4 EXTRICATION OF HEAT. [BOOK n, 



An entire Arum Dracunculus, in twenty-four hours, de- 

 stroyed thirteen times its volume of oxygen; without its 

 spathe fifty-seven times; cut into four pieces, its spathe 

 destroyed half its volume of oxygen ; the terminal appendix 

 twenty-six times; the male organs 135 times; the female 

 organs ten times. 



The same ingenious observer also ascertained that double 

 flowers, that is to say, those whose petals replace sexual 

 organs, vitiate the air much less than single flowers, in which 

 the sexual organs are perfect, 



Is it not then, concludes Dunal, probable, that the conse- 

 quence of all these phenomena is the elaboration of a matter 

 destined to the nutriment of the sexual organs? since the 

 production of heat and the destruction of oxygen are in direct 

 relation to the abundance of glandular surface, and since these 

 phenomena arrive at their maximum of intensity at the exact 

 period when the anthers are most developed, and the sexual 

 organs in the greatest state of activity. 



"To the above facts," says Dumas, " several valuable 

 remarks have been added by the Dutch savants, which serve 

 to complete the study of this curious phenomenon. They 

 found that the temperature of the flower rose as high in 

 oxygen gas as in air, whilst in nitrogen nothing similar could 

 be observed. They have also shown that in proportion as the 

 temperature rises, in the same proportion is carbonic acid 

 formed. In a word, they found all the characters of com- 

 bustion, in this phenomenon, and they did not hesitate so to 

 state it. It may be affirmed, then, that in Colocasia odor a, 

 there is, every day during fecundation, a considerable rise of 

 temperature, owing to the combustion of carbon, by which a 

 large quantity of carbonic acid is formed, and an intense 

 odour produced, which seems connected with this phenomenon 

 of combustion." 



These observations have been confirmed by Dutrochet by 

 thermo-electrical experiments, of which the following account 

 is given by Meyen : He says, plants possess a peculiar 

 warmth ; but it is completely absorbed by the evaporation of 

 the sap, by the evolution of oxygen by day, and of car- 

 bonic acid by night. It rather seems that, in the natural 



