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LXXXIX. Microfcopical Obfervations : In a 
Letter from Edward Wright, Ffq\ to Mr * 
Peter Collinfon, F. R. S. dated at Paris, 
Decemb. 26, 1755. 
Read Mar. 18, T'T appears from Mr. Needham’s- experi- 
l 7 S 6 - me nts, and thofe of Monk de Buffon, 
that animal and vegetable fubftances infufed in boil- 
ing water,, put into bottles completely filled, and fo 
clofely flopped, that no air can enter, and even kept 
for fome time in hot afhes, that in cafe there fho id 
be any latent ova of infeCts, they may effectually be 
deftroyed; it appears, I fay, from the experiments 
of thele gentlemen, that fuch fubftances, notwith- 
ftanding fuch precautions, afford microfcopical ani- 
malcules of various kinds, and that fooner or later, 
according to the greater or lefs degree of exaltation in 
in the fubftances. Hence they conclude, that there is 
a real productive force in nature, by which thefe ani- 
malcula are formed. 
Having read the accounts of thefe experiments, I 
was defirous to make fome of the fame kind,, which I 
accordingly did, in the fummer of the year 17^2. 
Though the greateft part of the animal fubftances, 
upon which I made any experiments treated in the 
manner above-mentioned, yielded, fooner or later,, 
great numbers of microfcopical animalcules ; yet moft 
of the vegetable fubftances, whether from the cold - 
nels of the feafon, which was not very favourable 
that year with us, or for fome fault in preparing the 
infufion, intirely failed, and underwent a fermenta- 
tion, 
1 
