390 Scientific hUelligence, — Botany, 



The entire day was cold and dry. In the evening the tempera- 

 ture being at 49° F., I repeated the attempt to inflame. The 

 attempt succeeded when the flame was applied beneath the pe- 

 duncles of some flowers fully developed, or only partly expand- 

 ed, particularly near the commencement of these flowers, where 

 the utricles are always more abundant. The inflammation, 

 though manifest, was not sufficient to pass spontaneously from 

 the base of one flower to that of another ; it was necessary to 

 excite it at each point in succession, which I did with sufficient 

 gentleness not to injure the stalks. Among those which pre- 

 sented the phenomenon, there were some which I had in vain 

 tried the preceding April ; some others, whose utricles having 

 been inflamed were destroyed, might still, after the lapse of a 

 week, be ignited anew, no doubt in consequence of other utricles 

 having come to maturation since the preceding experiment. In 

 the third attempt, on the 22d May, the development of the 

 plant being more advanced, the inflammation was excited with 

 great intensity over all the stalks. I have frequently since pro- 

 duced a repetition of the phenomenon on the same flower-stalk 

 at diff^erent periods ; and, having become more dexterous in 

 conducting the process, I have been able to reproduce it seven 

 or eight times this year in a sensible degree on the same 

 stalk, by choosing successively its different parts to apply the 

 inflammation to them. It is not necessary that the experi- 

 ment should be made particularly in the evening any more than 

 at any other time. In fine, the inflammation is always propa- 

 gated from below upwards, over an entire bunch of flowers, but 

 with much more facility from above downwards : it may also 

 take place on the peduncles of the centre, without occurring on 

 the lateral peduncles, though they may be in a fit state to re- 

 ceive the inflammation, by approximating the flame separately 

 to their surface. This possibility of succession in the pheno- 

 menon of ignition, as well as of its insulation, is very easily un- 

 derstood for a system of globules separately distributed over all 

 the parts of the plant ; but it cannot exist for a continuous mass 

 of inflammable vapour, such as that with which the fraxinella 

 was supposed to be encompassed The phenomena just de- 

 scribed are produced on all the varieties of the fraxinella, whe- 

 ther the red flower or white flower variety, less easily, however, 

 and less abundantly, on the latter, its utricles appearing smaller 



