SPOROGENES TEST. 3 



tion. Savage (12), who was among the first to apply the test for 

 this purpose, and who has studied the test probably more than any 

 one else, realized its limitations. He states that the test does not 

 show so close an agreement with the cleanliness of farm conditions 

 as does the estimation of B. coli. On the whole, however, he thought 

 that the sporogenes test might be of considerable value in estimating 

 pollution, especially in market milk. Ritchie (11) concluded from 

 his results that the sporogenes test was of little value. He obtained 

 no correlation between the number of positive reactions and farm 

 conditions. Barthel (1) was of the opinion that there never was a 

 direct relation between the hygienic quality of milk and the presence 

 of strict anaerobes. On the other hand, Weinzirl and Veldee (15) 

 have used the test as a means of determining the manurial pollution 

 of milk and believe it to be of distinct value. 



There is nothing new about the sporogenes test so far as its general 

 application is concerned. It has been known for a long time, but it 

 has not been given a thorough trial under controlled conditions of 

 production. From past results the test gives promise of being too 

 valuable to discard, yet it is too uncertain at present to use without 

 knowing its limitations. 



It is the purpose of this paper to present some results obtained 

 with the sporogenes test on milk produced under controlled con- 

 ditions. 



THE SAVAGE METHOD. 



Savage (12) first examined 1 c. c, 10 c. c, and 20 c. c. of milk, the 

 smallest quantity being added to a tube of freshly sterilized whole 

 milk, while the other quantities were placed in empty, sterile test 

 tubes. The milk was heated to 80° C. for 10 minutes, then cooled and 

 incubated under anaerobic conditions at 37° C. After 48 hours the 

 tubes were examined for the typical stormy reaction. These quan- 

 tities were found to be too wide apart to yield a satisfactory esti- 

 mation of the number of spores, so the following method was advo- 

 cated. Small, narrow tubes, about 4 inches by \ inch, were used in 

 batches of 10. The tubes were sterilized and 2 c. c. of milk added to 

 each, making a total of 20 c. c. in the 10 tubes. The tubes were 

 heated, incubated, and examined as mentioned above. Each tube 

 which showed a typical stormy reaction was recorded as 1. Thus, 

 if three tubes showed the reaction, the result was recorded as 3. 



Savage set the following arbitrary standard, which he says can not 

 be considered a rigid standard : 



or 1 tube positive =good milk. 



2, 3, or 4 tubes positive=unsatisfactory milk. 



5 or more tubes positive=bad milk. 



A number of samples of milk produced under dirty conditions 

 have been examined by the Savage 10-tube method. His method was 



