278 



These maxima might be ahnost compareci to the access of 

 an intermittent fever. 



That these phenomena should not be observed in ordinary 

 cases, is no proof that they do not also occur; for it is easy to 

 comprehend that, when flowers are freely exposed to the ex- 

 ternal air, the small amount of caloric which any one may 

 give off will be instantly dispersed in the surrounding air 

 before the most delicate instrument can be sensible of it ; and 

 that it is in those cases only of large quantities of flowers col- 

 lected within a hollow case, like a spathe, which prevents the 

 heat escaping when evolved, that we can hope to measure it. 



From experiments of Saussure, it seems certain that the dis- 

 engagement of heat, and, consequently, destruction of oxygen, 

 is chiefly caused by the action of the anthers, or at least of 

 the organs of fecundation, as appears from the following 

 table : — 



Names. 



Passiflora serratifolia 

 Hibiscus speciosus 

 Cucurbita maxima, 



male flower - 

 Arum italicum,spadix 

 cold - - - 



spadix hot 



24 hours after 



Duration 



of the 



Experiment. 



12 hours. 



24 



24 

 24 



Oxygen destroyed. 



By the bud. 



6 times its vol. 

 6 



7,4 



5 to 6 



By the 

 flower dur- 

 ing its ex- 

 pansion. 



12 



8,7 



12 



30 



By the 



flower in 

 withering. 



7 



7 



10 



It was also found that flowers in which the stamens, disk, 

 pistil, and receptacle only were left, consumed more oxygen 

 than those that had floral envelopes, as is shown by the fol- 

 lowing table : — 



