100 
E. B. ACKERMAN. 
ilized milk permanently free from bacteria, it would be desira¬ 
ble to subject all milk to this process immediately after milk¬ 
ing, and to bring no milk into commerce except in the sterilized 
state. Unfortunately only a process of sterilization which is 
carried ont in the vessels from which the milk is to be used 
assures a guarantee of permanent freedom from bacteria. That 
such a process cannot be carried out on a large scale is evident. 
All other processes in which the milk after heating come in 
contact with the air afford no security that milk which has once 
been made germ free will remain so. Under ordinary condi¬ 
tions therefore the sterilization of milk of commerce is of little 
use, as milk so treated between the time of sterilization and use 
has many opportunities to become infected with the most vari¬ 
ous kinds of germs. If the cooling takes place in open coolers 
all sorts of germs may be carried to the milk by the air. There 
is the further danger of infecting the milk from improperly 
cleansed vessels. The milk may in the storeroom of the dealer 
become infected with the germs of disease. If such milk is 
then used with the belief that germs are absent it may have an 
injurious effect on the health, and indeed under certain circum¬ 
stances more injurious than if it had not been sterilized. Steril¬ 
ization whether by simple heating or boiling or in suitable 
apparatus should always be carried out at the place where milk 
is to be used and a short time before use, and all processes which 
do not afford a guarantee of permanent freedom from bacteria 
should be entirely excluded.” 
I claim that the Walker process overcomes the only two ob¬ 
jections Prof. Stohman offers, viz.: ist, it does not allow of con¬ 
tamination after Pasteurization ; 2d, it is practical on a large 
scale—and, as he says, if that were practical it is the only way 
milk should be used. 
With this process milk will keep good for two or three 
weeks, hence no waste. Pasteurizing it under pressure keeps 
the normal emulsion and the cream does not rise of any account. 
It makes an improved milk to the taste, giving it more body 
characteristic of cream. 
