Artery Relaxation in Practice. 21 5 



New York and other dairy localities, where the quantity 

 of the blood supplying the udders of aborting cows is much 

 less ? The answer is ready : The coast-country cows of 

 Holland, Holstein, etc., have been trained to hand-milk- 

 ing for probably two centuries ; but if trained for only loo 

 years to the pail, supposing them to have begun with a 

 two-quart yield, and to have increased their yield only one 

 pint yearly ; at this small rate of increase their yield by 

 this time would have been 50 quarts, or over twelve gallons 

 per cow ! 



But here it is evident that the actual general yearly in- 

 crease in the yield of the dairy cows of Western Europe 

 can not have been as much through a long period as half a 

 pint yearly per cow ! This fact, together with the careful 

 habits and scant resources of the early trainers of these 

 large-yielding cows, indicates clearly enough that the yield 

 of these Netherland cows has been only very slowly in- 

 creased from the small yield of the ancient coast-country 

 cows, their udder-supply arteries having been only very 

 slowly expanded in size and increased in their wall sub- 

 stance; but not at any time engorged by extreme and over- 

 rapid increase in feed, that certainly precedes large and 

 rapid increase in yield. So the exemption of the large- 

 yielding cows of Western Europe from abortion, is ex- 

 plained by the very slow rate at which their capacity for 

 large yield 'has been developed. 



Now turn to Herkimer county. New York, where an 

 average increase of 70 per cent in yield is made in many 

 cheese-dairy herds, in less than two years, and in some 

 cases in a single grazing season ; and we see at once not 

 only that such a rapid rate of increase cannot possibly be 

 continued for ten nor even five years ; but also that the 

 udder-supply arteries of the cows subjected to this rapid 

 increase in blood must be engorged during much of each 

 grazing season, in many of these American dairy cows. 



