SPOROGENES TEST. 
14 samples of milk examined in this manner it is evident as shown 
in Table 1 that there may be a considerable variation in the results 
obtained from a given sample. 
Table 1. — Variation in the Savage sporogenes test, shoicing number of positive 
tubes of 2 c. c. each after incubating for 48 hours at 37° to 40° C. 
Number of positive tests. 
Range in 
Sample. 
number of 
positive 
Setl. 
Set 2. Set 3. Set 4. 
i 
Set 5. 
tests. 
1 
3 
5 16 3 
2 
2 to 6 
2 
4 
2 1 
3 
0to4 
3 
2 
2 ! 1 , 
2 
0to2 
4 
1 
1 1 

Otol 
5 
1 

1 
1 
Otol 
6 
1 
2 
1 
2 
0to2 
7 
2 
1 
2 2 
1 
lto2 
8 
1 
2 2 
2 
0to2 
9 
1 
i 

Otol 
10 
4 
4 1 3 
3 
lto4 
11 
9 
8 5,6 
7 
5 to 9 
12 
6 
8 
5 ! 6 
6 
5 to 8 
13 
7 
6 
3 \ 7 
6 
3 to 7 
14 
9 
8 
.| , 
9 
7 to 9 
The sample of milk in every case was shaken thoroughly to give 
as equal a distribution of spores as possible. The 2 c. c. samples 
used in the sporogenes test were removed in two different ways : 
(1) Ten 2 c. c. samples were removed from the sample of milk by 
means of a sterile 2 c. c. pipette ; (2) ten 2 c. c. samples were removed 
from the sample of milk by means of a sterile 10 c. c. graduated 
pipette, successive 2 c. c. portions being delivered for each sample. 
It was found that this variation in removal of the 2 c. c. samples 
had no effect on the results of the sporogenes test. 
The effect of the variations in the numbers of positive tubes and 
different sets of tubes of milk from the same sample of milk is ob- 
vious when one attempts to grade the milk by the Savage method. 
For example, in Table 1, Samples 2, 3, 6, 8, and 10 would be graded 
as either good or unsat is factory, according to the results of the 
sporogenes test and the Savage arbitrary standards. This is shown 
more clearly by consideration of the results obtained with Sample 2. 
Each set of 10 tubes represents a complete sporogenes test according 
to the Savage method. In Set 2 there were no positive tests and in 
Set 4 there was one ; therefore, the milk would be graded by either of 
these tests as good. In the other sets there were 2, 3, and 4 tubes 
positive, which according to the standards would necessitate calling 
the milk unsatisfactory. 
Two reasons at least may be designated as contributing causes for 
the variations in the sporogenes test: First, uneven distribution of 
the spores in the milk ; and, second, lack of development of the char- 
acteristic stormy reaction on which the test is based. Savage (12) 
mentions the fact that the lack of an even distribution of spores is a 
