SPOROGENES TEST. 



11 



USE OF 20 C. C. AMOUNTS OF MILK IN THE SPOROGENES TEST. 



While working with the Savage test where 2 c. c. amounts of 

 milk were used in 10 tubes, it seemed apparent that if the test was 

 to be used in the most efficient manner its range would have to be in- 

 creased so as to allow a greater difference, if possible, between good 

 and bad milk. It seemed probable that this might be accomplished 

 by using 10 c. c. or 20 c. c. quantities of milk. 



A series of tests was therefore made, using 2 c. c, 10 c. c, and 20 

 c. c. of milk, produced under the dirty conditions previously de- 

 scribed. The results in Table 3 show clearly the value of larger 

 samples of milk. They are arranged in the order of the number of 

 positive reactions in the 2 c. c. samples, and the corresponding results 

 with 10 and 20 c. c. are placed opposite. It should be kept in mind 

 that all the milk examined was produced under extremely dirty con- 

 ditions and contained an abnormal quantity of manure in many 

 cases. In other words, the milk represented the worst grade that 

 would ever be encountered in commercial conditions. 



Table 



-Comparison of number of positive reactions when different quantities 

 of milk were used. 



Sample 



No. 



Sets of 10 tubes , 2 c. c. 

 each. 



Sets of 10 tubes , 10 c. c. 

 each. 



Sets of 10 tubes, 20 c. c. 

 each. 



1 

 2 

 3 



4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 

 25 

 26 

 27 

 28 

 29 

 30 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



t 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



_ 



+ 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 



+ 



X 



+ 

 + 

 + 

 + 



— 



+ 

 + 

 + 



+ 

 + 



+ 



+ 

 + 



+ 



+ 

 + 



+ 



- 



+ 



+ 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 



+ 



+ 

 4 



+ 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 

 + 



+ 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 



+ 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



+ 

 + 



+ 



+ 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 



+ 



+ 



+ 

 + 



+ 



+ 



+ 



+ 

 + 

 + 



+ 



+ 

 + 



+ 



+ 

 + 



+ 

 + 



+ 

 + 



+ 

 + 



+ 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



+ 



+ 

 + 



+ 



+ 



+ 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 

 + 



+ 

 + 



+ 



+ 



+ 



+ 



+ 

 + 



+ 



+ 

 + 

 + 



+ 

 + 

 + 

 + 

 + 



+ 



+ 

 + 



+ 



+ 



+ 

 + 



+ 



+ 

 + 

 + 

 + 



+ 

 + 

 + 

 + 

 + 



+ 



+ 

 + 



+ 

 + 



+ 



+ 



+ 



+ 

 + 



+ 



+ 

 + 



+ 

 + 



+ 



+ 



+ 

 + 



+ 

 + 

 + 

 + 

 + 



+ 



+ 



_ 

 + 



+ 

 + 

 + 



+ 



+ 

 + 

 + 



Keeping this fact in mind, it is interesting to observe that more 

 than one-half of the samples in which 2 c. c. of milk were used 

 showed either none or only one positive reaction. The first 8 samples 

 showing no positive reactions could not be differentiated by means 



