310 THE EXAMINATION OF MILK 



along with regulations framed to secure the sale of milk 

 only from healthy cows, kept and milked under hygienic 

 conditions. In the British Isles at present the matter is 

 left largely to voluntary effort, and until the public can 

 be educated to demand a sounder, cleaner milk, there 

 will be no general improvement in the purity of this 

 important article of diet. 



Many investigations have been made to determine the 

 amount of dirt, the acidity, and the number and kinds of 

 bacteria in milk as it is actually delivered by the farmers, 

 dairymen, and others who sell it ; these researches are 

 useful in giving a clue to the standard which might very 

 well be adopted without hardship to the farmer or retailer 

 of milk. 



The imposition of certain regulations for the inspection 

 of cows and cowsheds, and the fixation of legal standards 

 of purity, all of which would be in the interests of public 

 health, would undoubtedly involve expense to the pro- 

 ducer and distributer, and this would have to be met by 

 the payment of a somewhat higher price for milk than at 

 present. 



For farmers, dairy companies, and others who are 

 desirous of supplying their customers with clean milk, 

 the following standards should be kept in view : 



(i) Dirt. As estimated by the method described in 

 Ex. 143, market samples of milk have been found to 

 contain from about 5 to over 120 volumes of dirt per 

 million of milk. Most of the impurity is introduced at 

 the farm, comparatively little being added during the 

 journey to the consumer. From the work of Houston 

 and Orr it would appear that the enactment of a regula- 

 tion that in any sample taken at the farm in this country 

 there should not be more than 30 or 40 volumes of 



