876 EXPERIMENT STATION RECORD. 



511, figs. 8). — The authors summarize their observations as follows: "A col- 

 lection of cultures of streptococci was made consisting of 42 cultures from 

 milk which formed chains in lactose bile at 37° C, 51 cultures from infected 

 udders, 114 cultures from bovine feces, and 39 cultures from the mouths of 

 animals. 



" The morphology varied under different conditions and could not be corre- 

 lated with the source of the culture, except that the udder cultures had a more 

 marked tendency to chain formation than those from other sources. The 

 ability of these cultures to liquefy gelatin and to form acid from dextrose, 

 lactose, saccharose, raffinose, starch, inulin, mannite, glycerin, dulcite, and 

 adonite was determined. Onlj^ one or two cultures utilized adonite or dulcite. 

 When glycerin was attacked, the fermentation proceeded slowly, failing to 

 reach its maximum in 14 days, in contrast to the fermentation of the sugars, 

 in which the maximum was reached in two or three days. 



"A high percentage of the udder cultures failed to give the characteristic 

 reduction in litmus milk. Twelve cultures liquefied gelatin ; one of these came 

 from milk and 11 from infected udders. The cultures from feces were charac- 

 terized by their activity in fermenting the sugars, including raffinose, and 

 their inability to utilize the alcohols. The mouth cultures fermented dextrose, 

 saccharose, lactose, mannite, and frequently raffinose, but were almost without 

 effect on starch and glycerin. The udder cultures were characterized by the 

 general lack of fermentive ability, which was limited almost entirely to 

 dextrose, saccharose, and lactose, with a comparatively small number utilizing 

 mannite, glycerin, and gelatin. 



" When the udder cultures were divided on the basis of gelatin liquefaction, 

 two groups were obtained. The fermentive activities of one of these, which 

 are similar to those of Streptococcus pyogenes, were limited to dextrose, 

 saccharose, and lactose, with an occasional culture fermenting mannite, starch, 

 or inulin. The second group fermented the 3 simple sugars, mannite, and usu- 

 ally glycerin and liquefied gelatin. When the milk cultures were considered 

 individually, it was found that with the exception of two which clearly came 

 from feces they could be included in one or the other of the two groups into 

 which the udder cultures were divided. Of the 41 nonliquefying udder cul- 

 tures 24 gave identical reactions. The remaining cultures differed from the 

 type in one or two characters onlj\" 



Dirt sediment testing. — A factor in obtaining clean milk, M. C. Schroeder 

 {Amer. Jour. PuT). Health, ^ U9H), No. 1, pp. 50-6Jt, figs. 12).— Aftev describ- 

 ing the various methods of making sediment tests, both of the gravity filtration 

 and centrifugalization types, the author gives the results of tests made of 416 

 samples of milk to ascertain the factors influencing gravity filtration. 



It was found that 11 per cent of the samples filtered through the cotton in 

 less than one minute, GS.9 per cent in from 1 to 3 minutes, 7.4 per cent in from 

 3 to 5 minutes, 4.3 per cent in from 5 to 10 minutes, 4 per cent in from 10 to 60 

 minutes, and 4 per cent in over 60 minutes. The filtration process did not seem 

 to be affected by the fat content, total solids, or the amount of sediment present 

 in the form of visible dirt, but a large excess of leucocytes or epithelial cells 

 tended to retard the filtration. Colostral and stripper milk filtered through 

 quite readily. Sweet cream diluted with an equal amount of warm water may 

 be tested, but in testing sour cream it is necessary to dissolve the curd by the 

 addition of an alkaline solution. A gauge has been devised for making com- 

 parative readings which represent the amount of dirt obtained by filtering liter 

 lots of milk to which have been added respectively 21, 5, 7, and 10 mg. of the 

 material which usually finds its way into the milk. 



