IOWA ACADEMY OF SCIENCES 
19 
will be more highly esteemed than it is at the present time. Latin, 
GreeR and the higher mathematics will be none the less valued, but 
the art of preparing pure food will be advanced many points. If the 
sages of the last century hau given as much attention to micro-organ- 
isms as they did to the “final perseverence of the saints” and to “total 
depravity” we would certainly have been drinking purer milk at this 
time. 
The sources of contamination of milk are many. Frequently some 
of them are evasive and baffle the skill of our present day scientists, 
while again other sources of contamination are so obvious as to offend 
our sense of common decency; especially it this true when we observe in 
the bottom of our glass or pitcher of milk dirt in its hideous forms. If 
each person is to eat his conventional “peck of dirt”, let him avoid it 
in milk, because of the extreme danger of its 'being associated with 
malignant disease. 
While the care of the body of the cow and the care of the barnyard 
is perhaps tu ' mo t iraportant iiiutter for the consideration in the effort 
to obtain pure mlk-. U.e next most important consideration is the per- 
sonal cleanliness of the milker. Many cases of contagious diseases have 
been traced to .the heme of milkmen. Impure water has been used in 
W'ashing the nhl]: c. ns or the utensils have not been siifflciently sterilized 
with boiling' v^ater. Pure milk from a healthy cow contains few bac- 
teria, while milk that is taken from a slovenly kept cow in a foul, dark 
■barn will have millions per cubic centimeter. 
The crusade for pure milk wdiich began some years ago, had its origin 
in the United States and in Switzerland with the milkmen themselves. 
This fact is both significant and hopeful. 
If consumers wmuld give more attention to pure milk than to cheap 
milk, the great cause wmiiid he helped immensely. 
Common sense and decency tells us that all food products should 
prepared clean and kept clean. It requires no scientific demonstration to 
show that dirt and fifth should be banished, but just how to fight and 
overcome such common foes demands the best skill of our boasted civili- 
zation. .A child knows that fire will burn his hand, though he cannot 
understand the principles of cornbustion, much less comprehend the 
scientific meaning of heat. It is a tvell known fact to every housekeeper 
that milk wull not x-eep as well as other foods. It -will sour, curdle and de- 
compose W'hile all other foods retain their swmetness and purity. This 
fact has been knowm fer ages, but the real cause was not understood until 
within the last tw'o decades. ^ 
While all foods snould be hanaied wdth care, extreme care is absolutely 
essential in the handling of milk. Science has demonstrated in the last 
few years that all the troublesome changes in milk are due to the pres- 
ence of bacteria. 
Success in handling milk depends upon two things: 
First, the ability to Keep bacteria from getting into the milk. 
Second, the ability to control the bacteria that may have unavoid- 
ably gotten into the milk. 
The science of dairying is based primarily upon the science of bac- 
teriology. -Bacteria are microscopic plants and perx^aps are as numerous 
in genera and spemes as the visible vegetable kingdom. It is said that 
