CHAP. I. VITAL PROPERTIES AND STIMULANTS. 



167 



unquestionably consider the mechanism by which this 

 effect is produced as designed for effecting this very 

 purpose. 



(4.) Dionaea muscipula. The leaves of the Dio- 

 naea muscipula, or Venus's Flytrap, consist of a flat- 

 tened petiole (fig. 151. a), at the extremity of which 

 are two fleshy lobes (6), 

 which lie when ex- 

 panded in the same 

 plane with the petiole. 

 These lobes are capable 

 of being elevated and 

 brought together in- 

 to a position perpen- 

 dicular to the surface 

 of the petiole (c). 

 They are furnished 

 with "ciliae,"or bristles, 

 round their margins, 

 which stand nearly at 

 right angles to their 

 upper surface ; and 

 there are besides these, three little short bristles placed 

 upon the upper surface of each lobe in a triangular 

 order. When a fly or other insect, crawling over the 

 surface of the lobes, touches either of these latter 

 bristles, the irritability is excited, the lobes suddenly 

 close, and the insect is imprisoned like a rat in a com- 

 mon gin. Some little time after the death of the 

 insect, the lobes unfold and wait for another victim. 

 The only plausible conjecture which has been made, 

 to account for the use and intent of this singular con- 

 trivance, supposes this plant to require animal manure 

 for the healthy performance of some function or other ; 

 and in corroboration of this opinion, it has been stated 

 that Mr. Knight, after having secured some plants from 

 the possibility of providing themselves with flies, fur- 

 nished some of them with scraped beef, and left the 

 rest without any such provision. The result of the 

 M 4 



