402 ILLINOIS STATE ACADEMY OF SCIENCE 



the cooking art as a constant ally: but the dairyman 

 works with a living animal in a barn, and with a feeble 

 tradition of personal cleanliness outside of the house and 

 not always a robust personal tradition of cleanliness in 

 the house. About the barn the dairyman is a barn and 

 field worker ; the provision in the barn of water supply, 

 soap and towels approximates the barn level rather than 

 the dwelling level. Though improvements are acknowl- 

 edged, a barn will remain a barn for a long time to come. 



2. Infection of milk. For a good while to come milk 

 will be exposed to sources of infection especially in the 

 animal and the milker. Only a few herds are tuberculin 

 tested, and most of the items of veterinary hygiene are 

 scarcely dreamed of. As to the controlling of disease 

 carriers among humans, we have hardly begun it. The 

 average disease carrier of an enteric, a respiratory, a 

 genito-urinary or a skin disease is not thought of as a 

 carrier until after he has spread contagion for a life 

 time ; then his control is a very indifferent matter. Milk 

 borne epidemics of disease are started usually by milk 

 handlers in approximately good health. 



3. Cooling, storage and delivery of milk. 



A strictly fresh milk, even if produced in a clean man- 

 ner, must be transported and stored, not reaching the 

 consumer as a rule for twenty-four hours and upwards. 

 There is always some bacterial life in any milk, either 

 pathogenic or such as to change the milk materially in 

 palatability and digestibility. Time and temperature are 

 the factors for the increase of this bacterial life. Proper 

 pasteurization only can defeat the effects of this con- 

 tamination in a clean milk delivered to the consumer in 

 the usual time. 



PASTEURIZATION NOT AN EXPERIMENTAL PROCEDURE 



In speaking confidently of pasteurization an experi- 

 mental procedure is not being considered. The greater 

 cities require it invariably. No unpasteurized milk is sold 

 to the public in Chicago, New York or other large cities, 

 but most of the smaller cities lag behind. Evanston on 



