BACTERIA IN FOODS 195 



vulgaris, B. fluorescent, and many liquefying bacteria were 

 frequently found. Their presence in milk means contam- 

 ination with putrefying matter, surface water, or a foul 

 atmosphere. 



A number of water bacteria find their way into milk in 

 the practice of adulteration, and foul byres afford ample 

 opportunity for aerial pollution. 



Another unclassified group occasionally present in milk is 

 represented by moulds, particularly Oidium lactis, the mould 

 which causes a white fur, possessing a sour odour. It is 

 allied to the Mycoderma albicans (O. albicans), which also 

 occurs in milk, and causes the whitish-grey patches on the 

 mucous membrane of the mouths of infants (thrush}. These 

 and many more are occasionally present in milk. 



3. The Disease-Producing Power of Milk 



The general use of milk as an article of diet, especially by 

 the younger and least resistant portion of mankind, very 

 much increases the importance of the question as to how 

 far it acts as a vehicle of disease. Recently considerable 

 attention has been drawn to the matter, though it is now a 

 number of years since milk was proved to be a channel for 

 the conveyance of infectious diseases. During the last 

 twenty years particular and conclusive evidence has been 

 deduced to show that milch cows may themselves afford a 

 large measure of infection. The recent extensive work in 

 tuberculosis by the Royal Commission has done much to 

 obtain new light on the conveyance of that disease by milk 

 and meat. The enormous strides in the knowledge of 

 diphtheria and other germ diseases have also placed us in 

 a better position respecting their conveyance by milk. 

 Generally speaking, for reasons already given, milk affords 

 an ideal medium for bacteria, and its adaptibility therefore 

 for conveying disease is undoubted. We may now suitably 



