They Hails 1 ORY 
been hatched into Worms, though before the 
cheefe was perfectly found and entire. I have 
likewife obferved, that this putrefaction in 
cheefe is confiderably augmented by the car- 
cafes of the Worms that happen to die in it; 
for there always die fome of them: and it is 
impoffible there fhould not, as it is a certain 
death to them not to be able to harden into 
Nymphs, and all of them cannot efcape out 
of the moift part of cheefe to a drier fituation, 
which is neceffary to fucha change. Further, 
I have obferved, that fome of thefe Worms 
contained other Worms within their bodies, 
but fo minute as to be fcarce difcernible. But, 
on extracting thefe fmaller Worms from their 
places, I found they were almoft of the fame 
form with the larger Worms, though they move 
themfelves from place to place in quite a dif- 
ferent manner. I could even difcover, in the 
tranfparent bodies of thefe {maller Worms, 
that, by examining with the microfcope, not- 
withftanding their almoft incredible miutenefs, 
they were furnifhed with pulmonary tubes, and 
other parts in common with the greater. 
It is certainly very difficult to explain in 
what manner Worms are bred in living ani- 
mals; as, for inftance, in the livers of Oxen, 
in the kidneys of Dogs, and even in the blood- 
vefiels, as is obferved by that celebrated ana- 
tomift and profefior of furgery at Amfterdam, 
Ruyfch. For my part, I freely own, that I 
want fufficient experiments to form any folu- 
tion of this furprifing phenomenon; though I 
have met with great numbers of different kinds 
of Worms, in the living and healthy bodies 
both of land and water animals, and even of 
fowls and flying infects. However, on this 
occafion, I cannot as yet advance any thin 
certain, or fatisfactory. 
I muft not omit a circumftance which I 
heard from Otto Marfilius, the late famous 
painter of flowers and infects. It was this, 
that he had feen, at the time when Caterpillars 
were bufy in divefting themfelves of their fkins, 
or when they had juft performed the operation, 
and were grown faint and weak with the fa- 
tigue of it, a great many Flies, fome bigger 
and others lefs, piercing the bodies of fuch 
Caterpillars, and depofiting in the wounds, fo 
made, quantities of little eggs; from which 
proceeded the Worms, that are every year fo 
commonly found in Caterpillars. As yet, I 
muft own, I never faw myfelf this ftrange 
operation: but allowing it to be fact, it would 
perhaps greatly help us in explaining the ge- 
neration of Worms found in the vifcera, or 
bowels, of larger animals; provided efpecially 
fuch Worms were found afterwards to turn to 
Flies, or other winged infects, which as yet I 
have not been able to determine experimental- 
ly, notwithftanding the pains and attention I 
of DIN) SOREC T's. 69 
have beftowed on the obfervations of changes 
in this kind. Admitting Marfilius’s account 
to be true, and that fome of the perforations 
he obferved were made into veins and arteries, 
and eges were depofited in fuch perforations, 
there can be no difficulty in conceiving how 
the circulating blood might have difperfed 
thefe feeds of animals all over the body. It 
muft however be owned, after all, that thefe 
things are as yet buried in a cloud of darknefs, 
which ob{curity, nothing but the brighteft light 
of experiments can ever difpel. In the mean 
time, we may fee, by the manner in which we 
are affected by the ftinging of a Bee, how an 
animal, without getting into our bodies, may 
convey a matter into it, capable of producing 
great alterations; for the Bee, at the fame time 
that it gives the wound, infinuates by it into 
the body a drop of poifon. This is not a place 
for explaining how eggs come to be found in 
the fubftance of plants; befides, that I have 
already fufficiently treated of that fubject. 
As to the opinion of fome people, that the 
Worms found in our inteftines proceed from 
the eggs of animals which we have fwallowed, 
it only deferves contempt, being altogether 
contrary to found reafon; unlefs the favourers 
of that fyftem would at the fame time allow, 
that the eggs fo fwallowed are thofe of Worms 
bred in the inteftines of other animals. This 
opinion cannot by any other means be admit- 
ted, as it is quite inconfiftent with the nature of 
things, that an animal fhould live for any time 
in a fituation fo different from that in which it 
naturally fhould live, and on fo different a food. 
Befides, for this to be true, it is requifite that 
fuch Worms, intended for living in other 
places, fhould alfo be able to endure the heat 
of the inteftines, and of the fluids pafling thro’ 
them. A thing which no man in his fenfes 
can admit. 
The generation of animals, or the laying 
and hatching of their eggs, is by no means a 
thing which requires little care or attention. 
Every creature has its own feafon, its own 
haunts and element, its own manner of living, 
and its own food. Every year we obferve the 
fame renewals of the feveral fpecies, per- 
formed in a manner limited by a conftant and 
inviolable law and order of Nature; as the 
illuftrious Redi, before mentioned, has, on an- 
other occafion, likewife obferved. For this 
reafon we always fee, that Worms of the fame 
kind, found in the inteftines of animals, have 
conftantly their blood of the fame colour, be it 
red, yellow, green, or white. 
In regard to Caterpillars, indeed, I have ob- 
ferved four different ways in which Worms lie 
hid within their bodies, and afterwards creep 
out of them *. The firft is, when one or 
more Worms make their way into the Cater- 
* The cafe in thofe Flies, which we fee hatched out of Chryfalis’s, from which we expected Butterflies, is exactly the fame with 
thofe produced from galls, and the other excrefcences of vegetables. The parent Fly is guided by inftiné to lodge her eges in 
the body of the Caterpillar, piercing its fkin, for that purpofe, with a fharp inftrument at its tail. I have feen the operation, x and 
the mifery of the Caterpillar, which can no way efcape from its winged enemy, is terrible, All the variation in number of the 
young 
, and other accidents, is owing to the different fpecies of the Flies, 
pillar, 
