on Milk and Milk-Products. 
391 
the latter being at fault, especially when it has appeared from 
that evidence that a connection existed between the milk and 
a previous case of the disease in question. 
There are three ways in which milk can contract infection, so 
that it becomes a source of danger to the consumer : — 1. Through 
the air. The gases emanating from privies and sewers are 
most likely to carry dangerous germs, and, by coming in con- 
tact with milk, to infect it. 2. Through water ; this is frequently 
highly contaminated when proper precautions are not taken 
that no intercommunication exists between wells and sewers, 
cesspools, and the like. The fraudulent addition of such water 
is not necessary, as simply washing the vessels used for the 
conveyance of the milk will suffice to contaminate the whole 
supply to an alarming extent. 3. There is the possibility of 
the milk-supply being derived from cows suffering from certain 
diseases. 
It has often been contended that the milk from cows suffering 
from pleuro-pneumonia gives rise to consumption in man. 
Milk from cows suffering from foot-and-mouth disease is known 
to have produced in some instances (not in all) aphthae round 
the mouths of those who had partaken of it ; and not long ago 
an outbreak of scarlatina was traced to milk from cows suffering 
from a peculiar skin disease affecting the teats and udder, and, 
in severe cases, other parts of the body of the animal. This is 
not the place to examine whether and how far the connection 
between diseases in man consuming milk from ailing cows, 
and the ailments of those cows, is based upon indisputable 
facts. What we desire to point out is, that the danger of 
particles of ejections from the lungs, runnings from the mouth, 
and chippings from the skin, entering the milk certainly 
exists. 
The dangers arising from foul air, contaminated water, and 
diseased animals can be, if not altogether avoided, at least re- 
duced to a minimum by having properly situated and constructed 
rooms to keep the milk in, by using boiling water and steam 
for cleansing purposes, by careful sanitary inspection of cows, 
and by separating those which exhibit even the most insigni- 
ficant signs of ailments and destroying the milk yielded by 
such animals. 
In the foregoing we have always assumed that micro- 
organisms enter the milk from outside, and after it has been 
drawn from the udder. The question arises — are there ever 
organisms of any kind present in milk when being formed ? 
This question must certainly be answered in the negative 
so far as healthy cows are concerned. No doubt numbers of 
micro-organisms are introduced into the respiratory as well 
