f 2-4 
yet it could never be any, real dif- 
advantage in the natural fituation 
of things, becaufe this fouled air 
may be correéted in the atmofphere 
by fome manner or other unknown 
to us; and, if not, we are, at any 
rate, immediately out of its reach, 
as it rifes by its being become light- 
er. But if fuch infectious plants 
are fhut up in {mall clofe rooms, 
they certainly might do a material 
injury to our conititution, and even 
occafion death. ¢ 
It appears, by experiment 41, 
- that a plant may really foul fo much 
air at night as fcarce to be able to 
correct in the day. But it is to be 
confidered, that fuch a plant, being 
maimed by its roots being taken off, 
_and by being fhut up in a narrow 
fpace, muft have loft fome of that 
_. yigour which plants naturally have 
| ~ when 
