218 ATMOSPHERICAL OXIQEN'. 



common air. The latter fpecirnen flowered very well j but 

 the former died away without opening one of its bloflbms. 

 With the fame Exp. 2. The event was the fame when I made ufe of a 

 la flower. branch of this fedum already in flower; for the plant withered 



and did not flied its petals; which is contrary to the ufual ha^ 

 bits of this vegetable, when it is left to the impulfes of nature 

 unthwarted by art. 

 With barren Exp, 3. Several plants of fedum acre were alfo confined in 



fame and fem- J^^^ ^^^^^ ^''^-^ azote laft fpring, before the flower buds were 

 pervivum tedo- formed upon them: not one of thefe attempted to vegetate; 

 '""^' on the contrary they all withered in the courfe of four or five 



weeks. This was not the cafe with other fpecimens, which 

 were placed befide them upon fimilar flands, under jars con- 

 taining common air and (landing in water; for they remained 

 green and vigorous, after the former were dead; they had 

 moreover produced a number of purple filaments fpringing 

 from the Jlalk; which is conftantly done by the fedum acre, 

 when fufpended by the roots. It is proper to remark, that the 

 air of the latter fet was frequently changed, with a view to keep 

 it near the ftandard of the atmofphere. The fempervivwn tec* 

 torum did not oflfer to vegetate when treated in the fame nian^ 

 ner by being confined in azote; but it appeared to be more te- 

 nacious of life under this kind of treatment, than the fedum 

 acre, 

 lofcrence from ^^^^ preceding experiments induced me to conclude, at the 

 thefe experi- time of making them, that the welfare of fucculent plants re- 

 ^^^ ' quires them to be expofed to the atmofphere, and that they 



cannot grow when furrounded by azote, nor even prefervethe 

 vegetative principle in it, for an indefinite length of time. 

 Seeds and bulbs ^ hdive fliewn in the fourth volume of the Manchefter Me- 

 in the fame pre- moirs, that feeds and bulbs are not lefs indebted for their prof- 

 perity to the agency of oxigen, than fucculent plants appear 

 to be from the prefent letter. Thus it is manifeft that the far- 

 ther we carry our refearches into the nature of organized bodies, 

 the greater is the number of them ; which are found to be in- 

 capable of performing their natural funflions, when deprived 

 of refpirable air; but as the truth of this maxim remains to be 

 extended experimentally to vegetables of a lefs humid confli- 

 tution, than the fedums, the following fa<5l may be related 

 with propriety. 

 Experiment ,£^J3. -t. A diminutive plant of cerajilum vulgalum was placed 



made with Qtt the 18th of February, 180k upon a ftand covered with a 



