I 



GENERATION OF ANIMALS, I. xix. 



menstrual discharge flows externally, and most con- 

 spicuously of all in women, who discharge a greater 

 amount than any other female animals. On this 

 account it is always ver^' noticeable that the female 

 is pale, and the blood-vessels are not prominent, and 

 there is an obvious deficiency in physique as compared 

 \\ith males. 



Now it is impossible that any creature, should pro- 

 duce two seminal secretions at once, and as the 

 secretion in females which answers to semen in males 

 is the menstrual fluid, it obviously follows that the 

 female does not contribute any semen to generation ; 

 for if there were semen, there would be no menstrual 

 fluid ; but as menstrual fluid is in fact formed, there- 

 fore there is no semen. 



We have said why it is that the menstrual fluid as 

 well as semen is a residue. In support of this, there 

 are a number of facts concerning animals which may 

 be adduced. (1) Fat animals produce less semen 

 than lean ones, as Ave said before, and the reason is 

 that fat is a residue just as semen is, i.e., it is blood 

 that has been concocted, only not in the same way as 

 semen. Hence it is not surprising that when the 

 residue has been consumed to make fat the semen is 

 deficient. Take a parallel from the bloodless animals : 

 Cephalopods and Crustacea are in their finest con- 

 dition at the breeding season. WTiy ? Because, 

 being bloodless, they produce no fat ; hence, what in 

 them corresponds to fat is at this period »secreted 

 into the seminal residue. (2) Here is an indication 

 that the female does not discharge semen of the same 

 kind as the male, and that the offspring is not formed 

 from a mixture of two semens, as some allege. Very 

 often the female conceives although she has derived 



E 97 



