76 FLANARIA FEL1NA. 



Our difficulties are not lessened by the 

 phenomena which just have been exposed. 

 Whence does it follow, that when either an 

 accidental or an artificial incision in the 

 side of a planaria is sufficiently large, a su- 

 perfluous body must shoot forth, while, if 

 the lacerated parts approach, those organs, 

 which would have protruded, to become se- 

 parate and distinct, are merged in the ge- 

 neral whole ? Is there a universal diffusion 

 of germs, or the elementary principles of li- 

 ving matter always in readiness for deve- 

 lopement, each moment that opportunity 

 shall admit ? Yet nature does seem to la- 

 bour more, and her powers to experience 

 greater difficulty, in accomplishing this kind 

 of reproduction, than in the renewal of or- 

 gans lost by spontaneous separation. Ap- 

 parently, few conditions are requisite for 

 the one ; it is enough that the division have 

 taken place, and that a certain temperature 

 of the atmosphere shall succeed : but for 

 the other, some essential and secret quali- 

 ty is indispensible, to which we know that 



