24 MASS. EXPERIMENT STATION BULLETIN 339 



diets: Basal diet plus raw milk, basal diet plus pasteurized milk, basal diet 

 plus raw milk with added iodine, and basal diet plus pasteurized milk with 

 added iodine. In one experiment the basal diet was high in carbohydrate 

 (cereal ', and in a second experiment the basal diet was high in protein (hamburg 

 steak). To date there have been no indications that either pasteurized or raw 

 milk will produce a putrefactive flora in the intestinal tract of the rats, nor did 

 the added iodine appear to control putrefactive flora which did occur. There 

 was considerable individual variation in the intestinal flora of the rats studied. 



A Comparative Study of Certain Presumptive Media for Testing 

 Raw Waters. (Ralph L. France.) The results of this study have been 

 published in the Journal of the American Water Works Association, Vol. 28, No. 

 6, June, 1936. 



The Indol Tolerance of Certain Strains of the Coli-Aerogenes Group. 



(Ralph L. France.) The results of this study have been published in the 

 Journal of Bacteriology, Vol. 32, No. 2, August, 1936. 



Studies on Acid Production by the Coli-Aerogenes Group. (Ralph 

 L. France.) An abstract of the preliminary report of this study has been pub- 

 lished in the Journal of Bacteriology Vol. 32, No. 1, July, 1936. Work on this 

 study is being continued. 



The Tolerance of the Coli-Aerogenes Group for Brilliant Green. 



(Ralph L. France.) Evidence obtained to date shows that the .Aerobacter 

 group has a considerably greater tolerance for brilliant green than the Escheri- 

 chia group. Work will be continued on this project using a large number of 

 strains of organisms and varying amounts of inoculum. Also it is planned to 

 study the action of bile on the tolerance of this group for brilliant green. 



The Action of the Coli-Aerogenes Group on Erythrosin. (Ralph L. 

 France and James E. Fuller.) A preliminary report of this study has been 

 made (Mass. Exp. Sta. Bui, 327, p. 21, 1936). A study of the action of the 

 intermediate members of the Coli-Aerogenes group shows that some strains 

 precipitated the dye while others failed to do so. These reactions checked very 

 closely with the methyl-red reactions of the various strains. However, a failure 

 to obtain consistent results with certain strains on repeated tests indicates a 

 need of further study of these strains. 



A Study of the Eijkman Test. (Ralph L. France.) A preliminary report 

 of this study has been made (Mass. Exp. Sta. Bui. 327, p. 21, 1936). Strains 

 of Aerobacter aerogenes and the intermediate group failed to produce acid and 

 gas in the Eijkman broth at 46° C. Some strains produced acid at 45° C. but 

 none produced gas. Further studies are being carried on with strains of the 

 Coli-Aerogenes group isolated from fresh feces. 



Laboratory Service. (Ralph L. France.) Following is a list of the numbers 

 and types of examinations made in the laboratory during the past year: 



Milk (bacteria counts) 1,289 



Ice Cream (bacteria counts) 148 



Water 85 



Miscellaneous: 



♦Butter Fat (Milk) 228 



♦Total Solids (Milk) 28 



Throat Swabs 24 



Total 1,802 



♦Analysis made by Feed Control Laboratory 



