334 
PHYSIOLOGY. 
BOOK II. 
flower began to fade. From the 14th to the 19 th the tem- 
perature increased daily, during the night and in the morning 
falling back to nearly that of the surrounding air. The 
maximum of elevation of temperature above that of the at- 
mosphere occurred, — 
On the 14th, at 3 p.m. 4*5° centigrade 
15th, 4 P.M. 10° 
16th, 5 P.M. 10*2° 
17th, 5 p.m. 11° 
18th, 11 A.M. 8*2° 
19th, 10 A.M. 2*5° 
These maxima might be almost compared to the access of 
an intermittent fever. 
Vrolik and Vriese consider the so called Arum cordifolium 
of the Isle of France to be the same as the aforesaid 
Colocasia odora, upon whose temperature they made very 
numerous hourly observations in the Botanical Garden of 
Amsterdam, the result of which w^as, that the maximum of 
difference observed between the temperature of the spadix 
and that of the green-house amounted to 10° centig. (Ann. 
des Sc. vol. V. 145.) Gbppert adds that plants are generally 
warmer than the air which surrounds them. ( Ueher warme 
Entwickelung in der lehenden PJianze. Wien, 1832.) 
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 
external 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 instances only of large quantities of 
flowers collected 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 
disengagement 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 fol- 
lowing table : — 
