qe RePoRT OF THE BACTERIOLOGIST OF THD 
molds to grow in the milk and produce changes in its composi- 
tion. This should not take place to an appreciable extent under 
twelve hours, and if the temperature is kept reasonably low, 
will not do so for a much longer period. | 
From this it will be seen that in the milk as it is orilinaeity 
delivered in the milk trade of the smaller cities or at the fac- 
tories there should be no odor due to plant growth. Whenever 
a disagreeable odor is present it can be ascribed either to 
aromatic substances absorbed or to holding the milk at too high 
temperatures. 
This statement of the matter may at first glance appear to 
conflict with practical observation; for sometimes a certain odor 
becomes noticeable soon after the milk is drawn and appears to 
increase in the cheese curd. In this case it would be more in 
accord with the known facts to assume that the same class of 
bacteria which brought about the decomposition of the exereta 
in the barn and produced from them the vile odor which was 
absorbed. by the milk also found their way into the. milk itself 
and there, later, produced similar foul smelling compounds. | 
Under ordinary circumstances we can begin to reckon -the 
twelve hours above mentioned, from the time the milk is drawn; 
but the interesting observations of Moore! and Ward? have im- 
pressed the fact that in some animals the bacteria work their way 
high up into the glandular tissue of the udder and convinuously 
attack the milk as it is formed. 
Anima] and absorbed odors are to be avoided as far as pos- 
sible, since they are never desirable. After they have once 
entered the milk aeration will assist in their removal. The pro- 
cess of pasteurization accompanied by a subsequent cooling of 
the milk by flowing in a thin sheet over a cold surface is recom- 
mended by some producers of fine dairy products as a means 
to the same end. 

*Moore, V. A., and Ward, A. R. Source of Gas and Taint-Producing 
Bacteria in Cheese Curd. Cornell Agr. Exp. Sta., Bul. 158, 1899. 
*Ward, A. R. The Invasion of the Udder by Bacteria. Cornell Agr. 
Exp. Sta., Bul. 178, 1900. 
