A BRIEF SUMMARY OF THE PROBLEM 167 



of infection is through tubercle bacilli from the cow's 

 udder, bacilli accidentally carried into healthy cows' 

 milk in small particles of the droppings of other, 

 diseased, cows,* or disease germs conveyed to milk 

 from the clothing of persons handling it, or in infected 

 water. Whatever the method of infection, the danger 

 is very real. We know, as surely as we know any- 

 thing in the whole range of pathology, that tubercu- 

 losis, typhoid, scarlet fever, diphtheria, and some other 

 virulent diseases are spread by means of infected milk. 

 Science and good sense again unite, proclaiming 

 that milk that is infected with the germs of disease 

 is not a safe food, either for infants or adults. It is 

 the chief advantage of the man of science over the lay- 

 man that he has the power, though often only at great 

 expense, to discover the danger. He is thus in a posi- 

 tion to guard against dangers which to the layman 

 are invisible. 



IV 



In this hasty summary of the disadvantages and 

 perils of cow's milk as a substitute for mother's 

 breast milk, there is one which we have not touched 

 upon, and which is too important to be wholly ig- 



* Shroeder has shown that if into a pail of milk drawn from 

 absolutely healthy cows a very small portion of dung from a 

 tubercular cow is dropped and the milk at once strained, a few 

 drops of the milk injected into a healthy guinea-pig wUl suc- 

 cessfully inoculate it with tuberculosis. 



