DAIRY B ARMING DAIRYING. ^07 



deterniininii: the absence of la('tall)umiii serve to determine if milk lia.s been heated 

 to SO to S5°, but the methodw are not 80 suitable for practical purposes. Some of the 

 methods are considered satisfactory in recognizing mixtures of raw and heated milk. 



The hygienic differentiation of market milk and its derivatives by biolog- 

 ical methods, V. Siox and N. Laptes {Zti<chr. Fleisch. u. MUcldujg., IS {1902), Xos. 

 1, j>}). 4-7; ..', pp. 33-37). 



Milk, H. DE Rothschild {Leluit. Paris: Octave Doin, 1903, pp. 90). — This little 

 book deals with pasteurization as applied to the dairy, the pasteurization and steri- 

 lization of milk, methods of analysis, and milk adulteration. A brief l)ibliography 

 is a])pended. 



The bacterial flora of freshly drawn milk, F. C. Harrison and M. Gumming 

 {Jour. Appl. Micros, and Lab. Mdh<,iU,5 {1902), Xos. 11, pp. 2029-2038; 12, pp. 2086, 

 2087; 6 {1903), Xos. 1, pp. 2130, 2131; 2, p. 2181).— The resume which is given of the 

 literature of this subject shows that decidedly different results have been obtained 

 by various investigators. In the experiments reported by the authors samples of 

 the fore and after milk of a number of cows were carefully collected in sterile test 

 tubes and studied as regards the number and species of bacteria present. Great 

 variations were observed in the inimbers of colonies which developed on gelatin plates. 

 Tlie results of a large numl)er of determinations showed on an average from 25,000 

 to 50,000 bacteria per cubic centimeter in the fore milk. The number in the strip- 

 jiings varied from none to 57,000 per cubic centimeter, varying greatly with the 

 rapidity of taking the sample. 



The several species found constantly present in the milk of all the cows were sys- 

 tematically studied as were also all the species found in the milk of one cow. Owing 

 to their characters being so slightly marked, except in the case of Bacillus acidi lac- 

 tici, the identification of the different species was difficult. Three lactic acid bacte- 

 ria, Bacillus acidi lactici (Nos. 206 and 202 of Conn) and B. lactis oerohans (Conn 197), 

 were the only species found in all the samples and they comprised at least 95 per 

 cent of the bacteria present. The following species, of which descriptions are given, 

 were more or less variable in their presence: Bacillus halofaciens n. sp.. Micrococcus 

 varians lactis. Bacillus 18 oi Conn (?) , Bacillus VII, Bacterium VIII, Bacterium exiguum, 

 and Micrncoccus X. All the species described were facultative anaerobes. The opti- 

 mum temperature for growth was 37° C. Conditions existing in the udder were 

 therefore probably favorable to their growth. The anaerobic faculty was especially 

 marked in the case of the lactic-acid bacteria, which accounts for their preponder- 

 ance over the other species. 



Udders were inoculated with Bacillus prodirjiosus, B. exiguum, and 7>. flnorescens 

 liijuefacicns l:)y smearing the ends of the teats with cultures. The l)acilli soon 

 disappeared from the milk. 



Cultures were made from the livers and udders of 3 cows which had been dry for 

 several weeks previous to slaughter. Bacteria were found in the livers of all 3 and 

 in the udders of 2 cows. While the results are not considered sufficient to warrant 

 a positive assertion they point toward infection by way of the blood or lymph rather 

 than through the teat. 



"In reviewing the subject, there can be no doubt that the number of bacteria 

 present in the milk as it exists before being drawn from the udder is somewhat 

 stai'tling, and were nothing more than an enumeration of the germs given there 

 might be some occasion for alarm. However, a systematic study of the germs 

 proves that with the possible exception of rare cases, this source of bacterial life 

 ■ is much more beneficial than baneful to the average consumer of milk and its 

 products." 



The biljliograph}' given includes 25 references. 



Improved method of studying milk bacteria, H. W. Conn and W. M. Esten 

 {Ecr. full. Lait, 2 {1903), Xos. 9, pp. 193-200; 10, pp. 224-2.33).— The authors have 



