Guenon Examined. 27 



outline form of tlie Yjeld Mark in different degrees ac- 

 cording to the elevation or depression of iLe muscles over 

 which its borders extend. So every cow makes a class, on 

 the basis of slight variation in form, while all the cows in 

 a State comprised but one class, on the basis of general re- 

 semblance. 



The increase in the size of the Yield Mark, and in that 

 of the udder, is shown in Plates I. and II., the loosely at- 

 tached skin of the twist on which the Yield Mark extends 

 being shown in the sections of the twist Figs. 5 and 6, 

 Plate I, A section of the folds of the Yield Mark, caused 

 by weight strain, is seen in Fig. 5, same Plate. The sizes 

 of the four udders above are successively doubled, showing 

 the extension of the Yield Mark higher and wider, and 

 the extension of the udder lower and wider, according to 

 increase of milk and its weight strain, the principle being 

 more clearly illustrated in Plate III., Figs, i, 2, and 4, 

 which are designed to illustrate the influence of Gravitation 

 in the udder and Yield Mark, not the anatomy of the parts. 



When Guenon failed to think of gravitation, he missed 

 the mark, and gave — no demonstration as to his classifica- 

 tion. We have shown that it has no natural foundation, 

 and therefore no foundation at all, in the posterior growth 

 of cows, the Yield Mark itself standing securely and nat- 

 urally as an Index of yield, and needing no other or fur- 

 ther classification than its extension in size according to 

 increase in yield; the increased strain, and its self-evident 

 marks on the skin of the twist, arising from increased 

 weight in the bottom of the udder, being as clear and cer- 

 tain as the influence of weight in a sack, or on a scale, or 

 as the force of gravity in any other instance or situation. 



But, while Guenon's classification or system building 

 failed for want of foundation, or rather because it was a 

 mere illusion of his fancy, he did two things of undeni- 

 able importance, publishing a description of the Yield 



