[ * 6 7 ] 
when I firft put a fprig of mint into a glafs-jar,. 
ftanding inverted in a veffei of water 5 but when it 
had continued growing there for fome months, I 
found that the air would neither extinguifh a candle,, 
nor was it at all inconvenient to a moufe, which I 
put into it. 
The plant was not affedled any otherwife than 
was the neceffary confequence of its confined fitua- 
tion j for plants growing in feveral other kinds of air,, 
were all affe&ed in the* very fame manner. Every 
fucceffion of leaves was more diminifhed in frze than 
the preceding, till, at length, they came to be no 
bigger than the heads of pins. The root decayed, 
and the ftalk alfo, beginning from the root ; and yet 
the plant continued to grow upwards, drawing its 
nouriihment through a black and rotten ffem.. In 
the third or fourth fet of leaves, long hairy filaments 
grew from the infertion of each leaf, and fometimes 
from the body of the ftem, fhooting out as far as 
the vefifel in which it grew would permit, which, in 
my experiments, was about two inches. In this 
manner a fprig of mint lived, the old hem decaying, 
and new ones fhooting up in its place, but lefs and 
lefs continually, all the fummer feafon. 
In repeating this experiment, care muft be taken 
to draw away all the dead leaves from about the 
plant, left they fhould putrefy, and affect the air. 
I have found that a frefh cabbage leaf, put under a 
glafs veffei filled with common air, for the fpace of 
one night only, has fo far affebted the air,, that a 
candle would not burn in it the next morning, and 
yet the leaf had not acquired any finell of putrefac-- 
