596 EXPERIMENT STATION RECORD. 



On the dairy control associations of Norway, H. Isaachsen ( Tidsskr. NorsJce 

 Landbr., 10 I 1908), No. 11, pp. f96-528). — An historical sketch and a criticism of the 

 work of the associations, especially as regards the data obtained for economy of 

 production. — f. w. woll. 



On the milk supply of cities, especially of Christiania, S. J. Benterud 

 ( Tidsskr. Norske Landbr., 10 (1908), Nos. 10, pp. .'/. r >r>-473; 11, pp. 487-495). 



The source and nature of bacteria in milk, D. II. Beegey (Pennsylvania Dept. 

 Agr. Bui. 125, pp. 40). — The investigations reported in detail in this bulletin relate 

 to the number and nature of the bacteria in Eresh milk, the nature and source of bac- 

 teria gaining access to milk in the ordinary manipulations following milking, the 

 occurrence and significance of leucocytes or pus cells in milk, the occurrence and sig- 

 nificance of streptococci in milk, and the relation of the streptococci found to those 

 encountered in several diseases of man and animals. The methods employed are 

 I >riefly described and the results are presented in a series of tables. The author 

 summarizes the results of his investigations as follows: 



"(1 ) In the samples of milk drawn directly from the udder the number of bacteria 

 found ranged from none (in H2 per cent of the samples) to 93,100 per cubic centi- 

 meter. The prevailing bacteria found in these samples are streptococcus, staphylo- 

 coccus, and Bacillus pseudodiphtheria. Other bacteria were also found in limited 

 numbers in some of the samples and they were no doubt derived from the orifice of 

 the teat, the hands of the milker, the hair of the cow, or the air of the stables and 

 laboratory. 



"(2) The bacteria which gain access to milk in modern dairies during the manip- 

 ulations of the milk in milking, straining, and cooling, are evidently derived from 

 several sources, as the air of stables and milk houses, the hair of the animal, and 

 from the different milk utensils, the latter being by far the most fruitful source of 

 the bacteria. 



"The bacteria gaining access to milk in the ordinary manipulations in modern 

 dairies are largely air, water, and soil organisms, as shown by the preponderance of 

 organisms of the type of putrefactive bacteria. The occurrence of the group of lactic 

 bacteria in such milk was found to be quite insignificant, though it is probable that 

 these organisms rind in milk a more suitable field of activity than do the putrefactive 

 bacteria and, hence, usually exceed them in numbers by the time the milk reaches 

 the consumer. 



"The occurrence of Bacillus coli and />. alkaligenes in these samples of milk indicates 

 contamination with manure, though these bacteria may gain access to the milk in an 

 indirect manner by being carried in the air or by Hies. 



"(3) Cells can be demonstrated in the milk of practically all cows, and hence the 

 number of these cells present in milk becomes a matter of importance. It is believed 

 that the occurrence of 10 cells per field of the ,'., immersion lens indicates the pres- 

 ence of pus in milk, especially if the cells occur in masses. The presence of pus in milk 

 always denotes an inflammatory reaction within the udder, from the fact that the pus 

 is always associated with pyrogenic organisms. 



" (4) Streptococci were found in nearly all the samples of milk, derived from COWS 

 which showed the presence of pus. These bacteria are usually the cause of catarrhal 

 mammitis, and are always encountered in the contagious mammitis. 



"Streptococci and pus cells were also encountered in samples of milk derived from 

 cows in which no inflammation of the udder could be discovered. This occurrence is 

 probably due to the fact that the disease was not very active or that it had persisted 

 for a considerable time and become chronic. 



"(5) Comparative studies of the different cultures of streptococci isolated from 

 milk revealed no marked morphologic or biologic differences. Neither could these 

 cultures be differentiated by this means from cultures of streptococci isolated from 

 pathological conditions in man. 



