On the Physiologij of Vegetalles. 



m 



arp not fair judges without trying the same plant the same way. 

 When he tried the common arum in the interior of the corolla 

 in the sun, it gave 6 or 7 above the state of the atmosphere. 

 I never got Hubert's account till after my own trials were com- 

 pleted ; but I have since tried to cut the spadixes of the arum, 

 and place them in the manner directed ; but it had no effect on 

 the thermometer. 



I shall now explain the trials 1 made both before and after I 

 received Sir J. E.Smith's letter: every thing that could be done 

 to guard the plant from receiving any heat from the hand was 

 done. Having arranged the approaches round the flowers to be 

 tried the evening preceding, a stick was placed to which the 

 thermometer of comparison was affixed, and a contrivance which 

 enabled me to slip on or off a paper cover, when I wished to try 

 tiie seeds, that I might not, when the pericarpiuni was below the 

 fiower, be obliged to pass the instrument through the corolla, 

 but into the seed-vessel at once, without the bulbs being exposed 

 to the atmospheric air: some sticks were so placed that I could 

 run the thermometer into the flower without injury, by the help 

 of a pair of long pincers, and the whole was covered with a large 

 umbrella to be turned off and on, as required. I began at 

 seven o'clock in the morning. 



When I tried the seeds, the bulb was placed in the midst of 

 them, without passing through the corolla. The result may, I 

 think, therefore, be fairly stated ; that the greatest part of the 

 heat (which was supposed to result from the seeds only) cer- 

 tainly comes fronr the corolla: for, cover the thermometer when 

 taken from the open air by any thing, and it will rise nearly one 



degree j 



