Milk and Mi I kino-. 21 



should be apportioned to the milker, because a tired 

 milker does not do good work, particularly as some 

 cows are difficult to milk ; some have an uncommonly 

 small orifice in the teat, some have strong closing 

 muscles ; others, again, strive to retain the milk en- 

 tirely. This may happen in consequence of the cow 

 feeling pain from the milking as, for instance, in sore 

 teats, or she may be afraid of ill treatment, or try to 

 retain the milk for her calf. To find an explanation 

 for this voluntary retention of the milk we must go 

 into the anatomy of the udder. We have already 

 mentioned the muscles closing the orifice of the teat r 

 we shall now see that a large quantity of blood is- 

 brought from the heart to the udder in strong arter- 

 ies, which, branching out into the minutest vessels,, 

 spread through the entire milk glands, enveloping" 

 the minutest cells and engendering their action of 

 producing milk, and that this blood is led back again 

 to the heart by an equally complicated system of 

 veins that are spread over the entire inner surface of 

 the udder, even down to the point of the teat envelop- 

 ing the entire tube or duct of the teat with a network 

 of veins. If the cow now retains her breath she pro- 

 duces a check on the flow of blood which tries to- 

 return to the heart, and, in consequence, the veins in 

 the udder become swollen and therefore help to close 

 the orifice and duct ; if she manages to repeat this 

 retention of breath in short repetitions she is able 

 to suspend the flow of milk entirely. The remedy 

 for this bad habit is either to give some mash or 



