248 MILK HYGIENE 



animal producing the milk. Microscopical examination 

 of these elements shows a majority of them to be poly- 

 morphonuclear cells, and these are generally considered 

 as indicative of suppurative changes. 



There seems to be absolutely no relation between 

 the number of these leucocytes in the milk and the 

 general leucocyte content of the blood, thus indicating 

 that a large number of leucocytes in the milk points to 

 a local condition only. 



Cattle not infrequently suffer from udder troubles, — 

 gargets of various types in which inflammatory pro- 

 cesses of varying degrees of severity may occur. In 

 some cases these may be so slight as apparently not to 

 affect the nature of the milk. Often, however, the milk 

 becomes viscous, sometimes clotty or stringy, and may 

 even be of a bloody nature. 



Occasionally such troubles as these develop into a 

 stage in which pus is actually present in such quantities 

 as to be easily recognizable. Milks of this character 

 should of course be excluded from food supplies. 



In these cases where a physical examination reveals 

 an abnormal condition a microscopical study naturally 

 presents a far different picture from that which one 

 obtains in apparently normal milk, and the increase in 

 the number of leucocytes is especially noticeable. 



In contrast to these cases where the physical exam- 

 ination and the microscopic findings are in harmony, 

 there are many instances where, although there are an 

 abnormal number of leucocytes present, no physical 

 changes can be demonstrated. 



Boards of health have adopted arbitrary standards 

 in a number of instances and rejected supplies with 

 abnormal leucocyte content on the ground that the milk 

 was unwholesome. 



Where the numerical standard set is a high one this 

 proceeding must be commended, since there are not 

 lacking unscrupulous people who will put on the market 

 milk from "gargety" cows which cannot be detected by 

 the ordinary chemical tests. The numerical leucocyte 

 test has been the means of detecting such milk, and trac- 

 ing it back to cows with manifest physical lesions in 

 many instances. 



