DAIRY FARMING DAIRYING AGROTECHNY. 37l 



The tubes tind cups were next kept iu a borax solution made by dissolving 

 1 lb. of borax iu 15 qt. of water. This did not sterilize the appai'atus. The 

 machine-drawn milk contained 17,817 bacteria per cubic centimeter and the 

 hand-drawn milk 8,767. 



In the seventh experiment the authors returned to the formalin treatment, 

 uging 3.5 per cent, but still the machine-drawn milk contained more bacteria 

 than the hand-drawn milk, the averages being, respectively, 7,857 and 6,355 bac- 

 teria per cubic centimeter. 



The formalin treatment was continued in the next experiment, but the air 

 taken into the teat cups was filtered through absorbent cotton. This reduced 

 the bacteria in the machine-drawn milk to 1,578 per cubic centimeter, while the 

 average number in the hand-drawn milk was 4.560. In a second series in which 

 the cotton filters were omitted the average bacterial content of the machine- 

 drawn milk was 11,521, and of the hand-drawn milk 7,467. 



In the final experiment lime water was used in the place of the formalin 

 solution. The bacterial content of the machine-drawn milk was 55,367 and of 

 the hand-drawn milk 5,908. 



The formalin treatment was, therefore, the only one tried which was efficient 

 in sterilizing the apparatus and at the same time was not injurious to the 

 rubber. 



In most cases the machine-drawn milk, notwithstanding the bacterial con- 

 tent was frequently higher, kept sweet longer than the milk drawn by hand. 



Effect upon milk yield. — This part of the bulletin gives the yield of cows 

 milked by hand and by machine. The results are submitted without discussion 

 or comment, the work being considered too limited to warrant any conclusions. 



Comparative studies with, covered milk pails, W. A. Stocking, Jr. {Con- 

 necticut Storrs *S7«. Bid. JfS, pp. 73-103, figs. 12). — The author has tested sev- 

 eral styles of covered milk pails taking the number of bacteria in the freshly 

 drawn milk as an indication of the amount of external contamination. The 

 different pails used are described and illustrated. The general conclusions 

 drawn from the work as a whole are as follows : 



" The use of the covered milk pail is of gi'eat advantage in any stable in 

 excluding dirt and bacteria from the milk. The relative advantage gained by 

 the use of the cover depends upon the sanitary condition of the stable. 



" The special form of cover does not seem to be important provided it is a 

 device practical for use and the area through which dirt can gain access to the 

 milk is reduced as much as possible. 



" Whether or not a strainer on the covered pail is desirable depends upon 

 the style of the straining device. 



" The use of the strainer in a pail where the dirt which falls into the open- 

 ing is likely to be driven through by the succeeding streams of milk is not 

 desirable. Its use tends to increase the germ content of the milk and injure 

 its keeping quality. 



" In pails where the dirt which falls in does not remain where the succeed- 

 ing streams strike against it a strainer cloth aids in keeping down the number 

 of Ijacteria which gain access to the milk. . . . 



" The use of absorbent cotton as a strainer ... is a decided advantage in 

 preventing the entrance of bacteria into the milk." 



Biological and biochemical studies of milk. V, Enzyms, C. J. Koning 

 {Milchic. Zenthl., 3 {1901), IVo. 6, pp. 235-261, figs. 2).— The catalase content 

 of milk, according to the author, increases with the age of the cow and with 

 the bacterial content of the milk. His experiments indicated that this enzym 

 is not produced by lactic-acid bacteria but by other oi'ganisms, sueh as those 



17305— No. 4—07 6 



