78 ZEBRAS, HORSES, AND HYBRIDS 



but the other two views, which may be termed (i) the 

 infection hypothesis, and (2) the saturation hypothesis, 

 demand more detailed treatment. 



The infection hypothesis supposes that the repro- 

 ductive organs of the mother are specifically altered 

 or infected by bearing offspring to a previous sire. 

 The method by which this is effected is now most 

 commonly thought to be by a fusion or blending of 

 some of the unused germ-cells of the first sire with 

 the unripe ova in the ovary of the dam. Physiologists, 

 however, regard this as very unlikely. Although at 

 the time that the ovum of a mare is fertilized there 

 are usually other ova almost mature, or approaching 

 maturity, these disappear during gestation. Subse- 

 quent offspring arise from successive crops of ova, 

 into whose composition it is most improbable that 

 the earlier spermatozoa could enter. Further, it is 

 known that in the Equidae the male germinal cells do 

 not live long within the body of the female ; they are 

 already disintegrating eight days after insemination, 

 and they probably lose their fertilizing power after 

 three or four days, if not sooner; hence it is not 

 possible for them to remain in the body during the 

 whole of a period of gestation and to fertilize the next 

 succeeding batch of ova. 



The second theory which attempts to account for 

 the phenomenon of telegony is termed the saturation 

 hypothesis. In the words of Mr. Bruce Lowe, who 

 has formulated the theory, we may say that, ' briefly 

 put, it means that with each mating and bearing the 

 dam absorbs some of the nature or actual circulation 

 of the yet unborn foal, until she eventually becomes 

 saturated with the sire's nature or blood, as the case 

 may be.' Although not very well expressed, it is 

 obvious what the author means ; and if this saturation 

 really takes place, it accounts for a good deal more 

 than telegony. It would affect the whole body and 



