16 UTILIZATION OP MINUTE LIFE. 



flowers carefully cut away as soon as they appear, 

 the plant, instead of remaining an annual, con- 

 tinues to live through the winter ; and if the same 

 operation be repeated throughout the following 

 year, our mignonette will soon become a ligneous 

 vegetable a real tree ; and from that moment the 

 duration of its life is unlimited. This then is the 

 whole secret of the " elixir of life," at least as re- 

 gards plants and inferior animals. Future research 

 alone can assure us whether the same principle is 

 applicable to higher organisms. 



Mr. Spence having remarked that the larva or 

 grub of a certain Aphidivorus fly (a fly feeding upon 

 the Aphis, or blight) had Lived about twelve months 

 without the slightest particle of food an example by 

 no means unprecedented in insect life says : " We 

 can attribute this singular result to no other circum- 

 stance than it having been deprived of a sufficient 

 quantity of food' to bring it into the pupa state, 

 though provided with enough for the attainment of 

 nearly its full growth as a larva. Possibly the 

 same remote cause might act in this case as operates 

 to prolong the term of existence of annual plants 

 that have been prevented from perfecting their 

 seed ; and it would almost seem to favour the hy- 

 pothesis of some physiologists, who contend that 

 every organized being has a certain portion of irri- 

 tability originally imparted to it, and that its life 



