26 



Director's Report of the 



(3) Quarantining the herd against outside dairy wastes and 

 animals coming from infected herds. Pasteurized dairy wastes from 

 outside might have been used safely. 



It has been intimated that a highly productive herd has been 

 developed. This is shown to be the case by the following statement 

 of averages made up from records of 1906-8 and 1913-14. 



The guiding principles in building up this herd have been: 



(1) A standard of selection that includes size and vigor as well 

 as productiveness. 



(2) The importation of males from a line of vigorous and pro- 

 ductive ancestry. 



(3) Avoidance of the forcing system in feeding animals used as 

 breeders. Eight pounds of grain has been the maximum daily 

 ration used in this herd. 



(4) Retention of the most promising heifers and turning off of 

 the poorest. 



bacteriological department. 



Microscopical investigations of the bacteria and tissue cells in milk. — 

 The use of the microscope as a means of determining milk quality 

 has been advocated for more than three-quarters of a century, 

 but it is only with the recent development of the sanitary control 

 of milk supplies that the microscopical methods of milk examination 

 have become of practical importance to the milk dealer and dairy- 

 man. Because of the great need for a simple method of determining 

 quickly the condition of a given sample of milk relative to bacteria 

 and tissue cells the Station has tested out a new method of making 

 such examinations by means of the microscope and has secured 



