460 



ON THE EAULY STATE 



ally interrupt the investigations of the naturalist, 

 I was deprived, for that season, of the power of 

 drawing any conclusion regarding this supposed 

 analogy. (The vessel in which my young brood 

 were contained, was overturned and broken, and its 

 inhabitants were destroyed.) The observation it- 

 self, however, in so far as I know, has not been pre- 

 viously made ; and it may possibly lead to some cu- 

 rious results connected with the physiology of the 

 lower classes of animals. 



I find that the fact of frogs and insects deriving 

 their nourishment from the mouth, and never by 

 means of any umbilical vein, is insisted upon by the 

 older naturalists, as forming a physiological distinc- 

 tion between these animals and such as strictly be- 

 long to the viviparous classes. In proof of this, I 

 may adduce the following passage from the writings 

 of Swammerdam, in which he treats of the changes 

 of the frog. 



" De plus on doit observer que de m£me que 

 les insectes, qu'on trouve renfermez dans les fruits, 

 dans le fromage, et dans la chair qui se gate, pren- 

 nent leur aliment par la bouche, et jamais par 

 quelque veine umbilicalc : de in erne aussi les pe- 

 tits de grenoiiilles ne sont point joints ni unis a 

 leur aliments par aucune sorte de veine ; mais ils 

 prennent de meme leur nourriture par la bouche : 

 et a la maniere des autres insectes, ils ne commen- 

 cent a manger, qu'apres qu'ils se sont clepouillez de 



