SPOROGENES TEST. - 19 
ditions. This has been emphasized in the discussion of the test in 
connection with certified milk and dirty milk, and is again illus- 
trated by the results shown in the last two sections of Table 6. 
SUMMARY AND CONCLUSIONS. 
1. The Savage test using 10 tubes with 2 c. c. of milk is not suffi- 
cient^ delicate to be of great value, evidently, because not enough 
milk is used in each tube. 
2. The Weinzirl test does not appear to correlate with the quantity 
of manure in milk. This seems to be due both to the method of 
making the test and to the variation in spore content of B. enteritidis 
sporogenes in manure. 
3. The experiments indicate that the majority of spores of B. 
enteritidis sporogenes gain entrance to milk by means of cow manure. 
4. With 10 tubes and 20 c. c. of milk to each tube, the sporogenes 
test as used throughout the experiments shows a fairly definite rela- 
tion to conditions of production. This relation is more definite than 
that shown by either the Savage or the Weinzirl test. 
None of the tests, however, show a definite correlation between 
the number of tubes positive and the quantity of manure in any given 
sample. But with 20 c. c. quantities of milk and discounting indi- 
vidual variation, there is a general trend of agreement between the 
test and manure. 
5. As a rule, the sporogenes test with 10 tubes and 20 c. c. of milk 
shows high results, that is, a large number of positive tubes with 
milk produced under dirt} 7 conditions. With milk produced under 
clean conditions, the test is apt to be negative or show only a few 
positive reactions. 
The test tends to differentiate between extremes in methods of pro- 
duction, and naturally most milk will fall between these limits. The 
nearer the conditions of production approach one extreme or the 
other, the more accurately will the sporogenes test indicate the con- 
ditions. 
It must be pointed out, however, that no reliance can be placed on 
one test with one sample. Individual variation with a single test 
makes a series of tests on a number of samples necessary for the 
result to have any significance. 
6. When the limitations of the test are understood and the results 
properly interpreted, its use with a series of samples from a given 
source should give considerable information as to cleanliness of pro- 
duction, particularly in connection with the extent of manurial pol- 
lution. The test, if used, however, should be taken as merely an indi- 
cation of the conditions of production, and should be verified by an 
actual inspection at the farm. 
