INHERITANCE, VARIATION AND SELECTION. 3! 



which the colt bore to Camel was that the latter had served his 

 mother the previous season." 12 



Miles gives 13 three cases of mares once served by jacks and 

 producing mules. When these mares were subsequently served 

 by pure-bred stallions they produced foals resembling mules. 



THOROUGHBRED HORSES. 



Speaking of horses in general, "Cecil," a famous breeder of 

 thoroughbreds, says: "It is curious to remark that when a thor- 

 oughbred mare has once had foals by a common horse, no subse- 

 quent foals which she may have had by thoroughbred horses have 

 ever evinced any pretensions to racing qualities. There may be an 

 exception, but I believe I am correct in saying that there is not. It 

 is laid down as a principle 'That when a pure-bred animal of any 

 breed has once been pregnant by one of a different breed, she is 

 herself a cross ever after, the purity of her blood having been lost 

 in consequence of this connection.' ' 



Mr. Day says 14 that since Cecil's time there has been only one 

 known case of a thoroughbred mare producing a winner after being 

 covered by a half-bred horse. If this be true for a horse that is 

 one-half thoroughbred, what must be the case when the stallion 

 is only a common horse with no thoroughbred blood? 



Darwin gives, 15 on the authority of Dr. Bower, the case of a 

 black hairless Barbary bitch which was first impregnated by a mon- 

 grel spaniel with long brown hair. She produced five puppies, three 

 of which were hairless and two of which were covered with short 

 brown hair. The next time she was put to a full-bred black, hair- 



(12) Farmers' Magazine, Vol. XXXV, p. 130. 



(13) Stock Breeding, p. 257. 



(14) The Horse. 



(15) Animals and Plants Under Domestication, Vol. II, p. 3. 



