BASIS GF THE PEOBLEM 43 



a tube, directly into the body of the female, and fertilization thus 

 takes place within the body of the female. 



5. When fertilization takes place without copulation it might 

 be thought that a small proportion of eggs only would be fertihzed, 

 that, so long as fertilization, for instance, depends on the wafting 

 by the wind of a pollen-grain over a considerable distance until 

 it alights on one small spot, or upon the chance meeting of a 

 spermatozoon and an egg in the water, there would be but a small 

 proportion of eggs fertilized. This, however, is not so ; observa- ' 

 tion shows that in a state of nature failure is comparatively rare, 

 and that the majority of female gametes are fertilized. This is 

 in the main due to the vast number of male cells compared with 

 the number of eggs. Among those forms in which copulation 

 takes place, fertilization is clearly dependent upon the strength 

 of the sexual instinct, which impels the male to seek the female. 

 That this instinct is very powerful is well known. It may for the 

 time overcome all other instincts. There is a frenzy of desire 

 among many animals. Male frogs and toads will remain clasping 

 the female for many days waiting for the extrusion of the eggs. 

 Female toads have been discovered smothered by the male in 

 the sexual embrace.^^ It has been noticed that birds, which under 

 usual circumstances are frightened by the sound of a gun, will 

 take no notice when in pursuit of a female.^ All the evidence 

 points to the fact that, owing to the strength of the sexual instincts, 

 females are rarely left undiscovered by a male in the sexual 

 season. Jenner records that one of a pair of magpies was killed 

 and that on the following day the survivor appeared with another 

 mate. One of this pair was killed and on the next day the 

 survivor again appeared with another mate. This was repeated 

 for seven days and on each occasion the survivor always appeared 

 with a new mate.^ In this connexion the great development of 

 those forms of secondary sexual characters may be referred to 

 which enable the two sexes to find and recognize due another. 

 Such are recognition marks, call-notes of many insects, birds, and 

 mammals, and the strong odours given off by many animals 

 during the sexual period. 



Generally speaking, the male is always prepared for the act 

 of copulation and the act takes place when the female is ready 



• Letoumeau, Evolutinn of Marriage, p. 8. ^ Darwin, Descent of Man, p. 384. 



* Letoumeau, loc. cit., p. 28. 



