406 ORIGIN OF MObLD: v. 
and all the refults were, toa certain degree, more 
or lefs fimilar to what are related. 
We may, in the firft place, deduce, that fow- 
ing the duft accelerates the production of mould ; 
fecondly, The thicknefs is increafed; thirdly, 
The height is lefs. Confidering thefe facts with 
refpe& to my object, it feems that the fecond 
proves the duft to be the real feed of the mould ; 
for more abundant produdtion arifes from {fcat- 
tering it. If the thicknefs increafes in proportion 
as the quantity fown is augmented, it is natural 
to fuppofe the fuperabundance of mould on fown 
fubftances an effet of the duft, or rather of the 
minute feeds fown ; and that all or moft part of 
the mould originates from them. This being 
the cafe, we cannot be furprifed if mould on 
fown fubftances is not fo high as upon unfown ; 
for, the plants being more numerous, each can 
not imbibe the fame nutriment from it as may be 
derived from that which is unfown, where there are 
fewer. The fame alfo fucceeds with other plants, 
which are fmalJer and fhorter in proportion as 
they are more crowded together. The firft con. 
fequence deduced from thefe faéts demonftrates, 
that the production of fown mould is earlier than 
that of unfown. I have thought it might be bes 
caufe the fubftances fpoil fooner ; fince it appears 
that, by means of the duft, they fooner contraét 
that principle of acidity and putrefaétion, on 
| which, 
