Vi ORIGIN OF MOULD. 209 
> The minute feeds or duft of mould poffefs the 
peculiarity of refifting a degree of heat, which no 
other feeds can fupport without lofing the power 
of germination. After boiling the feed in water, I 
poured the water, then become black, on fub- 
{tances apt to mould, and where it ufually grows 
thicker than on fubftances unmoiftened. The fame 
was done with duft expofed to much greater heat ; 
and I have found, that as this heat does not de- 
prive the feeds of the property of reproduétion, 
neither does it alter their fize or figure, which exa- 
mination with the microfcope both before and 
after expofure has demonftrated. 
- But does that mould, which {prings without be- 
ing fown, and by the care of nature alone, on in- 
finite fubftances, every where difperfed, alfo derive 
tts origin from the duft, which we may fuppofe 
difleminated through the air and on terrettrial 
matter? If natural and artificial mould are of 
the fame fpecies, and if the artificial is produced 
by the duft of the natural mould, I cannot fee 
why the latter fhould not originate from the 
fame principle, efpecially fince it is demonftrated 
that no other part of mould, fuch as roots and 
falks, aid the reproduction. The hypothefis, 
fuppofing that this duft is imvifibly feattered 
through all, and gives exiltence to an immenfity 
of natural mould, is one of the moft reafonable 
hypothefes in philofophy. If each ripe head can 
Vou, Il. 2) furnifh 
