DAIRY MEETING. 185 



This kind of dirt is never present in the milk as it comes 

 from the cow's udder. It is derived entirely from outside 

 sources. The amount of organic and earthy matters thus intro- 

 duced into the milk are, in themselves, harmless. The quanti- 

 ties- present in even a very dirty milk would not cause disease 

 to follow its use. If such dirt as this were all that entered the 

 milk the only objection to its presence would be the esthetic 

 one of poor appearance. The real cause for objection to the 

 presence of this physical dirt is that it carries, attached to it at 

 all times, bacterial dirt, or swarming myriads of bacteria of 

 various kinds. The real objection, then, to physical dirt is 

 that it forms the vehicle for the transmission of the harmful 

 bacterial dirt, which not only causes economic loss to the pro- 

 ducer, but also often results in disease among the users of the 

 resulting milk. Physical dirt is thus to be considered an indi- 

 cator of the bacterial condition of the milk in which it occurs. 



As you all know "bacteria" are minute vegetable organisms, 

 which multiply with great rapidity in favorable environment 

 and with proper food. Milk is one of the best foods for bac- 

 teria that exists. Therefore, unless precautions are taken to 

 exclude bacteria from milk, any that may enter it will rapidly 

 multiply to such an extent as to spoil the milk, and render it 

 unfit for human consumption. Bacteria do not spring spon- 

 taneously into existence. Each one comes from some previously 

 existing one. If they are found in milk they have come from 

 some bacterium that has entered the milk, either in the cow, or 

 after it has been drawn from her. Not all of these bacteria are 

 dangerous to health. In fact but few out of the thousands 

 that are known cause disease in man. But nearly all of them 

 will cause a milk to spoil if they enter it, and so are a source 

 of loss to the producer. 



In previous papers before this Association I have dwelt at 

 considerable length on the kinds of bacteria that enter milk at 

 various stages in its passage from the cow to the consumer, and 

 have dwelt mainly on the economic aspects of the problem, 

 merely stating that there are certain diseases that can be trans- 

 mitted through the agency of this food. Tonight I shall simply 

 enumerate the causes of economic loss to the producer, and 

 mainly call your attention to the possibilities of disease among 

 the users of a dirty milk, with illustrations of cases on record. 



