APPARENT CONTRADICTION. 93 



affected by so many chance circumstances, which cannot 

 always be known or estimated by even the most skilful 

 judge; as the food, the treatment, the temperament, 

 accidental diseases, inflammation of the udder, premature 

 calving, the climate and season, the manner in which 

 she has been milked, and a thousand other things which 

 interrupt or influence the flow of milk, without materi- 

 ally changing the size or the shape of the milk-mirror. 

 M. Magne, w T ho appears to me to have simplified and 

 explained the system of Guenon, and to have freed it 

 from many of the useless details with which it is en- 

 cumbered in the original work, while he has preserved 

 all that is of practical value, very justly observes that 

 we often see cows, equally well formed, with precisely 

 the same milk-mirror, and kept in the same circum- 

 stances, yet giving neither equal quantities nor similar 

 qualities of milk. Nor could it be otherwise ; for, 

 assuming a particular tuft on two cows to be of equal 

 value at birth, it could not be the same in the course 

 of years, since innumerable circumstances occur to 

 change the activity of the milky glands without chang- 

 ing the form or size of the tuft ; or, in other words, the 

 action of the organs depends not merely on their size 

 and form, but, to a great extent, on the general con- 

 dition of each individual. 



To give a more distinct idea of the milk-mirror, it will 

 be necessary to refer to the figures, and the explana- 

 tions of these I translate literally from the little work 

 already referred to, the Choix des Vaches Latter es, or ; 

 the Choice of Milch Cows. 



The different forms of milk-mirrors are represented 

 by the shaded part of figures 29, 30, 31, etc. ; but it is 

 necessary to premise that upon the cows themselves 

 they are always partly concealed by the thighs, the 

 udder, and the folds of the skin, which are not shown, 



