N^EW York Ageicultukal Experiment Station'. 853 



these tests — that the milking machine exerts only slight, if any, 

 adverse influence upon milk flow — is well sustained by the much 

 more numerous, longer, carefully-balanced comparisons made in 

 the Station tests here reported. 



In two of the earlier tests at other stations 



Machines the machines used and rejected differed from 



used. the type used in all later tests, including 



those at this Station. One of the early 

 milkers used was a nonpulsating, suction machine, and th© other 

 ftxerted a combined pressure and suction effect. All the other 

 machines whose tests have been reported, in America at least, have 

 used the principle of the interrupted vacuum, by which the action 

 of the calf's mouth is imitated rather than that of th© hand 

 milker's fingers. This is the principle employed in the B-L-K 

 machines, which are the ones tested at the Station and which are 

 at least typical of, if not the same as, those used in a great major- 

 ity of the other tests. In these machines the application and re- 

 laxation of the vacuum-produced suction is controlled by a " pul- 

 sator " which forms an integral part of the head of the pail used. 

 The teat-cups, by which direct attachment to the udder is made, 

 are conical or funnel-shaped metal tubes with wide-flanged m.ouths 

 to receive the teats. These mouths are partially closed with ring- 

 shaped, heavy rubber curtains which make air-tight connections 

 with the udder. In the older types of machines from six to eight 

 sizes of teat-cups were required to fit all the cows of our herd, but 

 ^vith the new form on© sLz© of cup milks th© herd more efficiently 

 than did the many sizes previously used. This, of course, simpli- 

 fies work with them and shortens the time needed. With thes© 

 C!ups, also, the amount of " strippings " from th© cows has been 

 reduced to a practically negligible amount; and with them two 

 cows were satisfactorily milked that would have been dropped 

 from a hand-milked herd. 



In 1906-7 the cows in the Station herd were 



Station tests on milked by hand and in 1907-8 by machine, 



milk flow. but since such alternate-year comparisons of 



hand and machine milking could not equalize 

 the influence of advancing age of the cows and climatic conditions 

 affecting food supply, it was thought best to divide the herd in 



