22 MASS. EXPERIMENT STATION BULLETIN 327 



incubators. In the few studies made to date with the intermediates of the 

 group, none produced acid or gas at 46°C. A few produced acid at 45°C, 

 though none produced gas. 



A Study of the Dye Tolerance of the Coli-Aerogenes Group. (Ralph 

 L. France. ) Because practically of all the recently devised presumptive test 

 media for water analysis make use of dyes as inhibiting agents, a study is being 

 made of the tolerance of the Coli-Aerogenes group for certain dyes. The dyes 

 being used are gentian violet, crystal violet, basic fuchsin, methylene blue, and 

 erythrosin. Data thus far obtained are insufficient to warrant the statement 

 of any results. 



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) 1,024 



Ice Cream (bacteria counts) 100 



Water 98 



Miscellaneous: 



*Butter Fat (Milk) 80 



*Solids (Milk) 1 



Sediment (Milk) 9 



Streptococci (Milk) 7 



Watering (Milk) 1 



Anaerobes 1 



Total 1,321 



*Analysis made by Feed Control Laboratory. 



Studies on Steam Pollution. (Leon A. Bradley, John B. Belknap, and 

 Carl F. Clancy. ) Stream pollution caused by private and municipal raw sewage 

 in near-by streams not only is a direct menace to health, but also has an 

 indirect effect upon wild life, scenic beauty, property values, and recreation. 

 An increased public interest in the recreational values of polluted areas will 

 shortly demand a satisfactory solution of pollution problems. Studies on 

 stream pollution in Amherst were made in cooperation with the local and 

 state Health Departments. It was hoped that the results of this investigation 

 might serve as a model for communities of similar size in the evaluation of 

 the extent of stream pollution within their townships. Sanitary surveys of 

 the watersheds of the principal drainage streams and the sewage treatment 

 plant, including over 500 bacteriological analyses, were completed. Stream 

 pollution was found which is serious enough to impair the suitability of the 

 principal streams for bathing purposes. The surveys also indicated the sources 

 and extent of this pollution. Recommendations were made for the improve- 

 ment of local conditions. 



