196 Oattle Problems, 



that UDDER SUPPLY ARTERY ENGORGEMENT is the Sufficient, 

 main, and consistent source di\\6.c3MStof €7nbryo sta?'vation, 

 and the necessary abortment succeeding, as the effect of 

 over'Sir^-in and relaxation in the udder supply arteries.^ 



*To give a simple and practical clemonwtration of the ofEect of extreme ex- 

 pansion of the udder-snpply arterii's, or rather of the thickness of the walls 

 of thi'!>L' blood-conveyinj; vessels, we procnicd a piece of snnill rubber tubing, 

 about a half -inch in diamelor— a smaller sizo would be better. Cutting off a 

 piece four inches long, we inserted a plug of ^\'ood, large enough to double 

 the size of the tube, in one end, cutting otT the plug close to the end of the 

 rubber. The thickness of the tube-wall at tlie expanded end of the tube is 

 reduced by this method of ex|):nision to about one-half the thickness of the 

 wall iu the small or w/iexpanded end of the tube. A similar thinning of the 

 walls of the udrler-supply arteries takes place from over-rapid and extreme 

 rates of incruasti in blood and yield ; the other results stated following ac- 

 cording to the various degrees of artery expansion and relaxation, that result 

 from very rapid increase in blood and milk yield. 



