THE EXAMINATION OE MILK 413 



typlioid, tuberculosis, diphtheria, etc., are in very many 

 cases conveyed by milk. Sources of infection are to be 

 found in the many insanitary conditions which surround 

 the milk-supplies in many parts of the country. The cow- 

 sheds in which the cows are milked are usually saturated 

 with excremental filth, the animals themselves are kept in 

 a very dirty condition, their hind-quarters and udders are 

 frequently soiled with dejecta, as is also the straw on which 

 the animals stand, which in itself forms an admirable 

 forcing-ground for micro-organisms. Other sources of 

 contamination are want of personal cleanliness on the part 

 of the milkers, and dirty dairy utensils, which are possibly 

 ' cleaned ' out with water from a surface-well which is pro- 

 bably polluted with farmyard drainage. Again, other risks 

 of bacterial contamination are introduced by want of proper 

 care and sanitary precautions when consigning the milk to 

 the consumers. The milk is cooled in open ' coolers ' ; it 

 is sent long railway journeys in loosely-covered churns, and, 

 lastly, is exposed for a considerable period of time on 

 counters in open vessels exposed to all kinds of street dirt 

 and dust. 



From the above, which is by no means an overdrawn 

 picture, it is easy to see that many millions of bacteria 

 find their way into the milk-churn, and it is remarkable 

 that, with so many sources of pollution, more epidemics 

 are not traced to the milk-supplies, considering the fact 

 that milk forms the staple article of food of young children. 

 Milk forms such an excellent medium for the growth and 

 multiplication of bacteria that they increase in this medium 

 with excessive rapidity. Dr. Freudenreich examined a 

 sample of milk purchased in Berne, and determined the 

 rate of the multiplication of the microbial contents on 

 keeping the sample at 15-5° C. The sample at starting 

 contained 27,000 organisms per c.c. ; these after four hours 



