93 HEAT OF THE ARUM. 



serts to be, for a few hours, " so hot as to 

 seem burning." The learned M. Senebier 

 of Geneva, examining into this fact, disco- 

 vered that the heat began when the sheath 

 was about to open, and the cyhndrical body 

 within just peeping forth : and that it was 

 perceptible from about three or four o'clock 

 in the afternoon till eleven or twelve at 

 night. Its greatest degree was seven of Reau- 

 mur's scale above the heat of the air, which 

 at the time of his observation was about 

 fourteen or fifteen of that thermometer. 

 Such is the account with which I have been 

 favoured l}y Dr. Bostock of Liverpool, from- 

 a letter of M. Senebier*, dated Nov. 28, 

 1796, to M. De la Rive. I have not hitherto 

 been successful in observing the pha?no- 

 menon in question, which however is well 

 worthy of attention, and may probably not 

 be confined to this species ot Arum, 



* It is now published in his Physiologie Vegetale^ 

 V. 3. ai4, where nevertheless this ingenious philosopher 

 has declared his opinion to be rather against the exist- 

 ence of a spontaneous heat in vegetables, and he ex- 

 plains even the above striking phienomenon upon che- 

 mical principles, which seem to me very inadequate. 



