PARTHENOGENESIS. 17 



impulse, but it also leads us to suppose that the same thing 

 may have befallen Herr Basler, whose moth belongs to the same 

 class with ours, and is closely allied to it in its nature and mode 

 of life. For if the first male which found its way into my room, 

 and which, no doubt, had slipped in through a small opening in 

 the window, had immediately copulated with the female, and 

 afterwards concealed itself in a corner of the room, or flown 

 away again, and the following day had not been so fine, so as to 

 give the opportunity for the above observations, I should have 

 obtained fertilized eggs from my moth, in exactly the same way as 

 Herr Basler, without thinking that a fecundation had taken place, 

 and perhaps without thinking an error possible." Bernoulli's 

 observation also is cleared up by Von Scheven with such weighty 

 objections, that every trace of credibility is entirely wiped out of 

 it. As Scheven has treated the subject with that felicity of 

 expression peculiar to his time, it would require too much space 

 if I were to reproduce his polemics in their full extent ; I shall 

 therefore only quote the most important part of his observations. 

 Amongst other things in Bernoulli's relation it had struck 

 Scheven, that in fifteen days after the spinning up of the cater- 

 pillar the little caterpillars had already escaped from the eggs, 

 for which reason he expresses himself upon this point as follows*: 

 " In the ordinary course of nature the caterpillar takes some 

 days before it becomes converted into a pupa in its cocoon. 

 The pupa usually lies at least fourteen days, and for the most 

 part still longer, in its cocoon, before the moth makes its ap- 

 pearance from it. But still more time is required, before the 

 young caterpillars come to maturity in their eggs and creep out 

 of them. The greater or less warmth of the season, or of the 

 place where the pupee and eggs are kept, certainly often gives 

 rise to a change in the duration of the time appointed for these 

 events. But that all these changes should occur within fourteen 

 days, is just as incredible as that a maiden, who has never seen 

 a man in her life, and for still greater security has gone into a 

 nunnery, can give birth to a child there, in an innocent way, 

 within fourteen weeks. In all probability another female moth, 

 which the author may have had long previously in this box, and 



* Loc. cit. p. 5-1. 



