224 AGRICULTURE OF MAINE. 



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pail and, by opening the milk cocks, the vacuum is extended to 

 the teats of the cow. The amount of vacuum created as indi- 

 cated on the vacuum gage should be about sixteen inches which 

 is equivalent to about eight pounds atmospheric pressure. The 

 exact amount may be varied slightly from this, depending upon 

 the animals in any particular herd, but it should be regular from 

 milking to milking. The number of pulsations or cut-oflfs by 

 the piston per minute can be regulated. Fifty-five pulsations 

 have been found to give the most satisfactory results. The 

 suction is applied to all four teats at once and as the air is 

 drawn from the teat cups the milk is forced out to fill up this 

 space. It is thence drawn into the empty pail. The inspection 

 glasses on the wall of the pail near the lid, or on the lid, en- 

 able one to see the milk as it passes from the udder into the 

 pail. By this means, together with the condition of the udder 

 and the characteristic sound produced by the suction at this time, 

 the operator can determine when the cows are milked dry. 



The teat cups and mouth pieces are the most important parts 

 of the milker. The cups must in every case fit the teats snugly 

 and be flexible and of the right size. If too tight, a congestion 

 of blood will occur in the teat with resultant disastrous effects 

 on the milk flow and on the animal. On the other hand, if too 

 large, air will penetrate the vacuum and the teats will be 

 drawn out abnormally. In some makes of machines the 

 teat cups must be selected for each individual animal on 

 account of the varying size of the teats. The ability of the 

 operator, together with his care in attending to the proper fit- 

 ting and adjustment of the teat cups and mouth pieces, will aid 

 greatly in the completeness of milking. In other machines 

 there is a so-called "Universal" teat cup which automatically 

 adjusts itself to the teats of different sizes. 



There are but few parts to the milking machine that wear 

 out rapidly so that the maintenance of a mechanical milker is 

 slight. 



We will now consider the effect of machine milking on milk 

 secretion. It is very difficult to draw conclusions comparing the 

 results of machine and hand milking from data compiled in dif- 

 ferent years, as many outside factors must be considered as 

 possibly affecting the lactation. It has long been advocated that 

 one man should milk the same cows continually on account of 



