallen off 3 cts. per pound in 

 value, the curd test narrowed the trouble down to 3 cows that gave 

 gassy milk. When the milk of these 3 cows was excluded the 

 trouble disappeared at once. In another brick-cheese factory where 

 similar trouble occurred "the curd test of each patron's milk revealed 

 the fact that in <> out of 28 cases bad milks were being brought to the 

 factory." When the milk from these patrons was excluded good cheese 

 was produced. An extract is given from the report of the traveling 

 dairy instructor of the Wisconsin Dairymen's Association to the effect 

 that the test " will locate tainted milk with unerring certainty," and 

 "is simple, practical, reliable, and very convincing." 



Contribution on rennet curdling, R. Benjamin (Inaug. Diss., Ber- 

 lin, pp. 32). — The author made investigations on the action of rennet on 

 the casein of milk in the presence of foreign substances or in the case 

 of milk treated in different ways, the action of rennet to which chloro- 

 form was added, and the action of rennet on other animal and vegetable 

 albuminoids. 



Milk with an acid reaction curdled most rapidly, that with a neutral 

 reaction more slowly, and a too strongly alkaline solution prevented 

 curdling altogether. Milk to which chloroform was added curdled some- 

 what more slowly, and milk diluted with water even more slowly. Boiled 

 milk refused to curdle with a strong rennet solution, but was curdled 

 by rennet powder in 5 minutes. It was found impossible to curdle ster- 

 ilized milk by any means. The addition of chloroform in very small 

 quantities in making up the rennet solution was found to increase the 

 curdling action of the rennet, while large quantities diminished it. No 

 animal or vegetable albuminoid, except the casein of milk, was found 

 to be acted upon by rennet. All solutions of casein which curdled with 

 rennet were found, like milk, to be alkaline toward lacmoid and acid 

 toward phenolphthalein; and casein solutions were not curdled except 

 in the presence of soluble lime salts. 



Further contributions on milk hygiene, Ott (Ztschr. Fleisch- u. 

 Milchhyg., 8, Xo. 4,pp. 69-74). — The author discusses the danger of infec- 

 tion with tuberculosis from using raw milk. Forty-three samples of 

 market milk were examined for tubercle bacilli by treating 2~> cc. of 

 milk with 2 cc. of caustic ammonia and 100 cc. of a mixture of ether and 

 petroleum ether in equal parts, removing the fat layer, and then treat- 

 ing the remainder of the solution in a centrifugal apparatus for 15 min- 

 utes. The sediment was then examined in the ordinary manner. Of 

 the 43 samples of milk tested 5 were found to contain the bacilli, the 

 number of bacilli in 4 cases being small. 



To test the virulence of the bacilli guinea pigs were inoculated with 



