18 BULLETIN 940, U. S. DEPARTMENT OF AGRICULTURE. 
The quantity of sediment from each pint of milk produced under 
these conditions is shown in Plates VI, VII, and VIII. A comparison 
of the disks on Plates VI and VII shows that the milk produced 
under dirty conditions with unsterilized utensils and that pro- 
duced under the same conditions with sterilized utensils, contained 
about the same quantity of cow manure. As stated, these sam- 
ples showed about the same results with the sporogenes test. 
When the cows were clean there was a decided drop in the quan- 
tity of manure found in the milk, as will be noted from the sediment 
disks in Plate VIII. Eeference again to Table 6 shows that under 
these conditions there was a decided drop in the sporogenes test, 
although the utensils used in the production of this milk were de- 
cidedly dirty. The extent of the contamination which came from 
these dirty utensils . is shown by the remarkably high counts with 
fresh milk in the lower section of Table 6. From these results 
it seems evident that, generally speaking, most of the spores of 
B. enteriticlis sporogenes which are found in milk are introduced 
through contamination by cow manure, but that occasionally a high 
sporogenes test may be the result of contamination by this organism 
from dirty utensils. 
Before considering the value of the sporogenes test any further 
it seems advisable to revert again to the subject of the lack of corre- 
lation between the test and the quantity of cow manure in milk. It 
has been shown that the test, as carried out by Savage and by Wein- 
zirl, bore no definite relation to the sediment which may be assumed 
is largely cow manure. In Plates VI, VII, and VIII the results of 
the sporogenes test are placed in the upper right-hand corner of 
each square containing a sediment disk, and the total count is shown 
beneath the disk. Particular attention is called to Plate VII. This 
shows sediment disks from milk produced under dirty conditions 
but with sterilized utensils. If there is any positive correlation be- 
tween the test and cow manure it should show with milk produced 
under these conditions. In making the test 10 tubes were used, each 
containing 20 c. c. of milk. 
It is evident that with these samples and with this method there 
was again no definite relation between the test and the manurial 
content of the milk. Sample 1, for example, showed negative sporo- 
genes test and evidently contained, from the appearance of the disk, 
as much manure as Samples 14, 15, and 16, in which all 10 tubes 
were positive. 
While there seems to be no definite relation between the sporo- 
genes test and the sediment test when individual samples under a 
given, condition of production are compared, there seems ito be a gen- 
eral difference in results when a number of samples produced under 
dirty conditions are compared with those produced under clean con- 
