NORMAL AND ABNORMAL MICROFLORA OF MILK 71 



Other Diseases of the Cow. Just as milk from cows suffering 

 from tuberculosis of the uterus and intestine may easily become 

 infected with tubercle bacteria, so milk from cows affected by 

 other diseases of the sexual and digestive organs may become 

 infected with the corresponding organisms. Experience has 

 shown that the milk should not be used for cheese making until 

 ten days after calving, the reason being that not only is the 

 chemical composition abnormal, but also that during this period 

 the milk is especially subject to infection from the uterus, and to 

 taints from the disinfectants often used during calving. The 

 small rod form, Bacillus abortus, which causes abortion, may 

 occasionally be found in milk 1 . The consequences of ordinary 

 diarrhoea have already been mentioned. Chronic diarrhoea, when 

 the motions contain blood or are otherwise abnormal, is far more 

 dangerous, for in such cases we are dealing with an infectious 

 disease and the organisms in question (according to C. O. Jensen, 

 often coli bacteria of the swine fever group) may cause similar 

 intestinal trouble in human beings, especially in children. Mor- 

 tality among calves will always be a danger signal for human 

 beings. Finally there will always be a danger of infection through 

 the milk in cases of anthrax and all skin diseases such as foot and 

 mouth disease, cowpox, etc., more especially if the udder is 

 affected, and possibly also in cases of udder actinomycosis, acute 

 lung diseases and rabies. The chemical composition of the milk 

 is affected through several of these diseases. 



Secondary Milk Defects. Milk may also be infected with 

 pathogenic organisms from human beings, and any one suffering 

 from an infectious disease or living in the same house with sufferers 

 should be forbidden to handle or sell milk. It is generally accepted 

 that tuberculosis, diphtheria, scarlatina, cholera and typhoid fever 

 may be transmitted by milk. Epidemics of typhoid, cholera, 

 scarlet fever and diphtheria have undoubtedly been caused re- 

 peatedly through milk infections. Although Bacterium typhosum 

 does not ferment lactose, it grows freely in milk, and it is also 

 stated to be able to live for some time in butter and cheese ; like 

 the organisms of the other diseases mentioned above with the 

 exception of that of anthrax, it is killed by pasteurisation at a low 

 temperature. 



1 Schroeder and Cotton, U.S. Dept. of Agric., Bur. of Animal Industry, 

 28th Annual Report, 1911 ; Alice C. Evans, " Journal of the Washington 

 Academy of Sciences," Vol. V., No. 4, 1915, and " Journal of Infectious 

 Diseases," Vol. XVIII., No. 5, 1916. According to the latter paper. Bacillus 

 abortus and other similar forms seem to be fairly common udder bacteria, 

 to be found in over 20 per cent, of the milk fresh from the cows. It appears 

 to be chiefly a fat-splitting variety (var. lipolyticus), which is killed after 

 warming only to 52 C. for thirty minutes. 



