OF f HE COMMON FROG. 



461 



la membrane, dont ils etoient revetm"—IIistoire 

 generate des Insectes, p. 199- 



Though ignorant of the cause, Swammerdam 

 seems, however, to have been aware of the circum- 

 stance of the tadpole reposing on this gelatinous 

 substance for some time after its exclusion from it. 

 This he attributes, not to any necessity resulting 

 from its present organization, but to the desire of 

 rest. Thus* in the passage immediately preceding 

 that which I have just quoted, he expresses him- 

 self as follows : 



" Et il faut bien remarquer ici que les petits de 

 grenoiiilles ne consument jamais tout leur aliment, 

 (by which last word he means the gelatinous bodies 

 formerly mentioned), mais lorsque les parties sont 

 separdes les unes des autres par le moien de Peau, 

 qui s'y est insinuee, et que cet aliment n'a plus que 

 la forme d'un nuage, qui flotte sur Teau, il ne s'en 

 sert plus que pour se reposer. Aussi nous voyons 

 que lorsqu'il est las de nager, il se renferme incon- 

 tinent dans ce nuage pour se reposer doucement." 



I have troubled the Society with this inconclu- 

 sive notice on the subject at this time, lest any of 

 its members, more able than myself to form an opi- 

 nion, should feel inclined to make the experiments 

 alluded to, during the ensuing spring. 



The time of their appearance is regulated by the 

 state of the season, and the nature of the situation 

 in which the spawn has been deposited. The 

 greater number are excluded by the end of the first 



