

EXPERIMENT STATION REPORTS. 235 



"While in service I was stationed at Riniecourt, Haute Marne, France 

 in tlie. laboratory of Base Hospital 52. I was in the army between the 

 dates February 4, 1918 and May 15, 1919. 



"I am continuing my studies upon the general problem (Adams la) Re- 

 lation of diseases of the cow to the milk, and have under way or projected 

 the following phases of the problem as applied to infectious abortion. 



"I. Study of the possibility of the udder, through the teats, being an 

 avenue of entrance for Bad. abortus. 



"II. Attempt to improve methods for studying the presence of Bact, 

 abortus in the udder. 



'III. Feeding experiments with Bact. abortus infected milk. 

 'IV. Nature of Bact. abortus infection in the udder. A bacteriological 

 and pathological study of Bact. abortus infected udders to be taken up in 

 cooperation with the Department of Pathology. 



"V. Study of strains of Bact. abortus and abortus-like organisms isolated 

 from milk." 



Mr. Ruehle has the following report : 



"The research work on butter has been on the Adams Fund Pro- 

 ject lb entitled, 'The Keeping Qualities of Butter.' This work is still 

 in progress but has not progressed to the point where publication would 

 be desirable. A preliminary report of one phase of the work has been 

 embodied in a paper entitled, 'A Microscopic Method of Examining Butter 

 for Microorganisms'. This was read before the Section on Sanitary and 

 Medical Sciences of the Michigan Academy of Science, on April 3, 1919. 

 An abstract of the paper follows this report. 



"In examining a substance for the presence of microorganisms, it 

 is always desirable to be able to analyze the material microscopically 

 as well as culturally. In preliminary examinations of the butter by the 

 microscope it was found that a large proportion of the bacteria are im- 

 bedded in particles of casein. This would indicate that any cultural 

 method of counting the microorganisms in butter would give counts much 

 below the actual number present in the butter. 



"After some experimentation the following technique was adopted 

 and is still being studied : 



"One gram of butter was weighed out and transferred to a clean 

 separatory funnel. One cubic centimeter of hot water was added to 

 the butter and the whole mass agitated until the butter was melted 

 and thoroughly mixed with the water. Then 50 c.c. to 100 c.c. of ether, 

 gasoline, or other fat solvent was added to dissolve the fat, when it 

 was allowed to stand until the two liquids had separated. The aqueous 

 portion was drawn off into a graduated cylinder and an equal amount of 

 sterile skim milk, which had been allowed to sediment for a week or 

 more after sterilization, was added to the aqueous extract of the but- 

 ter. After mixing 0.02 c.c. of the mixture was spread out with a needle 

 on a glass slide so that it covered an area of 1 square centimeter. Some- 

 times a larger amount of butter was used but in those cases a larger 

 amount of warm water was used so that in every case 0.02 c.c. of the final 

 mixture represented approximately 0.01 gram of the butter. The smears 

 were then treated in the same manner as the milk smears are treated in 

 the Breed method of counting bacteria in milk; namely, the smears were 

 dried quickly on a warm plate, immersed in xylol for a minute to dissolve 

 any trace of fat, fixed for one minute in alcohol, stained with a one per 



