DISEASES COMMUNICABLE IN MILK 29 



tial source of infection in others. Speaking by and large, disease germs 

 do not live long outside the body; they are parasites and cannot thrive 

 without the host. As a rule they do not live long and do not multiply 

 in water and in foods; these serve merely as the vehicle which transfers 

 them from one being to another and the shorter the journey the more 

 likely is the microbe to arrive in virulent condition. 



Milk a Vehicle of Infection. For a long time milk escaped suspicion 

 of being a conveyor of infection but in 1857 Dr. Michael W. Taylor traced 

 an outbreak of typhoid fever in Penrith, England, to it. Ten years lapsed 

 before an epidemic was again laid to milk, then in 1867 Taylor found 

 another epidemic in Penrith, this time of scarlet fever, was due to milk. 

 In 1872 Macnamera held an infected dairy in Calcutta, India, responsible 

 for Asiatic cholera and in 1877 Dr. Jacob determined that a milk supply 

 at Sutton, Surrey, England, caused diphtheria. Thus milk was impli- 

 cated in the transmission of four of the principal communicable diseases. 

 Notwithstanding the evidence that was then advanced a portion of the 

 medical profession remained skeptical as to milk being concerned and 

 dairymen were more than loath to accept the finding. The contentions 

 of Taylor and the others were sustained in 1881 by a paper read by 

 Ernest Hart before the International Medical Congress of that year, 

 wherein he gave an account of 50 epidemics of typhoid fever, 15 of scarlet 

 fever and four of diphtheria that were caused by milk. The paper clinched 

 the matter. Since then so much confirmatory evidence has accumulated 

 that it is almost universally believed that milk does carry several of 

 the most important contagious diseases. Such milk, that carrying the 

 specific virus of communicable disease, is called infected milk. 



Discovery of Disease Germs. In the early eighties discoveries were 

 made that enabled those who believed that milk was at times responsible 

 for the spread of contagion to speak out unequivocally, and at the same 

 time present the case to the public in tangible form. In 1882 Koch 

 brought out solid culture media which so advanced the technique of 

 bacteriologists, that soon afterward the specific germs of several of the 

 diseases were isolated and grown outside the body. The bacillus of 

 diphtheria was discovered in 1883, that of Asiatic cholera in the same 

 year, that of tuberculosis in 1884 and that of typhoid fever which was 

 first observed in 1880 was grown for the first time in 1884. 



So it was possible to inoculate these disease germs in milk and observe 

 how they behave. It was found they all live in milk and with the 

 exception of B. tuberculosis all multiply in it. Milk is as good food for 

 pathogenic and many other bacteria as it is for man; they thrive in it 

 which explains why a very slight infection is serious and why diluting 

 the infection by adding pure milk to that which contains the germs does 

 not materially lessen the danger of drinking such milk, after it has stood 

 awhile, as dilution of infected water with pure does. 



