DAIRY FARMING DAIRYING. 817 



drawn that "a temperature of 160° V. or above, for a period of one minute, suffices 

 to destroy the virulence of bovine tubercle cultures, so that the disease is not pro- 

 duced in experimental animals, like guinea pigs, inoculated with cultures ranging 

 from 2 to 5 mg." 



It is noted, however, that these laboratory experiments have been conducted 

 under conditions more carefully controlled than is possible in commercial practice, 

 and while the results are believed to lay a proper foundation for a safe and efficient 

 treatment of milk, it is suggested that variations in the conditions of exposure, and 

 also variations in the organism itself, must be studied before this new limit for the 

 efficient pasteurization of milk in machines of the continuous-flow type can be 

 accepted unreservedly. 



A graphic method of demonstrating the action of acid-producing bacteria 

 on casein, E. (i. Hastings (Wisconsin Sta. Upt. 1904, /'/>• 169-171, pi. 1). — The cul- 

 ture medium is prepared by adding 10 per cent of sterile skim milk to ordinary 

 nutrient agar. Plates are inoculated by making a single streak across the surface. 

 Paracasein monolactate, formed by the action of the acid produce* 1, is dissolved out 

 by tin 1 dilute salt solution of the medium leaving a transparent zone. A similar 

 effect may he produced by means of a thread moistened with lactic acid. A more 

 opaque zone immediately adjacent to the line of growth is d\u- to the presence of the 

 dilactate, which is insoluble in the salt solution. Previous references to this method 

 have been made (E. S. R., 14, p. 533; 16, p. 597). 



Some bacteriological investigations in dairy practice, H. Weigmann and 

 T. Grober (MUchw. Zentbl., 1 ( 1905 ), No. 1, pp. 3-6). — A peptonizing and rennet and 

 trypsin-producing micrococcus was isolated from cheesy milk or milk which was 

 found to curdle without the usual amount of acid. Large quantities of yeast and 

 also Oidium lactis were isolated from butter showing red spots. Salting the butter 

 was found to lessen the development of the coloration. 



Clabbered milk, causing digestive disturbances in consumers, showed the presence 

 of large numbers of Bacillus coli immobilis and also yeasts and some lactic-acid bac- 

 teria. Bacillus ladis aerogenes and other bacteria were isolated from butter showing 

 marked gas formation during storage. It was believed that these micro-organisms 

 gained access to the butter through the pure cultures in powder form used in the 

 ripening of the cream. Mention is also made of the isolation of a new species of 

 bacteria from slimy milk. 



Weather effects on the quality of milk (Marl: Lane Express Agr. -lour., 92 

 (1905), No. 8825, p. 76). — This is a brief statement concerning a report made by a 

 committee of the Essex County council consisting of B. Dyer, T. S. Dymond, and 

 J. C. Thresh, which was appointed to investigate the effect of dry and wet weather 

 upon the quality of milk and the use of preservatives in dairy products. 



Over 1,100 samples of milk were examined during the last 3 years and comparisons 

 made with the rainfall records during the same period. While great variations were 

 observed in different years and in different periods of the same year, the results were 

 considered^ affording no evidence whatever that excessively dry or excessively wet 

 weather produced any influence upon the quality of mixed milk. 



The standard of the Board of Agriculture, viz, 3 per cent of fat and <s.5 per cent of 

 eolids-not-fat, is considered neither unfair nor onerous to the farmer. The use of 

 preservatives in milk is condemned. 



Biological and biochemical studies of milk, C. J. Koning ( Rev. Gin. Lait, 4 

 (1904), Nos. l,pp. 9-16; J, pp. 31-38; J, />/>. 55-64; 4, pp. 76-85; 5, pp. 104-114; 6, 

 pp. 131-138; 4 (1905), No. 7. pp. 155-163). — A brief account is given of milk secre- 

 tion and the literature concerning the germicidal properties of milk is reviewed, fol- 

 lowing which the author reports 30 experiments on the latter subject and draws from 

 them a number of conclusions, including the following: 



Fresh milk contains toxic substances, probably of hematogenous origin. For a 



