114 COMPARISON OF VEGETABLE 



darting through the thickest of the crowd of 

 surrounding animalcules ; and the moment this 

 slender ligament is broken, each is seen moving 

 away from the other and beginning its inde- 

 pendent existence."* Now although we have 

 not in the vegetable world any instance of this 

 voluntary division, yet, in the all but sponta- 

 neous action, the reproduction of plants by the 

 division of their parts bears a strong analogy to 

 it, and in the cases to be further mentioned, the 

 resemblance is still stronger. The Hydra, or 

 fresh water Polype, " is capable of indefinite 

 multiplication by simple division : thus, if it be 

 cut asunder transversely, the part containing a 

 head soon supplies itself with a tail ; and the 

 detached tail soon shoots forth a new head, 

 with a new set of tentacula. If any of the ten- 

 tacula, or any portion of one of them be cut off, 

 the mutilation is soon repaired ; and if the whole 

 animal be divided into a great number of pieces, 

 each fragment acquires, in a short time, all the 

 parts which are wanting to render it a complete 

 individual. "t In this same animal (the Hydra) 

 which is thus capable of being increased by 



* Roget, Anim. and Veget. Physiol. p. 583. 

 t Ib. p. 586. 



