194 ON GENERATION. 



The females of some animals are likewise so libidinous that 

 they excite their males by pecking or biting them gently about 

 the head; they seem as if they whispered into their ears 

 the sweets of love ; and then they mount upon their backs and 

 invite them by other arts to fruition : among the number may 

 be mentioned pigeons and sparrows. 



It did not therefore appear likely that a few treads, in the 

 beginning of the year, should suffice to render fertile the whole 

 of the eggs that are to be laid in its course. 



Upon one occasion, however, in the spring season, by way of 

 helping out Fabricius, and that I might have some certain data 

 as to the time during which the fecundating influence of inter- 

 course would continue, and the necessity of renewed communi- 

 cation, I had a couple of hens separated from the cock for four 

 days, each of which laid three eggs, all of which were prolific. 

 Another hen was secluded, and the egg she laid on the tenth 

 day afterwards was fruitful. The egg which another laid on 

 the twentieth day of her seclusion also produced a chick. It 

 would therefore seem that intercourse, once or twice repeated, 

 suffices to impregnate the whole bunch of yelks, the whole of 

 the eggs that will be laid during a certain season. 



I shall here relate another observation which I made at this 

 time. When I returned two of the hens, which I had secluded 

 for a time, to the cock, one of which was big with egg, the 

 other having but just laid, the cock immediately ran to the latter 

 and trod her greedily three or four times ; the former he went 

 round and round, tripping himself with his wing and seeming 

 to salute her, and wish her joy of her return; but he soon 

 returned to the other and trod her again and again, even com- 

 pelling her to submit ; the one big with egg, however, he always 

 speedily forsook, and never solicited her to his pleasure. I 

 wondered with myself by what signs he knew that intercourse 

 would advantage one of these hens and prove unavailing to 

 the other. But indeed it is not easy at any time to understand 

 how male animals, even from a distance, know which females 

 are in season and desirous of their company; whether it be by 

 sight, or hearing, or smell, it is difficult to say. Some on 

 merely hearing the voice of the female, or smelling at the place 

 where she has made water, or even the ground over which 

 she has passed, are straightway seized with desire and set off 



