90-CALLED GERMICIDAL PROPERTY OF MILK. OI 
BACTERIA DECREASE IN MILK AFTER DRAWING. 
In 1901 Hunziker made an extended series of experiments 
to determine the presence and intensity of this ‘‘ germicidal 
action.’’ His conclusion was that ‘‘there is in the freshly 
drawn milk of some cows a substance or condition that has the 
power of destroying a certain percentage of the bacteria con-. 
tent; and by so doing the total number of bacteria in the milk 
is reduced.’’ ' His observations seemed to show that the action 
of this germicidal substance or condition varied with the indi- 
vidual cow, and that its duration was influenced by the degree 
of temperature at which the milk was kept. This germicidal 
action was most rapid at comparatively high temperatures, and 
the minimum number of bacteria was reached in a compara- 
tively short time; while at the lower temperatures the intensity 
of the action was lessened, and its duration was increased, so 
that the minimum number was reached at a later period. After 
this minimum had been reached, the germicidal property seemed 
to act no longer, and the number of organisms increased with 
great rapidity, the rate of growth being dependent upon the 
temperature at which the milk wds kept. Hunziker’s conclu- 
sions were based wholly upon results obtained by the determi- 
nation of the total number of bacteria found in the milk at 
different periods, as shown by the growth of colonies upon agar 
plate cultures. While he shows conclusively that there is nor- 
mally a falling off in the number of organisms during the first few 
hours, he was unable to explain the cause of this phenomenon. 
CERTAIN BACTERIA DO NOT THRIVE IN MILK. 
This subject of the germicidal action of milk has been studied 
in our laboratory, and the results have, in nearly all instances, 
confirmed the general conclusions reached by Hunziker. There 
seems to be no doubt that milk obtained under ordinary con- 
ditions contains, when a few hours old, a smaller number of 
bacteria than it did when first obtained from the cow. Hunzi- 
ker made no attempt to study the development of the various 
species found in the milk, but based his conclusions upon total 
numbers simply. ‘The results of studies made in our labora- 
tory upon the growth of different species of bacteria in milk 
suggested to us that possibly this reduction in numbers might 
be the result, not of any “substance or power’’ possessed by 
