SUGGESTED EXPLANATIONS 153 



rabbit, as in other mammals, unused sperms lose their fertilising 

 power and disintegrate long before the period of gestation comes 

 to an end." 



For these two reasons the above interpretation may be 

 rejected. 



(b) Somewhat subtler is the suggestion — often also called the 

 " infection hypothesis " — that although the sperms of the first 

 sire cannot be supposed to persist and fertilise ova discharged 

 long afterwards, yet it is conceivable that the disintegrated 

 substance of the sperms may persist and influence the ovaries 

 and the ova, or that the sperms may exert an influence which 

 does not amount to fertilisation. 



So great a physiologist as Claude Bernard seems to have 

 believed in the possibility of such an influence, though it is 

 somewhat suggestive of the " aura seminalis " of the ancients. 

 In this connection, however, Cornevin recalls the facts that a 

 turkey-cock's impregnation of the female suffices for the score 

 or so of fertile eggs which are laid during the season, and that 

 the common cock's act suffices for seven or eight eggs. In both 

 cases the fertile eggs are succeeded by other ".clear " eggs, which 

 are incapable of developing, and Cornevin asks whether we can 

 believe that there is a brusque separation between the two sets, 

 or whether the first at least of the " clear " set may not illustrate 

 this supposed partial fertilisation. Romanes also suggested 

 that the supposed effect was due to an absorption by the eggs 

 of surplus sperm-material. 



(c) Another slightly different suggestion is that the surplus 

 sperms derived from the first sire exert a physiological influence 

 on the constitution of the mother, such that subsequent gestations 

 are affected. Perhaps no one will deny that the male may in 

 this way affect the constitution of the female, and Brown- 

 Scquard's experiments on injections of spermine or testicular 

 extract may be recalled in this connection ; but it is difficult to 

 conceive that the influence should be of so precise a nature as to 



