80 The BOOK 
together improbable ; for the experiments that 
may be made concerning the matter, are in- 
volved in fo many difficulties, obfcured by fuch 
thick darknefs, and are fo inextricable, that 
one may be eafily induced to think thefe little 
creatures are really generated from the plants 
themfelves, 
This induced me to inveftigate, with much 
labour and difficulty, the origin of the Worm 
in the tubercles of Willow-trees. Dr. Redi 
fays, he could never fee that the Worm itfelf 
is changed ; and, I confefs, I fhould eafily have 
concurred in opinion with this gentleman, if I 
had not, though he did not fucceed, difcovered 
the abfolute change of this Worm into a Fly, 
and had not obferved the eggs in the Fly’s body 
to be like thofe which are found in the tu- 
bercles. I cannot agree with this very learned 
author, that the Worm has only fix feet, as it 
is reprefented by him; for I find, on the con- 
trary, that it is provided with twenty. 
Thefe are errors into which each of us may 
eafily fall. And, indeed, Ihave not advanced 
what I have hitherto faid with defign to con- 
fute a gentleman who is my friend; for Ithink 
none ought to be cenfured with the rod of 
correction, but thofe petulant perfons, who, 
fwollen with vain-glory, bark like Dogs at all 
writings whatfoever, and feek laurels for them- 
felves by defaming others, which Bartholinus 
endeavours to do on every occafion; and hence 
even his thefes are debafed by railings. In- 
deed, all our writings out to be directed to find 
out the truth with our beft firength: I fay, the 
truth, to which we all ought to adhere, whe- 
ther it favours or oppofes our own opinions, 
fince there is nothing really amiable but its 
beauty only. Therefore, though the opinion 
has an air of probability, I fhall not agree with 
the celebrated Redi, that any creatures are ever 
produced from vegetables, in the fame manner 
that leaves and fruits iffue therefrom. 
I know indeed fome learned men, and fome 
of very eminent rank alfo have been brought 
into this opinion. But I know too, that it will 
never be proved by experiments, however fair 
it may appear. For Iam really obliged to con- 
fefs, that opinion feems to be fo confonant to 
truth, that, unlefs thefe Worms had increafed 
into winged and ftinged animals before my 
face, I could fcarce have faid any thing to the 
contrary. Finally, in order.to give my own 
opinion, with which I obferve the very excel- 
lent phyfician Dr. Francis Redi formerly con- 
curred, I think, indeed, that all thofe tubercles 
of plants, leaves, fruits, and excrefcences in 
the which infects are found, are of no other 
ufe, nor do they grow for any other end or 
purpofe, but to give a fafe habitation to the 
animals in them, in order to preferve them, 
and likewife to ferve for food*. Indeed, ex- 
treme neceffity, in this cafe, required fuch pro- 
vifion ; for many of thefe Vermicles have no 
feet, by the help of which they might move 
of - 
MA 2 URE: or; 
about, and get food for themfelves. This is 
particularly remarkable with refpect to the 
-Worms of Bees and Ants, which have no feet; 
fince the former are, for this reafon, very care- 
fully nourifhed by the Bees themfelves; and 
the latter are, for that reafon, continually re- 
moved into different places, in which they can 
get food without affiftance. Tho’ the Worms 
which we have above defcribed have feet, the 
make moft ufe of them when they feek for the 
habitation, wherein they weave their webs; 
but they by no means ferve them to find out 
their food. Therefore, both in the conftitution 
of the parts, and in the food, which the Worms 
found in the tubercles, there feem to appear 
reafons of great moment, why thefe tubercles 
are produced. ‘Thefe are perhaps, however, 
mere conjectures ; while Nature herfelf never 
intended, in her works, any thing to verify 
them. God fhews himfelf every where equally 
adorable and immenfe. 
I think thefe Worms, which are found yearly 
within the fame kind of tubercles, and are pecu- 
liar and natural to them, are produced only from 
eggs of infects of the fame nature, or conge- 
nial with them; that is, fuch infecis as depofit 
their eggs on the plants, leaves, or fruit, and 
convey them thither from without, This is in- 
deed evident from what I have before obferved, 
with refpect to the eggs that lie in the tubercles of 
Willows, and thofe that are found in the bodies of 
Flies produced from thence: for thefe two kind 
of eggs do not in the leaft differ from each other, 
Now, then nothing further remains but to ex- 
plain the method whereby thefe eggs are conveyed 
into the leaves of the Willows. Nor do I fee 
much difficulty in this matter: for, fince the 
mother Fly is armed with one or two weapons, 
proper to pierce fuch fubftances, and with an- 
other inftrument, which is fitted for dire@ting 
and guiding the eggs iffuing out of her body; 
fhe may very eafily pierce the tender leaves, 
when recently fpringing out, and may caft her 
{mall, and almoft invifible eggs, into the little 
holes that are thus made: that this really happens, 
and in this manner, is the more manifeft; be-. 
caufe, in the new leaves that have juft appeared, 
the little egg is found every where loofe and dif- 
engaged ; and only a part of it is fituated be- 
tween or under’the coat of the leaf: nay, I have 
fometimes thought I {aw the little holes, thro’ 
which the eggs were conveyed into the fubftance 
of the leaf. 
I own, this hiftory would at length be com- 
pletely perfect, if I could fee all I have ad- 
vanced, as my opinion, which, I think, I thall 
hereafter be able to do. But though I have not 
hitherto done that, the experiments which I 
have now propofed, to confirm my opinion, 
feem to me fo ftrong, that no body can defire 
more convincing. I willingly confefs, I have 
not accurately and diftin@tly feen the perforation 
of the leaf in all its circumftances: but I fhould 
think, thatit is not poffible for it to come withinthe 
* Reaumer, indefatigable in his fearches into the infet-world, has given us an account of a peculiar race of creatures, which he 
calls Mineurs des Feuilles, miners of leaves. ‘Thefe burrow between the outer rind and fubftance of the leaf, feeding as they go, 
and leave a traét of white behind them, fo that the leaf feems variegated. 
I 
cognizance 
