B. X.] HE IIISTOEY OF ANIMALS. 289 



only reason of sterility : for if the woman contributes to 

 the semen and generation, it is evident that both the sexes 

 should be concurrent : for if the man is quick, and the 

 woman slow, in the emission of the semen (and many women 

 are comparatively slow), this will prevent conception; for 

 which cause they do not produce children by sexual union 

 with each other. They do so, however, when they happen to 

 be concurrent with each other ; for if the woman is desirous, 

 and prepared for the intercourse, and is inclined for it, but 

 the man is suffering previous pain, and of a cold disposition, 

 it is then also necessary that they should be concurrent. 



CHAPTER VI. 



IT is quite plain when animals desire sexual intercourse ; for 

 the female pursues the male, as hens pursue the cock and 

 place themselves beneath him, if the male is not desirous. 

 Other animals also do the same. But if all animals appear to 

 have these affections with respect to sexual intercourse, it is 

 plain that the causes must be the same throughout. This 

 bird, however, has not only the desire of receiving, but also 

 of emitting semen. This is a proof of it. If the male is 

 not present, she will emit the semen into herself, and be- 

 come pregnant, and produce barren eggs, as if she desired 

 both to emit semen, and when she had done so, soon ceased, 

 just as when the male was present. Others also do the 

 same, for a person has attempted to rear some singing lo- 

 custs, which he had taken in a young state. When grown, 

 they became pregnant spontaneously. 



2. From these considerations it is plain that every female 

 contributes to the semen, if this appears to take place in any 

 one class of animals, for the barren animal differs in no re- 

 spect from the other, except that it does not produce 

 an animal, and this because it was formed by the union of 

 both sexes. For this reason all the seminal fluid of the 

 male does not appear to be productive, but some parts are 

 barren, when not properly compounded from both sexes. 

 And when women have lascivious dreams, the same affec- 

 tions of weakness and debility often occur, as if they had 

 been lying with a male. It is plain, therefore, that if they 

 appear to have emitted a seminal fluid in their dream, they 

 will then conjecture that after their dream the same place 



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