6 BULLETIN &L0, U. S. DEPAETVLEXT OF AGRICULTURE. 
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 giying the test. This 
he belieyes 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 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 WeinzirFs 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, 
L0, 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 4i stormy " fermentation, and a negative sign 
the absence of the characteristic reaction. 
