146 STERILITY FROM Chap. XVIII. 



compatibility of the pair which are matched. Several instances have 

 been communicated to me by Mr. W. C. Spooner (well known for his 

 essay on Cross-breeding), by Mr. Eyton of Eyton, by Mr. Wicksted 

 and other breeders, and especially by Mr. Waring of Chelsfield, in 

 relation to horses, cattle, pigs, foxhounds, other dogs, and pigeons.''^ 

 In these cases, females, which either previously or subsequently were 

 proved to be fertile, failed to breed with certain males, with whom 

 it was particularly desired to match them. A change in the con- 

 stitution of the female may sometimes have occurred before she was 

 put to the second male ; but in other cases this explanation is hardly 

 tenable, for a female, known not to be barren, has been unsuccessfully 

 paired seven or eight times with the same male likewise known to be 

 perfectly fertile. With cart-mares, which sometimes will not breed 

 with stallions of pure blood, but subsequently have bred with cart- 

 stallions, Mr. Spooner is inclined to attribute the failure to the lesser 

 sexual power of the race-horse. But I have heard from the greatest 

 breeder of race-horses at the present day, through Mr. Waring, that 

 *' it frequently occurs with a mare to be imt several times during 

 " one or two seasons to a jDarticular stallion of acknowledged power, 

 " and yet prove barren ; the mare afterwards breeding at once with 

 '' some other horse." These facts are worth recording, as they show, 

 like so many previous facts, on what slight constitutional differences 

 the fertility of an animal often depends. 



Sterility of Plants from changed Conditions of Life, and from 



other causes. 



In the vegetable kingdom cases of sterility frequently 

 occur, analogous Avith those previously given in the animal 

 kingdom. But the subject is obscured by several circum- 

 stances, presently to be discussed, namely, the contabescence 

 of the anthers, as Gartner has named a certain affection — 

 monstrosities — doubleness of the flower— much-enlarged fruit 

 --and long-continued or excessive propagation by buds. 



It is notorious that many plants in our gardens and hot-houses, 

 though preserved in the mo.st perfect health, rarely or never pro- 

 duce seed. I do not allude to plants which run to leaves, from 

 being kept too damp, or too warm, or too much manured; for 

 these do not flower, and the case may be wholly different. Nor do 

 I allude to fruit not ripening from want of heat or rotting from too 

 much moisture. But many exotic plants, with their ovules and 

 pollen appearing perfectly sound, will not set any seed. The 

 sterility in many cases, as I know from my own observation, is 

 simply due to the absence of the proper insects for carrying the 

 pollen to the stigma. But after excluding the several cases just 



77 



For pigeons, see Dr. Chapuis, * Le Pigeon Voyageur Beige,' 1865, p. 66. 



