GENERATION OF ANIMALS, II. iv. 



is secreted, or (b) when the part of the female ana- 

 logous to the uterus is inserted into the male (as 

 is observed to take place in certain insects)." 



I have said already '' that the fluid which is pro- 

 duced in females and accompanies sexual excitement 

 contributes nothing at all to the fetation. The 

 strongest reason for believing that it does is that the 

 phenomenon of night effusions occurs in women just 

 as in men ; but this is no proof at all, because it 

 occurs with young men who come almost to the point 

 but in fact emit nothing, and also with those who as 

 yet emit infertile semen. 



Conception cannot occur without (a) an emission 

 from the male during copulation and without (b) the 

 presence of the menstrual residue either externally 

 discharged or available in sufficient quantity inter- 

 nally. Conception takes place, however, even if the 

 pleasure which women usually experience during 

 sexual intercourse fails to occur, if the part concerned 

 happens to be in heat and the uterus has descended 

 within. Generally, however, pleasure does occur, 

 because when the secretion, which is usually accom- 

 panied by pleasure in man and woman alike, takes 

 place, the os uteri has not closed, and in these con- 

 ditions a better passage is afforded for the semen of 

 the male. 



The discharge does not (as some suppose) take 

 place within the uterus, because the os uteri is narrow. 

 The discharge of the male takes place in front of it, 

 at precisely the same spot where the female dis- 

 charges the moisture which is produced in some 

 instances.*^ Sometimes it remains in this place, 



« Cf. 738 b 12. '' Bk. I, ch, 20. 



' Cf. 727 b 33 ff. 



189 



