908 EXPERIMENT STATION RECORD. 



endeavored to devise a method for determining with raj)idity and with some degree 

 of accuracy the numbers of the different species of bacteria in milk. For this pur- 

 pose two culture media have been used, one prepared like ordinary gelatin with the 

 addition of milk sugar and litmus, and one prepared by the addition of 15 per cent 

 of gelatin to whey. The gelatin medium gives a larger number of colonies and the 

 whey medium a sharper differentiation of the different kinds. Plate cultures are 

 made, the sample of milk being diluted with sterile water to such an extent that 

 from 200 to 300 colonies develop on each. The degree of dilution varies ordinarily 

 from 50 to 600 in moderately fresh milk and frequently above 200,000 in milk which 

 has been kept warm for 2 or more days. The cultures are kept at about 20° C. for 5 

 or 6 days, when the total numl)er of colonies is determined and a study is made of 

 the different kinds as recognized by their appeara,nce, the number of each type being 

 ascertained. No subsequent cultures are made. The authors have found it possible 

 in this way to differentiate accurately a large variety of colonies, several of the more 

 important of which are briefly described. The colonies are considered as represent- 

 ing groups of species rather than as necessarily representing individual species. This 

 method of identifying the different species and determining approximatelj' their 

 number, while not regarded as very accurate, has the advantage of being rapid and 

 of permitting observations to be made on the rise and fall of different types of bac- 

 teria in milk in a way not hitherto considered possible. 



Bitter milk and cheese, F. C. Harrison {Ontario Aijr. Col. and Expt. Farm Bui. 

 120, 2ip- 32, figs. 7). — This has been noted from another source (E. S. R., 14, p. 489). 



The percentage of ■water in Canadian creamery butter, F. T. Shutt ( Ontario 

 Dept. Agr., I)<iiry Division Bui. 4, n. xi'r., 1902, pp. 6). — Determinations were made 

 of the water content of 75 samj^les of butter received from creameries in different 

 })arts of Canada and of 30 samples obtained in Montreal from packages ready for 

 export. The butter was i^ractically all manufactured in July and August, and was 

 considered representative of the butter prepared for export to England. The maxi- 

 mum, minimum, and average water content of the samples from creameries was, 

 respectively, 16.77, 8.92, and 12.16 per cent, and of the warehouse samples 15.37, 

 7.94, and 12.69 per cent. Of the 105 samples 92 showed less than 14 per cent of 

 water. Only 1 sample contained more than 16 per cent and this was of butter 

 churned above 60° F. and washed at 64°, temperatures noted as unusually high in 

 Canadian creamery practice. The results are considered as fairly conclusive evi- 

 dence that Canadian creamery butter is well within the limit of 16 per cent allowed 

 by the English law. As regards the relation of the water content to inspection rat- 

 ing the author states that "the appearance of a butter as sampled affords, generally 

 .speaking, no criterion as to its moistui-e content." 



Control of rusty spot in cheese factories, H. A. Harding and G. A. .Smith 

 ( New York tStaii' Sta. Bui. 225, pp. 303-329) . — The trouble known as rusty spot manifests 

 itself in cheese from 4 to 8 days after pressing and is characterized by the occurrence 

 throughout the interior of the cheese of bright red or yellowish-red spots the size of 

 a pin point and larger. The time of their appearance is hastened by a warm curing 

 room and retarded by a cool one. The spots are usually most noticeable on the sur- 

 face of gas holes an<l other openings, where in the presence of free moisture they 

 may form a yellowish-red blotch the size of a thumb nail. The trouble is most evi- 

 dent in moist cheese made for home trade. The whole interior of the cheese may 

 in bad cases present an unevenly colored appearance. The use of cheese color is 

 not entirely successful in disguising the rusty spots. Outbreaks have occurred in 

 nearly every section of the State where white cheese is made, and liave been reported 

 since 1883. In an earlier bulletin of the station (E. S. R., 13, p. 85) this subject was 

 briefly discussed and the causal relation of Banllux riidensis was confirmed. Experi- 

 ments made at 4 factories during 1901 and 1902 for the control of this trouble are 

 recorded in detail in the present bulletiu. 



