THE VEGETABLE KINGDOM. 495 



sphere and shows us traces of animal hfe. The stamens 

 are agitated, and quit their places, bending towards the 

 stigmata. More rarely, as if modesty were inherent in the 

 delicacy of flowers, the pistils advance towards their 

 spouses. 



By means of thermo-electric needles it has been proved 

 that the elevation of temperature in the flower is a wide- 

 spread phenomenon. In some plants this heat is so great 

 that an instrument of accuracy is not requisite to show it ; 

 the simplest thermometer suffices. It is only necessary to 

 touch even the flower in certain arums to observe that it 

 is of a burning heat, and Ave are astonished that it can 

 support such a temperature without being consumed. De 

 CandoUe obseiwed that a thermometer plunged into the 

 spathe of an Italian arum rose to G2° (143° 36' Fahr.)^ 



From the remotest antic|uity men seem to have under- 

 stood the mysterious loves of plants. The question was 

 practically solved, for Herodotus tells us that the Baby- 

 lonians knew how to distinguish male from female date- 

 trees, and that in his day, in the environs of their immense 

 city, they occupied themselves with the artificial fecunda- 

 tion of the latter. 



The first travellers who, in imitation of Prosper Alpinus, 

 taught us true notions as to the manners of the Orientals, 

 state that they were so Avell acquainted with the fertilizing 

 power of the stamens, that they were accustomed, from 

 the most distant times, to place their female date-trees to 



^It ^Yas Lamarck who discovered that tlie flower of the arum gives out con- 

 siderable heat at the time of fecundatiou. Lie CandoUe verified this fact at ]\Iout- 

 pellier. It is a very remarljable phetiomenon. I observed tliat at a given moment 

 the flowers of certain C'olocasiai grew so warm, tliat their lieat was felt by the 

 fingers of those who touched them. In other flowers the phenomenon is less 

 evident, still it is general. Bronguiart, Dutrochet, Biot, and Schultze have recog- 

 nized it by means of thermo-electric needles. 



63 



