on Vegetables, with reference to their Temperature, 7 



Table C. 

 June 12th. Arum Walteri, a fresh group, &c. Thermo- 

 meter 86° Fahr. Dew-point 64°. Drying power 22°. Clear. 



Table D. 

 June 7th. Arum Walteri, &c., three hours after collection. 

 Thermometer 64° Fahr. Dew-point 51°. Drying power 13°. 

 Fahr. Clear. 



Parts of the plant examined. 



Spadix in vigorous / male part.., 

 action \ female part 



Petioles of various leaves 



Midribs of various leaves 



Stem (collection of petioles \ 

 two inches above soil J 



Stem one inch above soil 



Stem surrounded by soil 



Temperature of soil , 



Galvanometer. 



+ 13 

 + 13-7 

 + 8-8 

 + 13 



+ 2 



- 2-5 



—14 



-14 



+ 8-8 

 + 12-5 



14 



+ 7 

 + 12 



-14 



+ 8 

 + 11 



+ 7 



-14 



("Agreeing 



with the 



i thermo- 



t metric 

 measure 



To these tables many others might be added, as they all 

 tend to establish the same point. If we examine them solely 

 to ascertain whether they afford any proof of the existence of 

 a certain specific or vegetable heat, we are irresistibly led to 

 acknowledge that the proof is against any such vital agent, and 

 we deduce this, — . 



1st. Because in the four tables the atmospheric tempera- 

 tures quoted are 66°, 81°, 86° and 64° respectively, and yet 

 the plant varies with each. 



2d. We observe that the temperature of the soil is thesame 

 as that of the subterrene stem or root, and that the excess of 

 temperature, if any such exist, is found in parts remote from 

 the soil, and in which vital action is taking place. It is na- 

 tural that the root should be of the same temperature as the 

 earth, for along its vessels are passing the fluids derived from 

 the soil ; and the conducting power of the latter must tend to 



