6 BULLETIN 940, V. S. DEPAETMENT OF AGEICULTUEE. 



serious drawback to the utility of the test, while Simonds (14) 

 found that a failure to get the stormy fermentation does not neces- 

 sarily mean a lack of growth of the organisms giving the test. This 

 he believes from his experiments is due to not having the correct de- 

 gree of anaerobiosis in the milk tubes. 



How far the lack of development of the characteristic stormy 

 reaction influences the assumption of an unequal distribution of 

 spores is difficult to determine. As long as these variations in the 

 sporogenes tests continue, the value of the test is materially lowered, 

 and the reason for the variation is of little importance except that 

 if it were definitely known some remedy might be found. This defect 

 in the sporogenes test applies not only to the Savage method but also 

 to the other methods mentioned in this paper. 



THE WEINZIRL METHOD. 



A method of determining manurial pollution of milk in which the 

 sporogenes test is used has been suggested by Weinzirl (15). The 

 method of making the test is essentially the same as the first one used 

 by Savage, although the results were interpreted in a somewhat differ- 

 ent manner. The method of Weinzirl consists in using 5, 10, and 15 

 c. c. samples of milk from each sample which is to be examined. The 

 milk is heated to 80° C. for 10 minutes and melted paraffin poured 

 on the milk to make a layer one-eighth inch or more in thickness. 

 The tubes of milk are then cooled and incubated at 37° C. From his 

 examination of cow manure, Weinzirl calculated that there were prob- 

 ably 10,000 sporogenes per gram of manure in the partially dried 

 condition in which it usually enters milk. Based on this figure, he 

 estimated the amount of manure in milk as follows : A positive reac- 

 tion in the 5 c. c. tube indicates 1 gram of manure in 50 liters of milk ; 

 a positive reaction in the 10 c. c. tube indicates 1 gram of manure in 

 100 liters of milk ; and a positive reaction in a 15 c. c. tube indicates 

 1 gram of manure in 150 liters of milk. 



To determine the value of Weinzirl's method, 48 samples of milk 

 were examined which were produced under dirty conditions. The 

 same conditions of production prevailed as those previously described 

 under the Savage test. The results of the work are presented in 

 Plates IV and V, on which are shown sediment disks from each pint 

 sample of milk examined, together with the results of the sporogenes 

 test as performed by Weinzirl and the total bacterial count. Fresh 

 milk was examined in all cases. In the upper left-hand corner of 

 each square is shown the result of the sporogenes test. Figures 5, 

 10, and 15 represent the respective number of cubic centimeters of 

 milk used, and opposite each is a positive or negative sign. A posi- 

 tive sign indicates a " stormy " fermentation, and a negative sign 

 the absence of the characteristic reaction. 



