26 Cattle Problems. 



tion in cows of medium size than in large cows, in a ma- 

 jority of instances. 



The capacity or size of the udder as a containing organ 

 arises from storing the yield of milk. The weight of the 

 milk yield presses down in the bottom of the udder, re- 

 versing the direction of the hair on the Yield Mark by the 

 force of weight strain, or gravitation, as demonstrated in 

 the chapter on the origin of the Yield Mark. Hence 

 there is no ground whatever for classification, unless it 

 can be founded on difference in weight, and the strain due 

 to weight, in the udder. 



The total size of the Yield Mark varies with the weight 

 and weight strain of yield, in cows of <7«y size. There are 

 exceptions to this rule, but the rule holds good in ninety 

 per cent of all the best milk cows that we have met with 

 in twenty years, which have been many thousands, in dif- 

 ferent States. 



As to the variation in form of the Yield Mark, there is 

 variation in the form of every human hand and arm, from 

 the variation in size, and arrangement of the underlying 

 muscles, etc. There is also variation in the form and ex- 

 pression of the faces of cows, every one differing in some 

 particular or degree from all others, so that every face con- 

 stitutes a separate class, on the basis of slight difference in 

 form. The outline breech figure of every cow varies from 

 that of others as to width, hight, curvature, etc., which 

 modifies the form of the thighs, and the surface of the 

 breech growth, while the form of the flesh surface as to 

 undulation under the skin varies, from difference in fullness 

 of muscles, in every heifer and cow as naturally and as cer- 

 tainly as the forms of their faces. No two cows are pre- 

 cisely alike, though all have a general resemblance to one 

 another. Hence a thousand cows will every one of them 

 vary more or less in the flesh form which molds the skin, 

 or surface covering of the twist, causing variation in the 



