94 VARIATION IN SIZE. 



and so they are not always so uniform in nature as they 

 appear in the cuts. 



Their size varies as the skin is more or less folded or 

 stretched, while we have supposed in the figures that 

 the skin is uniform or free from folds, but not stretched 

 out. In order to understand the differences which the 

 milk-mirrors present in respect to size, according to the 

 state of the skin, the milk-mirror is shown in two ways 

 in Figs. 52 and 53. In Fig. 53 the proportions are 

 preserved the same as in the other mirrors represented, 

 but an effort is made to represent the folds of the skin ; 

 while in Fig. 52 the mirror is just as it would have 

 been had the folds of the udder been smoothed out, and 

 the skin between the udder and the thighs stretched 

 out ; or, in other words, as if the skin, covered with up- 

 growing hair, had been fully extended. 



This mirror, but little developed, just as shown in 

 Fig. 53, was observed on a very large Norman cow. 



It is usually very easy to distinguish the milk-mirrors 

 by the upward direction of the hair which forms them. 

 They are sometimes marked by a line of bristly hair 

 growing in the opposite direction, which surrounds 

 them, forming a sort of outline by the upward and 

 downward growing hair. Yet, when the hair is very 

 fine and short, mixed with longer hairs, and the skin 

 much folded, and the udder voluminous and pressed by 

 the thighs, it is necessary, in order to distinguish the 

 part enclosed between the udder and the legs, and 

 examine the full size of the mirrors, to observe them 

 attentively, and to place the legs wide apart, and to 

 sniuoth out the skin, in order to avoid the folds. 



The mirrors may also be observed by holding the 

 back of the hand against the perineum, and drawing it 

 from above downwards, when the nails rubbing against 



