256 



It is thought that mulch, eveu iu the warm climate of this State, can be profitably 

 used. The facts iu this regard should be learued by careful tests. 



It is advisable to plaut but few varieties, aud select theui with care, having la 

 view vigor aud productiveness of plant, size, character, aud quality of fruit. Pistil- 

 late varieties should be interspersed with perfect flowering sorts, usually three to 

 five rows of the former to one of the latter. 



Wisconsin Station, Bulletin No. 24, July, 1890 (pp. 18). 



A NEW METHOD FOR THE ESTIMATION OF FAT IN MILK, ESPECIALLY 

 ADAPTED TO CREAMERIES AND CHEESE FACTORIES, S. M. BABCOCK, 



Ph. D. — The object of this, as of several methods lately described (Short, 

 Parsons, Patrick, Failyer aud Willard, Cochran, and others), was to 

 devise a simple aud quick method for the determiuatiou of the per- 

 centage of fat in milk, fitted for the use of breeders and dairymen for 

 estimating the value of cows as milkers, in order to improve their 

 stock, and by creameries iu adjusting the i)rice to be paid to patrons. 



As iu several of the other methods named, acid is added to the milk 

 and the albuminoids, casein, fibriu, etc., are changed to soluble acid- 

 albumins, which offer less resistance to the rising and aggregation of 

 the fat globules. The peculiar feature of this method consists in plac- 

 ing the bottles containing tbe acidified milk iu a centrifugal machine, by 

 the rapid revolution of which the fat is made to separate more quickly 

 aud completely. 



The bulletin describes the apparatus, chemicals, and manipulation 

 of the method in sufficient detail to be understood by those who have 

 not the training of the laboratory. 



Approximately equal volumes of milk and commercial sulphuric acid 

 of 1.82 specific gravity are mixed iu a test bottle with a long graduated 

 neck. A pipette delivering about 17.5 cubic centimeters of milk, and a 

 measuring cylinder for the acid are used. The bottles are " whirled for 

 several minutes at a temperature of about 93° C. (200° Fah.), in a hori- 

 zontal wheel making from seven to eight hundred revolutions per 

 minute. This wheel is surrounded by a copper jacket, which may be 

 filled with hot water for heating during the test. "The separation of 

 fat by gravity alone is not complete even when the bottles are left 

 standing for -several hours; with the centrifuge, however, a perfect 

 separation is accomplished in a few minutes." If whirled at once no 

 heat need be applied, as that caused by the strong acid aud milk is suf- 

 ficient. After whirling, the bottles are filled to the neck with hot water, 

 returned to the machine, and whirled for one or two minutes longer, 

 after which they are filled with hot water " to about the 7 per cent 

 mark," and the machine is again turned for a short time, the tempera- 

 ture being kept up by means of a kerosene lamp or filling the jacket 

 with hot water. The fat separates out aud is read off while still liquid, 

 preferably at about 65° C. (150° Fah.), the reading giving the per cent of 

 fat directly without calculation aud being easily taken to 0.1 per cent. 



