386 EXPERIMENT STAIION RECORD. 



and 28.6 lbs. of butter per cow, or an average yearly yield of 5,940 lb.s. of milk and 

 343.2 lbs. of Imtter." 



The milk supply of Copenhagen, F. C. Harrison [Ontario Agr. Col. and Expt. 

 Farm Rpt. 1900, pp. 74-77, fig. 1). — An account is given of the operations of the com- 

 pany supplying milk to Copenhagen. The filtering apparatus in use is illustrated. 



A biological study of pasteurized and unpasteurized milk, E. W. Hammond 

 {Ontario Agr. Col. ami Expt. Farm Rpt. 1900, pp. 77-6"i).— Results of a study of the 

 bacterial content of unpasteurized milk and milk pasteurized at different tempera- 

 tures are summarized in tables. Different species of germs were isolated and inocu- 

 lated into sterile milk and into guinea pigs or rabbits, the results of the inoculation 

 being noted in each case. The author's coTiclusions are as follows: 



"When the milk was run through the pasteurizing machine at low temperature, 

 the effectiveness of germ destruction varied greatly. When the tem^jerature was 

 raised to 160° F., the effect was excellent. The number of germs was reduced, and 

 those of a disease-producing variety were all killed. . . . Previous tests prove that 

 continuous pasteurization has been made at too low temperatures to insure the getting 

 rid of the germs which cause bad effects. Heating milk to a temperature of 160° F. 

 insures the death of Bacillus tuberculosis in 15 minutes, reduces the number of other 

 bacteria, and does not give a permanent cooked taste." 



A study of the causes of the variation in the composition of butter, J. J. L. 

 Van Ryn {Landu-. Vers. Stat., 5.5 [1901), Xo. ^-.5, pji. 347-378). — Owing to the con- 

 troversy over the purity of certain Netherland butters during the past year, the 

 author sought to determine those factors influencing the variations in their compo- 

 sition. In a long series of trials the breed, age, and time of calving of the cows were 

 noted, and the soil, food, and method of, feeding. Tables of analysis are shown, 

 giving the refraction, specific gravity, volatile, sr)luble, and insoluble fatty acids and 

 saponification and iodin numbers. 



As the variations in the butter are more pronounced in the autumn the analyses 

 were made during the last 4 months of the year. The greatest variation occurred in 

 the volatile fatty acids; the numbers averaged by months as follows: September, 

 24.8; October, 23.7; November, 25.2; and December, 26.6. 



Out of 428 samples, 2.3 jier cent of the volatile-acid figures ranged between 17 and 

 21, and 6.5 per cent between 21 and 21.9. 



The iodin number did not vary with the volatile fatty acid number, and there 

 api^eared to be no constant relation between the two numbers. With an increase 

 in the volatile-acid number there was a fall in the refractometer figure. 



The influence of the various factors noted upon the composition of the butter is 

 discussed, the work of other authorities is quoted, and the influence of stall feeding 

 is especially pointed out. In conclusion, the author states that the comijosition of 

 the butter is determined by outside influences, and that care should be exercisea in 

 pronouncing a given sample adulterated. 



The manipulation of sour and thickened whole milk and the partial 

 removal of the milk foam, Hamilton [Molk. Ztg., 1.5 [1901), No. 21, pp. 361, 362, 

 fig. 1). — The author describes a method for neutralizing sour coagulated milk, thereby 

 permitting the manufacture of a good article of butter. The solution for this jjurpose 

 is made up of slaked lime and soda, full directions being given for its preparation. 

 About 11 ]}er cent of soda is added to water and enough of the lime so that a clear 

 solution may be obtained. The amount of the solution used depends upon the 

 acidity of the milk and the alkalinity of the soda solution. To facilitate the opera- 

 tion where the milk is much thickened, it is forced through a strainer and sweet 

 milk is added. The method of adding the solution to the milk is figured and 

 described. The milk is thoroughly stirred daring the addition, litmus paper being 

 used as an indicator. 



The addition of this solution to milk that is to be sold as such is not advised, it 

 being clearly an adulteration. With butter it is different, as the soda solution and 



