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TRACTS

ON THE NATURE

Ob'

ANIMALS and VEGETABLES.

8V

LAZARO SPALLANZANI, R. P. U. ?*

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*

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i

EDINBURGH,

PRINTED FOR WILLIAM CREECH, AND AR. CONSTABLE,

AND

T. CADKLL & W. DAYIES, AND J. \TIHTE, LONDON.

1 7 9 9-

\

2

TO

JAMES EARL OF HOPETOUtf,

VISCOUNT AITHRY, BARON HOPE,

S^ORD LIEUTENANT OF LINLITHGOWSHIRE,
ETC. ETC. ETC.

THIS TRANSLATION IS INSCRIBED.

TRANSLATOR’S PREFACE.

The celebrity of Signor Spallanzani occa-
fions our regret that we are fo little acquainted
with his works. This, which is now prefent-
ed in our national language, is replete with
matter fo new, fo fingular and amufing, that I
anticipate the pleafure every Philofophic reader
muft receive.

The treatife upon Animalcula I have ven-
tured to abbreviate. Perhaps it will be efteem-
ed a fufficient reafon, that only the detailed me-
thod of executing fome experiments, fome let-
ters corroborating the author’s difcoveries, and
controverfy with Mr Needham concerning the
animation of animalcula, are omitted. All the
experiments and the other treatifes, are given
as in the original. The degrees of heat are
reduced from Reaumur’s to Fahrenheit’s ther-
mometer. If inconfiftencies appear, and I can-
not fay there are none, probably they arife
either from the author ufing both thermome-
ters.

VI

translator’s preface.

ters, and negleCting to remark it in his work,
or to typographical error.

Animal Reproductions are not fo general-
ly known in Britain as they ought to be.
M. Bonnet’s treatife upon the reproduction
of the head of the fnail, is more concife than
any I have hitherto feen. Signor Spallanzani
(befides his Prodromo) has publilhed two me-
moirs, Sopra la riproduzivne della tejla neile
lumache terrejlri , which would with more
propriety have formed a part of this volume :
but I am not fo entirely mafter of my own
time, as the fuperintendance of publifhing two
or three hundred pages additional would re-
quire. Both memoirs are highly -worthy of
perufal.

Upon the merits of this tranflation, it be-
comes me to be filent. An anatomift will fee
where the words axilla , cubitus , and radius ,
might have been fuccefsfully ufed. Perhaps,
there is not a greater impediment to the dilfufion
of fcience, than the multiplicity of technical
terms, and the variety of nomenclature :
yet all are of infinite ufe, when acquir-
ed. In fome paflages, I confefs, I have not
been able to afcertain the authors’ meaning

wirh

translator’s PREFACE. Vli

with precifion. The language of experiment
is dull and uniform ; and, unlefs a total change
of arrangement, even of expreffion, is made,
it is often impoffible to tranflate with any fem-
blance to elegance. Frequently, fuch a change
cannot properly be made. — When all the requi-
fites of the Ikilful tranflator of afcientific work are
confidered, it will not appear furprifmg, if there
are errors here. The favourable, I may fay
the flattering reception, which my firft juvenile
performance has experienced in the world, in-
duces me to hope that there are likewife fome
perfons who may derive amufement from this.

Binns-House,

March 1799.

CONTENTS .

Observations and Experiments upon the Animalcula
of Infufions Page £

Obfervations and Experiments upon the Seminal Ver-
miculi of Man and other Animals, with an examina-
tion of the celebrated Theory of Organic Molecules 70

• ■ * ■ 3 ” il Lot’* " jOJJ i

Obfervations and Experiments upon Animals and Ve-
getables confined in Stagnant Air 1 95

Obfervations and Experiments upon feme fingular Ani-
mals, which may be Killed and Revived 251

Obfervations and Experiments upon the Origin of the
Plantuhc of Mould 325

Experiments upon the Reproduction of the Head of the
Land Snail

349

OBSERVATIONS and EXPERIMENTS

UPON THE

ANIMALCULA of INFUSIONS.

CHAP. I.

To difcover, whether long ebullition would
injure or deftroy the production of animalcula
in vegetable infufions, I infufed in diftilled wa-
ter, kidney beans, vetches, buckwheat, bar-
ley, maize, the feeds of mallows and beets ;
alfo the yolk of an egg. I took care that each
fpecies of feeds was from the fame plant. The
water ufed, was that in which feeds had been
boiled, obferving, that the water which had
boiled half an hour, was taken to infufe feeds
which had boiled half an hour. The veffels
containing the infufions, wrere loofely flopped
with corks.

Upon the 15th of September, I made thirty-
two infufions, and, upon the 23d, examined
them. There were animalcula in all ; but the
number and fpecies differed in each. In the

B maize

2

ANIMALCULA OF INFUSIONS.

maize infufions, the animalcula were propor-
tionally fmaller, and more rare, according to
the duration of the boiling.

In the infufion of kidney-beans, boiled two
hours, were three kinds of animalcula ; very
large ; middle fized ; and very fmall. The fi-
gure of the firft partly elliptical, partly umbel-
lated, attached to long filaments ; the fecond
almofl cylindrical ; the third nearly fpherical j
all incredibly numerous.

In the infufion boiled an hour and a half,
were animalcula of the largeft and fmallell clafs,
but few in number : flill fewer in that boiled
an hour j and very few in that boiled half an
hour.

The infufion of mallow feeds, boiled two
hours, produced middle-fized circular animal-
cula, and others very large, the head extremi-
ty hooked. In two infufions, boiled an hour
and a half, the number and fpecies of animal-
cula were the fame : when boiled two hours,
there were more, and as many as when boiled
half an hour.

An immenfe number was in infufions of
vetches, boiled two hours. When boiled an
hour and a half, they were very fmall and rare,
all femicircular, or bell-fhaped. Some may be
feen when the infufion has boiled an hour ; but
it gives the eye pain to difcover thofe in an in-
fufion bciled half an hour.

In

animalcula OF INFUSIONS, 3"

In the infufion of barley, boiled two hours,
were very large and numerous elliptical and
oblong animalcula. Boiled an hour and a half,
there was a moderate quantity of very minute
animalcula. A few were obferved, when boil-
ed half an hour.

There was no fixed rule with the other in-
fufions. In the buckwheat, boiled an hour
and a half, were more animalcula than in the
reft of the fame grain. This happened with
the beets and the egg : when boiled an hour,
there were more animalcula than in other in-
fufions of the fame kind, boiled various dura-
tions of time. But in two infufions, boiled
half an hour, there were fewer than iri the o-
thers.

Thus, it clearly refults, that long boiling the
feed infufions, does not prevent the production
of animalcula. To explain why the infufions
boiled for the fhorteft time have the feweft a-
nimalcula, I may obferve : That animalcula
Ihould appear in infufions, it is neceffary the
fubftances infufed, fenfibly begin to difl'olve ;
for, as this diflolution is effected, or at leaft
for a certain time, the number of animalcula
augments. Seeds of plants, boiled for a fiiort-
er time, are, for a fhorter period, encdmpaflfed
and penetrated by the diffolving power of the
fire ; confequently, when put to macerate, will
not be fo loon decompofed. This is doubt-

B 2 lefs

ANIMALCULA OF INFUSIONS.

lefs the caufe why animalcula will fooner be
feen in infufions of boiled, than unboiled feeds.,
A ihort ebullition is not fufficient to deeompofe
the feeds of vegetables ; for, decompofition o-
perates by long and gradual maceration.

Some days after making thefe experiments,
the number of animalcula increafed in the
fhorteft boiled infufions ; and, towards the
middle of October, the whole thirty-two infu-
fions were equally crowded. The only differ-
ence was in the figure, fize, and motion of
the animalcula.

Soon after, I made experiments, in the fame
manner, with peafe, lentils, beans, and hemp-
feed. The animalcula in all but the infufion
of beans, were more readily produced in the
Jhorter boiled infufions. To know whether
augmenting the intenfity of the heat would ob-
ftruct the production of animalcula, I flightly
warmed, in a coffee roafter, the eleven fpecies
of feeds, and then formed eleven infufions.
Neither the production nor the number was af-
feCted. They encreafed, as ufual, from afinall
number ; and, in the middle of October, twen-
ty days after the infufion was made, they
fwarmed fo much, that the fluid feemed per-
fectly animated.

I attempted to extend this experiment. I
roafted the feeds, and ground them as we do
coffee : the appearance was like foot. I then

made

ANIMALCULA OF INFUSIONS. $

made as many infufions as there were kinds of
feed ; alfo infufing the yolk of an egg, which
had been expofed to 279 of heat. Animal-
cula were equally produced from this powder $
only the time was a little longer before the
number was fo great : but the weather was
colder : and animalcula multiply much more
quickly in warm weather.

Further, I fubjeCted vegetable feeds to the
moll intenfe heat, the heat of burning coals,
and the flame from a blowpipe. I expofed the
feeds in an iron plate upon coals. When con-
verted to cinders, I reduced them to powder,
and made as many infufions as there were
kinds of feed. The cinders from the blov/pipe
were extremely dry and hard. I could fcarce-
ly believe my eyes, when I faw animalcula in
thefe infufions.

CHAP. 11.

I hermetically fealed veflels with the eleven
kinds of feeds mentioned before. To prevent
the rarefaction of the internal air, I diminifhed
the thicknefs of the necks of the veflfels, till
they terminated in tubes almofl: capillary, and,
putting the fmallefl: part to the blowpipe, feal-
ed it inftantaneoufly, lo that the internal air
underwent no alteration. It was ncceflarv to

j

B 3 know'

$ ANIMALCULA OF INFUSIONS.

know whether the feeds might fuffer by this inr
clufion, which might be an obftacle to the pro-
dudtion of animalcula. Other experiments had
fhewn me, i. veffels hermetically fealed have
no animalcula, unlefs they are very capacious :

2. animalcula are not always produced :

3. when they are produced, the number is
never fo great as in open veffels. Although I
ufed pretty large veffels, two fubftances, peafe
and beans, had not a Tingle animalcule. The
other nine afforded a fufficient number ; and to
thefe I limited my experiments. I took nine
veffels with feeds, hermetically fealed. I im-
merfed them in boiling water for half a mi-
nute. I immerfed other nine for a whole mi-
nute, nine more for a minute and a half, and
nine for two minutes. Thus, I had thirty-fix
infufions. That I might know the proper time
to examine them, I made fimilar infufions in
open veffels, and, when thefe fwarmed with a-
nimalcula, l opened thofe hermetically fealed.
Upon breaking the feal of the firft, I found the
elafficity of the air encreafed. Seeds contain
much air : a great quantity fhould efcape in
their diffolution, by heat or maceration, which
muff, of neceffity, render the portion of in-
cluded air denfer and more elafhic. However*
•this elafficity may originate partly from the e-
laftic fluid difcovered in vegetables, the nature
pf which is apparently different from the at-

mpfpheric

ANIMAL CULA OF INFUSIONS. J

mofpheric fluid. I examined the infufions,
and was furprifed to find fome of them an ab-
folute defart ; others reduced to fuch a foli-
tude, that but a few animalcula, like points,
were feen, and their exiftence could be difco-
vered only with the greatefi difficulty. The
action of heat for one minute, was as injuri-
ous to the production of the animalcula, as of
two. The feeds producing the inconceivably
fmall animalcula, were, beans, vetches, buck-
wheat, mallows, maize, and lentils. I could
never difcover the leaft animation in the other
three infufions. 1 thence concluded, that the
heat of boiling water for half a minute, was
fatal to all animalcula of the largefl: kind ; even
to the middle-fized, and the fma-lleft, of thofe
which I fliall term animalcula of the higher clafs,
to ufe the energetic expreflion of M. Bonnet ;
while the heat of two minutes did not afiecl
thofe I fliall place in the lower clafs.

Having hermetically fealed fix veflfels, con-
taining fix kinds of feeds producing animalcula
of the lower clafs, I immerfed them in boiling
water for two minutes and a half, three, three
and a half, and four minutes. The feals of
twenty-four veflfels being broken at a fui table
time, there were no animalcula of the higher
clafs feen, but more or fewer of the lower.
The air was almoft always condenfed. both in

j *

this and in the other experiments.

8 ANIMALCULA OF INFUSIONS.

In veffels immerfed feven minutes, I found
animalcula of the lower clafs. They appeared
in veffels immerfed twelve minutes.

The minutenefs of animalcula of the lower
clafs, does not prevent our diilinguifhing the
difference of their figure and proportions.

Boiling half an hour, was no obftacle to the
production of animalcula of the lower clafs ;
but boiling for three quarters, or even lefs, de-
prived all the fix infufions of animalcula.

We know, that the heat of boiling water is
about 212°. Thefe infufions were of this heat
at leaft, as appeared by the marks they exhibit-
ed of ebullition, the whole time the furround-
ing water boiled. Philofophers know, that
water, boiled in a clofe veffel, acquires a great-
er degree of heat, than when boiled in an o-
pen. To know how much lefs than half a mi-
nute the boiling might be abridged, and ani-
malcula of the higher clafs yet exiff, I made ufe
of a fecond-pendulum, and immerfed the veffels
in boiling water for a given number of feconds,
beginning with 29. In a word, boiling for a
fingle fecond prevented their exiftence ; and I
could only employ a degree cf heat lefs than
that of boiling water ; for example, 209, 207,
205, 203°, defeending to a degree which would
not injure their production.

At a medium of n°, I defeended from 200,
to 189, 178, 167°. Thus, I had four claffes

of

ANIMALCULA OF INFUSIONS. 9

of experiments, correfponding to the numbers
200, 189, 178, 167. In each clafs, were nine
fpecies of feeds, which made thirty-fix veflels.
After the time neceflary for the produdtion of
animalcula, I broke the hermetical feals, but
faw none of the higher clafs at 167°. I conti-
nued this retrograde motion by 1 1°, and came
to 155 and no°; fo that I had five clafles of
infufions, and forty-five veflels to examine.
Not a fingle animalcule was feen of the higher
clafs, in veflels hermetically fealed, and expof-
ed to the moderate heat of 1 1 30. This was
during the middle of April : the thermometer
in the fhade flood at 88°. I took eighteen vef-
fels ; nine had been expofed to 990 of heat,
and nine to 88°. No animalcula of the higher
clafs were produced in the former ; but I
found them in the latter. In each veflel, the
quantity and kind of animalcula, as in veflels
not fubjected to heat. The degree of heat fa-
tal to them, was 920.

Animalcula of the lower clafs, exift in foal-
ed veflels expofed to the heat of 2120; while
thofe of the higher clafs hardly appear at 920:
But, when produced, the fame intenfity of
heat that is fatal to the one, alfo deprives
the other of life • and animalcula of the high-
er, as well as ol the lower clafs, peri fh at ic69,
pr at moft at io8°.

Two

to ANIMALCULA OF INFUSIONS.

Two important confequences thence arife.
The firffc evinces the extreme efficacy of heat
to deprive infufions in clofe veffels of a multi-
tude of animated beings ; for, in open veffels,
are always feen a vaft concourfe of animalcula.
The fecond confequence, concerns the conflan-
cy of animalcula of the lower clafs appearing
in infufions boiled in clofe veffels ; and the
heat of 2 1 2°, protracted an hour, has been no
obftacle to their exiftence.

I have twice found animalcula produced in
metal veffels fealed with metal, and kept half
an hour in boiling water.

We are therefore induced to believe, that
thofe animalcula originate from germs there
included, which, for a certain time, withftand
the effects of heat, but at length yield under
it ; and, fmce animalcula of the higher claffes
only exift when the heat is lefs intenfe, we
muff imagine they are much fooner affected by
it, than thofe of the lower claffes. Whence
we ffiould conclude, that this multitude of the
fuperior animalcula, feen in the infufions of o-
pen veffels, expofed not only to the heat of
boiling water, but to the flame of a blowpipe,
appears there, not becaufe their germs have
v/ithftood fo great a degree of heat, but be-
caufe new germs come to the infufions, after
.ceffiition of the heat.

OIIAP.

ANIMALCULA OF INFUSIONS.

1 1

CHAP. III.

In the month of May, I took the eggs of
frogs from a ditch where they had been depo-
fited by the mother a few hours before. I di-
vided the quantity into equal portions, and ex-
pofed each to a different intenfity of heat.
The eggs were completely immerfed in the
water of a veffel, where I had put the ball of a
thermometer. I then placed the veffel upon a
flow fire, and, when the thermometer afcend-
ed to the requifite height, I took the eggs from
the warm veffel, and put each portion in cold
water. I had ten veffels, becaufe I had ten
portions expofed to different degrees of heat ;
no, 122, 133, 144, 155, 167, 178, 189, 200,
2120. The eggs expofed to no, 12 2, 1330,
produced young. At no°, almoft all were
fertile; there were fewer at 1220; and at
1 330, the number was very fmall. At a great-
er heat, all the reft became putrid.

The heat neither accelerated nor retarded
the produftion. Tadpoles were hatched in the
fame time as from thofe not expofed. The
tadpoles all expired at no°. The frogs which
had afforded the eggs, all perifhed at no°.
They were middle-fized green-backed frogs,
frequenting the ditches of plains and meadows.

I

12 ANIMALCULA OF INFUSIONS*

I know that there are frogs which live in warm
baths, although fubjedt to heat greater than
no°. For inflance, my friend Signior Cocchi
relates, that frogs are not injured in the baths
of Pifa at 1 1 50 ; but they may perhaps be of
a different fpecies. Perhaps, after being long
accuflomed to a degree that would at firft have
been fatal, they no longer experience any bad
effect. At lead we know, that men, who, the
firft time, can hardly endure the fleam-bath
fix minutes, and perfpire violently whenever
they enter ; in a certain time fupport it during
fifteen minutes, without any fenfible inconve-
nience.

The heat of i io° deflroyed the nymphs and
larvae of mufkitoes ; and io6° rat-tailed worms
and water fleas. Water newts and leeches
died at no0; the eels of vinegar at 113. In
my experiments upon the caterpillars of the
elm-butterfly, and the larvae of large blue
flefh-flies, the animals became refllefs at 93
and 950 : at 970, they were much affedted j
and all died at 108. The eggs of thefe infedls
long withflood the impreflion of heat: at 88°,
they produced the greatefl poflible number of
worms : at 990, they flill produced many.

The number decreafed with the heat, and none
were produced at 144 . The eggs of filk-
worms had the fame fate. The eggs of the
blue flefh-fly were very fertile at 1240 ; a fmall

number

ANIMALCULA of infusions. 13

number appeared at 135 and 137 ; none at
140°. The worms from the eggs became reft-
lefs at 88°, and died at 108. Full grown
worms of the fame kind all died at 108. The
flies of the fame worms perilhed at 99. Some
flies came from nymphs expofed to 104 or
106°; none from thofe to no.

I expofed grey peafe, lentils, wheat, lint-
feed, and the feed of trefoil, each to a differ-
ent degree of heat, 167, 178, 189, 200, 2120.
I fowed each kind of thefe feeds feparately, in
fmall diftindt fpaces of earth, fo prepared, that
each fpace might contain an equal number of
feeds: 167° did not injure them ; 178 begun
to affedt them, and very few were fertile. At
189°, there were produced only eleven plants
of trefoil, and ten at 200°. Only three of
thofe at 2120 germinated; fome trefoil feeds
could withftand the heat of boiling water.
The feeds were expofed to heat in a fand-bed :
in a fecond experiment, 1 put them in water,
which I (lowly heated, until it acquired the re-
quifite degree. By this means, the heat had
greater influence upon the feeds. Peafe, in
this way, at 167°, germinated as abundantly as
trefoil ; but the lintfeed, lentils, and wheat,
did not. At 189°, feven (talks of trefoil, and
one of flax ; at 200°, only fix of trefoil ; at
2120, none.

For thirteen days, I expofed the plants to

167,

14

ANIMALCULA OF INFUSIONS.

167, 178, 189, 200, 2120 of heat, by dipping
the branches in water gradually warmed. They
were inftantly replanted ; but all died. I faw
that 1 67° was a heat injurious to young plants :
155 and 1440 did not hurt them, as, upon be-
ing replanted, all continued to vegetate.

I heated in fand, as above, the following
feeds : Beans, barley, white and black kid-
ney beans, maize, vetches, parfley, fpinage,
beets, radilhes, mallows. All expofed to 167°,
germinated; forne at 178° begun to perifh ;
very few fucceeded at 189 and 200° ; and, at
212°, there appeared only one plant of white
kidney beans, and three of beans. I repeated
the experiment at 200, and 2120: not one
germinated.

It is demonftrated, by thefe experiments, that
the eggs of the animals upon which they were
made, withfland heat better than the animals
themfelves. Tadpoles and frogs perilhed at
iio°; their eggs only at 1330; and fome fup-
ported even a greater degree. Silk-worms and
the elm-butterfly died at 108°: their eggs be-
came fterile only at 133. The large flefh-flies
periflied at 990 ; their nymphs at no; their
larva; at 108 ; and their eggs at 140°. We re-
mark ahnoft the fame relation between plants
and their feeds, as between animals and their
eggs. Some feeds, as trefoil, kidney beans,
and beans, are fertile, though expofed to 212° ;

while

ANIMALCULA OF INFUSIONS. 15

while their plants cannot fupport 167. The
feeds of plants are more able to endure heat,
than the eggs of animals. All the feeds upon
which I made experiments by dry-warming,
have been fertile, though expofed to 167°, and
fome to 212 ; but no egg hatched after 1440.

Heat is much more noxious acting along
with water.

The life of an animal concealed and concen-
trated in the integuments of an egg, is very
faint, compared with that of an animal produ-
ced. During the firft hours of incubation, the
pulfation of the heart is the only indication of
life in the chicken. Before the egg is hatched,
its life is flill more faint ; it is a lejfer life.
Undoubtedly it is the fame with that of the
germs in the eggs of infedls, which have not
the degree of heat necelfary to hatch them.
May this feeblenefs of the life of the embryo
in the egg, be a reafon why it is better able to
fupport heat in this Hate, than when it is more
expanded ? It is certain, that minute animals,
which have in this Hate a life fo feeble, which
fo little merits the name of life, refill, with
greater impunity, external accidents, as the in-
temperance of the air, than w'hen they are more
vivacious. If we cut off the head, take out
the heart, or deprive a frog, toad, newt, fnake,
or viper, during winter, of fome members,
■while they are torpid by cold, and feem more

dead

1 6 ANIMALCULA OF INFUSIONS.

dead than alive, they live much longer after
fuch operations, than if they were to undergo
them in the vigour of life : and I have obferv-
ed, that infefts immerfed in water during win-
ter, live longer than if immerfed during fum-
mer.

The reafon why feeds withftand heat better
than eggs, rather feems to be, from the greater
abundance of fluids in an egg, which, being
expanded and put in motion by the heat, will
violently operate againfl: the fubtile filaments
of the germ, and occafion their rupture, and
its deftru&ion. Should the inftance, of feeds
refilling the influence of boiling water, induce
us to think the germs of animalcula have the
fame faculty, the idea is corroborated by direft
proofs, taken from the animals themfelves. M.
Duhamel obferved a cockchafer live in a heat
equal to that of boiling water ; and, Schaeffer
faw one fpecies of caterpillar live at the fame
degree.

Carolina, and the Cape of Good Hope,
fwarm with animals of all figures and fizes,
where the thermometer afcends in the fliade to
no and 1220. The direft heat of the fun is
double, fometimes triple, in the warmeft re-
gions : that of the fliade, at the Cape of Good
Hope, is at leaft 189°, and in Carolina 2 1 2.
If there are animals which luftain this heatj
and their eggs preferve their fecundity ; and.

ANIMALCULA OF INFUSIONS. I f

if there are animals in our climate, which can
fupport this degree of heat ; why {hall we de-
ny, that there may be animalcula of the fame
conflitution ? M. Sonnerat faw fifties fwim-
ming in fome waters in the Philippine Illands,
where the thermometer flood at 187°.

The germs of the higher clafs of animalcula,
however, cannot fupport fo great a heat as the
animalcula themfelves. The animalcula die at
1080: the germs are not developed after 950.
We mufi thence conclude, that the nature of the
germs of the higher clafs is very different from
that of the lower, with regard to the power of
refilling heat.

The difference in the eggs of other animals
is more marked. The eggs depofited by fome
butterflies upon the under fide of leaves, like
thofe which certain infedls depofit towards a
northern afpecl, perifti at 790 ; although this is
200 lefs than is neceffary to hatch the eggs of o-
ther infedls ; as of the afili, which depofit them
in the fkin of oxen or of cows ; and thofe
flies, which inflnuate them into the frontal fi-
lms of fheep, goats, and deer ; or thofe which
depofit them in the rectum of the horfe. We
may fay the fame of the eggs of feveral w’hich
multiply in the human body, and in that of
calves, where the heat is about 98°.

C

CHAP.

1 8

ANIMALCULA OT INFUSI0N3.

CHAP. IV.

I transported animalcula from the heat of

«

the atmofphere to the cold of an icehoufe. In
the month of Auguft, the thermometer In the
open air flood at 83°, and in the icehoufe at
36. The only change I could obferve, was, a
flight relaxation in the motion of the animal-
cula ; and they did not feem to fuffer further,
although expofed to this degree of cold for fe-
veral days. I then covered the veffels with
-ice. At the beginning of the fourth day, a
number of the animalcula died. Of twenty-
two infufions put in ice, thofe of feven only
remained alive. In eleven days, the animal-
cula in two of the feven had perifhed. After
two months, thofe in the other five were alive :
one fpecies appeared more numerous. Along
with thofe feven, I put in ice other two infu-
fions, yet flerile, becaufe lately made ; but,
in a few days, they were filled with an army
of the mofl minute animalcula.

During winter, I fubjected the animalcula
to new experiments. While the infufions pre-
ferved their fluidity, there was no particle
of ice obferved ; which was occafioned by the
quantity of vegetable oil the infufions contain-
ed, which fecured them againfl freezing. Not-

withflanding

ANIMALCULA OF INFUSIONS. 19

with landing the cold killed the animalcula of
feveral infnfions, there were fome more robuft
fpecies that lupported it. I took the advantage
of a very cold day ; and, although the thermo-
meter fell to 150 under the freezing point, and
the infufions were covered with ice ; upon
breaking it, and prefenting fome minute por-
tions to the microfcope, I found living animal-
cula in the parts not completely congealed.
They were immured in little grottoes of ice.
In thofe portions abfolutely frozen, the ani-
malcula were dead. They did not revive up-
on melting the ice. The refl retained their vi-
vacity in the parts of the fluid not yet congeal-
ed8. I could not decide whether the animal-
cula perifli, becaufe the cold has deflroyed them,
or becaufe the infufions have loft their fluidity.
It is a fa£t acknowledged by philofophers, that
water does not lofe its fluidity at 20, or even
220 below freezing, when at perfect reft ; which
may be attained by inclufion in a clofe veffel,
and removal from external motion. In this
way, the animalcula furvived, although they
fuftered cold almoft 20° below zero, in water
not frozen. They fwam about, but with a
flower motion than ufual, while the thermo-

C 2 meter

a Mr Muller of Copenhagen has clifcovered fome fpe-
cies of animalcula which furvive congelation. I regret that
his vfhrk did not come to my knowledge until the tranferip-
tion of my mnnufeript was finilhed.

20

ANIMALCULA OF INFUSIONS.

meter flood at i8° below the freezing point.
This was the greateft degree they could fup-
port, as they died at 20% although the water
was not frozen, but was beginning to be co-
vered by a thin cruft. Two fpecies furviv-
ed ; and I may perhaps, or even without per-
haps, fay, they would have fupported a more
mtenfe cold, had I been able to keep the water
longer fluid.

I made infufions fimilar to the preceding,
fealed hermetically, and expofed to cold, pro-
duced by a mixture of fine pounded fea-falt,
with fnow. The thermometer defeended to
340 below zero ; and the infufions were fo
much frozen, that they took half an hour to
melt. But the germs of the animalcula were
not injured, fince the fealed infufions, at the
ordinary time, afforded a number of animal-
cula. This fa£t well correfponds with what
has been obferved in thofe infects that have the
greateft analogy to animalcula. Some can fup-
port 420 under freezing, others die at 22, or
at moft at 240 : a very great number cannot
fupport the cold of freezing, and others die at
a degree far inferior. There is this difference
between animalcula, and infefts expofed to
cold, that the former retain fufficient life to ufe
their members, whereas the latter immediately
lofe their vivacity, and become motionlefs like
dead bodies. Some infers we may compare

to

AN I M A I- C,U L A OF INFUSIONS. El

to animalcula ; for, befides the podura of Lin-
naeus, which inhabits the blows of Sweden,
I have obferved the eels of vinegar -preferve
the motion of their members when expoled to
a very intenfe degree of cold ; for, although
this fluid does not freeze fo foon as water,
the eels fwim conftanrfy while it is not fro-
zen. Some kinds remain fluid 1 50 below freez-
ing ; other kinds remain fluid at 240 : but,
when the cold is thus encreafed, the eds be-
come like animalcula infenfibly motionlefs ;
but they move, although there is a thin cruft
of ice. As the congelation encreafes, they
continue motionlefs, extended in a flraight
line, or a little curved. If they receive hid-
den aid, by melting the vinegar, they will al-
mofl certainly be brought to life. If the ice is
allowed to harden, it is impcflible to revive
them. Thefe analogies between infects and
animalcula, exiit in the originating principle.

The winter of 1 yog is celebrated for its cold,
and the fatal effects it had upon plants and a-
nimals. The thermometer fell 330 below the
freezing point. Who can believe, exclaims
Boerhaavc, that the eggs of infects were net
entirely deflroyed by this rigorous winter ?
After the fpring begun to temperate the air, in-
fects were at the ordinary time produced, the
fame as after the mildeft winter. For five
hours, I kept various eggs of infefb, among

C 3 which

22 ANIMALCULA OF INFUSIONS.

which were thofe of the elm butterfly, and filk-
worms, enclofed in a glafs veflfel, in a mixture
of ice and fal-gem, where the thermometer fell
38° below zero. All the eggs produced worms
at the ordinary time.

The next year, by mixing ice and fal-gem
with fpirit of nitre, I obtained a degree of cold
56° under freezing. This did not injure the
eggs of infefts fubje&ed to it. The refult of
all this is, that cold is lefs noxious to germs
and eggs, than to animalcula and infefts.
Germs can, in general, fupport a degree of
cold 330 under the freezing point. Some ani-
rcalcula perifh at freezing; others about 180
under it. The eggs of feveral infefts fuftained
56°; the infefts they produced, only 16 or 18 :
■which I have remarked in filk-worms, and
thofe of the elm butterfly. And, although
there are caterpillars and chryfalids which with-
ftand a very great degree of cold, their eggs
will fupport a degree much more confiderable.
As animalcula and infefts can lefs fuftain heat
than their eggs, fo can they lefs fuftain cold.
What I faid before, will apply here. The bo-
dies of infects killed at 16 or 180 below freez-
ing, are fo indurated and frozen, that their
members will not yield to the preflure of the
finger, and feern perleft ice under the edge of
the knife. This never happens to eggs expol-
ed to a much more intenfe degree of cold.

Their

ANIMALCULA OF INFUSIONS.

23

Their humours preferve their fluidity. They
perhaps owe this advantage to the fpirituous
or oleaginous nature of their component parts,
which may diminifh the influence of the cold.

chap. v.

Man, like other animals, being fubjedt to
phyfical laws, is confequently liable to perifh
by an excefs of heat or cold. However, he
can fuftain both, when extended to a degree
one would imagine inlupportable. It is com-
monly believed, with Boerhaave, that man can-
not exilt in air as hot as the blood. This rule
had been eftablifhed by that philofopher, from
his obferving, that certain birds and quadrupeds
died in air heated to 1^9°, which is 530 greater
than that of the human blood. But, fuch an
opinion appears ill-founded, fince we know
there are regions, inhabited, where the heat is
greater than of the human blood. At the Cape
of Good Hope, the thermometer (lands in the
fhade at 1 130. The heat of Carolina is great-
er than that of the human blood, fince the
thermometer falls, when taken from the fhade,
and put in a perfon’s mouth. 1 he heat of a
warm bath fometimes equals that of the hotted
climates. There are waters which raife the
C 4 thermometer

2.4

ANIMAI-CULA OF INFUSIONS.

thermometer to 113, even to 122° a. Boer-
haave thought the greatcfl degree of natural,
cold was zero in Fahrenheit’s thermometer.
He obferved, that men, animals, and vege-
tables, perifhed at this degree. But we experi-
ence a much greater intenfity of cold. For
feveral winters, at Peterfburgh, the thermo-
meter fell to 6o° below freezing, and once to
67°. The cold at Quebec was 720 below freez-
ing : that at Torneao, obferved by Maupertuis,
83°. But thofe high degrees of cold, although
very intenfe when compared with that of our
climates, are incommenfurable with thofe that
chill many places in Siberia. At Tom Ik, Ki-
renga, Jenifeik, the thermometer falls 120°,
149, and even 1570 under zero.

We cannot deny, that cold fo piercing was
pernicious, and indeed fatal, during 6o° felt
at Peterfburgh : the face could not be kept
uncovered above half a minute. At Torneao,
where the thermometer fell to 83°, the bread:
felt as if lacerated. Some of the inhabitants
of the cold climates lofe their members in win-
ter,

3 Dr I'ordyce fupported 150° for twenty minutes with-
out inconvenience, igS° for ten minutes, and 262° for eight.
His refpiration for feven minutes was not affe&ed ; the
eighth, it became more fiequent. He fupported 220°a
long time without inconvenience. A dog did not fuffer
from being expefed to 560°, in a bafket, for thirty-two mi-
nutes.

ANIMALCULA OF INFUSIONS. 1$

ter, an arm or a leg. Ihe cold experienced
by Captain Middleton in Iludfon s Bay, fioze
all the liquors except brandy ; and the beds
were covered with a coat of ice thiee inches
thick, although the walls of the houfes were
of (lone, and two feet thick ; the window's
very narrow, clofed up with flrong boards ;
and although great fires were kept continually
burning. The Dutch experienced a fimilar
cold in Nova Zembla. One, by keeping in mo-
tion, may fupport a greater degree of cold.
The favages of the mod northern countries,
hunt during the grcateff cold ; and they know
fo well that motion alone can preferve their
lives, if any accident, during their expedition,
fhould threaten them with death, they accele-
rate it by rdf. From the narrative of fome
Dutchmen, who wintered at Spitzbergen in
78° of north latitude, we learn, that thofe who
fhut themfclves up in wooden huts, one after
another died with cold before the fire; where-
as, thofe who lived in the open air, and em-
ployed themfelves in hunting, carrying wood,
or other exercifes, preferved perfect health.

We muff conclude, that man is in a con-
dition to fupport a number of variations of
heat and cold, between a degree far greater
than that of freezing, and heat equal to, or e-
ven more intenfe, than of boiling water, which
{hows that he is not, by nature, meant to in-
habit

2 6 ANIMALCULA OF INFUSIONS.

habit certain determinate parts of the globe,
but to live, multiply, and exercife his domi-
nion in all, without experiencing an obftacle
in climate. It is not fo with quadrupeds. They
have been diftributed upon the earth ; fome
framed for warm, others for temperate, and
and others for cold climates. We have not
hitherto found any Ipecies that can accommo-
date itfelf to all indifferently. The lion, ele-
phant, tiger, panther, and leopard, dwell on-
ly in the warmer regions : when tranfported
to temperate climates, they become incapable
of generating, and quickly perifh in cold.
Our domeftic animals do not fuffer in the
warmeft regions : they cannot, however, exift
in the coldeft ; as, the horfe, the ox, the
Iheep. The elk, rein-deer, and ermine, inha-
bitants of the North, are never found in fouth-
ern countries ; and, fo far from being able to
exift there, they do not furvive in the tempe-
rate climates. This, at leaft, has been ob-
ferved with refpetl to the rein-deer, thenaturali-
zation of which has often been attempted in
France and Germany ; but all, inftead of mul-
tiplying, have perifhed. The law which forces
animals to remain in their native countries,
is under modifications. Some there are that
multiply in temperate, though they are origi-
ginally from warm climates ; while fome ani-
mals, which are ordinarily found in cold cli-
mates.

animalcula of infusions. 27

mates, live very well in warm. Ihe rabbit
and Guinea pig are examples of the former ;
the beaver and lynx, of the latter.

Birds may, in this refpect, be regarded as
divided into two claffes. Some, like quadru-
peds, do not wander far from their native
place, or at leaf! do not change their climate ;
others have no fixed abode, but change their
climate according to the feafons, being appa-
rently neceffitated to make fuch changes, either
from the fcantinefs of food, or from their in-
ability to refill the rigour of winter, or even a
flight degree of cold.

We have faid, with Boerhaave, that heat
1 490 above freezing, foon killed certain qua-
drupeds and birds. Indeed, 530 above blood
heat, is confiderable ; and feveral fpecies of a-
nimals cannot fupport it : but we do not find
that it is infuppor table, or that there are no a-
nimals which fuffer it under the Torrid Zone,
and in very warm climates. It feems to me,
that we fhould reafon upon the heat that birds
and other animals can fuftain, as we reafon in
relation to the cold ; and fince thofe of the
mod northern climates fuftain a great degree of
cold, fo fhould the animals of the fouthern
countries be able to fupport an exceflive heat.

It is eafy to determine, that the greatefl de-
gree of heat fquamous or cetaceous fillies ex-
perience, is equal to the heat of the water

where

23

ANIMALCULA OF INFUSIONS.

where they fwim, which is therefore lefs than
that of freezing. Thofe living in fait water
are expofed to cold a little more intenfe than
freezing. It thus happens, that fifhes are fe-
cured againft the rigour of cold, to which all
animals are fo much fubjefted, by the element
they inhabit : and, except thofe inhabiting

fhallow waters, they are fheltered from the
burning heat of the atmofphere.

_ There are carps in warm fprings which
fupport blood heat. I took the river carp,
and heated the water where they were to 106°,
without their feeming uneafy : at 108, they be-
came reftlefs, and died at 1 16. I made fimilar
experiments upon eels, tench and lampreys :
they died at a lefs degree of heat.

But, of all known animals, reptiles and in-
fects are thofe that Hand in greatefl dread of
cold, and feek for heat the mod. We may
fay, the heat of the fun is their foul. When
expofed to it, they have more fenfaticn and
motion ; and, as the heat of that luminary
is more powerful, fo are their vivacity, agility,
and boldnefs greater. The venomous are then
more terrible, their poifon more dangerous.
Cold produces an oppofite effect. A number
of infects would, at the approach of winter, be
expofed to hazard, did’ they not feek a fafe re-
treat in the rents of wralls, the midft of ftones,
the holes or . clefts in the trunks of trees.
Some feek for fafet in the caverns of moun-
tains

ANIMALCULA OF INFUSIONS.

29

tains and fubterraneous abodes, or in dung-
hills, where, during the feverity of winter,
they always experience a gentle heat. But
the bottom of waters, and the bowels of the
earth, are in particular two certain retreats for
the greater part of reptiles and infers. The
lethargic llumbers they are in during winter,
are the effe&s of the cold.

It is very poffible, that there may be among
quadrupeds and birds, perhaps even among
fi flies, fome which experience a fort of lethar-
gy like reptiles and infefts. With refpeft to
quadrupeds, I fhall fay nothing of toads, frogs,
green lizards, fmall lizards, which pafs ahnoffc
the whole winter in the water or in the earth,
in a conft ant torpor ; but we obferve the fame
fafts in hedgehogs, land-tortoifes, and alfo in
feveral fpecies of rats, marmots, and dormice.
Thofe animals conceal themfelves in the hollows
of trees, or in the earth ; fome in folitude,
and fome in fociety. Bats in winter are found
ftiff and motionlefs in the holes of trees, the
rents of walls, and fufpended to the vaults of
fubterraneous caverns.

There are birds fubjefl to the fame torpidi-
ty. At the end of the fine weather, we fee
hundreds collect, crowd together in clullers,
and plunge into the water, where they pafs the
winter in heaps, contracted within themfelves.
•The intelligent reader already anticipates that

I

30 ANIMAI.CULA OF INFUSIONS.

I here fpeak of fwallows. The fa£t is too well
afcertained, too well authenticated, to leave
any room for doubt. Many refpectable and
credible perfons declare, that they have not
only feen numbers of fwallows collect, and
throw themfelves into pools at the approach of
winter ; but that they have feveral times feen
clutters of fwallows taken out of water, even
from beneath ice. The queflion is, therefore,
whether the fwallows fpoken of are the fame with
ours ; that is, with thofe that conftrudt a neft of
earth in our houfes, and remain with us during
fummer ? or whether they are ftranger fwal-
lows, by which I mean a bird refembling our
fwallow, in figure, colour, and fize, but is, at
the fame time, of a very different fpecies ? I
have, for feveral years, endeavoured to folve
this. By experience I know, that the animals,
which are in a fort of lethargy during winter,
are, when expofed to a degree of cold, fubjeft
to the fame effect : fo that, if one expofes a
dormoufe, a frog, or a lizard, to the cold of
freezing during fummer, when molt vivacious,
they become motionlefs, and continue fo while
the cold remains. I thought of expofmg fome
of our fwallows to the air of an icehoufe, mak-
ing them gradually pafs from atmofpheres lefs
warm, as of a cave or a chamber adjoining to
the icehoufe, as a fudden change might be too
powerful. In the month of Auguft, they all

perifhed

animalcula of infusions. 31

perifhed in the adjoining chamber in three
hours. I could not obferve, whether they had
firfl become lethargic, although the thermome-
ter flood at 430 above zero, a degree of cold
rather too fmall, than too great, to produce
fuch an effect. I repeated the experiment ; but
all had the fame fate. Whence I conclude
thefe to be fpecifically different from the fwal-
lows found in water, and below ice.

There are certainly fome fifties, upon which
the influence of cold has the fame effect. If
we may credit Peclin, quoted by Haller, tench
are of this kind : he fays, he has feen them
bury themfelves at the bottom of the veffel up-
on the approach of winter, as we fee many rep-
tiles and infedts then enter the earth. But, in
general, fifhes are a clafs of animals, which has
the privilege of preferving vivacity and action,
however cold the atmofphere may be.

Whence does it happen, that all infects and
reptiles, at a certain degree of cold, lofe their
ftrength, their action, and appear as if dead ;
while man, the greater part of quadrupeds and
birds, retain their powers and livelinefs, when
cold is at this degree, and even beyond it ?
What is the immediate caufe of the death of
the former, and the prefervation of the latter,
in fimilar circumftances ? M. De Buffon is
the firft who has ferioufly invefligated this phe-
nomenon. He obferves, that the animals that

become

32 ANIMALCULA OF INFUSIONS*

become torpid are cold blooded, fuch as mar-
mots, dormice, hedgehogs, and bats ; that they
have not of themfelves any internal heat, but
only the heat of the atmofphere ; fo that, upon
the approach of winter, their blood refrigerates
with the atmofphere. This refrigeration is the
caufe of their torpidity ; and the ufe of the
fenfes and members is loft ; for it then circu-
lates, it is probable, in the larger veftels only.
I could have wifhed, that this explanation, fo
plaufible, was equally true. Haller, who has
differed feveral hedgehogs, affures us he has
found their blood warm ; and he obferves, that
Lifter, Robinfon, and Lancifi had before him
made the fame remark. I have made experi-
ments upon three hedgehogs, and found their
blood warm. I have found the fame in bats,
introducing, by the mouth, a fmall theriqome-
ter into the body of the animal. M. De Buf-
fon never faw the liquid rife ; on the contrary,
it fell fometimes half, and fometimes whole de-
grees. But, by my experiments, the thermo-
ter, introduced by the mouth of hedgehogs
and bats, always afcended to 99 and ioi° a-
bove zero, while kept there eight or ten mi-
nutes.

It was impofiible for me to procure mar-
mots, but I requefted a friend to make the fame
experiments. The confequence was, that mar-
mots had not cold blood, as M. De Buffon

imagined.

AN1MALCULA OF INFUSIONS. 33

imagined. The heat of one marmot raifed the
thermometer from 50 to 90° above zero. The
heat of another raifed it in five minutes to 920.

Some time afterwards I had two marmots. My
experiments upon them, perfectly agreed with
thofe of my friend. In the open air the ther-
mometer flood at 65°; when introduced by the
animal’s mouth, it rofe to ioi°.

There is a method of conciliating the oppo-
site faffs. It mufl be, that the French natur-
alifl has made his experiments in winter, when
the animals were devoid of fenfation and mo-
tion. Then they would actually refemble cold-
blooded animals ; the rigour of the feafon had
exhaufled the principle of internal heat. Rea-
fon, and my experiments prove, that thofe ani-
mals do not become lethargic while the inter-
nal heat which animates them remains undi-
minifhed.

It is at the fame time certain, that the blood
refrigerates in all animals that become lethar-
gic. But may we conclude, that this lethargy
is the immediate effeft of the refrigeration of
the blood ?

Frogs, toads, tree-frogs, water-newts, I /

have in my experiments obierved, after having
all the blood difeharged from the heart, or the
aorta cut, leap, run, dive, fwim ; have the ufe
ol fight and feeling *, in a word, perform e-
verv corporal function, for feveral hours, the

D fame

34 ANIMALCULA OF INFUSIONS.

fame as before. I refolved to make new ex-
periments, and' begun with frogs. I buried
in fnow feveral that were extremely, but equal-
ly lively : one number was untouched, another
deprived of the whole blood. I even endea-
voured to empty the heart and principal veffels
completely. In eight or ten minutes I took
fome from the fnow. Thofe which were, and
were not deprived of blood, appeared precifely
in the fame hate, that is, half dead, and not
attempting to efcape although at liberty. Fif-
teen minutes afterwards, I took others from the
fnow : all feemed contra&ed, motionlefs, and
almofl frozen. I returned them to the fnow ;
and in fome hours tranfported them to a warm
fituation, carefully obferving what happened.
By little and little, they flretched themfelves,
opened their eyes, and prepared to efcape.
This I obferved in all, without any difference.
I had the curiofity hill to bury them in the
fnow. I faw anew the fame phsenomena ; and
I conftantly found the refults the fame, when
the experiments were repeated at different fea-
fons of the year. • All the tree-frogs, toads,
water-newts, whether deprived of blood or
not, equally experienced the lethargic flum-
ber, when expofed to cold, but revived with a
fufficient degree of heat.

The coincidence of thefe fatts conftrains me
to fay, that the privation of fenfation and mo-
tion

ANIMALCULA OF INFUSIONS. 35

tlon is not effected by the refrigeration of the
blood, nor can we afcribe it to the more lan-
guid circulation : whence, it is confequent,

the lethargic torpidity muft arife from the fo-
lids alone ; which, being feverely affected by
the cold, are in a fituation very different from
the natural Hate. What is this fituation ? It
feems that we recognife it in the phenomena
torpid animals exhibit : they are contracted ;
the mufcles have loft their ufual flexibility ;
they become extended and rigid. It is there-
fore demonfirated, that when the tnufcular fi-
bre becomes very rigid, this rigidity injures the
irritability of the mufcles : how much mufl it
be affeCted by a rigidity fo great ! Of this I
was convinced, by irritating the fibres by dif-
ferent ftimulants ; but I fcarcely occafioned the
flighted indication of rugofity or contraction.
While irritability is commonly viewed as the
principle and fource of life, when that is great-
ly diminifhed by expofition to cold, it is not
furprifing a lethargy fimiiar to death enfues.
If this is the real and immediate caufe of tor-
pidity in the animals I have named, I find no
reafon to prevent its application to all animals,
that in the lame way become torpid. It is true,
that it is impoffible to deprive warm-blooded
animals of what M. De Buflbn imagines the
caufe of their torpidity, becaufe nature does
not admit that they fha.ll live without blood ;

D 2 b .u£

36 ANIMAI.CULA OF INFUSIONS.

but it is always certain, that their mufcular fi-
bre becomes rigid, and infenfible to every fti-
mulus, when in this lethargic flumber. This is
what I have obferved in bats, which I fprinkled
with fait, immerged in hot water, pricked with
pointed inftruments, and divided the peftoral
mufcle with a knife. All thefe methods were
ineffectual to awaken the irritability. The e-
leCtric fliock was equally fruitlefs. If cold fuf-
pends the irritability of warm as well as of cold-
blooded animals, and if the ceffation of this
power is fuch, as feems to me the only and im-
mediate caufe of the lethargy of the latter, I
do not fee why it may not be the fame with the
former.

All animals that become torpid, do not fo at
the fame degree of cold. That heat marked
temperate upon the thermometer, fo mild to
mankind, makes dormice torpid. A degree of
cold a little greater, affects bees, fnakes, vipers,
and feme fpecies of bats. That degree which
affects toads, frogs, newts, &c. approaches
freezing ; but this is fo far from affecting mar-
mots, that 1 1° under zero is required to make
them torpid. This variation can only arife
from the different nature of the mufcular fi-
bres, which fhould render certain animals more
fufceptible of cold than others, by fooner pro-
ducing the rigidity of the mufcles. I am well
perfuaded, that impediments to the circulation,
' may

animalcula of infusions. 37

UI717 occafion the death of many animals . but,
whence comes it, that there is a great num-
ber which ceafe not to live, although the cir-
culation of the fluids is fufpended for a time,
or even when abfolutely flopped ? In another
work, I have proved that feveral animals live a
long time after lofing all their blood ; that
they live when the circulation is fufpended, by
tying up the trunk of the aorta. I have re-
marked, that reptiles are fubjett to the fame
laws as vipers, fnakes, eels, &c. The death of
animals killed by cold, mull then enfue from
forne other caufe than from fufpending the cir-
culation.

To difeover the immediate caufe of the
death of animals deftroyed by cold, I made ob-
fervations upon fome rendered lethargic by a
degree of cold not intenfe. The phenomena
attendant upon death, are thefe. The mufcular
rigidity encreafes more and more, until the
flefh hardens and freezes. The freezing firfl
appears at the extremities, and gradually ex-
tends, until it reaches the centre of the animal.
If the animal is then removed into a warmer
atmofphere, that the parts may relax, they will
refume their priflinc flexibility; but the animal
will not revive. Its death is truly the confe-
quence of having been frozen. But we cannot
lay, that it happens from the freezing of the
blood only : firfi, from all the reafons I have

D 3 given ;

3$ . ANIMALCULA OF INFUSIONS.

given ; fecondly , becaufe having expofed, to the
cold of freezing, animals entire and deprived
of blood, all died in the fame time. Whence
I conclude, that death is occafioned by the
freezing of the folids. The mufcles, at a cer-
tain degree, become rigid ; and, when frozen,
ceafe to be irritable. Such is the apparent
caufe of the death of animals expofed to cold.
Cold contrails the mufcular fibre, by harden-
ing it, and confolidating the lubricating fluid.
Congelation further contributes to the deflruc-
tion of the fibres, by turning the liquid to a
number of little icicles, which, with their
points and edges, lacerate the fined and molt
delicate parts. If the mufcular flelh is then
examined, it appears full of thofe minute ici-
cles ; and when one attempts to twill or to
bend it, it breaks like a friable fubdance.-

CHAP. VI.

Certain odours are to infe&s the mod viru-
lent poifon. Reaumur has tried upon them
the effeft of turpentine, and the fmoke of to-
bacco. The odour of camphire, according to
Menghini, and its vapour, are dill more effica-
cious when heated. I expofed animalcu-la to
the odour of camphire ; and the refult was pre-

cifely

AfcIMALCULA OF INFUSIONS. 39

cifely the fame with what has been obferved of
infers. The vapour occafioned inquietude and
uneafinefs, among the animalcula expofed.
They endeavoured to retreat from the malig-
nant odour, by retiring deep in the infufions.
If the vapour was rare, they were much longer
of dying than if it was denfe. The odour of
the oil of turpentine killed them ; but the ef-
fe£t was lefs fudden than that of camphire.
The fmoke of tobacco became mortal in a few
hours: that of fulphur killed them immediately.

Oleaginous liquids were mortal to animal-
cula. Corrofive and fpirituous liquors killed
them in a moment. Urine not only kills ani-
malcula, but it has the property of reducing
them to very fmall particles. As Hartfoeker
obferves, we could not have believed that urine,
left at reft for fome days, produces animalcula,
if we had not remarked the fame phenomenon
in vinegar ; although this liquid kills animal-
cula as readily as urine, notwithftanding that, it
is full of microfcopic eels. The urine, after
ftanding fome time, is covered with a pellicle,
of an oblcure cinereous colour, in which the
animalcula are found : they are of a roundifh fi-
gure, in minutenefs like animated points. U-
rine kept for fome months, has always about
the fame number of animalcula, but there ne-
ver appears any new fpecies : and from the ef-

D 4 feffc

40

ANIMALCULA OF INFUSIONS,

feet of this urine upon other animalcula, that
fpecies muff be of a nature eflfentially different.
We know, that the eledtric fliock is fatal to
many animals, and that it kills them the more
eafily as they are fmaller. It requires a battery
ten feet fquare to kill a cat or a fmall dog ; a
pigeon is killed by one only two or three feet
fquare ; and a fmaller apparatus a goldfinch or
a canary. I expofed animalcula to the dif-
charge of Dr Bevis’ battery. Upon this bat-
tery I put a fmall fpot of pitch, open in the
centre, and filled the hole with fome drops of
infufion : from this hole I drew the electric
fpark. Although the infufion was full of ani-
malcula, not one furvived the fliock. I dimi-
nifhed the fliock, by giving the battery a fmal-
ler charge ; but the effedt upon the animalcula
was precifely as before. I augmented the quan-
tity of liquid expofed to the fliock, by drawing
upon the fpot a right line, proceeding from the
central hole, two-thirds of an inch in length,
and two lines in breadth. I then pafled the
fpark acrofs the whole fluid. This was a thun-
derbolt to the animalcula : all perifhed at the
fame inflant. I increafed the breadth of the
line, without augmenting the length. So long
as the breadth was only two lines, all the animal-
cula perifhed ; when greater, the whole did not
fuffer, as they did not die till fome time after.
Thofe in the fpace between the two lines were

ft tinned,;

ANIMALCULA OF INFUSIONS.

41

flunned, and revolved as if they had been car-
ried round in a vortex : this revolution became
gradually more faint, and in a quarter of an
hour they remained motionlefs. Thofe more
diftant from the formidable pofition, furvived
longer : the mod remote did not perifh, and
their vivacity and activity fhewed they were not
incommoded by the ele&ric fluid.

I made experiments by a Ample fpark drawn
from a conductor. I ufed the fame fpot of
pitch, placing it upon the conductor ; and,
drawing the fpark through the central hole,
it feemed more fonorous and brilliant. I fill-
ed with liquid, either the central hole, or the
little channel formed upon the fpot, and varied
the length and breadth. All the animalcula
in the central hole perilhed ; thofe in the chan-
nel only after drawing two or three fparks. I
applied a drop of infufion to a point upon the
conductor : the animalcula died if the eleCtric
fluid paflfed through it for fome time. In fhort,
I have obferved, in many repeated experiments,
that the weakeft lhock is always fatal to ani-
malcula. Simple electricity, that is, operating
filently, has no efteCt upon them. There is
no kind of animalcula upon which I have not
made experiments : but electricity has been a-
like fatal to all.

I filled feveral fmall glafs tubes with different
infufions. I he tubes were clofe at one end, and

open

42

ANIMALCULA OP INFUSIONS*

open at the other. I put them under the re-
• ceiver of an air-pump, at the fame time keep-
ing tubes in the open air filled with the fame
infufions. For fourteen days they were depriv-
ed of air, without the animalcula fuffering in-
jury. Upon the twentieth they begun to die,
and on the twenty-fourth all had perifhed.
Thofe in the open air were (till alive. I re-
peated the experiment, with other infufions
made of different feeds. The animalcula of
fome lived a month, and even five-and-thirty
days : thofe of others died in fourteen, eleven,
and even in eight days : fome animalcula lived
only two days.

The nature of certain animats is truly -won-
derful : they can perform in vacuo all the ani-
mal functions they exercife in open air. Vi-
pers and fnakes will creep, leeches fwim ; fome
infedls will feed, others actually copulate there.
Such is alfo the nature of animalcula. They
preferve every motion ; they even for fome days
propagate in vacuo. After a longer or a fhort-
er fpace, according as the animalcula are more
able to fupport the vacuum, their motion re-
laxes, and ends with the life of the animal. It
fometimes, but rarely, happens, that the ani-
malcula will recover life upon being taken from
the receiver.

%

I never found any animalcula in whatever
animal or vegetable fubflance left to macerate

in

ANIMALCULA OF INFUSIONS-. 43

In vacuo : the reverfe has uniformly happen-
ed, when there remained in the receiver a
quantity of air fufficient to keep thirteen inches
of mercury in equilibrio. I have obferved the
fame phenomenon with refpeft to the eggs of
infects. I have often put thofe of terreflrial
and aquatic infedts under the receiver of an air
pump $ but none ever hatched, although in e-
very other refpe£t in a condition to do fo. The
animal concentrated in the egg, enjoys the be-
neficial influence of the air, by means of a
multitude of minute pores by which the egg
is penetrated. Befide a number of animals re-
fpiring by the mouth, many receive air by
means of apertures in the fides of the body,
by the extremity of the abdomen, or by other
parts. This is accompliflied by many minute
channels, with openings at the furface of the
body, which, by ramifications, reach the moil
internal parts. Our animalcula, notwithiland-
ing their apparent fimplicity, difplay an organ,
which we mull imagine to be that of refpira-
tion. There are animalcula, that perifli the mo-
ment they are deprived of air ; and there are
others, whofe nature and Hate is fuch, that
they fupport this privation for a longer or a
fhorter time. A fparrow, a nightingale, a
chaffinch, and, in general, other birds, perifli
very foon in vacuo : a lizard, a frog, reptiles
and infers, ftill longer. All the different fpe-

44 AfalM ALCtJLA OF INFUSIONS.

cies of animalcula do not fupport it equally
well. But the lovvell rank of animalcula feems
to be that, of all other animals upon which
experiment has been made, which can live
longed without air. None can fupport it be-
yond a month ; and, although they fupport
privation of air a long time, they yield under
it at lad. I well know there are indances cit-
ed, of diderent animals faid to have exided
without enjoying the benefit of this element ;
fuch as, the accounts of frogs found alive in
the middle of the harded fubdances ; of living
toads difcovered in the centre of large dones,
or of entire trees, where the fmalled particle
of air could not infinuate itfelf into their re-
treats. But, thofe hidories are more the ob-
ject of the admiration, than the belief, of per-
fons who have made any progrefs in Experi-
mental Phiiofophy. It is requifite they fhould
be fupported by authority ; which is mod ef-
fential, in a cafe fo drange and paradoxical.
Until we obtain fa&s better afcertained, we
think ourfelves entitled to alfert, that there is
in nature no known animated being, which
can exid without enjoying the advantages pre-
fented by air.

CHAP.

animalcula of infusions.

45

CHAP. VII.

While we obferve animalcula of fome ipe-
cies, if we fee two united together, we imme-
diately fufpect they are occupied in reproduc-
ing themfelves. We have this opinion, al-
though the animals which excite it are infi-
nitely fmall ; becaufe many cafes fhew, that ani-
mals in this fituation labour abfolutely, and
the moll frequently, to propagate their fpecies.
Thus it has been thought, that animalcula co-
pulated, becaufe they have been feen united in
pairs. Such is the opinion of Mr Ellis, and of
Father Beccaria.

The tranfverfe divifion of animalcula, not
only exilts in the fpherical, and elliptical, but
alfo in others with pointed extremities, though
they have neither beak nor hook. The better
to obferve what happened, I ifolated the ani-
mal in a glafs of liquid. If the weather is
warm, the traces of a contraction are very foon
perceived about the middle of each fide ; the
contraction encreafes, and the animalcule fome-
what refcmbles an oblong blown bladder, tied
tight acrofs the middle. The contraction gra-
dually becomes deeper, and the animal is at
length changed into two minute equal fpheres
in contact in one point. Plate i. fig. i. AB C.
The connected fpherules continue to move as

before

46 AN1MALCULA OF INFUSIONS.

before the divifion, with this difference, that
they frequently ftop, but for a very fnort time.
The anterior fpherule feems heavier than thepof-
terior, which it drags along, the latter having no
fpontaneous motions, excepting thofe neceffary
to feparate it from its companion. The divifion
is at lad completed, and from a fingle animal-
cule there arife two. At firft they feem motion-
lefs ; but their reft or indolence is foon diflipat-
ed, and the two portions refume the agility of
their parent whole. The fize of the complete
animal is foon acquired. The parts, when very
near feparation, are not conftantly fpherical, but
more or lefs elliptic. They are not always in-
active at the moment of feparation, but often
retain the vivacity of the whole from which
they originate. What fpecially merits obferva-
tion, is, that in fome animalcula, when the por-
tions are juft about to feparate, each is almoft
equal in fize to the whole from which they ori-
ginate. Of the animalcula multiplying in this
way, I have counted fourteen fpecies ; but there
are only two that merit defcription. We fee,
in infufions of red and bearded wheat, a circu-
lar animalcule above the mean fize. Around
the circumference of the bodv is a circle of

J

minute protraChed points, refembling very fine
cones, and moving with great quicknefs. Thefe
points ferve the animalcule to fwim, the fame as
jt.he limbs of fo many aquatic animals. The a-

nimalcula

ANJMALCULA OF INFUSIONS. 47

nimalcula multiply by a tranfverfe divifion in
two. The divifion operates {lowly ; and one
fingularity is, that it is not completed till each
equals the fize of the whole, and each has du-
ring that time acquired minute points like thofe
of the old animalcule, excepting that they are
fiiorter.

The other fpecies is found in infufions of
the marfli lentil. The animalcula are fo large,
* as to be vifible to the naked eye, by illumin-
ating with the rays of the fun a very thin-fided
glafs tube full of the liquid. The obferver may
eafily fee the fucceflive divifions. Other ellip-
tic animalcula of this kind fwim when the di-
vifion is fcarcely begun, fome when it is con-
fiderably advanced, and others when it is ai-
med completed. In a fhort time, a fingle ani-
malcule will people a whole infufion.

There are likewife animalcula which multiply
by a longitudinal divifion. If a drop of infufion
is prefented to the microfcope, animalcula are
feen among the particles ; fome are fixed to
thefe by the filaments, and fome wander at
large in the drop. This filament proceeds from
the pofterior part of the animal ; and although
its natural pofition is a flraight line, it often
contracts and forms a fpiral. Then the filament
refumes its original pofition. If the filament is
free, it encompafies the animalcule. This it
frequently does, aimed periodicallv. It is of a

pearl

43 ANIMALCULA OF INFUSION'S.

pearl colour, and its llendernefs extreme, at
lead when compared with the animalcule : the
length is equal to that of the animalcule, or
more. The figure of the animalcule refembles
an onion ; therefore I have called it the bulb
animalcule. From a hole in the fore part be-
low, proceed a number of extreme flender fi-
bres, circularly difpofed ; PI. i.'fig. 2. Thefe
tibrilli, by their conflant vibration, occafion a
vortex in the fluid, which draws in the fmalleft
furrounding bodies, and even the mod minute
animalcula. When the larger fubftances enter
the hole of the animalcule, they are rejected,
but the fmaller remain ; we have therefore rea-
fon to believe, that they penetrate the body of
the animalcule by fome invifible channel, for
the purpofe of nutriment and prefervation.

I have faid, the filament has certain periodi-
cal motions ; I may add, that the animalcule
has other periodical motions, immediately fuc-
ceeding thofe of the filament. Always, when
this contracts, the animalcule likewife con-
tracts, and inftantly draws the fibres and the
hole within its body. Then it affumes the figure
of a fpherule, D ; PI. 1. fig. 2. It afterwards
extends the filament, and becomes like a pear,
E ; and then affumes its ordinary figure, F G.
The fibres and the hole re-appear : their mo-
rons re-commence with the vortices.

I

ANIMAL CUL A OF INFUSIONS. 49

I firft faw a little cleft open at the fore part
of the animalcule: it was the beginning of an
opening, which divided the hole in two parts.
The cleft encreafed, the vortex became double,
and each of the animalcula acquired, in divifion,
the rude figure of one. The two portions fe-
parated more and more ; their drape became
more perfect ; and, when upon the point of re-
paration, they were metamorphofed into two
complete animalcula. One remained attached
to the filament, foon becoming as large as
the whole, and, by new divifions, producing
new beings. The other animalcule wanted
the filament, rapidly traverfed the liquid, con-
tracting and extending itfelf; and we perceiv-
ed an appendage proceeding from the fupe-
rior part, which was the origin of the wanting
filament. Fig. 3. pi. 1. fhews the different de-
grees of divifion before reparation.

The bulb animalcula not only inhabit boil-
ed, but alio unboiled in hi lions of kidney beans,
and feveral other infufions of legumes, as len-
tils, beans, imall peafe, grey peale, &c. To fee
the multiplication with facility, it is fufficient
to macerate two or three portions of each kind
of feed in a watch-glafs. If the experiment is
made in fummer, in a few days fome animal-
cula are feen attached by the filaments to mi-
nute particles in the infulion. dhe animal-
cula will divide under the obferver’s eye. The

E number

50

ANIMALCULA OF INFUSIONS.

number fixed by the filaments will be propor-
tional to the number of divifions about to take
place.

Another fpecies of animalcule, which alfo
multiplies by a longitudinal divifion, is. produ-
ced by the macerated feeds. The fibrilli are not
fituated under the hole, but upon the lips.
The figure of the animalcule refembles a mo-
nopetalous flower.

In a larger fpecies of animalcule, fometimes
found in an infufion of beets, the multiplica-
tion is effected by means of a little fragment
detaching itfelf from the reft of the body. The
figure of the body does not change like that of
the reft : a fmall portion of the body detaches
itfelf commonly near the part where the fila-
ment originates ; PI. i. fig. 4. H. This frag-
ment is in continual motion : when detached,
it fwims with agility in the infufion ; and, al-
though not a twelfth part of the whole, equals
it in fize during the day. Then it begins to
multiply by the fame divifions.

The reader will doubtlefs be curious to
know, how I could ifolate the animalcula.
With the point of a writing pen, I tranlport
a fmall drop of the infufion into a watch-glafs.
I put a litcle drop of water two or three lines
diftant from the firft. I then make the two
drops communicate by a fort of common chan-
nel, which is a prolongation of one drop with

the

ANIMALCULA OF INFUSIONS.

5r

the pen. The animals traverfe the canal, and
arrive one after another in the drop. As foon
as I perceive one enter, I cut off the communi-
cation.

The volvcx, like mod animalcula, is very
tranfparent, and the internal ftructure is accu-
rately feen. Some obfervers have already dif-
covered young in the womb of the mother,
extending to the fifth generation. In my long
obfervations upon infufions, I have found two
abounding with the volvox ; thofe of hemp-
feed, and the tremella. They are atfo found in
the putrid water of dunghills. Thofe animal-
cula are at firft very fmall, but grow fo large,
as to be diftinguifhed by the naked eye. They
are of a greenifh yellow colour, of a globular
figure, and of a tranfparent membranaceous fub-
ftance. In the middle, are included feveral
very minute globes ; Fig. 5. pi. 1. Thefe mi-
nute globes, when examined with the moft
powerful magnifiers, appear fo many fmaller
vol voces, which have each their diaphanous
membrane, inclofing others {Fill lefs. I have
diftinguifhed the third generation, but never
the two others. It is pofiible they were not
vifible in thofe 1 examined, from their not be-
ing of the fize or fpecies examined by other
naturalifts. When all had quitted the mother,
the common membrane burft, and begun to
difiolve. Meanwhile, the new volvoces con-

E 2 tained

52 ANIMALCTJLA OF INFUSIONS.

tained others, burft, and then diffolved. By
ifolating them, I faw the thirteenth genera-
tion.

One of the ftrongeft objeftions made to the
fyffem of germs, arifes from the great difficul-
ty in conceiving the fucceffive envelopement of
animals in animals, and plants in plants. Of-
tener than once, we have found one egg with-
in another ; and fome offeous part of one foe-
tus has been found within another foetus.
The butterfly is included in the fhell of the
chryfalis ; and the chryfalis in the fkin of the
caterpillar. In the feeds of vegetables, are
feen the rudiments of plants ; and in the root
of the hyacinth, the fourth generation has
been difcovered. The volvox affords a new ar-
gument for inclufion. There, we fee it to the
thirteenth generation ; and probably that is
not the laff.

CHAP. VIII.

Mr Baker, in his treatife, intitled, The
Microfcope made eafy , fpeaks of innumerable
animalcula inhabiting water. He mentions a
fpecies difcovered by Lewenhoek in the marlh
lentil, remarkable for a long tail, which ferves
to moor it to the roots of this plant 5 likewife

foy

AN1MALCULA OF INFUSIONS. 53

for a cavity like a bell in the anterior part of the
body, and an internal motion, which contracts
and extends the animalcula and their tails at
pleafure. Thefe peculiarities are fo analogous
to thofe of my bulb animalcula, that I deter-
mined to fearch for the fpecies, with which I
was unacquainted.

I was obferving the motions of fome tad-
poles about the roots of marfli lentils I
had put in a veflel of water to feed them.
The folar rays fell direct upon the furface of
the water, ftiewing the roots diftindtly. One
was diftinguilhed from the reft by a flight tint
of Aiming colour furrounding it about the
middle. I was furprifed to fee the tint difap-
pear, and then appear, which feetned periodi-
cal. I cut away the root while the tint was
vifible ; it immediately difappeared, and in a
very fliort time appeared again. I examined it
more narrowly, and difcovered it to be a group
of the tails of the animalcula I have mention-
ed. There were more than fifty, each faften-
ed by the tail to a lentil root. They refembled
the bulb animalcule in the faculty of extend-
ing and contrafting the body and tail, in form-
ing a vortex in the water, and in directing the
fwimming corpufcula to the hole or bell. The
vortex is formed by fibres or minute points
proceeding from the edge of the bell ; Fig. 6.
pi. i. But as this fpecies is larger, fo are the

E 3 points

54 ANIMALCULA OF INFUSIONS.

points and the vortex alfo proportionally larger.
When the bell was well opened, and the ani-
mal extended, the funnel appeared to terminate
in the body by a little central hole, I. They
all died in a few days, without feeming to mul-
tiply.

Six days afterwards, I faw a new foot form-
ed upon the roots : I fay formed, for it cer-
tainly was not there before. This afforded
new peculiarities. One portion reprefented a
tree in miniature. From the trunk proceeded
feveral branches, which divided into fmaller
branches, and thefe into others, the fize al-
ways diminifhing. Each of thefe laft, at the
top, bore a bell animalcule. No object could
be more fmgular or more agreeable. Every
three or four feconds, the trunk contracted
towards the root of the marfh lentil where
it was attached ; and in the twinkling of an
eye, drew in all the branches, all the twigs,
and all the animalcules : but an inflant after,
the tree re-appeared in its former (late, with its
branches and its animals.

I detached the flirub from the marfh lentil
root, by cutting the trunk. The animals, the
branches, the twigs, no longer approached
the flem ; but the Item, the twigs, and the
branches, fuddenly furrounded the animals ;
and, at this moment, the vortices difappear-
ed. Amidfl thefe alternatives, the animals, de-
tached

ANIMALCULA OF INFUSIONS. 55

tached from their trunk, f\vam flowly through
the water, drawing along the plant and its
branches.

I vifited the plant the following day. In-
flead of feeing a fingle animalcule come from
the end of the branch, I faw two fmaller ; Fig. 7.
PI. 1. K ; and thefe, as yet alone, were lon-
gitudinally marked with a very fine furrow,
L. Upon examination, I found this ’to be the
indication of a begun divifion. They begun
to divide into two animalcula ; fo that each
was double. In half a day, they were fepa-
rated, and of their full fize. The multiplica-
tion was very great. Two new branches were
perceived to proceed from- each old branch,
and the reproduced animals fixed upon their
fummits. Thefe, when full grown, divided
like their parents, and remained implanted up-
on new Items ; l’o that the multiplication of
branches was proportioned to that of animal-
cula ; and this double multiplication was, in
the fame manner, continued for feveral days.

During this, the flirub had extended its
branches in fuch a manner, that its circumfer-
ence became triple. The Italic and the branches
encreafed in the fame proportion : but the
death of the animalcula occafioned that of the
plant. They begun to feparate from the
branches, as fruit feparates from the tree ;
and, as they feparated, the motive faculty was

E 4 loft.

56 ANIMALCULA OF INFUSIONS.

loft. No more contra&ion or extenfton were
feen ; the vibration of the fibres, nor the con-
fequent vortex : all femblance of animation
was gone. Soon after, the figure of each ani-
malcule was deftroyed. The tree lived until
it had loft all its animalcules. We may fay,
that it then neither lived nor vegetated, nor
exhibited any mark of fpontaneous or internal
motion.

Although the animalcula in general died
where they were produced, that is, at the ex-
tremities of their branches, or, at Ieaft, till
the moment they are thence detached ; it is
not uncommon to perceive forne fwimming in
the water, but always adhering to their ftem,
fince we fo term it. If, by chance, they touch
a lentil root with this ftem, they fix there, and
give exiftence to a tree, bearing as fnany bell
animalcula as branches. The animal upon the
root foon divides in two, then in four, in eight,
fixteen, thirty-two parts, &c. While thofe di-
vifions take place, or the animals multiply, the
parts of the tree multiply along with them.
The number of twigs and branches fupporting
animalcula at the extremities, encreafes. They
all proceed immediately or mediately from the
ftem attached to the lentil root. This original
ftem has already encreafed in length and thick-
nel's, and is truly the trunk of the microfcopic
tree.

This-

ANIMALCULA OF INFUSIONS. 57

This fpecies of animalcule, whofe mode of
production Lewenhoek could never divine,
and which was unknown to Baker, is a poly-
pus, very analogous to thofe called by M.
Trembley, polypes a inaffe. Bonnet calls them
polypes a pennaches. But thefe animalcula dif-
fer from thofe of M. Trembley ; for the laft pro-
duce the vortex, not by means of points, which
they have not, but by the motion of the edges of
the bell. Before the divifion, they lofe the figure
of a bell, and aflume that of a round corpufcu-
lum : they are different, becaufe they are not en-
dowed with this alternate contraction and exten-
fion, divide unequally in two, at the divifion the
vortex is fufpended ; and becaufe the extenfion
and contraction is not natural and periodical as
in our animalcula, but occafioned by accidental
influence, and is formed by the agitation of
the water.

The longitudinal divifions, of which I have
treated in this chapter and in the preceding, all
begun at the anterior part of the animalcule,
that is, the part which is before when the ani-
malcule advances, and where, in many, the
mouth is obferved. But, in other animalcula,
the divifion begins in the oppofite part. One
fpecies refembles a fea hedge-hog in minia-
ture ; the figure is fpherical, the furface of the
body fpinous, with long and pointed prickles.
We diftinguifh the anterior from the pofterior

part

53 ANIMALCULA OF INFUSIONS.

part of the body ; for it proceeds before, and
forms the vortex, by darting out the fpines, while
the other is behind : the red: of the points are in
conftant agitation, at leaft while the animal ad-
vances, or while it pleafes. Another fpecies re-
fembles the fegment of a fphere, or rather an
hemifphere, entirely covered with points. Thofe
in the concave part ferve for fins ; others form
a vortex ; thefe proceed from the fe&ion or
plane of the hemifphere, which is always the
anterior part of the animalcule. Thus, both
are feparate, and their feparation feems to
fmooth the body of the animalcule, which can
remove the points at pleafure : it even appears
that its agility or flownefs, and the magnitude of
the vortex, is regulated by the number of points
in motion. Thefe two fpecies inhabit the tre-
mella, and are of a coloffal fize, compared with
other animalcula ; divide longitudinally, but
the divifion begins at the pofterior part. As
ufual, a faint cleft was firft perceived, which
extended as the body of the animal encreafed,
until it feparated into two equal parts, which,
before the divifion was finifhed, were two com-
plete animalcula, equalling in fize the whole
from which they came. During the divifion
the vortex continues, and the points proceed
from the cleft, foon appearing fimilar to the
old. The completion of this divifion requires
a confiderable time.

In

ANIMALCUL.A OF INFUSIONS. 59

In an infufion of tremella we orten fee two
minute balls, attached by feveral continued
points, fwim rapidly throug'h the infufion, in
irregula rdireclions. Fig. 8. pi. i.M. Fhefe
balls are two animalcula upon the point of di-
vifion. In a moment the one ball will feparate
from the other, notwithftanding the apparent
ftrong adhefion. When it is of the proper
fize, there is a faint conitri&ion, and each
gives birth to two minute balls, which in their
turn divide again.

I have feen groups of different round cor-
pufcula in vegetable infufions. The group is
Sometimes formed of four animalcula, fome-
times of five or more. The corpufcula com-
monly differ in fize, according to the diverfity
of the groups. Fig. 8. pi. i. They feparate
one after another from the cluffer, and then
divide into as many portions as there were cor-
pufcula.

I ifolated one of thofe animated corpufcula ;
I confined it in a glafs the moment it feparated
from the group. The folitary corpufcules ra-
pidly encreafed, and, when of the fize of the
group from which they were taken, there were
feen feveral furrows in the body, which gra-
dually changed to a new group fimilar to the
old. This new group decompofcd into other
corpufcules or animalcula, which foon equal-
ed

6o

ANIMALCULA OF INFUSIONS.

ed in fize and number the old duller decom-
pofed.

But the moll furprifing and the mod extra-
ordinary multiplication I have feen, is that of
fome animated globes, which roll like pellets in
the infufions of water lentil, and are vifible
without the microfcope. They are externally
covered with tumours, formed of feveral ani-
malcula, fituated upon each other, and attempt-
ing to efcape ; Fig. 8. PI. i. N. Figure a body
alrnod fpherical, formed of concentric drata,
each of which is an aggregate of animals. The
animalcula compofing the exterior or fird ftra-
tum, feparate from this fort of fphere : then is
the fecond dratum laid open, which is compo-
fed of animalcula, and, by its feparating, difco-
vers the third. There are even drata inferior ;
fo that the whole globe is decompofed, from
the circumference to the centre. The globe
has no other than a rolling motion ; but the
compofing animalcula have the greated activi-
ty. Each globe produces more than an hun-
dred.

While the drata of the globes decompofed,
I feized fome animalcula, and ifolated them.
At fird, each did not equal one hundredth part
of the globe in fize ; but in three or four days,
every one was as large as the whole. Their
motion became flower, in proportion as they in-
creafed. When full grown or complete, they

rolled

ANIMALCULA OF INFUSIONS.

6 1

rolled with only the preceflion common to
thofe globes. The furface of the ftratum was
at firfl fmooth ; it became unequal, and loaded
with tumours. Thefe tumours were fo many
diftincT animalcula, which, after the feparation,
fwam in the fluid. The animalcula of the fe-
cond ftratum did the fame, likewife thofe of the
fucceflive ftrata, until the globe was entirely
decompofed.

Such are the modes of produ&ion among
animalcula propagating by divilion. They are
in reality fo many polypi, which I fhall term
the Polypi of Infufions, or rather Microfcopic
Polypi. Their kingdom is not bounded by the
limited confines of infufions. I have at vari-
ous times examined the water of ditches, dung-
hills, marflies, pools, ponds, fountains, melted
fnow, rain, bath and medicinal water, both of
mountains and of plains, and I can affirm, that
I have found them all full, more or lefs, and
infinitely varied with minute polypi. The
different claffes have their appointed times to
originate and be deftroyed. When one fpecies
of animalcula becomes very numerous, the
greater part of its individuals perifli, either by
difeafe or by a violent death. An infufion
fwarming with animalcula to-day, will, in a few
days, have almoft none. Signor Cord has ob-
ferved, that fome maintain a fierce war. We
know the ingenious method praftifed by that

cetaceous

62

ANIMALCULA OF INFUSIONS.

cetaceous fifh, called by the northern nations,
the Great whale. Having clofed up a multi-
tude of herrings in a proper fituation, it gives
the water a blow with its tail, fo as to occafion
a vortex of wide extent, and great rapidity :
The monffer prefents its vaft mouth and deep
throat, which are foon fdled with the herrings,
drawn in by the vertiginous current. The car-
nivorous animalcula alfo form a vortex in the
fluid, by means of the vibrating fibres. When
fo full as to feern more corpulent, they become
indolent ; but if they are kept faffing in dif-
tilled water, they become attive, and employ
themfelves only in devouring the fmall animal-
cula which are prefented. The tranfparency
of their bodies permits us to fee the devour-
ed animalcula (fill continue to move.

All the kinds of divifion I have defcribed,
may be feen at all feafons, even the moft cold
and frormy. We cannot deny, that heat pro-
motes the multiplication of animalcula, and
that cold retards it ; fo that we may fay, the
time necefiary for divifion is nearly proportion-
al to the heat of the atmofphere. During the
rigour of winter, feveral hours are requifite ;
in fpring and in autumn, it is fooner perform-
ed ; and in the heat of fummer, a quarter of
an hour is fometiines enough for entire com-
pletion. Upon this account, the fummer in-
fusions

ANIMALCULA OF INFUSIONS. 63

fufions are much more populous than the win-
ter.

CHAP. IX.

Several kinds of animalcula are viviparous
and oviparous. One of the oviparous kinds is
found in rice infufions. The fize is of the
largeft among animalcula. The figure refem-
bles a kidney bean, except that one extremity
is curved like a pointed hook or beak ; PI. i.
fig. 9. O. I ifolated one of thofe animalcula
in a watch-glafs, along with a fmall portion of
infufion, which, for fecurity, had been boiled
a long time. In feven hours, the animalcule
had a companion, fo like itfelf, that it was
impoflible to diftinguilh them. I had no rea-
fon to believe it came from without, or was
produced by the infufion. Half an hour after,
I vifited the glafs, and difcovered fomething
new ; that is, two minute fpheres at the bot-
tom of the glafs, one of which was oblong ;
PI. i. fig. 9. P. It moved itfelf feveral times,
and changed its place. The alternate motion
and reft continued an hour and a third ; then
became quicker, and entirely local. The
fphere begun to fwim flowly in the fluid ; and,
in a fliort time, the quicknefs of the fmallefl:

equalled

6 4 ANIMALCULE OF INFUSIONS.

equalled that of the other two animalcula.
The other fphere, (>, Included a fpherule fo
fmall, as to be with difficulty perceived, and
would not have been noticed, but for a flight
revolving motion upon itfeif, while the includ-
ing fphere was tranquil. In feveral days, the
integument kurft, and the confined fpherule
efcaped, expanded, and became flender at one
extremity, to form the curvated beak. Thefe
animalcula, therefore, feem to originate from
an egg, reprefented by this integument. The
following day, there were more than forty-five
animalcula in the glafs, fimilar to the firft
that was ifolated. There were alfo, at the
bottom, feveral minute balls, partly round,
partly elliptic ; the former lefs, the latter larg-
er. Of the round, one after another burft,
and as many inactive ill-fhaped animalcula
came out, which foon acquired figure and mo-
tion. To leave no doubt, I confined fome a-
nimalcula in a very fmall portion of water.
In fcarcely a quarter of an hour, one was, in
my view, delivered of a round corpufcule. I
faw more eggs laid in this manner. I counted
eleven, proceeding from the pofterior part of
the ifolated animalcula. Thefe gave birth to
an equal number of animalcula.

Two fpecies of viviparous animalcula are
carnivorous. They fwallow their prey by
means of a great vortex drawing them to the

mouth.

ANIMALCULA OF INFUSIONS. 65

mouth. We fee them diftin&ly pafs down the
cefophagus, and enter a little bag, in their way
to one larger, which apparently is defigned for a
ilontach. Each animalcule has a long tail,
the extremity of which is divided in two, and
ferves to fix it to the furrounding bodies.
Upon the fides of the tail, are feen two oval fub-
flances ; above thefe are two fmaller, refembling
two little narrow leaves ; PI. i. fig. io. R.
The parts refembling leaves, are parts of the
animal ; the two other, are real animalcula.
If kept in view with a magnifier, we fee them
expand, quit the mother, and fwim. The o-
pacity of this kind of animalcule prevented my
feeing the foetus before exclufion ; but, when
it came to maturity, two fma.ll ones were ob-
ferved, where the tail originates from the ab-
domen. I have never difeovered more than two
in each animalcule, although I have examined
many. I have indeed feen three attached in
the fame manner to other animalcula ; but
thefe I judged to be of a different fpecies, S.
Thefe two fpecies generally inhabit the tremel-
la of ditches.

Having taken an egg laid by an animalcule,
I put it alone in a watch glafs : afterwards, there
were as many animalcula feen, as eggs laid by
the animalcule excluded from this egg.

1 ifolated viviparous animalcula, taking them
before they were completely developed, and

F ’ dill

66

ANIMALCULE OF INFUSIONS.

ftill adhering to the body of the mother. After
the neceffary time, each ifolated animalcule of
the one fpecies became parent to other two,
and thofe of the other fpecies to three.

Thefe two genera of oviparous and vivipa-
rous animalcula, are, then, hermaphrodites in
all ftriftnefs. I lhould conclude, that herma-
phrodifm, which at firft feems confined to a
few fpecies, will extend far in the animated
world.

We muft fay, that the original inhabitants
of infufions originate from fome germ, or mi-
nute egg, which palfes from the ail* into the
infufion, and becomes the principle or fource
of this numerous colony. This is confirmed
by fa£ts. I took the liquid from a number of
eggs, fo as to leave them perfectly dry ; and
thus they remained for ten days. I then put
them in their native liquid, where they were
foon hatched.

Every liquid does not equally favour the
expanfion of the eggs of animalcula : pure wa-
ter, for example, is moft unfit for it. This is
no more a my fiery. We conftantly obferve,
that no animalcule almoft ever appears in pure,
or, for the greater reafon, in diftilled water j but
I have found no fluid more favourable to the
production of animalcula, than water with feeds
infufed, efpecially when the feeds begin to be-
come putrid.-

In

animalcula of infusions. 67

In my obfervations, I have particularly in-
quired, whether animalcula fpecifically varied
as the infufions of vegetable feeds were differ-
ent, fo that each might have peculiarly its
own ; but I have found nothing conflant. It
is true, I have often found certain fpecies of
animals only, in particular kinds of vegetables,
but I have frequently feen the reverfe. The
animalcula of the fame infufion were different,
at different times and different places ; and it
even is not uncommon to fee this variety in
twro infufions made of the feed of the fame
plant. All this well agrees with the vail va-
riety of animalcular eggs, fcattered in the air,
and falling every where, without any law.
Doubtlefs, the microfcopic polypi alfo proceed
from a pre-organifed principle : but is that an
egg, a germ, or other fimilar corpufculum ? If
fads are required to folve this queflion, I in-
genuoufly acknowledge, we have no certainty.
The polypi die w'hen the fluid is taken away,
nor do they revive when it is reflored. It may
happen, that the germs, or pre-organifed prin-
ciple, are too tranfparent, or too minute, to
fall under the fenfes. The idea, that animal-
cula come from the air, appears to me to be
confirmed by undoubted fads. I took fixteen
large and equal glafs vafes : four I fealed her-
metically ; four were flopped with a wmoden
Hopper, well fitted ; four with cotton ; and the

F 2 four

68

ANIMALCULA Of INFUSIONS',

four laH I left open. In each of the four claf-
fes of vafes, were hempfeed, rice, lentils, and
peafe. The infufions were boiled a full hour,
before being put into the vafes. I begun the
experiments n. May, and vifited the vafes 5,
June. In each there were two kinds of ani-
malcula, large and fmall j but in the four open
ones, they were fo numerous and confufed,
that the infufions, if I may ufe the expreffion,
rather feemed to teem with life. In thofe flop-
ped with cotton, they were about a third more
rare ; (fill fewer in thofe with wooden Hop-
pers ; and much more fo in thofe hermetically
fealed.

I changed the feeds, taking maize, wheat,
and barley ; but the fuccefs was the fame with
regard to the eflence of the experiment.

I then fubflituted, for Hoppers, nut and o-
live oil, with which I filled the tops of the vef-
fels. This new obfiacle diminifhed the num-
ber of animalcula.

The number of animalcula developed, is pro-
portioned to the communication with the ex-
ternal air. The air either conveys the germs
to the infufions, or aififis the expanfion of
thofe already there.

Although the organifation of animalcula is fo
fimple, that they appear but as granula invefi-
ed by an integument, yet we difeover many dif-
ferent parts, fuch as the fibrillee for the vortex,

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ANIMALCtJLA OF INFUSIONS. 69

and the points for fwimming. We fee a mouth,
an oefophagus, and a ftomach, where there is
obferved a periftaltic motion, which puts the
included aliments in motion. I fhculd men-
tion another organ which I have difcovered in
this new courfe of obfervations ; and which I
fufpeft to be deltined for refpiration. It con-
fills of two liars, with a very minute globe in
the centre. They are fituated as the foci of
elliptic animalcula above the mean fize ; PI. i.
fig. 1 1. T. The ftars are always in motion, whe-
ther the animalcula move or are at reft ; but
the motion is alternate and regular. Every
three or four feconds they fwell like a bladder,
becoming three or four times larger; then they
fall, and the inflation and eflation is performed
very flowly. The fame is feen in the rays,
with this difference ; when the globes are full,
the rays are empty, or when the rays fwell, the
globes fall. During this, there is feen in the
largeft animalcula a very long narrow ellipfe,
U, fituated on the fide between the two liars,
which is in continual motion.

f3

C 70 ]

OBSERVATIONS and EXPERIMENTS

UPON the

SEMINAL VERMICULI OF MAN AND OTHER ANIMALS,
WITH AN EXAMINATION OF THE CELEBRATES
THEORY OF ORGANIC MOLECULES.

INTRODUCTION,

The fubjeft I am about to treat, fhould form
a chapter of the preceding treatife upon ani-
malcula, from their analogy with fpermatic
vermiculi ; but the found arguments of M.
Bonnet have changed my determination. I
fent him the refults of my experiments upon
Animalcula, Spermatic Vermiculi, and Mould.
He honoured them with his approbation, and
advifed me to feparate the fubje&s ; to treat of
each in a feparate diflertation. In this form
he thought they would more readily fix the at-
tention, and attrafl the curiofity of readers. I
have found his advices falutary, and have pro-
fited by them ; they have enabled me to ex-
tend the fubjeft, and enlarge my refearcnes
upon Spermatic Vermiculi.

SEMINAL VERMICULI.

7*

The reality of the exiftence of thofe ani-
malcula, as well as the knowledge of their pe-
culiar nature, is a fubjeft as fit to engage the
inquiries of a philofopher, as they feem to re-
treat from his penetrating examination. I may
fay, that, like the Proteus of fables, their fi-
gure and appearance change with the natura-
lifts who attempt to ftudy them. The feminal
fluid of man, and of fome animals, examined
by Lewenhoek, appeared to him full of ani-
malcula ; which he named , vermes, from their
refemblance in figure and motion. But they
were foon confidered by philofophers, as a
phantom of the imagination, an illufion of the
fenfes, or fome imperfection of the microfcope.
They thought there was nothing real in what
the Dutch philofopher had defcribed.

By others he was judged with lefs feverity.
They agreed that there wras a number of cor-
pufcula in the feminal fluid ; but they denied
they were animals, and thought them unorga-
nifed particles, which, from their fubtility, were
raifed and evaporated fooner than the reft :
thus, forming a fermentation and motion in the
fluid, that created the idea of animation.

The celebrated Linnaeus adopts this opinion
nearly. He thinks the veriniculi are only inert
molecules, fwimming like oil in the feminal
fluid, moving and darting in various directions,

F 4 as

72

SEMINAL VERMICULI.

as they are agitated or heated by the tempera-
ture of the fluid.

Meflieurs Needham and BufFon, publifned
their fentiments upon the quefiion, which they
have elevated to the fubjed of the animation of
thofe microfcopic beings ; and it would appear
that their theories are directly oppofite. The
iirfl: thinks they originate from the vegetative
power ading upon the feminal fluid, after it
comes from the animal ; by which, it is necef-
fitated to vegetate, to expand, to put itfelf in
motion, and to change into beings not yet ani-
mated, but Amply vital.

M. De BufFon, enamoured of his organic
molecules, thinks he finds them in the vermi-
culi ; and, from a long detail of experiments
and obfervations, endeavours to eftablifh his
theory upon the ruins of that of Lewenhoek.

Who could imagine that fo many difputes,
and fuch oppofition of fentiment, would arife
upon a matter of fad ? I confefs, this has An-
gularly furprized me ; and I have often thought
that thediverfity of opinion arofe lefs from efien-
tial difficulties, than from the fault of obfervers,
who had not the proper methods of examina-
tion ; from a prejudice in favour of fome theo-
ry, made their fenfes the caufe of their errors ;
or, finally, from want of fufficient pradice in
the difficult art of accurate obfervation. As I
treated of a fubjed analogous to the hifiory of

fpermatic

SEMINAL VERMICULI.

73

fpermatic vermiculi, I wiffied to ftudy them,
to difcover, if poffible, where the truth was.
I applied to the enquiry with all the attention,
care, and reflexion, in my power ; and for the
greater certainty, endeavoured, firft, to for-
get all that had been written upon the fubjedt,
acting as if I had been the original author of
it. In controverted fadts, I have always found
this the fafeft method to avoid confounding
the opinions of the philofopher with the re-
fponfes of nature. After reaping a fruitful
harveft of facts, I prefumed to think, that I
knew what had been feen by others. I then
compared their refults with my own, and al-
lowed myfelf to give an opinion with refpedtful
deference. I doubt not but my fincerity will be
believed, when it is known that 1 have taken no
fide of the queftion, and that it was abfglutely
indifferent to me, whether my difcoveries were
correfponding, or contradidtory to thofe of o-
thers.

The feminal fluids I ufed, were that of man
and different quadrupeds. I did not negiedt
to examine that of the fmalleft animals. 1 em-
ployed the feminal fluid of man as recent as
poffible ; that is, taking it from dead bodies
while yet u'arm. I took the femen of animals
the moment they w’ere killed. I have frequent-
ly examined the feminal fluid of animals alive,
and ieveral times ufed that ejected during co-
pulation^.

74

SEMINAL VERMICULI.

pulation. The importance of thefe fafts, in
the iliuftration of this queftion, will be evi-
dent to the reader of the following chapters.

LETTER FROM M. BONNET.

I

“ In the Country, 16th Oftober 1771.

<e I agree to your requeft, my efteemed
t(' correfpondent, and delay not to inform you,
£C that I have received the excellent letter I
ec owe to your friendlhip for the Palingenefift.
tc Excellent book, I Ihould fay : it is almoft
<e fuch in fize: and I fhall add it to thofe of
<c the fame kind with which you have already
£C enriched my library. I could not refolve to
u engrofs to myfelf a work, almoft every line
“ of which demands ferious attention. I de-
<c termined to revife it with an obferver wor-
<c thy to underftand and to follow you : I
<c fpeak of my excellent friend, the illuftrious
<c difcoverer of the polypus. Yefterday, we
tc perufed it together ; and I am unable to tell
“ you how much we are enchanted with it.
cc When you give me time, I fhall detail your
“ obfervations along with you. But I ought not
<£ to avoid remarking, how defirous M. Trem-
“ bley and myfelf are, that you fliould publifli
6‘ feparately your obfervations and experiments
upon Infufions, Vermiculi, and Mouldinefs,

<c and

SEMINAL VERMICULI.

75

“ and upon the other fubje£ts of the fame na-
44 ture, which you have treated with fuch
44 learning and fuccefs. They are too import-
44 ant not to merit and require a feparate im-
44 preflion. They would make an admirable
44 appearance in detached treatifes, and w’ould
44 thus more firmly fix the attention of ama-
44 tears. Send me them when they come
44 from the prefs. M. Trembley and I will,
44 under our own infpeftion, caufe them be
44 tranflated into French as foon as poflible. I
44 doubt not that you will comply with our re-
44 queft. This new treatife upon infufions,
44 will form an appendix to the former. We
44 may even reprint the French tranflation of
44 the laft, and place it at the beginning of the
44 new work. Think of all this, and let me
44 know. I mentioned it to M. Trembley,

44 Your tracts upon infufions, &c. will, in
44 my opinion, be excellent rhetoric for the
44 ufe of naturalifts, which, I aflure you, in
44 my view, is not the leaft merit of your learn-
44 ed refeaiches.

44 You judged right, that I had affociated
44 M. De Saulfure in pur amufement ; and he
44 was not once abfent for fifteen days. He
44 is now abfent at Lyons ; but we fhall regale
44 him upon his return.

44 Still a word upon infufions. — Behold the
44 poor Epigenefift reduced to an impalpable

powder 5

76

SEMINAL VERMICULI.

“ powder ; and you have no lefs pulverized
cc his friend De BufFon. I have read nothing
cc upon fpermatic vermiculi with fo much fatis-
cc fa&ion j and 1 congratulate myfelf that I
<c induced you to fludy them. Your obferva-
“ tions are mod valuable, in my opinion : they
“ are both new and accurate. 1 would reani-
“ mate the worthy Lewenhoek. What plea-
tc fure would it afford him, to fee the attack
<c of M. De BufFon fo well repelled ! I hope
£C he will now be polite enough to acknow-
44 ledge, his microfcopes have not done him
44 juflice, and yield to your evidence.

“ Your mould is almoft as new as your

<c fpermatic vermiculi But I do not ob-

“ ferve that I begin to anfwer, in detail, your
<c interefling letter j and, if I continued, you
<c would not fo foon know that I had received it.
46 I therefore end, renewing the afFurance of
my inviolable regard.

<c Bonnet.

CHAP,

SEMINAL VERMICULI.

77

CHAP. I.

The feminal fluid taken from a dead human
body, refembles coagulated milk a. When ex-
amined with a magnifier, the caufe of its opa-
city is not difcovered ; but, wdien it begins to
diflolve, and afiumes the colour of foapy wa-
ter, if examined with a magnifier of fmall
power, the irregular parts feem to be in an in-
diftinch, flow agitation. I obferved, that thofe
parts were moved by corpufcula infinitely more
minute, of a globular figure. Each had a fort
of filament, or fliort appendage; PI. 2. Fig. 1.
A. It is evident, that the more grofs part of
the feminal fluid is put in motion by globular
corpufcula ; for there is no motion, unlefs
they are in agitation. The corpufcula have
two motions, one ofcillatory, from right to left,
and from left to right, curving the appendage
from one fide to another. The other is pro-
greflive : the vermiculus tranfports itfelf by of-
cillation. When we confider this mode of
moving, we would imagine them blind. They
ftrike againft every obftacle, and, when amidd
a number, make a thoufand contortions to e-
fcape, at lad taking that way where they feel

lead

* Dec. 21. The thermometer 4S0 above c.

7S

SEMINAL VEU MICULI.

leaf! refiftance. Thus they are in continual
motion. In twenty-three minutes, the motions
of ofcillation and progreflion had diminilhed ;
and, in an hour and a half, it had leflened fo
much, that a very fmall number of corpufcula
preferved any appearance of motion. In gene-
ral, the progreflive motion ceafes before the
ofcillatory ; fo that, at laft, the corpufcle mere-
ly bends from right to left, and reciprocally.
They continue fixed to the fame fpot, until the
ofcillatory motion infenfibly dies away.

After all motion is gone, the corpufcles re-
main entire in the fluid, and then they are bet-
ter feen than even when the liquid is diluted
with water. Each corpufcle is not properly
globular, but elliptic ; and the appendage is
not only longer than it appears, but the breadth
is not equal throughout like a thread, but en-
creafing as it approaches the body; Fig. i. B.
It was impoflible to difcern where the filament
terminated, being fo much immerfed in the
fluid. When the corpufcula have ceafed to
move, the appendage remains extended in a
flraight line, or with little deviation.

When the feminal fluid has been kept for a
day, or indeed for lefs, in a watch glafs, it
becomes tranfparent, although preferving its
original vifcofity. It depofits a fediment of
whitilh matter, refembling a mafs of flender
rags.

The

SEMINAL VERMICULI.

79

The feminal fluid having diffolved later than,
that of the preceding oblervation, I put iome
particles in rain water a. The fhapelefs cor-
pufcula fwimming in the liquid, with the double
motion of ofcillation and progreflion, became
motionlefs when touched by the rain water.
Other waters mixed with the feminal fluid, pro-
duced the fame effedt as that of dunghills,
rivers, fnow, ice, and even diftilled water. I
have found nothing but faliva preferve the mo-
tion of the corpufcula. It may be ufed indif-
ferently, either from the mouth, or when it is
cold. I have often employed it to continue my
obfervations. The ovular corpufcula I then
found ; and the phenomena exhibited, were
precifely the fame with thofe of the preceding
obfervation.

When the liquid drop dries up, all the
corpufcula, without exception, become mo-
tionlefs. And as it dries firft at the circum-
ference, that is, where it is thinner, and advan-
ces to the centre, the corpufcula firfl: becoming
motionlefs, are thofe at the edge, then thofe of
the interior part, and laftly thofe in the centre
of the drop. If a drop of faliva, or of the fe-
minal fluid, is put upon that which is dried,
the corpufcula do not recover motion, though
the humidity continues long. The corpufcula
of this obfervation became fooner motionlefs.

In

a January n. The thermometer 36° above c.

8o

SEMINAL VERMICULI.

In fourteen minutes they were languid; in three
quarters of an hour there was complete repofe.
At lad they had no progreflive motion, al-
though a remnant of the ofcillatory continued;
fo that when the two motions ceafed, mod of
the appendages remained extended in a draight
line.

The feminal fluid taken from a dead human
body, was chiefly coagulated a. It was then
peopled by the corpufcula I have defcribed. In
one of the preceding obfervations, it appeared
to me, that there were fome larger corpufcula
among the red. I apprehended I was deceiv-
ed; that this difference of fize might arife from
minute portions of the femen attached to the
corpufcula : but I was convinced this could not
be the cafe, becaufe, when the feminal fluid
was completely diffolved, the corpufcula re-
tained the fame fize, although I paffed them
through another fluid ; Fig. 2. C. The mo-
tion ceafed two hours after the femen was ta-
ken from the body.

The feminal fluid of man was like milk rea-
dy to coagulate. I took a fmall portion for ex-
amination b. It prefented a Angular phteno-
menon. I faw four corpufcula attached by the
filaments to a clot, which diffolved. They
feemed to me to make every effort to difen-

gage

a February 18. The thermometer 490 above o.

b March 8. The thermometer 510 above o.

SEMINAL VERMICULI. 8l

gage themfelves from this incumbrance, by ma-
ny motions and contortions ; but they remain-
ed fixed. The filament fometimes defcribed a
curve, and was fometimes extended in a ftraight
line. Amidft the ftruggles, one extricated it-
felf from the clot, and begun to fwim in the
fluid. Like the reft, it had the motions of of-
cillation and progreffion. The other three cor-
pufcula did the fame, one after another ; and,
by degrees, detached themfelves entirely from
the clot.

The novelty of this phenomenon made me
defirous to take other molecules of femen not
Completely dilfolved, to fee if I could find other
ovular corpufcula in the fame fituations. In
fome, the corpufcula were free, and I faw them
fwim in the place of the clot diffolved ; others
I faw, attached by the appendage to that part
of the clot yet entire, and endeavouring to dif-
engage themfelves by all the contortions I have
jult mentioned. I faw, that when entirely de-
tached from the fpermatic molecules, they li-
berated themfelves, and fwam about in the flu-
id. I found fomething more. One of the
clots was partly in filaments 5 many ovular cor-
pufcula were feen about the filaments, which,
notwithflanding their endeavours, were unable
to fet themfelves free. In this femen the cor-
pufcula lived two hours and a half.

G

When

SEMINAL VERMICULI*

82

When I took the leminal fluid from a dead
human body, mod part feemed diflblved a. Ma-
ny of the corpufcula furpafled the common flze.
In this experiment, my objett was to fearch,
with all poflible care, for what I had feen in
the courfe of the preceding obfervations. I
faw all I had obferved, excepting the pheno-
menon of the corpufcula attached to clots,
which could not happen here, as the femen
was perfectly coagulated. Some of the cor-
pufcula continued to move for three hours.

In the examination of this feminal fluid b,
which was at firft a little thick, I difcovered,
by chance, a method of feeing, with more con-
venience and precifion, the figure of the corpuf-
cula and their appendages. I put a clot of fe-
men upon a talc Aider ; as the thicknefs pre-
vented my feeing it with accuracy, I fwept it
with a fmall pencil, but the talc was not fo clean,
that fome little portion of the fpermatic mat-
ter did not remain. I cannot tell what induced
me to examine the talc again with the micro-
fcope ; but I there found what I had no idea of
dilcovering. I faw fcores of the corpufcula ve-
ry diflincl, although motionlefs, becaufe they
were dry. They were feparate, without any
mixture with the fpermatic matter : the appen-
dage of fome was ftraight, of others curved,

and

a March 27. The thermometer 540 above o.
b April 15. The thermometer 6o° above o.

SEMINAL VERMICULI. 83

and nearly of the fame length in all ; that is,
about fix times the length of the body, the ex-
tremity not much pointed, but thicker as it ap-
proached the body ; and it was diftinctly feen,
that the corpufcle made but one whole with
the appendage, which, in the thickeft part, is
thrice as fmall as the body, and even more.
Each corpufcle is fomewhat like the red glo-
bules of blood, but fmaller. The appendage,
as the corpufcle, feemed to be compofed of a
homogeneous matter ; Fig. 2. D.

After this fortunate event, I frequently
wiped the talc whereon I had put fome drops
of femen, and I conftantly faw the corpufcula
with the fame precilion. I may add, they re-
mained dry upon the talc, without any altera-
tion of figure, for feveral days. In this femen
they became motionlefs in two hours and a
half.

I wifhcd to proceed rigoroufly with my re-
fearches, as it appeared the refults I had hither-
to obtained, were inefficient to beftow the cha-
racter of real animals upon the ovular corpuf-
cula. We have not effectually had that con-
grefs of chara&eriftic marks to decide their a-
nimality. Doubtlefs, we may name them mov-
ing corpufcula, or polfeffing a fpontaneous mo-
tion ; for the teftiinony of our fenfes will not
permit us to fuppofe, this double motion of of-
cillation and progreilion, the effect of anv ex-

G 2 ternal

§4

SEMINAL VERM1CULI.

ternal caufe. The iequel of the work will
make us more perfe&ly acquainted with their
nature.

Thefe obfervations have like wife demonflrat-
ed another truth, that the duration of motion,
after the corpufcula come from the body of the
animal, depends, in a certain degree, upon the
temperature of the atmofphere. At 36° above
o, all motion was gone in three quarters of an
hour ; at 470, in an hour and a half ; at 490,
in two hours ; at 510, in two hours and a half ;
at 540, in three hours ; and at 590, only afeer
the elapfe of three hours and a half.

From this I remarked, that the motion of
the corpufcula continued longer, as the tempe-
rature of the atmofphere encreafed. Examin-
ing the human femen in the warmer months,
to learn whether the phenomena I had already
witnelfed might be then obferved, I had the
pleafure of feeing them again in the fame man-
ner. I conftantly obferved, that as the heat
was greater, the duration of motion encreafed ~7
fo that in the middle of fummer, when the ther-
mometer had afeended to 8i°, our corpufcula
continued to move for feven and three quar-
ters, and even for eight hours.

While this heat continued, I varied the ex-
periments. I expofed a portion of the feminal
fluid, taken from a man, to the air of an apart-
ment where the thermometer flood at 82°; I

put

' SEMINAL VERMICULI.

85

put another portion in a cave, where the heat
was 65°; and a third portion in an icehoufe,
where the thermometer flood at ai° . Here
the corpufcula continued to move half an hour;
in the cave, four hours ; and in the apartment,
eight hours. Corpufcula abounded in each
drop of the fluid, and, although the drop was
fmall, it included an innumerable multitude.

After examining the feminal fluid of man, I
examined that of the horfe. No method of
obferving it could be more convenient, as I al-
ways obtained it at the moment of copulation.
I made ufe of the femen of different horfes.
The firffc I obferved, was without clots, very
fluid, and of a light cinder colour a. The
corpufcula, in motion or fwimming, were
not fo numerous as thofe of human femen.
There was no difference in the fize of human
corpufcula and thofe of the horfe, only the lat-
ter feemed a little larger. The appendage is
more vifible, probably becaufe it is thicker.
It is diftinctly and completely feen, although
immerfed in the feminal lymph ; Fig. 3. Their
ofcillatory motion is not fo great as that of
the human corpufcula, which may be the rea-
fon they advance further in the fame time.
Their progreffive motion is quicker, and fome-
times faltatory. The lize of all is not the
fame, nor do all die at the fame time. Some

G 3 move

a March 1 1. The thermometer at 430 above o.

86

SEMINAL VERMICULI.

more more than a quarter of an. hour after the
reft. The greater part died in three quarters
of an hour, and fometimes they did not live
above half an hour. When the ipotion ceafes,
they remain entire, with the appendages ex-
tended in a ftraight line, or a little curved.
The femen of the horfe, is very glutinous and
filamentous a. We fee corpufcula moving
about, attached by the body, and in particu-
lar by the filament, to various irregular fub-
flances mixed with the fluid ; and being urn
able to difengage themfelves, the fubftances
are fenfibly agitated by their motion. More
than once corpufcula are feen attached to-
gether, which might induce us to think them
larger than the reft ; but, with attention, the
two feparate appendages are foon perceived,
each ofcillating by itfelf ; and if the obferva-
tion is continued, it is not uncommon to fee
the bodies divide, and thus form two diftinft
corpufcula. I am well affured it is not an op-
tical illufion, with regard to the corpufcula of
a different fize, but a pofitive fa ft. I may fay
there were forne a third larger than the reft.
I made this obfervation before, upon the 1 1
of March.

I made many attempts to follow the diminu-
tion of their motion. It is in proportion to
the time the feminal fluid has been expofed to

the

March 22. The thermometer 5° above o.

a

SEMINAL VERMICULl.

§7

the air. Scarcely has it proceeded from the
animal when the corpufcula are feen in great
agitation ; darting forward with vail rapidity,
and ofcillating to both hides. This alacrity in-
fenfibly diminifhes ; fo that if they at firft de-
fcribe a certain given fpace in a fecond, in a
quarter of an hour they do not traverfe a third
of it in the fame time. The arcs of olcillation
fucceffively become fmaller ; and at laft the
motion of the corpufcula is reduced to a lan-
guid vibration of the body and appendage,
without any change of pofition. The tremor
foon difappears, and the appendage remains
extended in a ftraight line, after the manner of
thofe beings.

Many aquatic animals of the apodal clafs
tranfport themfelves by the contortions of their
members, which vibrate and ofciilate from fide
to fide ; and indeed one may pofitively affirm,
that the anterior part of the body is pufhed
forward, and moves progreffivelv bv the con-
tortions and ofcillations of the policrior part.
I paid the molt ftrhft attention to fee whether
the anterior part of the corpufcle was pufhed
forward by the ofcillations of the appendage.
When the motion is very rapid, it is impoffible
to obferve it diftin&ly, from the quicknefs of
the mutual vibrations of the body and appen-
dage ; but when it relaxes, we perceive with
facility the mode by which they advance. Afrd

G 4 it

88

SEMINAL VERMICULI.

it is the fame with that of the aquatic animals
/ I have juft mentioned. When the ofcillation
of the appendage ceafes, the progreflive mo-
tion of the body ceafes ; but the body begins
to move when the ofcillations of the appen-
dage recommence. I made this important ob-
fervation, not only upon the corpufcula in
the feminal fluid of- the horfe, but upon thofe
in the femen of all the animals that I fliali af-
terwards name. The motion in this obferva-
tion did not continue above an hour and a
half.

The corpufcula in the two portions of the
feminal fluid of the horfe, mentioned before,
were very numerous ; they were rare in the
laft a. Thefe were perfectly fimilar to the o-
thers both in figure and properties. Their
motion continued two hours.

I examined the femen of other fix horfes.
The corpufcula were fimilar to the preceding,
without difference in figure or number ; I
therefore think it needlefs to flop and defcribe
them. When the feminal fluid is mixed with
water, or even with faliva, all the corpufcula
inftantaneoufly become motionlefs.

The feminal fluid of the bull, contains mov-
ing corpufcula, in numbers furpafling thofe in
the feminal fluid of man b. The appendage is

longer

a May 2. The thermometer 64° above o.
b March 30. The thermometer 570 above o.

SEMINAL VERMICULI.

89

longer than that of the human feminal corpufcu-
la, and the body alfo feems a little larger 5 Fig. 4.
The whole length, to the extremity of the ap-
pendage,, is diftinCtly feen, though deeply im-
merfed in the feminal matter, which is perfect-
ly fluid, and of a whitifh colour. The pro-
greffive motion is performed while the appen-
dage ofcillates. This motion is different from
that of the human corpufcula ; it is much more
rapid, and fufpended for fliort intervals ; which
is not to be feen in the corpufcula of human
femen. The fmall quantity of the femen of
the bull I had upon this occafion, prevented me
from extending my refearches farther.

I was more able to fatisfy my curiofity upon
another occafion, when I had a greater quantity*.
Befide the phacnomena already defcribed, I alfo
remarked, 1. That the corpufcula not only
fwam horizontally, but rofe and funk in the
femen, as fillies do in water : 2. When the fe-

men dried, the motion of the corpufcula was
irrecoverably gone : 3. In times of equal heat,

the motion was quicker than of thofe of man,
or the horfe : 4. The mixture of every kind

of water, and even of faliva, with this femen,
was fatal to the corpufcula.

The fame phenomena were feen in the fe-
minal fluid of other three bulls. 1 had the fe-

* May 30. The thermometer 6S° above o.

men

90

SEMINAL VERMICULI.

men from thofe three at the moment of copu-
lation.

Having opened the tefticles of a dog, alive
and in perfect health, the epididymis was full
of femen a. It was a little vifcous, very thick,
and of a cinder colour. The thicknefs pre-
vented my feeing the corpufcula accurately. I
only perceived a confufed agitation of the fub-
ilance, which ceafed upon mixing the femen
with water : the corpufcula, become motion-
lefs, were diftin&ly feen. I then fufpetted,
that they were the caufe of the agitation,
which the mixture with water had deftroyed.
My fufpicions were confirmed upon mixing fa-
liva with the femen ; for the tumultuous mo-
rion continued. I faw it was produced by the
corpufcula, the number of which was prodi-
gious. The reader will not therefore be fur-
prifed, if I fay nothing of their figure, fize,
motions, &c. fince I w'ould have to repeat all
I have faid of the corpufcula in the human fe-
men ; for the corpufcula in the femen of the
dog perfectly refemble thofe of the human fe-
men. They became motionlefs in three quar-
ters of an hour.

The femen of a dog, I procured during the
moment of copulation, was a little vifcous, and
like muddy water b. The moving corpufcula

were

a Feb. 14. The thermometer 48° above o.
b April 27. The thermometer 61 above o.

SEMINAL VERMICULI. 9 I

were not fo much immerfed, as in that taken
from the epididymis ; and it was unneceflary
to mix it with any other fluid, to fee the cor-
pufcula. Every part was fufficientiy vifible,
and their motion very rapid ; but this rapidity
infenflbly diminilhed ; and, two hours after the
fluid came from the animal’s body, all motion
was gone ; the corpufcula remaining with the
appendages extended in a flraight line.

I repeated thefe experiments upon the femen
of other five dogs, and found the refults per-
fectly alike.

Nine hours after a ram was killed, I open-
ed the tefticles, and exprefled the feminal fluid
into the glafs of a -watch b. All the corpufcu-
la were inotionlefs ; they wrere larger, and thus
were more eafily feen than thofe of the dog, or
of man.

Having taken the feminal fluid from the tef-
ticles of a living ram, I found all the corpuf-
cula in motion c; the oval part, or body of
each corpufcle, fometimes immerfed itfelf in
the fluid, and fometimes efcaped the eye, then
re-appearing on the furlace. Their properties
refembled thofe of other corpufcula, if we add
a gentle vibration and a greater activity.
When the corpufcle contra&ed itfelf, the ap-
pendage was lei's curved from right to left ;

but

b May io. Tiie thermometer 66° above c.
c June. The thermometer 66° above o.

92

SEMINAL VERMICULI.

but the total duration of motion was much
fhorter than in the others. Although the heat
of the atmofphere raifed the thermometer to
66°, they all ceafed to move in half an hour.

I examined the epididymis of another ram
ftill alive. The quantity of feminal fluid was
fo great, as to fill two thirds of a watch glafs.
Viewed with the eye, the liquid feemed in con-
tinual motion, although the glafs was fituated
upon an immoveable plane. I examined a drop
with a magnifier of fmall power ; the whole
appeared in motion, and the microfcope proved
this motion to be produced by the agitation of
the corpufcula alone. Their motion ceafed in
an hour.

After examining the feminal fluid of all
thofe warm-blooded animals, I thought of
examining the femen of fome whofe blood is
cold. I begun with filhes ; and, for this
purpofe, delayed until they fpawned. I took
the milt of a living carp, and exprefled the
fluid into a veil'd. The fluid was tenacious,
thickifh, and of a dull white. Many mov-
ing corpufcula were feen ; but I could not ob-
tain diftinft vifion, until the denfity of the fe-
men was diminifhed by water. Then I had
new obje&s : the corpufcula were no longer
compofed of two parts, a body and an appen-
dage, like the corpufcula of other fluids ; but
were a united whole, refembling minute fpheres,
and apparently folid ; PI. 2. fig. 5. Thofe

fpherules,

SEMINAL VERMICULI.

93

fpherules, of a darkilh colour to the naked eye,
fwam through the liquid in every direction j
advanced, retreated, mutually avoided each o-
ther, iminerfed themfelves deep in the fluid,
and ceafed to move in a moment. In a word,
they had many of the motions and properties
of animalcula. The number was infinite, and
they continued their courfe a quarter of an
hour : then they flopped, and moved no more.
I repeated the experiment five times, expref-
fing anew the fluid of the milt, and the confe-
quences were the fame. If the liquid mixed
with the femen was frelh, fuch as water, faliva,
and the like, I was fure of putting the fpheri-
cal corpufcula in motion, or rather of increaf-
ing their motion. But if the mixing liquid
was ardent or corrofive, inftead of being in-
creafed it was deftroyed.

At that time, I had two water newts. I cut
the tefticles of a male into feveral pieces, and
exprefied the liquid, which was thick and glu-
tinous. I expofed it to the microfcope, and it
changed to a mafs of long flender corpufcula.
Some were extended in a ftraight line, others
curved ; fome folitary, others entangled like a
Ikein of thread. I examined thofe ajone, as
the molt eafily diflinguiflied. They are not
throughout of equal thicknefs. Each corpuf-
cle is compofed of a body, and a very long
appendage ; Fig. 6. They moved with diffi-
culty.

94

SEMINAL VERMICULI.

culty, the greater pari of the body being im-
merfed in this vifcous fubftance. I refolved*
likevvife, to dilute the mafs with common wa-
ter ; by which means, I faw the corpufcula tra-
verfe the whole liquid. As the fluid was at
perfect reft, and as I faw no external caufe to
aft upon the corpufcula, I was inclined to
think this motion fpontaneous, and peculiar
to them. I then adopted an idea, that I had
difcovered the efficient caufe of the motion ;
for, looking ftedfaftly, I faw tw'o rows of mi-
nute points cover the whole appendage of each
corpufcle, moving like the moft minute oars j
Fig. 7. During this motion, the fituation of
the corpufcula changed ; but, when they ceaf-
ed, the corpufcle alio ceafed to move.

When the mixture of femen and water dried
up, the motion of the corpufcula was irreco-
verably loft, although again wet with the li-
quid : but thofe in the mixture which did not
dry, ceafed to move in an hour.

I repeated fimilar experiments upon the
fluid taken from the tefticles of other newts,
and I had the fame refults : but, upon dilut-
ing the fluid, I often faw the corpufcula colleft
in numbers, place themfelves parallel to each
other, and then bend into a circle. When all
collefted, they bent themfelves fo much, that
the point of each appendage almoft touched
the oppofite extremity of the body. In this

pofition,

SEMINAL VE RMICULI.

95

pofition, they begun to revolve around a com-
mon centre. The figure was fomewhat like a
funnel. They preferved this vortical motion
for fome time.

I found the corpufcula not only in the tef-
ticles of newts, but alfo in the vafa deferentia.
The veflels refemble two very white pipes :
they are fituated about the middle of the ver-
tebrae of the kidneys, one upon each fide.
One end is fixed near the head of the animal ;
the aperture of the other is in the part through
which the excrement pafles. The veflels are
almoft always full of feminal fluid, but in par-
ticular while the males fecundate the eggs of
the females. The femen is white like milk :
the number of corpufcula it contains is fo
great, that the fluid part is fmall, compared
with the mafs they form. The corpufcula are
perfe&ly fimilar to thofe in the feminal fluid of
the tefticles : at the fame time with this differ-
ence, that they need neither water nor any o-
ther liquid to encreafe their motion. In the
femen, they naturally move with the quicknefs
of the corpufcula in the fluid from the tefticles,
diluted with water.

1 he corpufcula of the vafa deferentia retain
motion longer than thofe of the tefticles ; and
the duration of their motion equals that of the
human corpufcula, thofe of the horfe, &c. I

have

9 6

SEMINAL VERMICULI.

have always found this kind of corpufcula in
male newts at every feafon of the year.

By exprefling the feminal fluid from the
tefticles of frogs, it may be feen, that it is full of
corpufcula. They are (horter than thofe of the
newt. They poflefs loco-motion as they ad-
vance. They vibrate, making gentle contor-
tions of the body ; are of a long elliptical figure,
Fig. 3. ; and very foon ceafe to move.

CHAP. 11.

After this courfe of obfervations upon the
feminal fluid of man and different animalsy I
thought of reading and examining, what Lew-
enhoek and De Buffon had faid upon the fub-
jeft, as they had made it their particular ftudy.
Several years had elapfed fince I read their dis-
coveries upon Seminal Vermiculi, fo that only
a general idea of their opinion remained. I
even wiftied to profcribe that remembrance, and,
in thefe refearches, to have my mind as a pure
tablet, the more fit to receive the real impref-
fions of what my eyes might behold, without
any danger of alteration, by adding any part of
the obfervations of others.

I fliall begin with Lewenhoek : and, that the

reader may have before him the real fentiments

of

/

SEMINAL VERMICULI.

97

of this naturalid, and that he may compare his
obfervations with mine, I think it necefifary to
tranfcribe fome of the chief pafiages, where he
fpeaks of Spermatic Vermiculi. Bufifon has, be-
fore me, employed part of the pafiages, to com-
pare his own obfervations with thofe of this
illudrious obferver ; and here I have the plea-
fure of following his example. This excellent
Dutch philofopher wrote, 1 677, to Lord Broun-
ker, Prefident of the London Royal Society, to
communicate his microfcopical dilcoveries upon
the Human Semen.

“ Poftquam excellentifiimus dominus pro-
“ fefifor Cranen me vifitatione fua fsepius ho-
“ norabat, litteris rogavit dominus Ham cog-
“ nato l'uo, quafdam obfervationes mearurn vi-
“ dendas darem. Iiic dominus Ham me fe-
64 cundo invife'ns fecum in Iagenula vitrea fe-
“ men viri gonorrhoea laboraniis fponte didil-
“ latum attulit, dieens fe pod pauciffimas tein-
“ poris minutias(cum materia ilia jam in tantum
(i elfet refoluta, ut in fidula vitrea immitti poffet)
“ animalcula viva in eo obfervaffe, quae cauda-
“ ta et ultra 24 horas non viventia judicabat.
c< Idem referebat fe animalcula obfervaffe mor-
“ tua pod fumptam ab aagroto terebinthinam.
“ Materiam praedicatam ddula vitrea immif-
tc fam, praefente domino Ham obfervavi quaf-
44 dam in ea creaturas viventes : et pod decur-

Ii “ fum

98

SEMINAL VERMICULI.

<c fum duarum aut trium horarum eandem fo-
u lus materiam obfervans, mortuas vidi.

“ Eandem materiam (femen virile) non se-
<c groti alicujus non diuturna confervatione cor-
<c ruptam, vel pofl aliquot momenta fiuidiorem
tc fadtam, fed fani viri flatim pofl eje&ionem, ne
“ interlabentibus quidem fex arterice pulfibus
<£ faepiufcule obfervavi, tantamque multitudin-
“ em in ea viventium animalculorum vidi, ut
<£ interdum plura quam rnille in magnitudine
6i arenas fefe moverent : non in toto femine, fed
tc in materia fiuida craffiori adhaerente ingentem
<c illam animalculorum multitudinera obferva-
“ vi, in craffiori vero feminis materia quafi fine
<c motu jacebant, quod inde provenire mihi i-
ct niaginabar, quod materia ilia craffia ex tain
“ variis cohtereat partibus, ut animalcula in ea
<c fefe movere nequirent : minora globulis fan-
te guini ruborem adferentibus haec animalcula
“ erant, ut judicem millena millia arenam gran-
(C diorem magnitudine non tequatura. Cor-
(i pora eorum rotunda, anteriora obtufa, pofte-
£C riora ferine in aculeum definentia habebant :
“ cauda tenui, longitudine corporis quinquies,
<c fexiefve excedente et pellucida craffitiem ve-
£C ro ad vigefimam quinquam partem corporis
ec habente prsedita erant : adeo ut ea quoad
cc figuram cum Cydaminis minoribus longani
44 caudam habentibus optime comparare que-
4C am : motu caudte ferpentino, aut ut anguil-

Ice

SEMINAL VERMICULI.

■99

*£ I32 in aqua natantis progrediebantur : mate-
“ ria vero aliquantulum crafliori caudam o6Hes
M deciefque quidem evibrabant antequam lati-
“ tudinem capilli procederent. Interdum mi-
“ hi irnaginabar me internofcere pofie adhuc
ec varias in corpore horum animalcu'orum par-
Ci tes quia vero continuo eas videre nequibam,
“ de iis tacebo a.”

Thofe obfervations were accompanied by o-
thers, written byLewenhoek to the Secretary of
the Royal Society, 1678. He compofed them,
becaufe fome one had fuggefted to him to ex-
amine the feminal fluid of animals.

“ Si quando canes coeunt” (Lewenhoek an-
fwers the Secretary) “ marem a faemina ftatira
“ feponas, materia quaedam tenuis et aequofa
“ lyinpha fcilicet fpermatica ex pene folet pau-
u latim extillare : hanc materiam numerofifli-
“ mis animalculis repletam aliquoties vidi, e-
“ orum magnitudine quae in femine virili con-
“ fpiciuntur, quibus partictilae. global ares ali-
<c quot quinquagies majores permifcebantur.

“ -A cuniculorum lymphns fpermaticae gut-
<c tulam unani et alteram e faemella extillantena
examini fubjeci, ubi animalia prcedictorum fi-
“ milia fed longe pauciora comparuere.”

In the fame year 167-8, Lewenhoek alfo com-
municated to the Royal Society, the animalcu-
la he had found in the femen of the Dog.

H 2 “ Se minis

* Pbilolopliical Traufadtions, N°- 141.

IOO

SEMINAL VERM I CULI.

tc Seminis canini tantillum mifcrofcopio ap-
“ plicatum iterum contemplatus fum in eoque
<c antea defcripta animalia numerofifiima con-
“ lpexi. Aqua pluvialis pari quantitate adje-
“ £ta iifdern confeftim mortem accerfit. Ejuf-
<{ dem feminis canini portiuncula in vitreo tu-
“ bulo, uncise partem duodecimalem craffo
<c fervata, fex et triginta horarum fpatio con-
“ tenta animalia vita deftituta pleraque, reli-
u qua moribunda videbantur.”

Lewenhoek confirmed his difcoveries during
the following years, and made additions to
them. In a letter to Mr Wren, he thus ex-
prelfes hitnfelf refpefting the fpermatic vermi-
culi of Frogs.

<c Hie animalculorum numerus erat tantus
“ ut credere fubiret ad quodvis femellte ovu-
<c lum a mafculo emitti forte talium 10,000 ta-
“ lium animalculorum, qus in femine ejus
ct continentur.”

In the year 1699, Lewenhoek wrote to the
Royal Society of London upon his theory of
Seminal Vermiculi. He believed them to be
male and female.

“ Si porro his addamus, quod me antehac
<c in obfervationibus meis animadvertere cen-
6C fui inter animalcula ex femine virili quaedam
“ apparuiife, qux aliquantulum ex fe mutuo
“ differre videbantur, unde concludere non ve-
tc rebar, alterum genus mares alterum vero

“ frcmellas

SEMINAL VERMICULI.

IOI

« femellas repraefentare, atque fi cogitemus i-
dem in omnibus leminibus mafculinis locum
<c habere, nullus video

There is another paflage coinciding with

this.

« Sed jam ubi in feminibus mafculinis ani-
<c malium avium, pifcium, imo infectorum, re-
“ peri animalcula, multo certius effe ftatuo,
<c quam antea, hominem non ex ovo, fed ex
“ animalculo in femine virili oriri : ac prae-
“ fertim cum reminifcor, me in femine mafcu-
“ lino hominis et etiam canis vidilfe duorum
“ generum animalcula. Hoc videns mihi ima-
“ ginabar, alterum genus elfe mafculinum al-
<c terum fcemininum.”

In 1701, Lewenhoek wrote to the Royal
Society in thefe words :

“ Die Julii vigefima feptima, circa nonam
“ horam vefpertinam, accepi telticulos juvenis
<e Arietis. Cum vero lanius hifce tefticulis pri-
“ mam detraxilfet cutem feu membranam, ego
“ viciffim quoque eos altera privavi membrana,
<c ut hac ratione vafa feminifera nuda vifui ex-
“ pofita jacerent. Primo ergo aperui vafa fe-
“ minalia in tefticuli parte exteriora fita, iif-
“ que exemi femen mafculinum (quod nudo
“ obfervatum oculo album repraefentabat colo-
<c rem) illudque microfcopio appofui, atque hoc
<c pacto oculo admovi, quando mihi animalcula
“ feminalia tarn ftupendo apparuere numero,

H 3 “ ut

1 02

SEMINAL VERMICULI.

<c ut vix fidem apud quemquam, nifi teftem o-
tc culatum, inventurus fit. Hxc animalcula
<c nubium in morem, integris agminibus, inter
fC fe vagabantur, natabantque, quorum mul-
“ tas eodem tendere natatu videbantur, ut mox
“ aliquot millena fefe ab uno agmine feparantia
“ alteri fefe agmini adjungebant, illudque fequi
c< videbantur.”

Lewenhoek adds :

iC Haec vero animalcula nuper a me obfer-
u vata caudas habent juxta corpus crafliores,
<{ atque fenfim fiunt tenuiores, adeo ut eorum
“ extremitates ubi materia, cui animalcula in-
“ funt, atque innatant, paulo denfior eft, vifum
<c plane effugiant : atque fic horum animalcu-
“ lorum caudse fabrica plane convenit cum o-
“ mnium pifcium caudis'.”

What refpe&s the properties of Spermatic
Vermiculi, is prefented in thefe refults by Lew-
enhoek.

“ Quotiefcumque animalcula in femine maf-
“ culino animalium fuerim contemplatus, at-
£c tamen ilia fe unquam ad quietem contulifle,
<c me nunquam vidiffe mihi dicendum eft, ft
“ modo fat fluidse fuperelfet materiae, in qua
“ fefe commode movere poterant : at eadem
tc in continuo manent motu, et tempora quo
“ ipfis moriendum, appropinquante motus ma-
<c gis, magifque deficit ufque dum nullus pror-
*c fus motus in illis agnofcendiis fit.”

From

3EMINAL VERMICULI. I03

From thefe quotations it may eafily be feen,
that Lewenhoek and myfelf have remarked the
fame faOs in the Human femen. This obferver,
under the appellation of Animals, or Spermatic
Vermiculi ; and I, under that of Moving Cor-
pufcula. We both agree, i. upon the figure
affigned to the corpufcula in the feminal fluid
of man, the ram, the dog, and the rabbit.
Defcribing the corpufcula, I have faid, they
feemed compofed of two parts, a body and an
appendage. Lewenhoek alio acknowledges the
exiitence of thofe parts; 2. We agree con-
cerning the fize of the body, the length, the
figure, and proportions of the appendage ;
which will further appear from the defigns he
has given of the fpermatic vermiculi of man,
or the corpufcula of which I have fpoken. 3.
We have each difcovered a prodigious number
of beings in the femen : we have remarked the
fize of fome different from that of the reft :
we have allowed them the fame properties : we
have faid, their motion in fwimming was fer-
pentine, like that of eels ; that it was uninter-
rupted ; that towards the end of their lives,
they became languid ; that the vermiculi in the
groffer parts of the fluid met great oppofition
to their progrefs. But I have obferved all this
in the preceding chapter. We have both re-
marked, that rain water deprived the canine
vermiculi of motion. 1 have alfo found, that

II 4 this

104

SEMINAL VERMICULI.

this effect was produced upon thofe of man, e-
ven by other kinds of water, as dunghill, ice,
fnow, and river water. I have conftantly ob-
ferved, that when motion ceafes, the appendage
never encircles the body, but always remains
extended in a ftraight line, or in one very lit-
tle curved. This had been remarked by Lew-
enhoek, as appears from his engravings of
the feminal vermiculi of the dog and the rab-
bit. When he means to reprefent them dead,
he exhibits the appendage extended ; if he
means to reprefent them alive, it is with the
appendage curved.

The moving corpufcula found by me in the
femen of man, the horfe, the bull, the dog,
the rabbit, the ram, newts and frogs, are there-
fore precifely the beings Lewenhoek terms
worms, or fpermatic animals. I fhall likewife
ufe this laft appellation, not only to fpeak in
the- language of this naturalift, but becaufe I
elfeem the faffs I have related fufficient autho-
rity to beftow upon them the name of animals.
The fpontaneous motion, and the contortions
of the body, by means of which they move
from one place to another, are charafleriftics
fufficiently decifive of their animality. Of this,
we (hall in the fequel have more conclufive
evidence.

What I have faid, is enough to drew how
erroneous the opinion of Sir Charles Linnaeus

muff

seminal vermiculi. 105

muft be, when he maintains, that the fperma-
tic vermiculi are only particles of inert matter,
fufpended in the fluid, and put in motion by
the heat. As the celebrity of the Swedifh na-
turalift might induce us to fuppofe he does not
advance this without evidence. I fhould men-
tion the reafons which determine him to adopt
his fentiments ; and, that none of their force
may be loft, I {hall give them, fuch as they have
been explained by the author himfelf, in a La-
tin thefts, while he was prefident in December
1759, under the title, De Generatione Ambi-
gena.

“ Vermiculos feminales Lewenhoekii vivos
44 efle vermes, in omni genitura prolifica ma-
44 ris prsefentes, ad noftra tempora firmiter
44 fatis credidit orbis eruditus. N. D. Praefes
44 Lugduni Batavorum 1737, commoratus cu-
44 rioforum quorundam amicorum, et commi-
44 litonum utebatur confortio quales erant, J.
44 F. Gronovius Floras Virginicas auftor, ho-
44 die Conful Leidenfts : D. Van Svieten hodie
44 liber Baro, et Archiater Imperatoris : Ifaac
44 Lawl'on pise memoriae Scotus medic, exerci-
44 tus Anglia: : D. Lieberkuhn P. M. Beroti-
44 nenfis : D. Kramer auftor libri artis Doci-
44 mafticse : Johan. Bartfch P. M. Regiomonte
44 Baruflus medic. Surinamenfis : etD.Abrah.
44 Ens Pomerano, Petropolitanus. His igitur
44 quodam die congregatis. Oftendebat Do-

mmus

106 SEMINAL VERMICULI.

“ minus Lieberkuhn praellantiflima fua micros
“ fcopia, quem rogabat N. D. Prasfes, ut ho-
££ rum, ope, vermiculos in cane ob'fervandos
££ praeberet quod ftatim impetravit : contern-
“ plabatur illos adcurate atque infettorum na-
££ turae gnarus ftatim vermiculos hofce Lewen-
££ hoekianos, non efl’e corpora organis prtedita
££ et animata, atque adeo neque infefta neque
££ vermes, fed particulas motas, quarum motus
“ a calore dependeret liquoris rotundo ore ex-
t£ clamat. Praefentes omnes attenti hos intue-
£c bantur et oculis fuis alii credere, alii vix qui-
££ dem videbantur. Conclufionem hujus rei in
££ differtatione de fponfaliis plant arum , anno
££ 1740, p. 24. edidit N. D. Prcefes his quidem
“ verbis : Vermiculi ijli Lewenhoekiani minime
££ funt animalcula propria et voluntario motu
££ gaudentia fed corpufcula inertia , qua calida
££ genitura innatant ; non /ecus ac particula
££ ole of a, quod felccla Licberkuhnii microfcopia
££ nobis manifefte ofenderunt. Hoc poftea etiam
££ vidit et confirmavit fummus phyfiologus il-
££ luftris D. V. Hallerus ut adeo aucloritas ver-
<£ mium feminalium jam prorfus fere in defue-
£C tudinem venerit.”

This fingular opinion of Linnaeus was un-
known to me, until it was communicated in a
letter from M. Bonnet, dated 20th April 1771,
who tranfcribed the words ufed by Linnaeus:
He, undoubtedly from politenefs, added the

following

SEMINAL VERMICULI.

107

following paragraph, or perhaps with a defign
to encourage me to profecute my refearches
upon fpermatic vermiculi. <c You perceive
“ there is cited here, the eminent teflimony
“ of a Gronovius, a Van Swieten, a Lieber-
“ kuhn, &c. and even that of Haller. At fome
“ future period I fhall write to him about it.
“ Neverthelefs, all thofe authorities could not
“ have weight with me ; could not, in my view,
“ balance your opinion : becaufe I know you
<e to be a much better judge of fuch things,
“ than the philofophers the author names in
“ his thefis. You have paid much more at-
“ tendon to the animalcula in queftion, and
“ you have long fludied the animalcula analo-
“ gous to them. You have thus obtained a
ec kind of touchftone, which experiment more
<e and more improves, and which can never
“ prove deceitful.”

Before confidering what was advanced by
Linnaeus, I could not diflemble my extreme
furprife, to fee Haller cited as one of thofe
who denied the exiftence of fpermatic animals,
whereas he had always been one of their mod:
ftrenuous fupporters. The notes he has made
upon the Le&ures of Boerhaave, his Elements
of Phyfiology, his Phyfiology at large ; in a
word, all his works bear the mod: manifeft evi-
dence of it. In the fequel of this treatife, I

{hall

Io8 SEMINAL VERMICULi.

fhall have occafion to ufe the authority of fo
great a naturalift.

We fee how eafily the opinion of the cele-
brated botanili of Upfal is eltabliffied. Scarce-
ly has he viewed Lewenhoek’s animalcula,
•when he decidedly pronounces them not to be
animals. I leave it to the judgment of an im-
partial reader, whether a hafty glance of the
vermiculi is fufficient abfolutely to decide their
nature ; and to decide it better than Lewen-
hoek, who had, during a number of years, ex-
amined fo many fpecies with fo pra&ifed and
attentive an eye. We know well the time and
labour naturalifts have bellowed, to be alfured
of the mature of certain organized bodies,
doubted whether to be animals or plants. At
the fame time, thofe bodies were not, like femi-
nal vermiculi, inicrofcopic animals : their fize
admitted of their being completely manipula-
ted, and eafily feen with the eye. Linnteus
ffiould have been better convinced ; he who
has certainly charadlerifed fo many bodies in
the three kingdoms, who has made many re-
iterated attempts, and made them with fo much
patience. If his laborious and ufeful occupa-
tions had left him fufficient leifure to penetrate
the world of invifibles , where, as Muller ob-
ferves, he might well be a ftranger without a
crime, and had he applied to this fubjeft with
that wifdom and penetration he has difplayed

in

SEMINAL VERMICULI.

I09

in the difcoveries he has made upon the vifible
world, we cannot doubt that he would have
omitted in his thefis the quotations we have
juft made from it. For, with an attentive
view of the fpermatic vermiculi, he would ea-
fily have feen, that they do not fwim upon the
liquid, like oleaginous particles ; but that they
fwim at forne depth. I have had eminent
proofs of this. Penetrating the firft ftratum
of the femen of the dog with the microfcope,
I prefled it downwards, fo as to reach the
lower parts : in each I faw an equal number of
fpermatic vermiculi.

I adopted the fame method, with a confi-
derable quantity in a watch glafs. Wherever
the focus of the magnifier penetrated, I faw
the motion of vermiculi.

Finally, a third experiment has demonftra-
ted their prefence for a confidcrable thicknefs.
I filled a thin-fided chryftal tube with femen ;
the calibre was half a line, the length five in-
ches. I held it perpendicular ; and, in this
pofition, applied the lens to the fides, the great
tranfparency of which ealily permitted me to
fee the included femen, when the tube was in-
terpoled between the fun and the eye. When-
ever I applied the lens, whether to the top, the
middle, or the bottom of the tube, I always
few the vermiculi. I repealed this experiment
with a tube of much greater capacity ; it was

a

I 10

SEMINAL VERMICULI.

a third of an inch in diameter within, and at
lead: four inches long ; but the opacity of the
femen, occafioned by its great abundance, pre-
vented me from feeing the vermiculi it con-
tained. I examined the drops oozing from the
lower part of the tube, which was infecurely
flopped, whereby fome drops efcaped. All the
drops were equally full of vermiculi, as the li-
quid in the higher part of the tube. When
the experiments were repeated in this manner
upon the femen of the dog, and that of other
animals, the confequences were the fame.

In the fecond place, had the Swedifh natu-
ralift beftowed upon fpermatic vermiculi that
attention they deferve, he mufl have perceived,
they are not inert corpufcula ; but that they
have a fpontaneous motion, well charafterifed ;
that this motion is regulated by the manner in
which they advance ; that they fwim in the
fpermatic lymph, contorting and vibrating their
members, like many other aquatic animals. He
would not have afcribed the motion of the ver-
miculi to the heat of the femen, fince, when
this is gone, and there remains the heat of the
atmofphere only, which happens a little after
the femen comes from the animal, the vermi-
culi do not ceafe to move ; but their motion
continues for a given time, which is fometimes
feveral days, when they are included in fmall
tubes.

In

SEMINAL VERMICULI.

1 1 1

In fhort, the fpermatic vermiculi of frogs,
fifties, and newts, completely deftroy the opi-
nion of Linnmus, their feminal fluid being def-
titute of every fenfible principle of internal
heat. Since the blood of moft of thofe ani-
mals is cold, heat cannot here occalion the mo-
tion of the vermiculi ; but they fhould be ab-
folutely motionlefs.

All this evinces how much two modern na-
turalifls, Valmont de Bomare and Ernefl Afch,
are deceived in thinking, that fpermatic vermi-
culi do not exid, or that they are only the mod
active parts of the femen ; and this they main-
tain from their never being able to difcover
them, notwithftanding repeated obfervations.
A fimilar objedtion had been darted, after the
difcoveries of Lewenhoek, who was content with
remitting its authors to their ftudies, as unfit for
obfervers. “ Dominos illos nondum tantum pro-
“ fecifle, ut eos redle obfervando contemplari
“ valeant.” I mud be pardoned if I make the
fame anfwer to thofe new opponents ; for we
mud fay, their obfervations have been very un-
fortunate, or their vifion very bad, or their mi-
crofcopes good for nothing, or their unexadt-
nefs and inexperience very great in the art of
obfervation. It is true, M. De Bomare aflerts
his eyes are very good, and his microfcopes ex-
cellent ; and makes no hefitation to fay, “ We
<{ have repeated all the experiments of natural-

“ ids

112

SEMINAL VERMICULI.

<s ifts upon fernen; and although our eyes were
<c very good, and our microfcopes excellent,
<£ we have been able to difcover nothing.” I
was almofl induced to exclaim, May heaven
preferve fuch good eyes, and fuch excellent
microfcopes, for with them we fhall run no rifk
of regarding as illufions the moll beautiful dif-
coveries philofophers have hitherto made ; and
we need not fear that we and our polterity will
be forced to relinquilh the profpeCt of making
new ones ! With this acutenefs of vifion, and
this perfection of microfcopes, we Ihould be ob-
liged to revifit the ignorance of our anceflors
in the world of invifibles. But I would rather
believe M. Bomare’s fight is acute, and that
his microfcopes are perfeCt. What reafon can
we alfign for the unfuccefs of his attempts to
fee any thing in femen with all that affiftance ?
The conclufion is fimple. We mull not fay he ,
is unaccuftomed to the art of obfervation ; I
do not with to leffen the efteem due to his me-
rit : he has acquired the name of a laborious
and indefatigable compiler. His Mineralogy
and his Dictionary, which are an alfemblage of
fragments copied here and there, will do him
this jullice. But no one knows, that he has
been, or that he may be, a microfcopical ob-
lerver : and to make microfcopical obfervations
with accuracy, many natural and acquired qua-
lities are requifite, and many more are necef-

fary

r

SEMINAL VERMICULI. II3

fary to guard againft being deceived in the fub-
tile refearches after thofe beings infinitely mi-
nute.

I have frequently, viva voce , confirmed the
difference of fentiment, that books afford con-
cerning the nature of fpermatic vermiculi,
by means of perfons whom I caufed obferve
the femen of man, and of other animals. Some,
although all had diftinguifhed merit, were cer-
tain they faw nothing, although they looked
long at a time through the microfcope, and
even returned frequently to obfervation. The
number of perfons who could fee nothing, was
not great. Others, after a very long and pain-
ful examination, feemed to fee a very indiftin£t
and obfcure fermentation in the fluid. A few
could fee the body, or corpufculum of the ver-
miculi, but were unable to diftinguifh the ap-
pendage. And a very few could perceive their
form and all their motions. Thefe lafl, indeed,
were well accuftomed to ftudy microfcopical
objects, and might with real'on be termed, pro-
feflional obfervers. Let thofe who deny the
exiftence of fpermatic vermiculi, attempt to en-
ter this lafl clafs of perfons, and praclife upon
minute objefts, and I allure them, if they will
repeat their experiments upon the feminal fluid,
they will fee fpermatic vermiculi, as I, and Lew-
enhoek, with many other naturalifls, have feen
them long before me. Then, if they choofe to

I communicate

U4

SEMINAL VERMICULI*

communicate their obfervations, they will have
the advantage of knowing, if their publications
already made excite the compaflion of the learn-
ed, their future works will merit an eulogium.

CHAP. III.

We defcend from the obfervations of Lewen-
hoek, to thofe of M. De BufFon, which, al-
though very numerous, comprehenfive, and
fpecific, we fhall but abridge. M. De BufFon,
with the compound microfcope, obferved the
fluid from the feminal veflels of a dead human
body yet warm. It was full of filaments, mo-
ving about, and branching into many parts.
The filaments fwelling, burfi, and many ovu-
lar corpufcula efcaped, which ftiil remained
attached to the filament, as by a thread ;
then they ofcillated like a pendulum, and du-
ring thofe ofcillations the thread extended.
The corpufcula, at length detached from the
filaments, traverfed the moll fluid part of the
femen, along with their filament, the extreme
length of which impeded their motion, and
they feemed to him to endeavour to free
thenifelves of it. Having diluted the fe-
men with rain water, the microfeopic view
was better defined. It clearly appeared, that

each

SEMINAL VERMICULI.

IXS

each ovular corpufcle had a double motion of
ofcillation, and of progreffion. In two or
three hours, the feminal matter acquired great-
er fluidity ; the filaments difappeared ; the
number of corpufcula encreafed ; the threads
contracted ; the ofcillations relaxed ; and the
progreflive motion encreafed. In five or fix
hours, the ovular corpufcula having loft the
threads, refembled animals more than ever ;
not only becaufe their quicknefs in fwimming
was greater, but becaufe they directed their
courfe to every quarter. In twelve hours, the
a&ivity of the corpufcula was great ; and fome
revolved upon their axis ; others changed the
ovular to a globular figure, under the obferver’s
eye. Some divided afunder ; fo that one form-
ed two. At the end of one day, the number
diminifhed ; and, upon the third, none were
to be feen.

In other femen, which feemed entirely fila-
mentous, the ovular corpufcula did not pro-
ceed from the filaments ; but thefe, dividing m
two, were metamorphofed into corpufcula.
They were embarrafled by a thread. The
longer it was, the more it impeded their mo-
tion ; but it gradually contracted, and was at
laft completely deftroyed. The figure of thofe
ovular corpufcula refembled that of thofe of
infufions. They fwam with a progreflive mo-

I 2 tion,

SEMINAL VERMICULI.

1 16

tion, though, at firft, the thread occafioned a
Ample ofcillation.

M. De Buffon having examined a new drop
of femen, ten or twelve hours after it was taken
from the animal, he faw the whole corpufcula
proceed in a crowd from the fame fide, where
there were filaments like a thread, to which
many were fixed. They gradually difengaged
themfelves from it. The body of the thread-
then diminilhed j fo that it appeared lefs by an
half.

The author thought, in his firft obfervation
upon the human femen, that the corpufcula
became gradually finaller. At the fame time,
he was not certain of it j but another obferva-
tion convinced him.

He then obferved the feminal fluid of a dog.
He found it clear, and without filaments. The
ovular corpufcula almoft completely refembled
thofe of the human femen ; only, he found
them more adlive, and lefs numerous. Upon
the fourth day, very few of the corpufcula had
threads.

In another portion of the femimal fluid of
the fame dog ; befide this, he faw corpufcula
proceeding from a mucilaginous fubftance in
the femen, which, to him, feemed internally
animated by an inflating motion, which indu-
ced him to think the mucus fwelled in fome
parts to form little tumours. Thofe corpufcles

were

SEMINAL VERMICULI.

117

were all without a thread. The figure of fome
changed. They extended, contracted, and in-
flated themfelves ; and, amidfl: thofe wonder-
ful operations, divided afunder, and gave ex-
iftence to two corpufcula, whofe figure and
properties were fimilar to thofe of the generat-
ing corpufcula.

The French naturalift extended his experi-
ments to rabbits. From the feminal veflels,
he took the fluid, and, mixing it with fre/h wa-
ter, obferved the following phenomena : In
three hours, the globular corpufcula became
fmaller ; and thus conftantly diminiihed until
the eighth day, when they were fcarcely vifi-
ble. But, in proportion as their fize diminifh-
ed, their number and a&ivity encreafed : in
the fame manner their figure varied, they were
ovular, fpherical, and elliptical.

He repeated the experiment upon the femen
of another rabbit, ejected at the moment of co-
pulation. He found ovular corpufcula ; fome
with the filament, others without it. The
former greatly refembled thofe of the dog, and
of man ; excepting that they were lefs, more
agile, and the thread much fliorter. He could
not be certain that they were real threads, but
only little fpirals, formed in the liquid by the
courfe of the corpufcula.

The femen of the ram prefented corpufcula
moving in every dire&ion. They were ellipti-
cal, without filaments, and equal in fizc.

I 3

M.

1 I 8 SEMINAL VERMICULI.

M. De Buffon alfo examined the feminal
fluid of fome fiflies ; the carp, the pike, and
the barbel ; procuring it while the animal was
alive. There, he found a number of corpuf-
cula in motion, which were of a dark colour,
almoft black, and very fmall.

Such is an abbreviation of the obfervations
made upon the femen of animals, by the il-
luftrious author of Natural Hiftory. And he
draws a general conclufion, that the corpuf-
cula, examined and defcribed by Lewenhoek
near a century ago, could not, by the Dutch
obferver, or by any one, be termed Spermatic
Vermiculi, becaufe they poflefs no characte-
riftic of animality. The labour they experi-
ence in drawing along their tails ; i-n divefling
themfelves of them ; in changing their figure
fo often, to form anew under the obferver’s
eye ; and their divifion into parts, and dimi-
nution of fize : feem, to him, peculiarities in-
compatible with animality. On the other
hand, not being able to fay that they were bo-
dies completely inert, becaufe he had really
feen in them figns of animation ; he inclines
to conllitute them into a particular clafs, giving
them the appellation of organic molecules , which
are particles difieminated through all matter, o-
original, incorruptible, animated, and always
a&ive. Nor does he hefitate to confide the
formation of the animated univerfe to thofe

I U 4 i . J 9 » t 1 ' *■

molecules.

SEMINAL VERMICULI.

119

molecules. I enter not, here, into a difcuflion
upon organic molecules ; but, occupied folely
with the fatfts M. De Buffon relates, I iincere-
ly acknowledge, that the effential differences I
found between his account, and what I have
myfelf feen, have made a deep impreflion up-
on my mind. It is not, that I wifli to flatter
myfelf, my obfervations are of more value than
his, from exa&nefs of execution, or afliduity
of continuance. If I may be allowed, I fhall
even fay, that mine Ihould be preferred, as
they are much more numerous. At the fame
time, M. De Buffon’s perfeft conviction of
the truth of his obfervations ; the great confi-
dence he has, that his readers, who repeat
them, will find them fcrupuloufly exaCt ; the
liberal and natural manner in which he op-
pofes them to thofe of Lewenhoek ; and the
errors with w'hich he reproaches him : all
makes me judge it poflible, that the Dutch na-
turalift and myfelf might be deceived. All
thofe things w'ere aided by a confideration,
which, though foreign to the fubjeCt, is at the
fame time plaufible ; I mean, the amazing ce-
lebrity and reputation, the French naturalift de-
fervedly enjoys. I long hefitated whether I
ought to profecute my obfervations, and fub-
je£t them to as rigorous an examination as
might be poflible ; or, whether it would be
tnore proper to abandon them, left they might

I 4 not

120

SEMINAL VERMICULI.

not be credited, from the formidable trial they
had to undergo, i would a&ually have done
l'o, had not my illullrious friend M. Bonnet,
who is well (killed in fuch matters, diverted
my intention. He (Irenuoufly advifed me to
ftudy the fpermatic veriniculi of various ani-
mals. I replied, I had already done fo par-
tially ; but I had fufpended my labours, upon
finding my obfervations fo very different from
thofe of M, De Buifon, whofe authority I re-
fpe&ed. He had the goodnefs to anfwer,

<s You judge well, my valued correfpon-
<c dent, that I am not much furprifed to find
tc you in oppofition to M. De Buffon, with
<c regard to fpermatic vermiculi ; nor do I for-
get what he in fame meafure told us, and
<c which I repeat after him, that his theory
ct precedes his obfervations. Now, you know
ct as well as I do, that a favoured theory is a
<c mirror which changes the appearance of ob-
<c jects.

c< Do not fear that the authority of M. De
“ Buffon will in the leaf! invalidate your dif-
<c coveries upon fpermatic vermiculi. You
<c have proved yourfelf an excellent obferver ;
<c you have acquired the right of being believ-
sc ed. You have cherifhed no theory : you are
fatisfied with interrogating nature, and with
“ giving the public a faithful account of her
^ refponfes. You will always be liftened to

(i' bv

• j

SEMINAL VERMICULI.

I 2 I

cc by philofophers ; and they will judge your
“ obfervations fo much the more fure, that
£< you prove you poffefs the art of obfervation,
“ and that you negledt no rule of this art, fo
“ little known. Proceed then, my dear Mal-
“ phigi ; extend your refearches upon fperma-
<£ tic vermiculi as far as you can ; and infti-
“ tute all the cornparifons in your power be-
“ tween them and animalcula.”

I was encouraged, by thofe obliging invi-
tations, to draw my obfervations from the ob-
fcurity in which I had left them, and to conti-
nue to encreafe them as much as my humble
talents would admit. Without interruption,
this was my employment during the greater
part of three years. But the different fa&s I
gradually difcovered, of which I fhall give an
abbreviated narration, little agree with the re-
lations of M. De BufTon : at the fame time, it
appeared to me, that I had, during this long
refearch, difcovered feveral realons which might
have induced this naturalirt to think as he
does.

One of the principal phenomena which the
French author views as the chief balls of his
hypothefis, is, what is feen in the aftual for-
mation of the fpermatic vermiculi, in the mu-
cilaginous parts of the femen and its filaments,
which, under the obferver’s eye, change into
animated beings, as he imagines he has feen

in

122

SEMINAL VERMICULI.

in the femen of mau and of the dog. Mr
Needham readily embraces this opinion. He
thinks that feminal vermiculi do not exift in
the femen, while in the body of the animal,
but that they are formed fome minutes after it
comes from the body, when it begins to change
and decompofe by the influence of the air a.

In the experiments I have made upon femen,
which are related in the firfl chapter, I have
not mentioned this adtual formation, becaufe I
had not feen the leafl indication of it. When
I made obfervations upon femen, whether I
faw the vermiculi at firfl, or not till the femen
fettled, I never perceived the grofs or filament-
ous parts give exiftence to the vermiculi. It is
true, in the firfl courfe of experiments, I did
not think of examining this part of the fubject
profoundly : my attention was not fixed upon
it, as it had been in my other experiments. I
therefore directed my whole obfervations to
what happened to the folid and filamentous
part of the femen, at the moment of its difio-
lution. But I never could fee the adtual pro-:
duction of the vermiculi. I have even incon?
teftible evidence of the contrary. In the mean
time, I have difcovered the paradox of the;
French naturalift. I wifli to demonflrate this,
accompanied by fome fadts which I muft bq
permitted to detail.

From

* New Microfcopical Obfervations.

SEMINAL VERMICULI.

I23

From human femen, as yet but partially co-
agulated, I feparated two little clots, forming
a line of filaments, which I meant to confider
with attention. The vermiculi included in the
filaments occafioned a motion ; the filaments
diffolved under the eye ; and the two clots, in
a few feconds, became two drops of femen.
It was with fingular furprife I faw the fmall
number of vermiculi in thefe drops, compared
with the numbers to be feen in others much
lmaller, not formed, as they were, by the dif-
folution of the coagulated femen, but by a
portion of the femen found fluid in the feminal
veflels.

I repeated this experiment upon a clot not
fo folid as the two former : there I found ftill
fewer of the vermiculi. I then begun to fuf-
peft, that perhaps the vermiculi did not inha-
bit the grofler parts of the femen, but thofe
that were fluid. This fufpicion was fortified,
upon my feeing all the corpufcula perifh when
the fluid evaporated. But, that this idea might
be verified or deftroyed, I examined many clots
from each fpermatic fluid, which at firlt was
very difficult to accomplifh ; for the folid and
confident parts of the human femen, even
while in the feminal veflels, are commonly im-
merfed in the fluid parts. I was at length able
to overcome thofe trivial obftacles. With the
extremity of a pair of fmall pincers, J drevy

from

124

SEMINAL VERMICULT.

from the feminal veffels a portion of human fe-
men, fimilar to milk a little coagulated : as
it was moift, I drew it along a dry piece of
glafs, that it might depofit its humidity. I then
put it in a watch glafs, attending its diffolu-
tion, in order to examine it with the micro-
fcope. It was not deftitute of vermiculi. I
made a general comparifon of the number,
with the number of vermiculi in the veffels,
which had been put into the glafs of a watch
on purpofe for this comparifon. But there
was no proportion ; the number in the folid
parts was fo much fmaller than in the fluid
parts.

Thefe refults did not fatisfy me. I faw that
the few vermiculi in the folid femen, might be
owing to fome little portion of the fluid re-
maining in the folid piece. At the fame time,
inftead of finding few, I could have wifhed to
find none at all, or at lead a very fmall num-
ber. Having taken another clot of human fe-
men from the veffels, I endeavoured to difen-
gage it as far as poflible from the feminal .fluid
that might remain about and within it. Here
I fhould pbferve, en paJJ'ant , that this opera-
tion of drawing along the folid part to take a-
way the fluid, fhould be performed with great
adroitnefs and celerity, otherwife the folid part
gets time to diffolve during expofition to the
air. And it then happens that drawing it long,

or

SEMINAL VERMICULI*

125

or flowly, along the glafs, inftead of drying, it
always becomes more humid. I fucceeded, at
laft, in freeing a clot of human femen from all
fenfible moiflure. I put it in a watch glafs,
and, when dilfolved, examined it with the mi-
crofcope. Truth obliges me to declare, that
here I found no vermiculi ; nor did I find any
in other clots managed after the fame manner,
although they were numerous in the fluid parts
of the femen in the feminal veflels of the ani-
mal which had afforded me the clots and the
femen. I did not delay a repetition of this
important obfervation. In my journal of ex-
periments, I find this has been done fourteen
times, in thirteen of which the dilfolved clots
exhibited no vermiculi ; and only once I found
a fmall number in the coagulated clot.

The feminal fluid of the rabbit is always
partially coagulated ; fo that whenever taken
from the veflels, it afforded me the means of
repeating my experiments. But I have never
difcovered vermiculi, when I was able to take
the fpermatic lymph completely away. Thefe
united facts convince me, that the habitation
of the vermiculi is in the fluid part of the fe-
men. The fame fafts afcertain the degree of
credibility we fhould bellow upon what M. De
Bufton fays of their formation. It is evident,
that far from being generated by the folid or
filamentous part of the femen, from which

they

126

SEMINAL VERMICULI.

they detach themfelves, they do not branch
out as I have demonftrated : if they are even
found there, they proceed from the fluid part,
which is the place of their natural abode, and
which is at this moment mixed with the
folid. It is doubtlefs this which occafions the
error of M. De Buffon. He faw the molt
grofs and filamentous part agitated and mov-
ing : amidfl: its agitations and contortions he
faw vermiculi proceed from it : he even ob-
ferved the number encreafe, proportionally as
the bulk of the grofs and filamentous part de-
creafed : he likewife remarked, that the num-
ber was greatefl when the filaments had entire-
ly difappeared ; and, allowing himfelf to be de-
ceived by thefe appearances, it was eafy to be-
lieve the decompofition of the filaments was
the produ&ive caufe. But the fact is, the
vermiculi pre-exifted in the filaments ; they
were concealed and enveloped in the parts im-
merfed in the feminal fluid ; and, only when
difengaged, do they become vifible to the ob-
ferver : nearly in the fame manner, as if
one had fleeped a piece of ice in an infufion
full of animalcula, and taking it out it was
carried to the fire ; as it melted, it would ex-
hibit the animalcula that had infmuated them-
felves into the crevices.

M. De Buffon, by a very Ample experiment,
might have fatisfied himfelf, that the vermiculi

exifled

SEMINAL VERMICULI#

127

exifted before the diffolution of the femen. He
fhould firft have examined the fluid part of the
femen, which, upon opening the feminal veflels,
we find mixed with the folid. There he would
have found abundance of vermiculi, although
at that time they could not be produced by the
difiolution of the folid femen ; fince we fee
that this folid part begins to diflolve, only when
it proceeds from the animal, and experiences
the influence of the air.

What I have already faid, and what I
lhall continue to fay, proves the falfity of Mr
Needham’s opinion, who allures us, the vermi-
culi are produced fome minutes after the femen
comes from the animal’s body j that is, when
it begins to be altered and decompofed by the
adtion of the air. Refpedting the femen of
man, it is necdfary to confider whether the
portion is folid or fluid. If the former, when
deprived completely of the fpermatic fluid, no
vermicide is ever feen, although it remains du-
ring fome time expofed to the air, and although
it changes and is decompofed. If the latter,
the vermiculi appear in it before the time re-
quired for this alteration. It has often hap-
pened, that the time I confumed in taking the
fluid matter from the feminal veflels dill warm,
to prefent it to the microfcope, did not exceed
a fecond ; yet I found the fame number of ver-
miculi as afterwards, even when the fluid had

been

128

SEMINAL VERMICULI.

been expofed to the air fufficient time to efledfc
its decompofition.

The obfervations I have made upon the fe-
men of other animals, further convinces me of
the falfity of fuch an opinion. I prepared a
ram, alive, and vigorous ; fo that a friend cut a-
way the epididymes, which are commonly full
of femen ; and while he cut them, one might
take a drop of femen, and immediately prefent
it to the microfcope, where I kept the eye ready
to obferve. It may eafily be feen, that the time
in performing this operation could not be fhort-
er. We faw numbers of vermiculi, and all
were very vivacious. I repeated this experi-
ment upon the femen of the newt, and I faw
the fame. Further, in the fpring, when the
*uafa deferentia are full of femen, it was unne-
ceffary to open the animal, to obtain it for ob-
fervation. Upon preffing the belly gently, it
efcaped by the anus, where the two veflels ter-
minate.

This animal has afforded me a proof (till
more decifive. I let the males fuffer hunger
fo long, that they became very emaciated ; then
the vafci deferentia contained a very finall quan-
tity of femen, and, from the tranfparency of
the tunics of the veflels, which were rendered
thin, it might eafily be obferved with a magni-
fier. Opening the abdomen, and applying the
microfcope to the veflels, without affecting or

deranging

SEMINAL VERMICULI.

129

deranging their iituation, we faw the vermi-
culi fwimming in the fluid ; and they were vi-
fible to thofe who were leaf! fkilled in the art
of obfervation, becaufe, as I have remarked in
the firfl chapter, they were much longer than
others.

I may therefore conclude, that the fpermatic
vermiculi of man, and of animals, exift in the
femen, previous to any alteration or decompo-
fition by the influence of the air ; and that they
are aCtive in this fluid, even while it is includ-
ed in the organs of generation.

CHAP. IV.

4

I continue to examine the other principal
refults, from the obfervations of M. De Buffon.
In this number I place the appearance of thofe
very long and (lender filaments, the vermiculi
drag along in their courfe ; the contraction and
difappearance of the filaments ; the activity
the vermiculi acquire with age ; the facility of
motion in every direction ; the change of form,
divifion, diminution of fize ; and, laftly, their
total deftruCtion in a few days.

To begin with the firft, I may obferve, that
Lewenhoek and other naturalifls have remark-
ed, that each vermicule in the femen of man,

K or

I30 SEMINAL VERMICULI.

or of feveral other animals, has a long appen-
dage, which it drags along with at as it fwims.
But this appendage is not fuch as M. De Buf-
fon would incline ; he imagines it a thread or
long corpufculum, having no analogy to a tail,
or any other member, and entirely foreign to
the fpermatic vermicule. I have always found,
that the appendage, as I have [hewn in my firft
chapter, has every characteriftic of an aflual
tail. It has the Ihape ; and the diameter always
becomes greater, as it approaches the body of
the vermicule to which it is united. So that
it clearly appears to form one whole with it, as
is feen in the rat-tailed worm : fo much the
more, as, in fwiniming through the fpermatic
fluid, the vermicule makes ufe of the tail. In
effect, it bends it firft to one fide, then to ano-
ther, and in every different direction, as aqua-
tic worms are wont to do while they fwim. I
have often feen this, and in the moft diftinft
manner. So that I muft difcredit my eyes, if I
thought or wrote differently.

It is true, that this microfcopic obfervation
upon the tail of human fpermatic vermiculi, is
the moft nice and delicate of any I have made;
it demands the greateft care, and the moft ftridh
attention. The tail is wonderfully [lender, and
at the fame time tranfparent ; whence it hap-
pens, that too ftrong a light confounds it with
the feminal fluid, fo that we entirely lofe fight

of

SEMINAL VERMICULI.

I3I

of it. The choice of the light fit for obferva-
tion, is then of the greateft importance. The
direct light of the fun is too powerful, as is
that of a lamp ; at leafi, unlefs it is by fome
method moderated. The light I have found
molt apt for this fine obfervation, is that of a
window oppofite a white wall, moderately il-
lumined ; as, for example, when it is expofed
to a part of the Iky covered with white clouds.

In the fecond place, the finer and thinner
the Aiders are, on which the drop of femen is
depofited, the more eafily are the tails difco-
vered. I prefer talc to chryftal.

Thirdly, the fpermatic drop fhould be as
thin as poflible, otherwife the origin of the tail
will not be feen, the reft is concealed in the li-
quid : and, even when the feminal fluid is trou-
bled, it is neceflary to refine it with another
portion more clear.

Fourthly, when the vermiculi fwim, as the
tail is always a little lower than the body, we
rauft deprefs the focus of the lens a little, to
obferve it.

Finally, a microfcope of a fingle lens, fuch
as that called Lewenhoek’s, fliould, for this ob-
fervation, be preferred to the compound micro-
fcope.

Although M. De Buffon mentions, in his
obfervations, only one or two of the precau-
tions alluded to, and which he feeyis to have

K 2 ufed*

I32 SEMINAL VERMICULI.

ufed, yet I am not willing to think he has ne-
glected the reft ; for the exception of only one,
would prevent him from making the real ob-
fervation. He fays, that he always ufed the
compound microfcope, to examine the femen of
man and animals. I doubt not, his microfcope
was as excellent as he fays ; but it was a com-
pound one, and had all the defeats of corn-
found microfcopes, among which this is fpe-
cially placed : the objeCt obferved is never feen
fo diftinft, or its outlines fo well defined, as
with a perfect microfcope formed of a fingle
lens. This faCt is^cknowledged by all obfer-
vers ; and the obfervations I . have made upon
human fpermatic vermiculi, with Lewenhoek’s
microfcope, confirm it more. Ufing the firft,
I faw the vermiculi precifely as I have defcrib-
ed them and with the other, I had a confu-
fed view of the body, which I frequently doubl-
ed to be round or oval : the outline was al-
ways in a fort of mill or cloud. The tail,
which is infinitely more -delicate, appeared Iefs
fenfible ; and I only knew to diftinguilh it as a
long flender body. It is not furprifing, there-
fore, that M. De Buffon calls this part of the
vermiculus, a foreign body, a fort of long, de-
licate, and fubtile filament, fince to him it ap-
peared truly fuch, when viewed with the com-
pound microfcope.

But

SEMINAL VERMICULI. I33

But it may perhaps be thought, that the
compound microfcope ufed by me was not fo
good as M. De Button's. However, I can af-
fert, that my microfcopes are the mold perfect
now made in London. I fhall aifo add, that
I was defirous to view fpermatic vermicuh with
the microfcope M. De Button has ufed, that is,
Cuff’s compound microfcope, which was pre-
cifely that of Mr Needham, and which, M. De
Button fays, he ufed in his obfervations upon
the feminal fluid. But it fhowed me no more ;
and I may fay, that my obfervations and expe-
riments, as well upon fpermatic vehniculi, as
upon the animalcula of infufions and other fi-
milar beings, could never have been exempted
from contempt, 1 will even fay error, if I had
preferred the compound microfcope to that of
Lewenhoek.

Let us flop a moment, to ettablifh the cer-
tainty of the exigence of tails in the human
fpermatic vermiculi. The fa& is confirmed in
fo convincing a manner by the experiment up-
on talc, where the tails appear complete, and
not confounded with the femen, that this ex-
periment would put it beyond a doubt, w^as
there no other proof. In the mean time, we
may obferve, that fuch extreme circumfpettion
and fo many precautions, are not necettary to
diftinguifh the tail of the vermiculi of many

K 3 animals.

*34

SEMINAL VERMICULI.

animals, when Lewenhoek’s microfcope is ufed
for examination.

Refpeding the contraction and entire dis-
appearance of the tails, which M. De BufFon
fays he obferved, when the vermiculi remained
long in the femen after it came from the ani-
mal’s body ; I can oppofe nothing, except that,
in my numerous obfervations, 1 always faw the
contrary. The vermiculi constantly preferve
this member, not only while alive, but alfo
after death, and even long after death ; fo that
it only begins to Spoil, and be destroyed, when
the vermiculi themfelves arrive at this (late. I
Shall fay more : the maceration of the dead bo-
dies of the vermiculi produced by boiling or
infufion, is not Sufficient to deftr'oy their Struc-
ture or their form. Vinegar, nay urine, fluids
which entirely deftroy the contexture of molt
animalcula, cannot, until after a confiderable
time, aSFed the body or the tail of our vermi-
culi. It would therefore be neceflary to deny
the evidence of all thefe fads, to agree with
M. De BufFon concerning the contra&ing and
difappearing of the tails of feminal vermiculi.
That my obfervations may have greater weight,
to eflablifh the certainty and continuance of
thofe tails, I Shall cite the authority of the
great PhyfiologiSl of Bern — “ Nunc quod cau-
“ das attinet perpetuam particulam vermiculi
V. fpermatici, ea nimis certos et Side digniffimos

u teStes

SEMINAL VERMICULI. 135

cc tefles habent, quibus meum fuffragium per
<c experimenta natura addidiffe liceat a.”

The other phenomena of fpermatic vermi-
culi obferved by M. De Buflon, fuch as, an
increafe of action they acquired with time,
their change of fhape, their diminution, their
diviiion, and the duration of their lives from
four to eight days, feem to me no lefs para-
doxical, if we attend to the repeated obferva-
tions mentioned in the firft chapter, and if we
recal thofe of the celebrated Lewenhoek. The
acknowledged merit of M. De Buffbn, pre-
vents me, at the fame time, from confidering
this colledion of fads as chimerical : but, not
being able entirely to reject his fingular inicro-
fcopical obfervations, however defective his mi-
crofcope might be, it could not occafion fuch
a difference of phenomena. 1 therefore deter-
mined to refolve his doubts, by taking the
trouble to make a new courfe of experiments
upon the human feinen, and alfo upon that of
other animals : but, notwilhftanding all my
care, precaution, and all my pollible vigilance,
I could difcover nothing new, at leaft elfential-
]y affeding the fads I have fpoken of. But,
with refledion upon M. De Buffon’s obferva-
tions, and the repetition of my own, I cannot
reproach him with feeing what did not exift.
I thought that all this might be an equivocal
K 4 effed,

a Haller. Phyfiolog. tom. 7.

1 3 O’ SEMINAL VERMICULI.

effett, which feeined to me the more likely, as
the phenomena he fays he obferved in fperma-
tic vermiculi, might be occafioned by beings of
a very different nature. My experiments upon
infufions, fuggeded this idea. I had remarked,
that there is no part of an animal which, when
infufed, does not give exidence to a particular
kind of animalcula. They are produced indif-
ferently, by the mufcles, brain, nerves, mem-
branes, tendons, veins and arteries. The fame
is done by the blood, ferum, milk, chyle, fali-
va, &c. mixed with water, or even by them-
felves. I had not yet made experiments upon
the human femen for this purpofe ; but it was
mod probable, that the putrefa&ion of this li-
quid would give exigence to particular beings :
— and who knows, faid I to myfelf, that they
have not inadvertently been confounded with
feminal vermiculi, and that M. De Buffon has
not afcribed to the latter the properties and
phenomena exhibited by the former ? When
I again perufed Haller’s Phyfiology, I found
that he was of this opinion, and that he even
fufpefted, M. De Buffon had never feen the
fpermatic vermiculi. — “ Porro Buffonius, ut
<c cum illuftris viri venia dicam, omnino non
<c videtur vermiculos feminales vidiffe. Diu-
fc turnitas enim vita; quam fuis corpufculis tri-
u buit, oltendit non effe nodra animalcula, id
“ ed fpermatica, quibus brevis et paucarum ho-

<s raruin

SEMINAL VERMICELLI.

*37

« rarum vita eft.” And in another part of
the fame volume he adds — 44 Ea experimenta,
“ id eft Buffonii, manifefte ducunt ad animalia
cs putredinofa.” However, I thought of af-
certaining this fad, by obferving what fuccef-
fively happened to the femen when long pre-
ferved in a watch glafs.

I mademyfirft experiments upon the human
feminal fluid a. The vermiculi died in three
hours and a half, and were precipitated to the
bottom of the glafs. Upon the flxth day, the
feminal fluid begun to exhale a foetid and dif-
agreeable odour ; but I could perceive no ani-
mated being ; only, upon taking fome drops
from the bottom of the glafs, I obferved the
dead bodies of the vermiculi apparently very
entire. The feventh and eighth days, I faw no
change ; but the fcetor encreafed. On the
ninth, I difcovered very minute animalcula,
their fize nearly equalling that of fpermatic
vermiculi ; but they had no tail, and greatly
refembled moft minute fpherules. Like the a-
nimalcula of infufions, they fomctimes flapped
at little fragments of corrupted femen : fotne-
times their courfe was very rapid, retrograde,
rifing and linking in the fluid : in a word, they
pofieffed every property of infufion animalcula.
They were feen in every ftratum of the femen ;
and thole at the bottom, put in motion the dead

bodies

3 February 1 1. The thermometer 450 above c.

i38

SEMINAL VERMICULI.

bodies of the feminal’ vermiculi, which were
flill entire, and remained fo fome days longer.
In the feminal animalcula, we remarked the
fame terms, with regard to the encreafe and di-
minution of the numbers, and their end, which
we generally remark in the hiftory of other a-
nimalcula ; only, when the globular animal-
cula decreafed, there came other two genera-
tions : the laft of which could fcarcely be dif-
cerned with the naked eye, and, in fome obferva-
tions, remained until the eighteenth day. While
examining the femen in this glafs, I obferved a
portion of the fame kind which I had put in
another glafs, and placed it in a ftove, that it
might experience a greater degree of heat.
The effed of this temperature was fuch as we
might expect. The vermiculi lived longer,
and the infufion animalcula appeared fooner.
The vermiculi died in five hours, and the ani-
malcula were feen in five days. They were of
a globular figure, had no tail, and ail were of
the fame fize and fpecies as thofe of the pre-
ceding obfervation. The other two colonies of
fmaller animalcula then appeared ; the globu-
lar always remaining.

Having again prepared the fame kind of fe-
men a, I had an (opportunity of feeing the ef-
fect of heat in accelerating the produdion of
animalcula. I found fome in the feminal fluid,

in

3 May 22. The thermometer 65° above 0.

SEMINAL VERMICULI. I 39

in lefs than twenty- three hours after it was ta-
ken from the dead body. The fpecies were
different from the globular ; they were three
times as large, and of a cylindrical fhape.
When fwimming, the body undulated like a
ferpent ; which did not occur, or was not ob-
ferved, in the globular animalcula. The dead
vermiculi appeared to be their food ; fmce the
animalcula, inceffantly in motion, furrounded
them, and pecked at them with the anterior
part of the body. In three days I faw other
animalcula, as minute as the fpermatic vermi-
culi, along with the cylindrical animalcula ;
and I remarked a circumftance, which in femen
I had not obferved before. In the treatife up-
on the animalcula of infufions, I have fpoken
at large of a propagation by a natural divifion,
which happens with many fpecies. I have faid,
that, in feveral, the divifion begins in fuch a
manner, that the animalcula is gradually cleft
afunder, until it is divided into two equal parts,
which become two animals fmaller than the
firft. But it remained to enquire, whether this
mode of propagation could happen with ani-
malcula fimilar in fize to feminal vermiculi.
More than ten divided tranfverfely before my
eyes ; and this divifion, or propagation, conti-
nuing feveral days, the feminal fluid, which
had become exceilivelv foetid, now teemed with

J J

life : but the number of thefe, as well as of the

cylindrical

140 SEMINAL VERMICULI.

cylindrical animalcula, gradually diminifhed, in
the fame way as the numbers of infufion ani-
malcula decreafe ; and upon the twenty-firft
day all had difappeared. There only remained
in the femen, a univerfal obfcure fermentation,
in no particular direction : but the feminal mo-
lecules were tumultuoufly driven about in eve-
ry direction. I was not long of perceiving,
that this irregular agitation was occafioned by
a multitude of the moll minute animalcula,
concealed among!! the femen, which, in their
courfe, they put in motion : and of this I had
complete evidence, by diluting the femen with
water, as they were then accurately difcerned,
appearing about half the fize of the fpermatic
vermiculi.

The phaenomena, difcovered in the femen of
the horfe, were analogous to thofe I found in
the human femen. The vermiculi lived feven
hours, and then were precipitated to the bot-
tom of the femen, where they long remained
entire. The body and tail were complete for
a month. In fourteen hours the femen began
to exhibit fymptoms of putridity, and then
were feen the animalcula of infufions : they in-
creafed; and, at the beginning of the fifth day,
there were many fpecies. One particularly de-
mands our notice. Not only did it multiply
by a longitudinal divifion, but the figure and
fize of the animalcule changed every moment.

Sometimes

SEMINAL VERMICULI.

141

Sometimes the animalcule contracted, and be-
came round 5 fometimes it dilated, and became
elliptical j as I have remarked in feveral fpecies
of infufion animalcula.

When this experiment was made upon the
femen of the horfe, I made one, fimilar, upon
that of the rabbit. The vermiculi perifhed
and fell to the bottom in four hours ; the ani-
malcula of infutions appeared only after fif-
teen. Two fpecies multiplied by divifion, and
one exhibited the contractions and inflations I
mentioned before.

I made the fame experiments upon the fe-
minal fluid of the ram, the dog, the bull ; up-
on that of frogs and newts. The refults were
conftantly analogous. At the beginning, and
during the progrefs of putrefaction, each produ-
ced animalcula ; which occafioned our remark-
ing, in all that appeared, a number of various
circumftances. Their number encreafed, it di-
minifhed, and became very fmall. The ani-
malcula were different in figure and fize ; and
fome fpecies multiplied by divifion : which e-
vinced, that animal femen refembled infufed
vegetable feeds, from the many kinds of beings
to which it gave exiftence.

Thefe faCts afforded new light to illuftrate
a truth, fufficient to fatisfy me, how erroneouf-
ly M. De Buffon had afcribed to the feminal
vermiculi, properties belonging only to the

animalcula

SEMINAL VERMICULI.

142

animalcula of infufions. Let us, in a few
words, collect the circumftances. According
to this author, after a certain time, the vermi-
culi were deprived of their tails. He fliould
have faid, that the animalcula of infufions
came in the place of the vermiculi which were
already dead, and precipitated to the bottom
of the liquid. He was arrefted by their firft
appearance, and took them for feminal vermi-
culi deprived of the tail, which, in truth, they
often very much refemble. When difengaged
from the tail, M. De Buffon adds, they acquired
greater activity. This was a neceffary confe-
quence of the firft miftake. When the infu-
fion animalcula had taken place of the vermi-
culi, their encreafed agility could not be unob-
ferved, fince the animalcula move with much
greater quicknefs than the vermiculi. This
erroneous fuppofition being admitted, M. De
Buffon had to relate, as he has done, the re-
mainder of the phenomenon. He had to fpeak
of the imaginary changes of the vermiculi, of
their divifion and their diminution, with the
more confidence, as his opinions had to be con-
firmed by a repetition of his experiments, if
not upon all, at lead upon many fpecies of in-
fufion animalcula in the femen.

I think I have had too numerous, and too
decifive proofs, to doubt that the phenomena
feen in infufion animalcula of femen, are dif-
ferent

SEMINAL VERMICULI. 1 4$

ferent from the phenomena exhibited by the
feminal vermiculi. Will I not be permitted at
once to oppofe my experiments to thofe of the
illuftrious M. De Buffon ? I fee that all the
feminal fluids he has ftudied, and where he
has difcovered the phasnomena of which I
have fpoken, have alfo been ftudied by me.

I perceive that I have even examined more,
both of cold, and of warm-blooded animals.
His obfervations upon the fluids, were only
made at certain times, and in one feafon. I
efteemed it neceflary to extend my obferva-
tions to all feafons. My microfcopes were not
inferior to his, as I have faid ; nay, I may fay
they were much better. How then is it pof-
fible, that, being in the fame circumftances
with the French naturalift, and being even in
fituations more advantageous, for obferving the
phasnomena of fpermatic vermiculi ; how is it
poflible, I fay, that I have never obferved thofe
phasnomena, that I have never obferved fome,
or remarked but a Angle one ? What do I
fay ? Not only have I never obferved any of
thofe phaenomena ; but I have feen what com-
pletely contradi&s M. De Buffon’s obferva-
tions, and remarked it in all the fluids I have
many, many times examined. Such, for ex-
ample, is the imaginary activity the vermiculi
acquire, in proportion to the time they remain
in the femen, w'hich would confute all I have

feen

144

SEMINAL VERMICULI.

feen and related in the firft chapter. For, af-
ter being expofed to air, their motion becomes
much more languid : before this, it is quicker:
and its greateft rapidity is, when the femen is
in the body of the animal, which, as I have
obferved, was remarked by Lewenhoek. Fi-
nally, M. De Buffon fays, he obferved thofe
phenomena three or four days after the fe-
men proceeded from the animal, and even up-
on the eighth day, in that of the rabbit. But
this mu ft be impoffible : becaufe, it cannot
happen that thefe vermiculi, like thofe of hu-
man femen, which live longeft when expofed
to air, could live during the time mentioned
by M. De Buffon ; and, in this ft ate, they
could not live above feven or eight hours.
When fecured againft the influence of air, in
glafs tubes hermetically fealed, they do not
live three days, as we Ihall afterwards fee. It
is therefore decided, that the phaenomena ob-
ferved by the author in his experiments, could
be exhibited only by the animalcula develop-
ing in the feminal fluids when on the verge of
corruption, or when they do corrupt, as hap-
pens to other liquids which will corrupt, or are
already corrupted.

I cannot fupprefs my furprize, that M. De
Buffon never doubted that the animated beings
he faw in femen, were really fpermatic vermi-
culi, or only animalcula originating there ; I

mean

SEMINAL VERMICULI.

J45

mean to fay, the animalcula of infufions. He
well knew, that this lall fpecies of animals ori-
ginates no lefs in animal, than in vegetable
fubftances, when they begin to corrupt. For
he fays, that in two infufions, one made with
the tefhicles of a ram in water, and the other
with thofe of a dog, he, in fome days, found
living animals fimilar to thofe he had feen in
the femen of animals ; that is, globular or o-
vular vermiculi, without tails, moving with
great a&ivity, and often changing their lhape.
If the animalcula of the two infufions were
perfectly fimilar to thofe he had obferved in
feminal fluids, how did he not fufpect, that,
inflead of being fpermatic vermiculi, they
might have been infufion animalcula ? He had
an additional caufe to think fo ; for he mud
have remarked, that thofe changes of figure, di-
vifions, diminutions of fize, wrere not to be feen
in recent femen, but in that kept for fome
time, and about to corrupt. Of this, he mufb
have had certain indications, and an indubita-
ble proof, from the foetid and cadaverous o-
dour the femen then exhales ; which is alfo a
convincing proof, that animalcula are produ-
ced in it, upon account of its putrefcence j
and confequently, that we cannot confound
lhem with the fpermatic vermiculi. Another
remark might have occurred, and might have
faved him from miftake, had he chofen to

L make

SEMINAL VERMICULI.

146

make it, was, not to examine the furface of
the feminal fluid only, but alfo the bottom.
There, he would have found the vermiculi
entire, although dead ; which would have de-
monftrated, that the animals he then faw in
motion could not be feminal vermiculi.

But all I have hitherto faid againft the theo-
ry of M. De Buflfon, receives greater weight
from the comparifon I have drawn between the
fpermatic vermiculi, and the animalcula found
in putrid femen. In another work, I have
fliewn, that a confiderable part of the animal-
cula of infufions, appear, before the microfcope,
an aggregate of minute veficles, fmaller or
larger, and in greater or lefler number j that
the veficles are inverted by a common pellicle,
which forms the exterior of the animal ; that
the pellicle and its veficles are loft and deftroy-
ed when the animalcula die ; and if, while a-
live, they are wet with urine or vinegar, the
body is deftroyed, and reduced to nothing a„
All thefe Angularities are amply exhibited and
verified, in the putredinous animalcula of fe-
men ; but, with all care and attention, I have
never been able to fee any thing like feminal
vermiculi. The texture of the body and tail
is not vafcular : it is uniformly homogeneous ;
equally folid and compafit. For this reafon,
perhaps, the vermiculi, when dead, fall to
the bottom of the feminal fluid j and the in-

fufion

a Saggio de obfervazioni microfcopiche.

SEMINAL VERMICULI.

147

fufion animalcula commonly fwim. Likewife,
the veriniculi continue entire, long after death :
urine, vinegar, even ebullition, cannot dif-
folve or decompofe their contexture. We muft
therefore conclude from all this, and from all
‘that has been already faid, that the animalcula
of infufions, and confequently thofe of putrid
femen, are of a nature and conftitudon effen-
tially different from thofe of fpermatic vermi-
culi. We may eafily determine that this muft
be real, fince a fluid, which affords a falutary
dwelling to the one, is fatal to the other. The
putredinous feminal animalcula develope and
live in corrupted femen, but they die in that
which is recent and entire. On the other
hand, the vermiculi live with fafety in recent
femen, but they die when put in that which is
corrupted. The animalcula become more live-
ly and more adtive when water is put in the
femen ; the vermiculi, at lead feveral fpecies,
then become motionlefs and die. Of all thefe
fadts I have often convinced myfelf. Whence
I conclude, infufion animalcula, and fpermatic
vermiculi, to be two fpecies of animals, which
we cannot confound without offending nature.

I. 2

CHAP.

I4S

SEMINAL VERMICULI.

CHAP. V.

As I have taken the liberty refpectfully to re-
mark the errors of M. De BufFon concerning
this fubjedt, I muft hill requeft permiffion to
.{how the deductions which may be made from
his noted theory of organic molecules. But,
to perforin this with the greater fuccefs, it
will be neceffary to bring under our view, fome
of the chief points of that theory.

The illuflrious French naturalift fuppofes,
that every animal and vegetable fubftance in-
cludes a number of organic molecules, that is,
aCtive and incorruptible particles. He thinks
they ferve for the nutriment, encreafe, and
multiplication of all beings, W'hether they en-
ter the body of animals by means of food, or
that of plants with the fap they imbibe from
the earth : that they intimately penetrate every
part, there unite, and are identified, if we
may fay fo, and afford nourifhment to the
plant or animal. If the plant or animal is
young, it appropriates all the organic mole-
cules, incorporating them with itfelf. The
molecules, expanding, extend their fibres, and
by this means effect increment. But if the be-
ing is already an adult, if it is no longer fuf-
ceptible of expanfion, then all the molecules,

being.

SEMINAL VERMICUXI.

1 49

■being unemployed in nutrition, thofe which
are fuperfluous are depofited in the organs ot
generation, and ferve for the propagation ol
the fpecies, which takes place when the or-
ganic molecules of the male are mixed with
thofe of the female ; fo that the moft analo-
gous tend to approach each other, in virtue of
certain relations, and form fingular wholes,
refembling in miniature the different parts of
the two individuals in which they are model-
led. From the wholes together, there refults
a general whole, which is the embryo.

If the organic molecules, afforded by the
male, are more numerous or more a&ive than
thofe of the female, the embryo will be a
male ; if the molecules of the female are more
numerous, it will be a female. The greater
number afforded by the male or the female,
will occafion the greater refemblance of the
embryo to the individual from which it has re-
ceived them.

Large animals are lefs fruitful than fmall :
the reafon is evident. The former extraft
fewer organic molecules in nutriment than the!
latter. A bull draws lefs nutriment from hay
and draw, and confequently fewer organic
molecules, than a bee does, in proportion, from
the fineft parts of flowers. Animals covered
with fcales are more fertile than thofe covered
with hair ; probably becaufe the former per-

L 3 fpire

150 SEMINAL VERMICULI.

fpire lcfs than the latter, and becaufe they ac-
cumulate a greater number of organic mole-
cules.

If, inhead of collecting in the organs of gene-
ration, the molecules are carried to other parts
of the animal, there they form minute liv-
ing animals, as the tenia and afcar'ides ; worms
fometimes inhabiting the intehines, the liver,
and the finuofities of the brain.

It is thus that M. De Buffon, in his theory,
(explains thofe phaenomona, and fome other,
which, for the fake of brevity, I lhall omit.
As he willies this theory, the offspring of his
genius, to be adopted by nature, he recurs to
the feminal fluids of animals, and the infufions
of plants, becaufe, in both, according ro his
opinion, are organic molecules, clearly exhibit-
ed under the form of globular, ovular, or other
fhaped corpufcula, endowed with motion, fub-
jedted to various changes of figure, may be de-
compofed into feveral fmall bodies, and, hav-
ing fo much the greater activity, are further
decompofed, until their minutenefs renders
them invifible.

This lalt trait of M. De Buffon’s theory,
proves that it refts entirely upon the faCts re-
lated by its author, that is, upon a falfe hypc-
thefis. For with refpect to infufions, we have
already feen, that there is in them nothing to
indicate organic molecules, fince the moving

corpufcula

SEMINAL VERMICULI.

corpufcula there, are actually animals, fome oi
which are viviparous, and others oviparous ;
and becaufe thofe multiplying by divifion, do
not produce that progreflion of fucceffive dimi-
nution in fize, which M. De Buifon imagined
he faw : but the fmalleft encreafe like other a-
nimals.

Having found the living putredinous beings
of fernen, to be precifely of the fame kind
as thofe of infufions, by a direct and con-
clufive confequence it follows, that they could
never be confounded with organic molecules,
and we may fay the fame of feminal vermiculi,
whofe animality I have fufficiently proved by
the fafts already related in this treatife, and by
thofe which are engroifed in the fubfequent
chapters.

The theory of M. De Buffon is thus com-
pletely deitroyed. Such is too often the fate
of thofe hypothefes, favoured by the inventive
imagination' of fome philofophers, and which
they afterwards fearch for in nature. This in-
genious naturalift, dilfatisfied with the theories
of generation already framed, and hurried on
by his tafte for novelty, imagines in the body
an animated matter, original, incorruptible,
and always active, which he fpeciouily deno-
minates organic molecules. Making them adt
according to certain terms, and with a certain
effect, he thinks he can explain the great work
of generation, and the moft infcrutable phte-

L 4 nomena

SEMINAL VERMICULI.

152

nomena it prefents. In this attempt, he ufes ail
the powerful and perfuafive eloquence which
charaCterifes him as the orator of the age. Pre-
judiced in favour of his theory, it was not dif-
ficult for him to find it in nature. His views
were lefs directed to fee what actually exided,
than to what he wifhed to find. Like his cele-
brated countryman, the Reformer of Botany,
who fancied that metals and {tones vegetated,
and thought he had evidence of this imagi-
nary vegetation ; that he law feeds and plants,
where there were none. If this learned acade-
mician, who has ever pcfieffed my full efteem,
would take the trouble to repeat his experi-
ments, upon the femen of man and animals,
with the bed microfcopes, and, forgetting the
organic molecules, fo dear to him, by impofing
a rule upon himfelf, to receive, as truths, but
the images tranfmitted by the fenfes, without
adding the corrections of his imagination, as
is the duty of a veracious naturalid ; I may af-
fure him, that he will find all I have fo largely
defcribed in my works. I earneftly entreat
him, not to reject this without a trial, which
mud certainly refult to the advantage of truth.

I mean now to examine M. De Buffon’s ob-
jections, to prove that the living beings feen in
fpermatic fluids are not real animals. Some of
thofe objections I have already anfwered in the
beginning of chapter 3. And it appears, from

SEMINAL VERMICUXI.

*53

what I have hitherto faid, that fome of them
are falfe ; fuch as, the formation of the animals
under the obferver’s eye, the lofs of the tails,
and the diminution of their fize. Two yet re-
main, of which I have not fpoken ; their divi-
sion into parts, and their frequent change of
lhape. Thefe phenomena are real, although,
as we have feen, they are never obferved in Se-
minal vermiculi, but only in the animalcula of
putrid femen. M. De Buffon efteems fuch
phcenomena incompatible with the (late of ani-
mals.

With regard to the objection concerning
the diviSion of the animalcula, I judge it need-
lefs to flop here for a difcuffion ; and I pafs to
the Second, which relates to the metamorpho-
fes of the putredinous animalcula. It is true,
that the body of the animals familiar to us, is
So conftruSted, that the fhape never varies, and
cannot be materially altered without deflruc-
tion. But it is no lefs true, that there are o-
thers, and even many, experiencing the con-
trary ; as for example, among infects, feve-
ral fpecies of worms. To be convinced of this,
it is only neceffary to open the works of natu-
ralifls, and to glance the works of nature. Se-
veral worms of this kind have been elegantly
defcribed by Rhedi and Vallifnieri. In fhorr,
a Single fpecies may ferve for many : this may
be the cucurbit worm. Is it not certain, accord-

154 SEMINAL VERMICULI.

ing to the obfervations of thofe two, and efpe-
dally of the Tufcan philofopher, that they af-
fume various fliapes, and, in the words of this
learned naturalift, “ fometimes they contrad
<c and fwell like purfes, fometimes they extend
“ and curve in a femicircle ?” Does not Reau-
mur fay the fame of certain worms changing
to flies, whofe head, that part conftantly the
fame in moll animals, in this infed, fo wonder-
fully changes its appearance, that it is fome-
times extended, fometimes deprefled, fome-
times contraded, fometimes obtufe in one part,
and acute in another ? Do not we daily fee
the fame changes in earth worms, fnails, and
particularly in leeches ; extending the body
till it becomes long and flender, then contrad-
ing it till it becomes fliort and corpulent ;
grows thick at one end, and fmall at the o-
ther ? What (hall we fay of the wheel animal,
that aquatic creature, which, from its wonder-
ful and incredible metamorphofes, we may
term the Proteus of the infect tribe ? If wheel
animals, leeches, fliell and naked fnails, fo ma-
ny fpecies of vermes, are not degraded from
the quality of an animal, notwithftanding their
metamorphofes, the fame fliould be the cafe
with the animalcula of putrid femen.

I have ftill to appretiate two other objec-
tions. One is deduced from the Angular mo-
tion of fcminal vermiculi ; the other from the

different

SEMINAL VERMICULI.

*55

different effects of heat and cold upon them.
Let us attend to the firft. An animal, what-
ever it is, according to the reafoning of M. De
Buffon, is fubject to change its inclinations
fometimes its motion is quick, fometimes flow ;
then it flops and refts. But nothing of this is
feen in fperrnatic vermiculi : they are in conti-
nual motion, they never flop, they never reft ;
and when once they flop, it is for ever. Hence,
they cannot be animals.

This obje&ion is like the former, both be-
ing founded upon the analogy of the large
animals belt known to us ; but as they pre-
ferve their fliape, they likewife have effentially
the vicifli tudes of reft, of motion, and of an ac-
celerated or retarded motion, See. But, to be
certain that fuch viciflitudes are a chara&erif-
tic quality of animals, it is improper to attend
to large animals only ; but it is neceffary to
examine other genera, and other fpecies, and
to dwell particularly on the fmalleft, efpecially
thofe inhabiting fluids, which have more ana-
logy to fperrnatic vermiculi. It is certain, that
among them, M. De Buffon would have found
feverai animals, which, far from having the
alternatives of motion and reft, are naturally
in motion, fo that their life feems to confift of
a perpetual motion. To be allured of this, it
is fufticient, during the Spring, to obferve the
water of marflies, ponds, and ditches, where

all

SEMINAL VERMICULI.

*5$

all infeds are. There we fhall fee fome in
motion, but by contortions : fuch, for exam-
ple, are the worms mentioned by M. 1 rem-
bley, ferving the polypi for food ; the body is
in a conftant ofcillation a. But, without the
trouble of feeking them in the country, M. De
BufFon may, at his leifure, obferve them at
home. The eels generally found in vinegar
will evince it. If a fmall portion of this liquid
is put in a thin glafs velTel, and oppofed to the
light when the fun is bright : examining with a
magnifier the higher parts, where the eels are
more diftindly feen : their contortions appear
inceffant ; they dart from one fide to another ;
and this continues, without intermiflion, from
morning till night. Thus, they perfevere for
feveral months ; that is, till the end of their
lives. It would feem, that this perpetual mo-
tion cannot be a fufficient reafon to prove that
fpermatic vermiculi are not animals.

But, farther, fuch a motion is not natural to
the vermiculi ; it is forced and violent. When
they have quitted their natural abode, to enter
our atmofphere, they experience the lively im-
prefiion of the air, which pains them, and b-
bliges them to perpetual flight. Doubtlefs, the
air is noxious to them, and occafions their con-
tinual motion, as is proved by the fads. To
afcertain the point, I waited until the human

femen

a Memolres fur Ip Polypes. Mem. fecond.

SEMINAL VERMICULI.

I57

femen cooled ; I then took fome drops, fpread-
ing them very thin upon the glafs of a watch.
It conftantly happened, that the vermiculi of the
fpread drops, although of confiderable thick-
nefs, perifhed fooner than thofe of the complete
portion ; becaufe, as I think, the former were
more expofed than the latter to the air. At
the fame time, I put two equal portions of the
fame femen, one into a clofe, the other into an
open veffel : the vermiculi in the latter always
died fooner than thofe in the former. The
privation I made them undergo, proved well
how injurious this element was to them. They
lived longer in vacuo, than in the open air ; fo
that when in vacuo they were hill alive, all
were dead in the open air. The difference of
time at which they died was an hour and a
half, two, even three hours, and fometimes
longer, according to the feafons when the ex-
periments were made. Thefe fads dernon-
flrate, that the air is noxious to the vermiculi,
and the following prove that it is the caufe of
their being in continual agitation. With the
blowpipe I formed capillary tubes, one end of
which I immerfed in recent femen : it afcended
the cavity, filling the tube to a certain height.
Breaking the tubes near the part to which it
afcended, I prefented this extremity to the blow-s
pipe, and immediately fealed it hdhnetically*
I did the fame to the other end, by which

means

I58 SEMINAL VERMICULI.

means the feminal fluid was deprived of all
communication with the external air. I drew
out the tubes fo, that the thinnefs of the glafs
permitted me to fee the vermiculi within. The
peculiarities prefented by the vermiculi in the
tubes, were very different from thofe of the
reft. All, or at leaft moft part of them, had a
fingular mode of moving. Some had that fort
of activity obferved in thofe which experience
the influence of the open air. Others had a
continued irregular motion; they changed from
quicknefs to inactivity, and reciprocally. O-
thers flopped entirely, and, after refting fome
minutes, refumed their former velocity : be-
fides, we did not fee them inconfiderately run-
ning againft the folid portions of the femen, a9
I remarked in the fir ft chapter, but always a-
voiding them, turning afide, or retreating. It
is true, thefe peculiarities always fucceeded bet-
ter, and with more uniformity, when the tubes
were kept warm. I have before faid, the long-
eft period of life of the human fpermatic ver-
miculi, was feven or eight hours, when expo-
fed to the open air ; but this period is greatly
prolonged when they are included in tubes.
In Summer I have fucceeded in preferving them
two days and more ; and in Spring and Au-
tumn they have lived almoft three.

■ It is undoubtedly very furprifing, that th<?
vermiculi live longer in Spring and Autumn,

than

SEMINAL VERMICULI. I 59

than in Summer : the reverfe fhould take place ;
becaufe the heat of Summer fhould be more
congenial to them, as it approaches nearer to
the natural heat of man in life. At firft it
gave me confiderable furprife, which increafed
upon refle&ing, that in the open air the ver-
miculi live much longer when the weather is
warm. This circumflance induced me to re-
peat my experiments ; but I conflantly found,
that during Summer, they never lived as long
in the tubes, as during Spring and Autumn.
In Summer, I may even fay, that they die foon-
er upon the warmefl days. With a little re-
flection, it is not difficult to comprehend the
caufe of the difference. We have feen, that
the femen of man, and of animals, when re-
moved from its native fituation, very foon be-
comes putrid ; and that this happens fooner, as
the heat is greater to which it is expofed. It is
to this caufe, therefore, that I afcribe the more
immediate death of the vermiculi, in capillary
tubes, during Summer. Having filled funilar
tubes with recent femen, and fealed them herme-
tically, I expofed fome to the heat of the atmo-
fphere at about 63°, and others to the heat of the
human body, keeping them under the arm-pit in
a large glafs tube. My own heat, when in a
flate of health, is about 970. The vermiculi
expofed to the heat of the atmofphere, lived
two days and a half ; fome even three : but

thofe

l6oi SEMINAL VERMICULL

thofe experiencing the heat of my body, fupj
ported it only from eleven to thirteen hours.
This more immediate death cannot be afcribed
to the greater degree of heat they fuffered,
fince it is inferior to that they ufually experi-
ence, or in which they naturally live. Nor can
it be occafioned by the air ; for the tubes be-
ing hermetically fealed, the air can have no
influence. We cannot afcribe it to any other
noxious principle ariflng from the nature of
the tubes, fince they were abfolutely fimilar to
thofe expofed to the atmofpheric temperature,
in which the vermiculi live much longer. It
is therefore neceflary to recur to forne altera-
tion, or fome noxious quality contracted by
the femen, which makes the heat accelerate
their death ; and I acknowledge, that I cannot
find this alteration, or this bad quality, but in
the principle of putrefaction of the femen,
which is manifefted by the fcetor experienced
upon breaking the tubes. It is doubtlefs this
odour which mult be fatal to the vermiculi, as
I have demonftrated in chapter 6. The pu-
trefying principle does not take place in femen
expofed to the open air feven or eight hours
in Summer, as I have convinced myfelf ; but*
upon the other hand, the heat of Summer,
more nearly than that of any other feafon, ap-
proaches the heat which the vermiculi experi-
ence in us. Thus, we clearly fee, why they

live

SEMINAL VERMICULI.

161

live longer in the open air during Summer, than
at any other time ; of confequence, we may
comprehend why their life is abridged in pro-
portion as the cold encreafes.

But it is time to come' to the objeftion of
heat and cold, which our author thus pro-
pofes. Upon expofmg the feminal fluid to the
cold air, the vermiculi did not feem to fuffbr
from it ; and they continued to move with
their ufual quicknefs, as long as thofe that were
not expofed, although the feminal fluid had
acquired that degree of cold, in water upon
the point of freezing, as one piay be convin-
ced by touching it. Upon the contrary, if the
fame vermiculi experience heat, their motion
ceafes, although the heat is moderate. In con-
fequence of thefe fafts, if the vermiculi are
real animals, {it is M. De BufFon’s reafoning J
relate), they would prefent an appearance and
conftitution very different from the appearance
and conftitution of other animals ; as too great
a degree of cold relaxes and deftroys their mo-
tion, and a mild and moderate heat preferves
their a&ivity.

It is to be regretted, that our author, in-
ftead of employing taflion to judge of cold
and heat, did not ufe a thermometer ; for all
philofophers know, that the touch is a very e-
quivocal proof. He ought to have difcovered
precifely, at what degree of heat the motion.

M - of

162

SEMINAL VERMICULI.

of the vermiculi ceafes, and what is the degree
of cold by which it is not relaxed. I have
therefore elteemed it moft effential to fupply
this defeft, in order to obtain arguments more
conclufive and decifive, and to know, if, with
refpett to heat and cold, the vermiculi are of
a nature and conllitution differing much, as
M. De Buffon imagines, with the nature of o-
ther animals.

Although the obfervations of chapter i. do
not feem to beftow upon them that vigour of
conftitution fufficient to enable them to refift
the cold, becaufe it appears that their motion
decreafes with the heat of the atmofphere, fo
that, when the thermometer Hands at 36°, they
continue to move only an hour and a half j I
refumed my experiments, refolving to extend
them further, and to fubjeft the femen to a
degree of cold equalling freezing, carefully
obferving what fliould happen to the vermiculi.
The femen I ufed, was that of the horfe. Up-
on the 14. of January, I expofed it to cold :
the vermiculi could not be more vivacious :
but this diminifhed under the eye ; and, in fix-
teen minutes, all were motionlefs, although
the femen was not frozen.

The cold becoming more intenfe, upon the
18. I repeated the experiment. The vermiculi
became motionlefs in eleven minutes ; the ther-
mometer

SEMINAL VERMICULI. 163

mometer {landing 70 under freezing. The fe-
men was ftill fluid.

I often repeated thofe experiments during
this Winter. They conftantly proved, that the
duration of the motion of the vermiculi, was
proportioned to the temperature of the wreather.

In Summer, I profecuted my experiments
upon the femen of the horfe. Then a
thought ftarted, of fubje&ing the vermiculi to
the cold of freezing, by putting the glafs in
which they were, among fnow. The feme ef-
fect was produced by fnow, as by the Winter’s
cold ; that is, in fourteen minutes, it made them
motionlefs ; although, when expofed to the
heat of the atmofphere, they continued to move
feven hours and a half. But an accident that
happened in this experiment, executed during
Summer, afforded new intelligence, and divert-
ed me of a prejudice. Oblerving that the ver-
miculi had become motionlefs, I took the glafs
from the fnow, and left it expofed to the air,
when the heat was 8i°. An hour after, by
chance obferving this femen with the micro-
fcope, I was aftonifhed to find all the vermiculi
reanimated, and in fuch a manner, as if they
bad juft come from the feminal veflels. I then
few, that the cold had not killed them, but
had reduced them to a ftate of complete inac-
tion. I replaced them in the fnow, and in
three quarters of an hour took them away.

M 2 Thefe

164 SEMINAL VERMICULI.

Thefe are the phenomena I obferved. In a
few minutes, their vivacity relaxed, and the
diminution encreafed, until they loft the mo-
tion of progreflion, and retained only that of
ofcillation, which likewife ended in a few mi-
nutes more. Exactly the reverfe was obferv-
ed, when they palled from the cold of the fnow
to the heat of the atmofphere. The firft mo-
tion that appeared, was that of ofcillation :
the body and the tail begun to vibrate languid-
ly from right to left : then the motion was
communicated to the whole vermicule ; and,
in a Ihort time, the progreftive motion begun.
At firft, it is fcarcely perceptible : it foon en-
creafes, and becomes very confiderable. I may
alfo add, that as cold does not deftroy the mo-
tion of all the vermiculi at the fame moment,

* ' ■ x >

but of fome later than others ; fo does not heat

, ‘ * . . «. •

affeft them all with equal power.

I fubje&ed the femen of man, and of the
bull, to the fame experiment, and had the fame
refults as from the femen of the horfe, except-
ing only that a degree of cold, lefs than that
of freezing, deftroyed all motion in the vermi-
culi of the bull.

Upon the approach of the following Winter,
I refumed the fame experiments, and I fucceeded
in reanimating the torpid vermiculi, by breath-
ing upon the femen, by applying the finger to
the ta|f upon which the drops were put, or

by.

SEMINAL VERMICULI. I65

by placing it near the fire. When removed
from this heat, they fell into the fame lethargy
as when in Summer : they paflfed from the
atmofpherical temperature, to the cold of the
fnow. During this rigorous feafon, I expofed
our vermiculi to a more fevere trial. I fubjec-
ted them to cold, more than 90 under freezing.
As I expe&ed, this immediately made them
motionlefs. In five minutes, not a fingle ver-
micule moved. When they had been expofed
five minutes longer, I tranfported them into
warm air, leaving them there for fome time.
Although this intenfe cold continued ten mi-
nutes, the femen was not frozen ; but it had
fatally injured a complete third of its inhabi-
tants, which exhibited no fign of life, when
removed to, and kept long, in a warm Situation ;
on the contrary, they had all the appearance
of death. The other vermiculi recovered, in-
deed ; but their motion was languid, in compa-
rifon to what it was before. This experiment
was made 27 December, and I repeated it
upon the evening of January 5, at a degree of
cold io° under freezing. I perceived, that in
about a quarter of an hour, the femen begun
to congeal about the edges of the glafs. I then
put it into a ftove, but this had no effeft upon
the vermiculi. Not one recovered, and thofe
enveloped by the ice perilhed, as well as thofe
in the fluid part. The fame happened to the
M 3 vermiculi

1 66

SEMINAL VERMICULI.

vermiculi of other two glaffes, upon which I
made the fame experiments this evening ; al-
though I took care to regulate the different de-
grees of heat, left too fudden a tranfition from
cold to heat might be injurious.

Such were the experiments made by cold :
any one may draw the conclufions. Very far
from excluding the vermiculi from the rank of
animals, it furprifingly confirms them in it :
for, what can better prove animality, than lan-
guor and lofs of motion, when affefted by cold ?
What effect can more fatisfaftorily evince it,
than to fee this languor more immediate, as
the cold is more intenfe ; and to fee the ver-
miculi revived, when brought to heat ; and to
witnefs their adtual death, when the cold is of
a greater degree ? Such is the ftate of the
greater part of fmall animals, when deprived
of adtion, and rendered torpid by cold : with
heat they recover life and motion, and yield
under cold (till more intenfe.

But how can thefe fafts, multiplied, repeated,
uniform, confequently certain and incontrovert-
ible, fubfift with the affertion of M. De Buffon,
who thinks that cold does not impede the mo-
tions of the fpermatic vermiculi ? Inftead of ne-
gativing the affertion of this illuftrious French-
man, I think there is a method of conciliating
our obfervations. We have already noticed the
error which occafioned his confounding the fe-

minal

SEMINAL VERMICULI. t6j

minal venniculi with animalcula, afcribing to
the vermiculi thofe properties pertaining to the
animalcula only.

It is very likely Ihat the effeft of cold, which,
he fays, he has obferved upon vermiculi, is alfo
a confequence of the fame miftake ; and this is
the more probable, as it is feen in the putredi-
nous feminal animalcula. Not only do the ani-
malcula of infufions, at leaft feveral fpecies of
them, withftand cold of a great degree ; but
thofe found in putrid femen, are undoubtedly
of that number. I am convinced of this from
feveral experiments, which, to avoid the ennui
of my reader, I fhall not flop here to detail.
But there is one circumftance I ought not to
pafs in filence. Although the animalcula can
fupport a greater degree of cold than the fe-
minal vermiculi, yet their motions become
more languid, and they perilh like the infects
which yield under the greateft degree of cold.

When I found thofe modes of conciliation,
between the obfervations of M. De Buffon and
myfelf, with regard to the phenomena from
cold, I attempted to find the fame refpecting
thofe exhibited by the effect of heat. But this
was impoflible. My obfervations have been
completely oppofite to his. Thofe of M. De
Buffon are comprehended in a few words :
“ The motion of the vermiculi ceafes, when
“ they are expofed to a fmall degree of heat.”

M 4 ’ I

SEMINAL VERMlCULLr

*68

1 entreat the reader to examine mine, that he
may be enabled to compare and form a judge-
ment of them.

I placed upon the water of a veffel two watch
glades, one of which contained a given portion
of recent femen, full of vermiculi ; the other,
an equal quantity of the fame femen, old, and
fwarmingwith putredinous animalcula. Toknow
the fucceflive degrees of heat, I had put the ball
of a thermometer into each glafs. The water
was gradually heated upon a flow fire. As the
liquid in the thermometers afcended, I took
fome drops of femen from the glafies, for exa-
mination with the microfcope. The putredi-
nous animalcula lived at 99° 5 at 104, their
motion begun to grow languid ; and at 106
and 108, all perilhed- The feminal vermiculi
are of a more hardy conftitution. At 1060,,
they were very active ; fome begun to perifh
at 120°, and at 131 there was not one alive 5
fo that the difference -which occafions the de-
ftruction of the one and of the other, is about
220. The vermiculi were thofe of the human
femen. I repeated the fame experiments upon
the femen of the horfe, the bull, and the dog.
Thofe of the horfe and the dog perifhed at
126°; thofe of the bull at 133.

I varied the experiment. I filled fome ca-
pillary tubes with femen, one part of which
Nivas full of feminal vermiculi, the other of the

putredinous

SEMINAL VERMICULI.

putredinous feminal animalcula. I fealed them
hermetically, and put them at the bottom of
a veffel full of water, which was gradually-
warmed ; I alfo immerfed the ball of a ther-
mometer.- When the water had attained 99 *

I begun to examine the tubes, one after ano-
ther. In this new experiment, the feminal
vermiculi of man, and of the animals I have
mentioned, died at only 122 and 124 j and
the putredinous animalcula, at 106 and 1080.

Thefe fads demonftrate, that, if we fpeak
of animalcula originating in putrid femen, they
are of a conftitution better calculated to refill:
a degree of heat, which feveral other animals
eannot fupport, and are killed by heat, only
when it arrives at that degree, or about it,
which is fatal to putredinous animalcula. If
we fpeak of feminal vermiculi, we fee, that
inltead of ceafing to move, and perilhing at a
fmall degree of heat, according to M. De Buf-
fon, they fupport a degree which deftroys fe-
veral other animalcula. But this, far from be-
ing wonderful, is rather congenial with their
nature, fince they live in the bodies of warm-
blooded animals ; that is, in an atmofphere in
general much warmer than the air, and the
other fluids where the reft of animalcula are
found.

CHAP.

SEMINAL VERMICULI.

170

CHAP. VI.

I flatter myfelf that the reader will not be
difpleafed, if, in the reft of the obfervations, he
does not find the fame order and connexion I
have before endeavoured to preferve. It is ne-
ceflary to confider what follows as an appen-
dix, which, I think, mult indifpenfably be add-
ed, to prove, with greater certainty, the anima-
tion of the vermiculi, this being one of the
chief objeCts I propofed ; and, when once e-
ftablilhed, we fhall not only fee confuted the
contradictory opinions that have been formed
concerning the nature of feminal vermiculi,
which have already been explained and difeuf-
fed, but wre may alfo anticipate every new hy-
pothefis that may be fuggefted.

One day during Winter, I had a great quan-
tity of femen then taken from a dead body a ;
and, wifhing to preferve the vermiculi fome
hours alive, I put the watch-glafs where
they were in the funfhine without a window.
The heat of the fun was 70°, which kept them
alive a confiderable time ; but, obferving the
vermiculi an hour after, I was extremely fur-

prized

a When the kind of femen ufed is not fpecified, that of
man is always underftood.

SEMINAL VERMICULI.

tyx

prized to find almoft the whole motionlefs. I
knew not whether this was the indication of
real or apparent death ; and, thinking to fatis-
fy myfelf, by expofing them to a greater de-
gree of heat, I tranfported them near the fire.
Experience had taught me, how inflrumental
the influence of heat is in reftoring the vermi-
culi to life. But this was vain ; and although
I kept them at this degree of heat a length of
time, they exhibited no fign of life. It was o-
therwife with thofe I had left in the fhade, and
then carried to the fire ; for I had another
portion of femen in a watch-glafs, in the fame
apartment. The vermiculi had become mo-
tionlefs like the firft ; but they foon refumed
their original vivacity. What was furprizing
in this phenomenon, feemed to me the effed:
of peculiarity ; and I did not think of repeat-
ing the experiment during this Winter and the
following Spring. But I had afterwards occa-
fion to obferve, that the fun, in a few hours,
was conflantly fatal to the vermiculi, although
the intenfity of the heat did not equal that de-
gree which is fatal to them, of which I have
l'poken in the preceding chapter. This I afcer-
tained, by means of the fun in Autumn : but
tfye phenomenon, which I at firft thought
accidental, has to me appeared conftant and
invariable. The influence of the fun, at the
fame time, has no quality noxious to the pu-

tredinous

I1]! SEMINAL VERMICULI.

tredinous animalcula of the fame femen, pro-
vided the intenfity of the folar heat does not
raife the thermometer to 106 or to8°; which
alfo contributes to prove the difference between
the vermiculi and animalcula.

The novelty of the refults was fufficient to
incite me to invefligate the caufe, experiment
having fnewn me, that a certain degree of fo-
lar heat quickly kills the fpermaiic vermiculi,
although the fame degree in an apartment does
them no injury. I could not be perfuaded
that the fimple heat of the fun occafioned this
deftru&ion. I imagined the caufe entirely
different. My firft idea was, the agitation of
the air. I thought that when I put the femen
without the window, the vermiculi were more
affedted by the violent adtion of this element,
and fooner yielded under it, than thofe within
the apartment ; at leaft, it was here lefs agitated.
But this imagined caufe was falfe : for I put
two glaffes, provided with the fame femen,
without the window, and equally expofed to
the air ; with this difference only, that one
was in the funfhine, and the other in the fhade;
Thofe expofed to the funfhine, always died fe-
veral hours fooner than thofe in the fhade.
Further, I put a divilion in the feminal fluid of
the fame glafs, feparating it into two parts ;
fo that one was expofed to the funfhine, and
the other was not. It always happened, that

the

SEMINAL VERMICULI. 173

the vermiculi of this latter portion long furvived
thofe of the other.

Attentively contemplating the femen with
the naked eye, I fufpeded another caufe. I
faw the femen not only greatly diminilh, but
become more denfe, and change colour. I
then thought that this groflnefs might be noxi-
ous to the vermiculi. To afcertain the fad, I
employed an eafy method, which was, to pre-
vent the evaporation of the femen in the fun-
ihine, becaufe the denfity might be occafioned
by the evaporation of the more volatile parts :
and I attained my purpofe, by hermetically feal-
ing feveral capillary tubes full of femen, then
expofing them in the funlhine, along with an-
other portion of femen, in a watch glafs. The
heat of the fun raifed the thermometer to 72°,
The vermiculi in the watch glafs did not live
an hour ; but thofe in the capillary tubes re-
tained all their vigour at> funfet, although the
experiment was made in the morning ; and an
hour after mid-day, the heat of the fun equal-
led 104°. Upon the following days, I expofed
to the funlhine other capillary tubes, prepared
as above : the vermiculi were long alive. Thefe
repeated fads therefore prove, firfb, that the
fuddcn death of vermiculi in the funlhine, is not
properly the elfed of the heat of the fun, as it
would have killed thofe in the capillary tubes
almolt as foon as thofe in the open velfels ; fe-

condlv.

*74

SEMINAL VERMICULI.

condly, we cannot afcribe their immediate
death but to fome vicious quality or alteration
acquired by the femen, when expofed to the
air, and againfl which it is fecured in a clofe
veffel. But as it does not feem to arife from
any other caufe, than from the thickening of
the femen, fince putrefadion cannot begin in
fo fhort a time, we are induced to fuppofe this
thickening to be the foie caufe of their death,
or at lead an effential reafon.

Thofe fads have been illuflrated by the fol-
lowing. I placed in the fun two glafs tubes,
filled with femen to a given height, and flop-
ped with a flopper well fitted j with this diffe-
rence only, that the flopper of one tube touch-
ed the femen, and that of the other was an inch
above it. The tubes were placed ered, each
containing an equal quantity of femen. In an
hour and a half, the influence of the fun had *
occafioned no evaporation in the tube with the
flopper touching the femen : it was indeed im-
poffible, as there was no vacuity between them.
But the femen in the other tube had evaporat-
ed. I faw the infide of the glafs covered with
a thin pellicle, formed of a very tranfparent
fluid, which could only be the more fubtile
parts of the femen volatilized by the heat. The
quantity of the femen was diminifhed, which
could not be otherwife, as it was a little thick-
er : neither of which circumflances was re-
marked

SEMINAL VERMICULI.

J75

marked in the other tube. I examined the two
femina with a magnifier. The vermiculi of that
where no evaporation appeared, were full of
vivacity ; thofe of the other all were dead.
Thus it is evident, that the folar heat does not
kill the vermiculi, but that their death is occa-
fioned by fome noxious quality imparted by
heat to the femen ; which either confifts in it
becoming more grofs, or in fome other quality
it thence derives, or which is produced upon
this occafion. This circumftance alfo corre-
fponds with the nature of the animals, which
are injured and perifli, if the ambient fluid in
which they live begins to alter or fpoil.

It yet remains to explain how two degrees
of heat, different in effect:, but equally intenfe,
can have fuch oppofite effefts : for the imme-
diate attion of the funfliine changes the feminal
fluid in fuch a manner, that it kills the whole
vermiculi ; while the fame degree of heat, in a
heated apartment, does them no injury. I
have not made enough of obfervations to folve
this problem.

We have feen, that the feminal vermiculi
continue to move complete days in clofe vef-
fels, and perilh in fome hours in the open air.
I have fhewn, that this long continuance of life
in clofe tubes, arifes from their being (heltered
from the influence of the air. From analogy
' cne would think, that this might occur at all

feafontj.

ij6

SEMINAL VERMICULI.

feafons. But arguments drawn from indudion
fhould not be ufed by philofophers, fince they
are often fupported by deceitful fads : the pre-
fent cafe may afford a new inftance. During
Winter, the vermiculi, in tubes hermetically
fealed, become motionlefs in the fame time as
thofe in watch glaffes expofed to the open air :
that they fhould become motionlefs, the cold
of freezing is not required. In an hour and a
half, I found them motionlefs in the tubes, the
fame as in the open air, when the thermometer
was at 450. That the vermiculi may live in
fmall tubes, a certain degree of heat is necef-
fary, which my experiments indicate to be 52
or 540.

When the vermiculi become motionlefs from
cold in open veffels, it is not always a fign of
death : fometimes it only indicates a Ample le-
thargy. When included in tubes, I have, by
means of heat, from perfed reft reftored them
to their natural motion. I have even produced
this reft and motion fucceffively, by tranfport-
ing the tubes from heat to cold, and vice verfa.
We muft remark, that the repetition of this
operation enfeebles the vermiculi fo much, that
in a certain time they cannot recover motion,
and perifh for ever.

I wiflied to learn how long the vermiculi could
remain lethargic without deftrudion, fo that,
palling them to a warm fituation, they might

{till

SEMINAL VERMICULI. IJJ

flill refume their power and motion. I have
found myfelf unable to determine the limits of
this ; hut it appears in a great meafure to de-
pend upon the degree of cold to which they
have been fubjedted. If the cold furpafles
freezing, and we delay fome hours to remove
them to a warm fituation, then they revive
no more, or but a few are re-animated, and
thefe are generally very weak and ill. If
the cold is lefs intenfe, and the thermometer
falls only to 39 or 41% they may remain le-
thargic fourteen hours, and even longer. I
do not intend here to demonftrate to the
reader, that the accidents happening to ver-
miculi in capillary tubes, completely quadrate
with thofe experienced by animals expofed to
cold, and that cold is fatal to them as to many
infers : this may be underftood wdthout ex-
planation. If we fhould now unite thefe traits,
with the reft difperfed throughout this work ;
with the death of the vermiculi caufed by
poifonous exhalations, by the odour of cam-
phire, the oil of turpentine, the fumes of ful-
phur and tobacco, by the effluvia of moft ar-
dent liquors, and the eleflric fpark, as I have
proved ; we fhall have an affemblage of proofs,
fo convincing, fo decifive of the real and ab-
folute animality of the feminal vermiculi, that
I know not what other evidence could be re-

N quired.

178

SEMINAL VERMICULI.

quired, to prove that atoms fo minute are of
fuch a nature as the vermiculi feem to be.

I wifh to excufe the inconfiftency between
what I have hitherto faid of feminal vermiculi,
and the little I faid of them in my firft treatife
upon infufions. There, I fpoke carelefsly of
them ; I had not then ftudied them ; I had
confulted what others had written upon them,
and adopted the theory which feerned to be
bed; fupported by facts. I did not hefitate to
adopt the opinion of M. De Buflfon, and with
him fuppofed the vermiculi not to be real ani-
mals ; as this opinion appeared to be fupported
by obfervations more numerous, better detail-
ed, more conne&ed and convincing, than thofe
of Lewenhoek. Then, I thought thus, and
fhould always have thought the fame, had not
the obfervations I have related convinced me
of the contrary ; and I flatter rnyfelf, that I
fhall not be reproached if my former opinion
was different from that I now have.

This chapter {hall be finiflred with reflec-
tions upon forne queffions, as curious as nice,
refpe&ing our vermiculi. To me they were
communicated in a letter from M. Bonnet ;
and the reader cannot better judge of them,
than when he has them before his eyes. After
informing me of the Angular opinion of Lin-
nceus, that the vermiculi are inert corpufcula
floating in the femen, he adds, ‘ I return to

c the

SEMINAL VERMICULI.

*7 9

the feminal vermiculi, and I cannot doubt
their exigence. They are, of all the aniraal-
cula of liquids, thofe which have mo ft excit-
ed my curiofity : the element in which they
live, the place of their abode, their figure,
motion, their fecret properties, all, in a word,
fhould interell us in fo fingular a kind of mi-
nute animated beings. How are they found
there, how are they propagated, how are
they developed, how are they fed, and w'hat
is their motion ? What becomes of them
when the liquid they inhabit is returned by
the vefifels, and mixed with the blood ? Why
do they appear only at the age of puberty ;
where did. they exifl before this period ? Do
they ferve no purpofe, but to people that
fluid where they are fo largely fcattered ?
How far are we from being able to anfwer
any of thefe queflions ! And how probable
it is, that future ages will be as ignorant of
the whole, as our own I if, as I have faid,
part 12. and .13. of the Palingenejie , our
world has been chiefly made for under (land-
ings, which enquire into the hiflory of fper-
matic vermiculi, and that of the mod myfte-
rious productions of the globe. You may
fee, in articles 131, 132, 134, 135, of my
corps organifes , that, in my youth, I attempt-
ed to confider our animalcula. Obferve what
is laid upon this occafion in article 135, con-

N 2 4 ccrning

i8o

SEMINAL VERMICULI.

c cerning the animalcula of infufions : 44 Re-
44 fpeCting the appearance of animalcula in fub-
ce fiances which have been boiled, or fubjected
44 to a degree of heat, at which we cannot con-
44 ceive that any animal may live : the difficul-
44 ty ought not to furprife us too much, as it
44 is founded only upon our ignorance of the
44 heat which certain animals may fupport.
44 Befides, it is not certain, that thofe animal-
44 cula were in the infufed fubftances. Per-
44 haps they might inhabit the air confined in
44 the veffel, and pafs from it to the infufed
44 matter. Perhaps there is a perpetual circu-
44 lation of thofe aerial animalcula in organifed
44 bodies, and in bodies organifed in the air.”

4 I know no animalcula more fit than femi-
4 nal vermiculi, to demonftrate how well it
6 pleafes the Supreme Wifdom to multiply fen-
4 tient beings, and to leave no portion of na-
4 ture void. Could we have fufpe&ed, that
4 this precious liquid, the reproductive principle
4 of large animals, was at the fame time deflin-
4 ed for the aliment and pleafure of an innu-
4 merable multitude of moft minute animated
4 beings ? It is thus, that this Adorable Wif-
4 dom has prefided over the formation of the
4 univerfe, and has known to make the fame
4 production ferve for fuch different purpofes.
44 The Author of Nature,” have I faid, Con-
templation, partie 5. cbapit. 17. 44 has -left no-

44 thing

SEMINAL VERMICULI. l8l

“ thing ufelefs. The pollen confumed in the
“ generation of plants is very little, compared
“ with the whole quantity each flower affords.
“ Wifdom has, therefore, created the induf-
44 tricrus bee, which ufes the fuperfluous part
“ of this duft, with an art which the molt
“ fkilful geometers know not fufficiently to ad-
44 mire. The pollen of the ftamina apparent-
44 ly fupplies the neceflities of many other in-
44 fedts.” And thofe infedts are in fome re-
4 fpedt to the pollen, what the fetninal vermi-
4 culi are to the feminal fluid.

4 The origin of certain worms in the human
4 body, and in the body of animals, is a pro-
4 blem as yet unfolved by naturalifls. Such,
4 in particular, is the origin of the tenia. I
4 fpoke at length of this Angular worm in my
4 diflertation. The origin of fpermatic vermi-
4 culi is a problem (till more profound. How-
4 ever, I fhould much incline to prefume, that,

4 as thofe I have mentioned in my diflertation,

4 they originate from without. The change of
4 temperature, abode, and nutriment, may pro-
4 duce, iirft in individuals, and then in fpecies,

4 very material alterations, to our eyes difguifing
4 the primitive appearance. A worm deflined to
4 live in the waters, and tranfported to our in-
4 teflines, might not perifh, and yet be very
4 much difguifed, efpecially if introduced when
4 young, or under the form of an egg, or of

N 3 4 femen :

1 82

SEMINAL VERMICULI.

6 femen : and, if the worm was to propagate,
the fubfequent generations would be (till
6 more difguifed. Let us fuppofe, therefore,

4 that the fernina of certain infufion animalcu-
4 la may be introduced into the feminal refer-
4 voirs, by the circulatory dufts : they might
4 be developed and live there. There is no
4 doubt, that this- new abode, a temperature
4 and aliment fo different, may greatly affe6t
4 the original form of the animalcula ; and at
4 length occafion changes, which may more
4 and more remove them from their firff ap-
4 pearance. All mankind had the fame origin.

4 What varieties, and ffriking varieties, are
4 there in the human fpecies ! Let us com-
4 pare the inhabitants of the Frigid zone, with
4 thofe of the Temperate region ; and thofe of
4 this, with the inhabitants of the Torrid zone j
4 and we may fee the different fpecies of men.

4 The fernina of certain infufion animalcula
4 are probably fo minute, that they may eafily
4 arrive at the refervoirs of the feminal fluid.
4 Apparently, they are excluded only in thofe
4 feminal liquids that have acquired a certain
4 perreflion ; which happens only at the age
4 of puberty. It would be a molt curious ex-
4 periment, to try whether the animalcula of
4 infufions would live in fome feminal fluids :

4 and, in the fame manner, to try whether the

5 feminal vermiculi would live in infufions.

4 It

SEMINAL VERMICULI.

183

£ It would, above all, be neceffary to regulate
4 the temperature of the place, and of the fluid.
4 Who can fay, that this experiment, which is
4 certainly very new, will not fucceed. I com-
4 municate to you all the ideas that fugged
4 themfelves to me. My maxim, in natural
4 hiftory, is to defpair of nothing ; and to in-
4 terrogate nature in every way, even the mod
4 uncommon. Why fhould we fay a thing is
4 impoflible, becaufe we have not feen it fuc-
4 ceed ? I found my maxim upon our pro-
4 found ignorance of the fecrets of nature, and
4 upon the deviations which, in many cafes,
4 Ihe feems to make from her ordinary courfe.
4 Every where I fee an univerfal latitude, the
4 limits of which I am ignorant. They can be
4 difcovered by experiment alone. And how
4 much may experiments of every kind be
4 combined, multiplied, repeated, and per-
4 fe&ed ! *

The difficulty of the queflions propofed in
this valuable extratt of a letter, is too well de-
fined by its illuftrious author, not to be feen by
one who has the fmallelt portion of philofophy.
It will always afford me a good excufe, if I only
attempt to anfwer the doubts by diftant conjec-
tures. The queftions may be reduced to three.

1. What is the origin of the feminal vermiculi ?

2. How do they propagate ? 3. What purpofe

do they ferve ?

N 4

I

J 84

SEMINAL VERMICULI.

I return to the firft. Although M. Bonnet
makes no aiTertion, we neverthelefs perceive his
inclination to think the vermiculi have an ex-
ternal origin. Such has been the opinion of
many authors in efteem ; and fuch is the opi-
nion of thofe who think that the worms in the
body of man and animals originate from with-
out. Sir Charles Linnaeus believes the abode
of the tenia to be in the waters ; there he has
found them very fmall, and even in fome fifhes,
particularly in tench, which feems to favour this
opinion a. But we fhould be certain of the iden-
tity of the fpecies of tenia found in the waters,
with that found in the human body ; and of this
wehave not yet fufficient proof. We cannot deny,
at the fame time, that very certain obfervations
demonflrate that fome worms of the human body,
at leaft of the bodies of particular animals, are
actually produced by infers of the great world.
Such are thofe inhabiting the redum of the
horfe, the frontal finus of fheep, goats, and the
larynx of flags ; by the difcoveries of the cele-
brated naturalifls, Vallifnieri and Reaumur.

With refpect to feminal vermiculi, my obfer-
vations will not allow me to afcribe them to an
external origin ; for, was it fo, certainly I muff
once have perceived it. More than fourteen
years have elapfed fince I have been occupied

with

a See the Italian tranflation of La Contemplation, part.
10. chap. 26. Note, at the words molte centcna'ia de picdi.

SEMINAL VERMICULI.

I§5

with infufions, fince I have ftudied the waters
of marfhes, ponds and ditches. I can however
fay, with abfolute fincerity, that among the in-
numerable multitude of minute animals, there
are none refembling the feminal vermiculi of
man and other animals a. I do not deny, that
by fuppofmg they pafs from the water to ani-
mated bodies, they may poflibly undergo fome
change or alteration, operated perhaps by the
caufes the Genevefe philofpher details, which
he has rendered probable by demonftrating, that
animals changing their climate and aliment, fuf-
fer an alteration : “ Ranae in Ebufum infulam
“ delatas colores mutant ; aves in regione Sep-
<e tentrionali albefcunt, in Meridionali nigref-
<e cunt : fic vulpes, urfi, lepores mutato loco,
“ colores et quandocunque mores mutant.” I
alfo acknowledge, that the form of the body of
vermiculi may change in its proportions ; that

the

a This had been already remarked by Lewenhoek, as
appears in his 301. letter : “ Licet varias et indole diver-
“ fifiimas aquas contemplatus fim, nec iftius modi animal-
“ cula (id eft fpermatica) nec quidquam quod animalcula
“ ifta fimilitudine aliqua vel figura referret in ullis unquam
“ aquis obfervaverim.” Other obfervers agree as much as
I could dcfire, with Lewenhoek and myfelf. Among 146
genera which Muller has claffed, he has only feen one re-
fembling the fpermatic vermiculi of the (heep. It is that
he calls Cercaria. But this fpecies, which is the only one
that has been obferved, and very feldom found, (in infu-
fione animali raro), would be far from being able to give
exiftence to all the different fpecies of thofe vermiculi.

1 86

SEMINAL VERMICULI.

the parts may become larger or fmaller, accord-
ing as the new element agrees with their na-
ture : but I cannot think they will lofe their
prifline figure, to affume one very different ; or
that the firft change will be fuch as to prevent
them being recognifed ; for then the internal
ftrudture muff be changed alfo. But it would
be as if one fhould fay, that after their former
organs were entirely or partially changed, they
were new beings. This would rather be a
creation, than a change.

The feminal vermiculi not only differ from
nnimalcula in fhape; I have likewife fhewn them
to be of a nature and conflitution effentially dif-
ferent. Such are the differences mentioned in
the former chapter, and in that preceding it j
and I omit them here, to avoid repetition.

M. Bonnet fuggefts an ingenious experi-
ment : to try whether the feminal vermiculi
would live in infufions, and the animalcula of
infufions in feminal fluids. I had already done
this in part ; but upon palling the animalcula
of putrid into recent femen, and the vermiculi
of recent femen into that which was putrid, I
faw the whole vermiculi and animalcula perifh.
At the fame time, to fatisfy the curiofity of my
illuftrious friend, inflead of corrupted femen,
I made ufe of vegetable infufions. I took the.
precaution, that thofe where I put the vermi-
culi were of the fame heat as the femen when

in

SEMINAL VERMICULI.

187

in the body of the animal ; and that the femen
wherein the animalcula were put, fhould have
the temperature of the atmofphere : but I never
could by this method prevent their death. There
was, however, a little difference : the feminal
vermiculi perifhed immediately, and the infu-
fion animalcula died in a few minutes.

The very great difference of aliment to which
the vermiculi muff be accuflomed, upon paffing
from without to the femen of animals, feems to
me a fufficient reafon why that cannot be their
origin. For, the fmallefl animals of our world
perifh when obliged to change their food, as
we fee in caterpillars feeding upon determinate
plants ; when the plants are changed, they die.
So that, if we give filk-worms any other than
mulberry leaves, they very foon fuffer, if they
do not immediately die. Befides, not only do
infe&s perifh when the plants are changed, but
alfo when the places of the fame plant they na-
turally occupy are changed. How many hun-
dred fpecies of infedls feed upon the pear tree ?
The ligneous parts ferve fome for food and ha-
bitation : fome infinuate themfelves between
the bark and the wood, and never quit their
retreats : others, to conceal themfelves, fold fe-
veraldeaves together, and feed upon the mofl
delicate parts : others prefer the branches, and,
penetrating, form tumours there : fome me-
nace the flowers, and others the fruit. Let us

change

i8S

SEMINAL VERMICULI.

change this order : let us tranfport the infe£M
of the wood into the bark, and, reciprocally,
thofe of the leaves to the roots, and fo on with
the reft, changing their nutriment and abode.
Doubtlefs, we ftiall fee them quickly perilh. I
cannot perceive why the fame thing Ihould not
happen to fpermatic vermiculi, if they palled
from water to the femen, fince their aliment is
completely changed. It is not enough to fay,
that we have an example in the worms in the
horfe, the Iheep, or the ftag, which live in a
place, however, where their exiftence did not
begin ; for I may reply, that they have not paf-
fed from a large to a little world, after living
in the former, but are developed in the quad-
rupeds where they have been depofited by flies,
where they remain until maturity, and where
they feed upon the fubftance of the animal.
If, before they acquired this maturity, their fi-
tuation was fortuitoully changed, itis molt like-
ly they would perilh. We Ihould fee them pe-
rilh, or rather, not expand, if the producing
flies laid their eggs elfewhere. Whence it fol-
lows, that this example confirms the general
lawr.

But if we cannot believe that the vermiculi
come from without, what is their origin ? We
fhall reply, what Vallifnieri has faid upon the
origin of the worms of the human body : They
are produced, fed, and they multiply in us

and

SEMINAL VERMICULI.

189

and in other animals : they pafs from genera-
tion to generation with the nutriment the mo-
ther affords in the uterus, and the milk which
is imbibed. This hypothefis feems to me more
likely than the other. According to M. De
Buffon’s aflertion, the femen of the female is
full of vermiculi perfectly like thofe in the fe-
men of the male. I doubt not the truth of
this : it has been obferved before him, and de-
fcribed by Signor Bono, a celebrated phyfi-
cian, and an excellent obferver of fpermatic
vermiculi, incapable of altering any fatt, as
he is unprejudiced in favour of theory a . What
has been obferved in the female femen by thofe
two naturalifts, I have fometimes, but rarely,
feen in the blood. In my long refearches up-
on the phenomena of circulation, I happened
to obferve in the mefenteric blood of a frog,
and three newts, I know not how many of
the feminal vermiculi peculiar to thofe amphi-
bia. There was no hazard of being deceived,
becaufe there was no room for miftake. One
could not fay that thofe vermiculi fortuitoufly
mixed with the blood, from the rupture of
fome of the blood vefiels of the tefticles or the
vafa deferentia, fince the frog and two of the
newts were females, and the blood vefiels, as
well as the generative organs of the male, were
entire, as I aflured myfelf by a careful exa-
mination.

a Vallifnieri, tom. 2. edit, in folio.

I90 SEMINAL VERMICULI.

mination. The vermiculi were actually im-
prifoned in the veffels, and were pretty viva-
cious. They were feen in the arteries, ex-
cepting a fingle time that I faw them in a vein.
The artery of a frog tadpole (hewed me fome
again ; I even faw fome in the blood of a fuck-
ing calf, and alfo fome in the red globules of
the blood of a fheep. I recognifed them as
real feminal vermiculi, for they had all their
chara&erftics. Thofe obfervations prevented
my furprife, when mixing a drop of femen
with a drop of blood, fo that the vermiculi
were forced from their native place, they dill
lived as before. I have obferved the fame
phasnomenon with faliva ; and it is natural to
fuppofe that it will be found in other animal
fluids.

From thefe facts I draw two conclufions.
The fir ft, that it is not abfurd to fuppofe, that
the mother may ferve as a conveyance for the
fpermatic vermiculi, to pafs them to the young.
The fecond, that they live in the fluids of the
young, particularly in the blood, and are in a
manner retained there until puberty ; then, the
femen matured, affords them aliment, and a ha-
bitation fit for their propagation. I fay, in a
'manner; becaufe the rarenefs of the feminal ver-
miculi in the blood, fufliciently proves it not
to be a fluid, which agrees too well with them,
happening perhaps from the aliment found

there

SEMINAL VERM1CULI.

I9I

there not being very fit for them. Although
the fenien is derived from the blood, yet are
they two very 'different fluids. To this it may
be oppofed, that the vermiculi found in the
blood of the male are the feminal vermiculi,
re-abforbed by the veffels, and mixed with the
mafs of the blood. This objeflion would be
well founded in adult males ; but it is ineffi-
cient where they are not fo, as in tadpoles and
fucking calves : in the former, the organs of
generation are not developed, and thofe of the
latter are not inhabited by vermiculi.

The father may be an inftrumental caufe of
the propagation of the vermiculi. This may
take place in almoft every fpecies of animals.
This method I find at leaft more direct, or per-
haps more natural, than the other : I fpeak of
the aft of fecundation, which may convey the
germs of the vermiculi to the embryo, by the
immediate vehicle of the femen. That the
eggs of females may be fecundated, they mufl
be bedewed by the fpermatic fluid of the male,
which muff aft upon the included embryo : it
fhould aft not only externally, but alfo inter-
nally, for we know that it regulates the parts
of the foetus a- It is therefore neceffary that
the foetus fhould be penetrated by it ; and in
this manner it will be eafy to introduce the ver-
micular germs. Thefe germs expand, and lay

the

a Bonnet, Preface de la Contemplation.

192 SEMINAL VERMICULI.

the foundation of a litlle colony of vermiculi ;
which takes poflefiion of the feininal fluid, and
gives birth to a numerous people.

The fecond queftion refpe&s the manner in
which the vermiculi propagate. In the almoft
infinite number of experiments which I have
made, I have always paid attention to this in-
terefting point. After feeing a prodigious
number of infufion animalcula multiply by a
divifion of the body, I inveftigated whether the
feminal vermiculi propagated in the fame man-
ner. But I have had no indication of this. It
is true, when they proceed from the animal’s
body, or when the vermiculi begin to be ill,
they are lefs fit for dividing than when in their
natural ftate, when they are vigorous and full
of life. I do not deny, that this is poflible ;
but, fay it was fo, it feems morally impoflible
that among fo many millions of vermiculi
which I have at different times obferved, a-
mong fo many fpecies, there was not one in a
ftate to divide, or which did divide, as is ob-
ferved with the animalcula of infufions : nei-
ther have I obferved, that the vermiculi propa-
gate by fhoots, like polypi. So that, abiding by
the different modes of propagation hitherto
known, it would feem a proper conclufion, that
the vermiculi multiply by means of a foetus, or
of eggs : but I mult admit that I never faw
either the one or the other.

I

SEMINAL VERMICULI. I93

I arrive at lafh at the queftion ; What is the
life of the vermiculi ? Lewenhoek’s opinion is
well known ; he thinks they are the immediate
authors of generation : fo that thofe of man
will be fo many homunculi, and thofe of horfes
fo many foals, and thus of the reft. We can-
not deny, that this idea is very ingenious : it
is unfortunate, that it is not real. I fhould de-
part from my plan, did I attempt to refute it :
authors celebrated, and known to philofophers,
have done this with fuccefs. But I cannot re-
fill: faying a word upon the beautiful difcovery
of Haller, which is completely decifive. He
proves by fadts, fo convincing that we cannot
refufe our aftent, that the foetus belongs to the
female ; that, entire, it pre-exifts fecundation.
It is therefore clear, that the male vermiculi
cannot be foetus. The circumftances eftablilh-
ing this difcovery, are explained in bis treatife
upon the chicken.

If we refufe the vermiculi this noble pur-
pofe, we do not fail to afcribe others to them.
Some phyfiologifts have thought them the caufe
of venereal pleafures : others, that they preferve
the fluidity of the femen : and others, that they
effect certain unknown purpofes. All have en-
deavoured to divine it. There exifts in us and
in other animals, this wonderful multitude of
animated beings, and many larger vermes, of
which Rhedi has given a hiftory, in a work

O upon

194 SEMINAL VERMICULI.

upon the fubjett, beginning with man, and de-
fcending to all animals, not excepting the fmall-
eft a. Each has externally animals which it
feeds, as this naturalift proves in the fame work.
But why do all thofe generations of animals in-
habit the external and internal parts of others j
why were they created ? This I think is be-
yond the fphere of human knowledge ; and it
will not difpleafe, if here I fhould be filent.
And I hope I fhall be pardoned for only guef-
firig at the other two : their intricacy has pre-
vented me from doing more.

The intent of this work, was to examine,
■with all poffible attention and accuracy, the
properties and nature of the myfterious inhabi-
tants of animal femina ; allowing myfelf to dif-
ctifs and refute the opinions of others learned
in the fubject, becaufe their celebrity and di-
vifion had created doubt. I leave the learned,
judicious, and impartial reader to confider,
whether I have fucceeded, and whether I have
diffipated, or at leaft diminiflied, the clouds
which veiled them from the truth.

a Degli animali viventi, negli animali viventi.

EX PE-

f I

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’

' . ■

. f ,

/

’

.

'■ it -j

v.

.

• *.

• •

■ 1 .

/

i

[ *9 5 3

EXPERIMENTS and OBSERVATIONS

UPON

ANIMALS AND VEGETABLES CONFINED IN
STAGNANT AIR.

INTRODUCTION.

If the privation of air is a powerful method
of preventing the production of animated be-
ings, and of deftroying life in thofe already in
exigence ; the prefence of air itfelf is confider-
ed equally noxious, when its circulation is im-
peded. A general rule has been eflablilhed,
T hat all animals and vegetables, forced to re-
fpire the air of clofe vefl'els, perilh irrecover-
ably. It is thought equally certain, that feeds
do not germinate, and that eggs are not ex-
cluded in the fame fituation. The great Boer-
haave fpeaks thus of all. “ Ovula quorum-
<c cumque infe&orum in vitris accurate claufis
“ non producunt, licet tepore fota foetus fe-
“ mina plantarum vitce macerata, optima; com-
<£ mifla terrae atque requifito excitata calore,

O 2 tc non

Ip6 animals and vegetables

<£ non tamen crefcunt, neque dant vitas ulla
<c figna adluofas.”

Such is the opinion of all philofophers and
naturalifts, which for feveral years I confi-
dently adopted, which I believed certain with
refpedt to the animal and vegetable kingdoms.
But my experiments upon infufions, infpired
me with a juft diftruft of it. I had difcovered,
that the animalcula of infufions were produced
and lived in veffels hermetically fealed ; and I
had feen the feeds I made ufe of, germinate
there. Thcfe fa£ts did not agree with the opi-
nion generally received, which induced me to
inveftigate the limits and conditions of the
maxim, That air which is confined \ and cannot
he renewed , is noxious to the beings in life , whe-
ther animals or vegetables , fubjecled to its influ-
ence. With this defign, I refolved to repeat and
to diverfify my experiments upon the animal-
cula of infufions, and the feeds of plants grow-
ing in clofe veffels. I Likewife wiflied to make
experiments upon fome animals, the great ana-
logy of which with the animalcula of infufions,
would induce us to fuppofe, that the noxious
influence of ftagnant air would not fo eafily af-
fect them, as it would animals ranking higher
in the fcale of beings. I therefore made expe-
riments upon the eggs of many terreftrial and
aquatic infedts ; and nature' has afforded thofe

ill u ft rations.

CONFINED IN STAGNANT AIR. TQ7

ill uft rations, which former authors have fought
in vain.

From eftedts I afcended to caufes, and en-
quired why confined air could, in certain fitu-
ations, be injurious to animated beings. Thus
I palled from one refearch to another. The
■work infenfibly encreafed in my hands, and be-
came much more confiderabie than I at firfl
expected. Since I prefume to publilh it ; to
leflen the tsedium of the reader, it is divided in-
to three chapters or fedlions. The two laft, in
particular, explain the caufe of the death of
animals ; and the firft takes a comprehenfive
view of thofe which are fubjedt to the impref-
fion of ftagnant air only in certain circum-
ftances.

198

ANIMALS AND VEGETABLES

CHAP. I.

/

I provided a certain number of veffels. In
each I put an infufion of vegetable feeds, and
then fealed them hermetically. I had got them
exprefsly made at the glafs-houfe : they were
large, each would contain 14 or 15 pounds of
. water a. To examine the infufions, it was not
necelTary to break the veffels ; but it fufHced to
caufe the included liquid pafs to a dry part of
the glafs, and then obferve it with a powerful
magnifier. The glafs was fo tranfparent, that
the animalcula were feen fwimming in the fine
pellicle adhering to the internal furface of the
vafe.

My experiments were made towards the end
of Spring ; and it was not long before animal-
cula begun to inhabit the veffels, and to inha-
bit the whole. The periods of their encreafe,
diminution, and deftruftion, were the fame
here, as in the open air.

Upon repeating the fame experiment feveral
times with different feeds, all afforded animal-
cula. I remarked one difference : the number
• of animalcula was never fo prodigioufly great,

which

3 Twelve ounces in the pound.

CONFINED IN STAGNANT AIR. I99

which I have obferved before. One mode by
which thofe animals propagate, is the natural
divifion of the body ; and this divifion likewife
takes place in confined air. Applying the mag-
nifier to the fide of the veCel, I fometimes faw
the animalcula dividing through the middle, fo
that the parts were conne&ed by a fhort fila-
ment : others appeared like two minute elon-
gated fpheres, touching in feveral points : ci-
thers exhibited, on the outline of the body, a
contra&ion, or the rudiments of a divifion
hardly begun.

The duration of life, and the multiplication
I had obferved in the animalcula of infufions,

I likewife faw in the anguillae of vinegar con-
fined in clofe vefiels. From the beginning of
April, till the end of November, they were
feen ; and they continually became more nu-
merous. It is true, as the Winter advanced,
the eels perifhed ; but the fame happened to
thofe in vinegar in the open air, the caufe of
which was the encreafed cold. We know that,
during Winter, vinegar is without eels.

While I made thofe experiments, the wa-
ter of fome ditches was full of worms, in-
fers, and the tadpoles of frogs. Upon thefe,

I made the fame experiments I had made upon
the animalcula of infufions, and the eels of vi-
negar. I begun with the larvae of infedts. Se-
veral I confined in veffels with ditch water,

O 4 that

200 ANIMALS AND VEGETABLES

that they might find aliment among the quanti-
ty of heterogeneous matter, of which the vra-
ter was full. The larvae did not fuffer from
this confinement : all changed to nymphs, from
which, in time, proceeded winged flies.

Several tadpoles were alfo confined in the
yefiels along with a fuflicient quantity of water,
wherein 1 had put the rnarfh lentil to feed them.
During twenty-four days their fize conliderably
encreafed ; and they died, it is probable, lefs
from the fiagnation of the air, than becaufe
the lentil w?as completely confumed. The tad-
poles were young. I repeated the experiment
upon grown tadpoles, whofe limbs had already
begun to appear. This period I chofe, to learn
whether they underwent their metamorphofis
in confined air. Several did undergo it, and
diverted themfelves of the tadpole form, to af-
fume that of the frog. But others perilhed be-
fore attaining their new ftate.

Thofe animals inhabiting the waters, are not
under the fame neceflity of refpiring air conti-
nually renewed, as the animals which nature
has deftined to live amidft the airitfelf: I
therefore thought of making fome experiments
upon them. But, as I had made experiments
upon tadpoles, that is, upon a fpecies of ani-
mal changing its ftate, I was defirous to re-
peat theih upon fome other animals of the fame
pat ure. Caterpillars firft fuggefted themfelves ;

and

CONFINED IN STAGNANT AIR.

201

and my fir ft experiments were made upon filk-
worms. Thofe I ufed with this intention,
would a few days after have begun to fpin their
webs. Sealing them in a veffel hermetically,
they were fixed upon the leaves of a mulberry
branch, the ligneous extremity of which I had
immerfed in water, that the verdure of the
leaves might be preferved for lome time, and
ferve as food to the worms. More than a third
perifhed ; but the refl proceeded, as ufual, till
the eleventh day : they worked at the webs as
ufual, fixed them to the fide of the glafs, and
there fhut themfelves up. Butterflies came
from nine webs ; from two there came none.
Upon examining the flerile webs, I found the
larva transformed to a chryfalis ; but the but-
terfly did not come out, as it died while in this
form. The webs of the eleven butterflies
changing to caterpillars in this clofe veffel, were
of good filk ; and their only difference from o-
thers, was in not being fo hard and elaflic as
webs generally are.

Other caterpillars, efpecially thofe of the
elm and the oak, underwent the fame changes
as the filk-worms did in clofe veffels. 1 purfu-
ed the fame method, of confining them in vef-
fels where I had put fome branches of the trees,
immerfing the lower extremity in water.

The metamorphofes of the larvae of large
flefli-fiies, were more diftindtly feen. 1 put a

piece

202

ANIMALS AND VEGETABLES

piece of flefh, nearly putrid, at the bottom of
one of the vefiels : it ferved them for food nine
days, that is, all the time they were worms, and
until they became nymphs. We know, that
•when their change to nymphs approaches, they
abandon the mafs of putrid flefh, and, feeking
a dry fituation, mod commonly conceal them-
felves under an arid dufly earth.

Thofe I had confined, likewife abandoned
the flefh, traverfed the veffel, and were in con-
flant motion more than half a day. Their
anxiety to efcape, was clearly evinced ; but be-
ing unable to effect it, they retired to the Tides
at the extremity of the neck, which was almoft
parallel with the table, and became perfectly
tranquil. There they infenfibly contracted ;
their fhape and colour difappeared ; they af-
fumed a light chefnut colour, and exhibited
every fign of being changed to nymphs. In
this Hate they remained fourteen days j then
the fhell of the nymphs burfting, the flies, com-
pletely refembling the parent fly, efcaped. The
winged infers lived feveral days in their prifon,
and then died, apparently for want of food.

I may fay a few words concerning what hap-
pened to the feeds I ufed for infufions. They
developed like the animalcula, all germinated
well, and in a few days the budding of the
branches and the leaves filled the capacity of
jny veffels. I fliould not negleft to obferve,

that

CONFINED IN STAGNANT AIR. 203

that all thefe vegetations appeared to be difeaf-
ed, whether from their decay before producing
fruit, or becaufe their colour was yellowifli.
But, fufpecting that this difeafe was not fo
much the effeCt of the privation of the air, as
of the beneficent influence of the fun, and the
moifture they muft require to be fupplied by
the roots, which could not be obtained from
the fmall quantity of water, I endeavoured to
difcover the real caufe. I put the fame quanti-
ty of feeds into veffels hermetically fealed ; and,
inflead of water, fubflituted a given portion,
of earth well moiflened. The plants foon
fprung up ; and being fome hours of the day
expofed in the beams of the fun, in a fhort
time they reached the fummit of the veffel,
without yellowing, and they did become yellow
only after a confiderable period. I fhould add,
that the feeds I made ufe of were, peafe, maize,
kidney-beans, red and bearded wheat, and rye.
I planted two (talks of rye under the neck of
the veffel, where there wras a fufficient fpace
for their elevation : the neck being very long,
they exhibited unequivocal marks of vegeta-
tion, and the ear fliot out of the calyx. This
fructification would have made the greatefl
progrefs, but for the approach of Winter.

To complete what I have laid of feeds con-
fined in veffels, I fhall remark, in palling, that
although I have in this way obferved more than

twenty

204 ANIMALS AND VECETAELES

twenty fpecies at different times, ‘I have not
found one that did not germinate. We muff
not negleCt a fa£t effential for their production.
Whenever they fpring in water, which takes
place as well in clofe as in open veffels, the in-
fufed feeds muff be partially above the water,
otherwife they perifh. This precaution was
before me difcovered by the celebrated natu-
ralift M. Duhamel.

But if vegetable femina germinate without
exception in confined air, what are we to think
of animal femina and the eggs of infeCts, which,
according to Boerhaave’s opinion, and that of
many philofophers, fliould remain fferile, even
when the operation of circumftances the moft
favourable to their production concurs? With
refpecl to this, I thought it was better to con-
fult nature, than to truft to the fcience of others.
I therefore made experiments upon many eggs.
Thofe I made ufe of, were the eggs of feveral
fpecies of fmall beetles, flies, large flefh-flies,
ncCturnal and diurnal butterflies ; and I took
care to mark fcrupuloufly what happened to
each kind. I forefee the anxiety the reader
muff experience to learn the refult of thofe ex-
periments ; and, in two words, I fatisfy his cu-
riofity by faying, the whole different fpecies
were produced the fame in confined as in open
air. Boerhaave, adopting the received maxim
concerning the fferility of eggs in confined air,

thus

CONFINED IN STAGNANT AIR. 20$

thus exprefles himfelf in the Prceledtiones Aca-
demic# a. “ Ova Bombycis in aere calido ex-
<c cluduntur ii libere admittatur. Eadem in
« phiala claufa nunquam producunt fuum ani-
“ mal.” Now, the faft is, that thofe eggs
hatch very well in clofe veflfels, as I have been
convinced by every experiment I made.

We mull conclude, from all I have faid, that
the air of clofe veflfels is not an impediment to
the production of plants or animals ; but that
plants, without any exception known to me,
grow well there ; that animals encreafe and
propagate their fpecies. Thofe which undergo
metamorphofis, experience the whole fuccef-
fively, in clofe, as well as in open veflfels.

Why do we generally believe that ftagnant
air injures the production of animals and vege-
tables ? Analogy is, I believe, the caufe of this
remarkable error. It was obferved, that the a-
nimals and vegetables upon which experiments
were made, foon perilhed in clofe veflfels ; that
feeds and eggs confined there were fterile : and
a general conclufion was drawn, that ftagnant
air was decidedly noxious to both the kinds of
living beings.

In the beginning of this chapter, I have faid,
the veflfels I employed were very large ; that
each might contain fourteen or fifteen pounds
of water. With thofe veflfels I obtained the

refults

1 Tom. 2.

2o6 ANIMALS AND VEGETABLES

refults I have mentioned. But the confe-
quences were very different when I ufed veffels
fucceffively fmaller. In proportion as their ca-
pacity decreafes, the eggs or feeds do not ger-
minate, or they perifli when fcarcely deve-
loped. Animals of every fpecies in a fhort
time die there. All the naturalifts who have
feen in their experiments a different refult
from that afforded by mine, have undoubtedly
made ufe of veffels too fmall, otherwife they
would certainly have had the fame confe-
quences with myfelf. However, I do not deny
that their error refpefting animals, might arife
from the nature of the animals upon which
their experiments were made ; for thofe ani-
mals muff inevitably have perifhed, however
capacious the veffel might be ; for example,
warm-blooded animals. To underhand this
better, and to evince the truth of what I fay, I
Ihall enter upon fome details.

The animalcula of infufions originate, live,
and propagate, in the veffels I firft fpoke of :
this alfo happens in veffels one third of the fize >
only we then begin to perceive the difadvan-
tages of the ffagnant air. When the capacity
is fuch as to contain three pounds and a half
of water, the number of animalcula is lefs ;
they multiply lefs, and die fooner. Upon di-
minifliing the veffels, the larger animalcula
are not feen ; and neither large nor fmall, if

• the

CONFINED IN STAGNANT AIR. SiOyf

the internal capacity does not exceed feven or
eight inches.

The nymph of the gnat feems to fupport
this fuuation better than the animalcula of in-
fufions. In five inches of air, feveral changed
to the winged (late. As the quantity leffens,
they perifh proportionally fooner.

The eels of white vinegar are particularly
remarkable : they live and multiply prodigi-
oufly in a volume of air not exceeding three
inches ; and die in feveral days, only when
confined in a tube where there is an inch va-
cuum. I fpeak of white vinegar, for the effects
are very different in red. In my experiments,
the eels of this did not live five days in a vef-
fel where the vacuum was eleven inches. This
did not happen becaufe the vinegar underwent
an alteration in the veffels, but rather becaufe
the eels of red vinegar are of a nature different
from thofe of white ; which I believe to be the
more probable caufe of the difference I remark-
ed in the figure of each fpecies.

Tadpoles perifhed in a very few days in nine
inches of air ; and in three hours, if the va-
cuum was only three inches.

When caterpillars and the larva; of flies are
confined in but eleven inches of air, they die
before transforming to chryfalids. The larvae,
in particular, foon after being confined in a
clofe veffel, defer ted the putrid flefh put in a-

long

dOo ANIMALS AND VEGETABLES

long with them for food, and with agitation
traverfed the veflel, difregarding the flefh.
They lofl motion and life after various times,
longer or fhorter. If the veflel was larger,
they lived longer : if fmaller, they died

fooner.

Larvae, when changed to nymphs, fufFered
lefs from the fmall quantity of air. In a veflel
where larvae had died, I confined the fame
number of their nymphs. The flies of fome
came out : but it is neceflary to obferve, that
the wings and body were diftorted : they Teem-
ed to have been produced againft the will of
nature. This never happened to the butter-
flies of feveral fpecies of chryfalids, although
the vacuum of the veflel was very fmall.

What I have hitherto faid, will apply to
feeds and eggs. I omit telling the reader, the
trouble I had to find the fucceffive capacities of
the vefiels where the feeds and eggs ceafed to
germinate : but, adopting the general refult, I
fhall fay, that when the capacity of the vefi'els
was but three or four inches, neither feeds nor
eggs have developed.

We muft therefore conclude, that the pro-
duftion of vegetables, and of fome animals,
takes place, as wrell in confined, as in open air,
provided the quantity of air in the vefiels is
confiderable ; but, on the contrary, when it is
not, that it becomes fatal to both. The pre-

cife

CONFINED IN STAGNANT AIR. C09

cife quantity which may be noxious, can only
be determined by the nature, conftitution, and
quality, of the animals and vegetables confined.

My experiments being made at different
feafons of the year, I difcovered another fa£t,
which is ; That the death of animals is not
only accelerated by diminifhing the fize of the
veffels, as I have demonftrated, but alfo by the
encreafe of heat. This is particularly feen in
thofe animals, which are eafily procured at any
time of the year, and live long without food :
fuch are, newts, leeches, land and water fer-
pents, vipers, and fome fpecies of fifhes. I ob-
ferved, as much as poffible, that the individuals
I took for my experiments fhould be of equal
fize, and equally vigorous ; fo that the compa-
rifons might be more juft. Here follow the
fa£ts which I found. Upon the fifth of April,
along with other things, I prepared three jars ;
the firft might contain fix pounds of water,
the fecond four, and the third two. In each,
four newts were confined. My experiments
led me to examine, whether the animals died
fooner as the volume of air was diminifhed.
This was the cafe.

In the fmalleft veflel, the four newts perifli-
ed in forty-one hours ; in the intermediate vef-
fel, in two days ; and in the largeft, in feven
(Jays,

P

Upon

210

ANIMALS AND VEGETABLES

Upon the fame day of April, I made a fimi-
lar experiment with leeches. I confined four
in each veffel. They lived there a long time,
in comparifon to the newts. In the fmallefl
veffel, they perifhed in three days ; in the
next, in nine ; and in the largeft, in thirty-two
days.

I repeated this experiment 12. May, in
the fame veffels, and with the two fpecies of
animals. Both died much fooner. In twenty-
feven hours, the newts in the fmallefl: veffel
died ; in the next in three days, and in the
largeft in four days.. The leeches in the fmall-
eft veffel died in two days, in the next in five,
and in the largeft in nine. The more fudden
death of the newts and leeches in the month of
May, I fufpedled to be occafioned by the en-
creafed heat of the feafon ; feeing, in the month
of April, during the greateft heat, the thermo-
meter afcended to 570, while in May it flood
at 70°. My fufpicions were realifed, fince, in
the months of June and July, the death of the
animals was accelerated. In July, the ther-
mometer being at 82°, the four newts in the
largeft veffel died in twenty-three hours, and
the leeches in thirty-five.

What has been faid of leeches and newts,
fhould apply to fnakes, vipers, and fifties. The
refults from thefe, correfponded with the for-
mer. The death of the whole was not only

accelerated

CONFINED IN STAGNANT AIR.

211

accelerated in proportion to the fmall quantity
of air they were forced to refpire, but alfo in
proportion to the encreafe of heat : I obferved
the reverfe only twice, which we muff view as
arifing from fome accidental circumftance.

I waited until Winter, to make the experi-
ment inverfely ; that is, to learn whether the
death of animals was retarded in proportion
to the encreafe of cold. This experiment fuc-
ceeded with vipers and newts, which were
the two fpecies I then had at command.

The newts in the fmalleft veffel lived twen-
ty-two days, in the middle fuzed thirty-four
days, and in the largeft two months. Vipers
lived ftill longer. The velfels were placed in
a fituation where the thermometer flood at
48°.

In a greater degree of cold their life was
protradled ftill longer. The newts and vipers
did not perifti in three months, when the fmall-
eft velfels were kept under fnow\ Both kinds
died upon being expofed to the temperature of
the atmofphere for fome days during Spring.

Such are the principal refults I have been
able to colle£t, from the experiments related in
this chapter. Thofe refults are of great utility,
becaufe they elucidate the fubjetl ; but they
leave us at liberty to fancy the caufe, or rather
the defire of feeking it. If the obferver is a
philofopher, he will endeavour to difcover the

P 2 reafon

212

ANIMALS AND VEGETABLES

reafon accelerating the death of animals in
fmall veffels, and retarding it in large. Why
is it accelerated more by heat than by cold ?
Whence arife thofe diverfities in the time of
an animal’s death ? Why may one quantity
of air be noxious to one fpecies of animals, and
indifferent to another ? The folution of thefe
problems depends upon our knowledge of the
caufe of death in flagnant air. This ancient
and moft famous queflion has always divided
the celebrated modern philofophers. Notwith-
ftanding its importance, I fhall attempt to dif-
cufs it. I fhall examine what has been already
written upon it, and fhall adopt the opinion
which to me feems the mofl confiflent with
fa£ts ; that is, with truth. Since we have feen
that the eggs of animals, and the feeds of
plants, remain fterile when put in a fmall
quantity of air, I fhall not fail to add a fhort
fentence or two upon the caufe of their fte=
rility.

CONFINED IN STAGNANT AIR.

113

CHAP. II.

'Those who have killed animals in clofe vef-
fels, have, in their experiments, remarked two
phenomena : firft, that there is accumulated
upon the Tides of the veffel a quantity of va-
pour exhaled from the animal ; fecondly, that
the air has loft a certain degree of its elafticity.
Thefe two phenomena have produced different
opinions. By one, the death of the animals is
afcribed to thofe exhalations which, being
confined in the veffels, are refpired by the ani-
mals, and thus become fatal. Another opi-
nion maintains, that the exhalations cannot be
mortal ; but that the diminution of the elafti-
city of the air, occafioned by the exhalations,
or a portion of the air being deftroyed by refpi-
ration, becomes fatal to the animals.

The experiment of Piftorini of Bologna is
fpecious. To appretiate the force of both o-
pinions, he reafons thus. Suppofing both o-
pinions to be juft, it fhould neceffarily happen,
that two animals confined in the fame veffel die
fooner than if they were alone, provided the
veffel is the fame, and the animals of the fame
fize and fpecies. We muft therefore recur to
the exhalations from the animal, or the dimi-

P 3 nifhed

214 animals and vegetables

nifhed elaflicity of the air, occafioned by the
effluvia efcaping from its body, or by the refpi-
ration itfelf. But it is always certain that,
doubling the number of animals, the exhala-
tion and refpiration are doubled ; and confe-
quently the diminution of the elaflicity of the
air fhould be doubled. Piflorini did not find
this refult. Two animals died in the fame
time as one ; although he ufed the fame veffel,
and animals of the fame fize and fpecies a.

The fmgular conferences of the experi-
ment, induced others to repeat it, among whom
was the illuflrious Profeffor Verati. His expe-
riments were made upon birds, and upon frogs.
A pigeon lived three hours and three quarters.
Two pigeons in the fame veffel lived only half
the time. Three fwallows died in little more
than half an hour, two fwallows in lefs than an
hour, and one fwallow lived almoft two hours.
He remarked nearly the fame with fparrows
and quails : three died fooner than two, and
two fooner than one. But with frogs it was
quite different. In eight days four died as foon
as two, and one alone lived no longer than
three. So that the experiments upon birds were
very different from thofe of Piflorini ; and thofe
of Piflorini agreed with the experiments Sig-
nor Yerati made upon frogs. And here we
fee, that, in this mode of death, nature is dif-
ferent

f Aft. Bononien. tom. 2. part. i.

CONFINED IN STAGNANT AIR. 2I5

ferent in different animals, which is the caufe
of the difcrepancies between Verati and Pif-
torini.

Signor Cigna, a celebrated profeffor, has al-
fo engaged in an examination of thofe differen-
ces : he thinks to have deftroyed them by his
exa<5t experiments ; the refult of which is this.
Where the frogs confined in the veffels are de-
prived of water, as it would appear thofe of
Signor Verati have been, there, it is true, that
the plurality of frogs does not accelerate the
death of thofe confined ; at leaft, this is often
the cafe. When frogs are confined along with
water, which is their natural aliment, it is al-
moft certain that the acceleration of death is
in proportion to the number of thofe amphi-
bia a.

The experiments related in the preceding
chapter, induced me to engage in this enquiry
alfo. If it was true, that feveral animals of a
given fpecies confined in the fame veffel, died
in the fame time as when there was only one
animal, and if the phenomenon was not acci-
dental, but conflant, it muff (as I faid before)
be regulated in a manner proportioned to the
fmalleft quantity of air confined along with the
animals. But we may eafily fee, that the fmall-
eft quantity of air fhould always be where there
are molt animals. As frogs, according to Sig-

P4

s> Mifcell. Taurin. tom. 2.

nor

21 6

ANIMALS AND VEGETABLES

nor Verati, had difturbed the order eftablifhed
by this law, and as 1 could not repeat the ex-
periments of Piflorini, becaufe he has not fpe-
cified what animals he employed, I made my
experiments upon frogs alfo ; fome in veffels
with water, and fome in veffels without, thus
to come near the method followed by thofe au-
thors. In three veffels, each of which would
contain five pounds of water, I hermetically
fealed up frogs ; that is, two in one, four in
another, and eight in the third. In this laft,
the eight frogs perifhed in twenty-fix hours ;
in the fecond, the four frogs perifhed in one
day ; and in the fir ft, the two frogs perifhed in
two days.

At the fame time, I made a firnilar experi-
ment with other three veffels, as large as the
firft, with the fame diftribution in the number
of frogs ; fo that there was no difference be-,
tween this experiment and the preceding; only,
in it, there was no water in the veffels, and in
this four ounces were in each. In two days,
none of the frogs were alive in the veffel with
eight : in that with four, they lived three days
and a half ; and five days where there were
two frogs. During thefe experiments, the ther-
mometer flood between 63 and 70°.

I repeated both experiments ; the circum-
ftances the fame in every refpeft, excepting
that the heat of the weather was greater, and

then

CONFINED IN STAGNANT AIR. 11J

then the thermometer afcended to 90°. In the
firft of thefe experiments, the eight frogs in the
firfl veffel died in twenty hours ; the four in
the fecond in nineteen ; and the two frogs in
the third in about two days. As to the fecond
experiment, made at the fame time, and in
which each veffel contained about four ounces
of water, the refult was as follows. The eight
frogs in the firft veffel died in thirty-two hours;
the four in the fecond in two days ; and the
two in the third in three days and a half.

I repeated both experiments feveral times,
which, to avoid the taedium of dry details, I
{hall not circumftantially defcribe, and will on-
ly fpeak of the refults which I had from the
veffels without water. Sometimes I obferved
thofe irregularities which I have already re-
marked. It fometimes happened, that a great-
er number of frogs perifhed in the fame time,
and fometimes later than a leffer number. But
when the frogs were in water, they conftantly
perifhed fooner, as their number was greater :
eight died firft, then four, and laftly two. It
happened only once, that all the eight were a-
live when one of thofe was dead in the veffel
confining four.

From all thefe fads, added to thofe related
by Signor Cigna, it muft refult, that frogs cor-
roborate the general rule, That animals , with-
out exception , perijh in conjined air fooner , accor-
ding

£lS animals and vegetables

ding as their number is encreafed. At the fame
time, difcrepancies will be feen in frogs con-
fined in veffels without water : but I know not
whether they Ihould be regarded as fuch, be-
caufe the privation of water is injurious to thofe
animals ; which is remarked by Signor Cigna.
Frogs in open veflels die in a fhort time, if
they want water. It is therefore abfolutely ne-
ceffary to profcribe this caufe difturbing our
experiments.

The reafon of the difcrepance in frogs being
found, perhaps it would not be fo difficult to
find it in the animals of Piftorini, had he men-
tioned the fpecies, and the manner in which he
conduced his experiments. With refpect to
what Signor Verati relates, we only know, in ge-
neral, that he made ufe of birds. But he has
found that this kind of animals, as I have my-
felf found, and as I fhall foon obferve, agrees
well with the rule of which we fpeak. We
have therefore reafon to fufpedt, that Pifto-
rini’s experiment has met with fome accident,
without knowing in what the accident confid-
ed, which rendered his refults different from
thofe of others. Perhaps it was occafioned by
the birds themfelves : perhaps, that one which
he confined alone, was lefs vigorous than thofe
he confined together ; whence they all died in
the fame time. Perhaps, in the experiment
with the two birds, all communication with

the

CONFINED IN STAGNANT AIR. 21$

the external air had not been prevented ; which
might eafily happen, if the top of the vefiel had
been covered only with leather, or any fub-
ftance of a fimilar nature ; or if, upon invert-
ing the mouth of the veffel, it had not been
well fixed with maftic, or fome fuch fubftance,
to the plane of pofition. It is very pofiible that
fome invifible hole might remain, or fome o-
pening, by which the air might get admiffion
to the velfel. To take away all fufpicion of
foreign air, it is neceflary to feal the veffel her-
metically, or to immerfe the mouth deep in
water ; as I fhall more clearly explain.

In the preceding chapters we have feen, that
the heat of the weather accelerates the death of
the animals confined. May not we fufped that
Piftorini had made the experiment upon a fingle
bird in very warm weather, and that upon the
two birds in very cold ; and the death of the
two birds by this means be retarded, by the
coldnefs of the air, which would occafion the
death of both, in the fame time as that of the
bird which was alone, becaufe the death of this
bird might be occafioned by the greater heat ?
Here I fhall leave this irregularity. But, before
refuming my principal objeft, I fhould throw
a glance upon a doubt which occurred upon
feeing animals die fooner in a clofe than in
an open place, when the number of them is
encreafed. I know not whether the more im-
mediate

220

ANIMALS AND VEGETABLES

mediate death is caufed by the diminution of
the volume of air alone, or if the number of
animals will in another manner effett the more
immediate death, and become a new caufe why
it fhould happen. To be fatisfied which was the
cafe, I felecled three equal veffels, and a certain
number of the larged: frogs, as equal in fize as
poflible. I confined two in one veffel, along
with a pound of water ; and put one alone in
each of the other two veffels, along with a
pound of water, adding a quantity /of water
equal to a frog in fize. To difcover what
quantity equalled the bulk of a frog, I im-
merfed it in a veffel, obferving the quantity
that overflowed. By this method, the quan-
tities of air in the three veffels were equal, al-
though in one veffel there were two frogs, and
in each of the other only one. If the greater
number of animals occafioned the acceleration
of their death abfolutely, becaufe the volume
of air was diminifhed ; in this cafe, the bulk of
air was equal in all the three veffels, and the
four frogs fhould die in the fame time nearly.
If the greater number of animals influenced the
acceleration of death, .the two frogs in the fame
veffel fhould die firfl. I have faid nearly, for
although every thing is equal, it would be very
remarkable if the animals died in the fame
time. The two frogs in the firfl veffel lived
two days 5 that in the fecond veffel died in

three

CONFINED IN STAGNANT AIR.

32T

three days and feventeen hours ; and that in
the third, died in three days and a half. This
refult will demonftrate the influence of number
in accelerating the death of animals ; and other
experiments confirm it in a manner which can-
not admit of contradiction. Five times I have
repeated the fame experiment, with the fame
confequences. The two frogs in the firft veflel,
always died fooner than thofe in the fecond and
third ; and the difference of time was very per-
ceptible ; it has uniformly been a day, fome-
times a day and a half, and fometimes longer.

I made a variety in the experiment in ano-
ther manner. Inftead of two frogs, I put three
in the firfl veffel, and only one in the reft ;
but equalizing the volume of air, by adding a
quantity of wrater equal to two frogs in bulk,
which made the quantity of air equal in each.
The three frogs in the firfl: veffel died not only
fooner than thofe in the other two, but the
difference here was ftill more confpicuous than
before ; it was two days and feven hours in
the death of the frog in the third veffel. En-
creafing the number of frogs in the firft veffel,
their death was conftantly accelerated with re-
fpect to the frog in the fecond and third ; al-
though I took care to equalize the volume of
air, by adding water equal in bulk to the frogs
in the firft veflel.

This

222 ANIMALS AND VEGETABLES

This experiment upon frogs I extended ;
and changed the fubje&s ; making experiments
upon feveral fmall terreflrial quadrupedes and
birds. But, notwithftanding the equal quan-
tity of air in the veffels, I always found that
as the animals were more numerous, they died
fooner, and that the acceleration of their death
was conflantly in proportion to the encreafe of
the number.

Thus it is evident, that the death of animals
in clofe veffels follows this invariable rule,
that it happens fooner as the animals are more
numerous. But, by what phyfical agent ; by
what means are they in this manner deftroyed ?
Perhaps it is by their breath, or perhaps by
the humidity of the air which they refpire.
Let us examine thefe two opinions with care ;
beginning with that which is founded upon an
alteration in the hate of the air.

That the air lofes part of its elafticity, evi-
dently appears by barometers placed in the
veffels where animals are confined. The de-
fcent varies. Stair obferved, that his barome-
ter fell an inch in a veffel where a rat had
died. In the experiments of Verati, it fome-
times fell eight lines, fometimes nine, twelve
and more, according to the nature and number
of the animals confined. The experiments of
Mayow, Boyle, Hales and others, agree in

eftablifhing,

CONFINED IN STAGNANT AIR. <21$

eftablifhing, that a portion of the air is deftroy-
ed by animals confined in a clofe veffel.

We cannot from thence conclude, that the
death of animals in clofe veflels is occafioned
by the diminifhed elafticity of the air ; at leaft,
there are no experiments pofitively proving it.
We mud firfl fee whether this alteration of the
air always takes place when animals die in
clofe veflels. Secondly, whether this degree
of alteration is fufficient to kill the animals :
for we know that every degree in the diminu-
tion of the elafticity of the air is not fatal to
them.

In this Signor Cigna has laboured in a
manner worthy of praife, and I fhall make ufe
of fome of his ideas. I have made a courfe
of experiments with the fame intention, which
fhall be abbreviated after mentioning the me-
thods employed. I ufed feveral air-pump glafs
receivers. I immerfed them in water, invert-
ed on a plane. They were of that kind open-
ing and clofing above by means of a flop-
cock. The receiver being left open when im-
merfed in water, there was a free pallage left
for the internal air to efcape above, in propor-
tion as it was comprefied by the rifmg water -
and thus the remanent portion of air in the
receiver preferved the natural degree of den-
fity of the external air, which was abfolutely
neceflary for the exa&nefs of the experiment.

This

224

ANIMALS AND VEGETABLES

This being done, I clofed the vefiel ; and, to
make it more fecure, I palled feveral folds of
leather around the flop-cock, which took away
all communication with the external air : I
was certain that the external air could not in-
finuate itfelf, for I ufed the fame receivers as
in my pneumatic experiments. Having put
the animals in the receivers, I could mark the
diminution of the elaflicity of the air, by the
afcent of the water within. If the animals
were aquatic or amphibious, I let them remain
in the water. If terreflrial, I put them in a
veffel which was fufpended by a hook at the
top of the receiver.

My firfl experiments were upon frogs. I
confined feven in one receiver, leaving a bulk
of air equal to a pound of water. In half an
hour, the water within began to rife above the
level of that without ; which evidently proved,
the elaflicity of the internal air was affected.
The afcent continued until all the frogs were
dead, or dying. The water had rifen eleven
lines.

I repeated the experiment in the fame man-
mer, confining only four frogs in the receiver.
When they were dead, the water had afcended
ten lines.

The elevation of the water was one line
higher, in an experiment with two frogs.

The

CONFINED IN STAGNANT AIR. 22^

The water afcended nine lines, when I ufed
only one frog.

I made thefe experiments upon newts, re-
ferring in the receiver the lame quantity of air
as for the frogs. The death of eight newts
raifed the water fcarcely an inch • of four
newts, nine lines ; of two, fix lines ; and of
one, five lines. The elevation of the water,
therefore, diminifhed with the decreafe of the
number of newts.

After the death of eleven leeches, the water
afcended five lines and a half ; and after the
death of three, only one line.

Several naturalifls have remarked how much
fmall animals deftroy the elafticity of the air.
I had remarked this alfo in birds : it was chiefly
upon them that the refearches of Verati were
made. But nobody, that I know of, has made
experiments upon an animal which partakes
both of the nature of a bird and of a quadru-
ped, although it is not properly either the one
or the other. I fpeak of the bat ; this animal*
fo difgufting and forbidding in appearance, but
which is at the fame time as perfect as other a-
nimals, and connefts quadrupedes with birds.
The ambiguity in the nature of thofe ani-
mals, made me wifli to make them refpire the
fame air in clofe veflels ; but I thought firft
of trying how long they could fupport a va-
cuum. They died fooner than cold-blooded ani-

mals.

12 6

ANIMALS AND VEGETABLES

mals. Five bats, fucceffively fubje&ed to the
experiment, did not live three minutes. They
were of that fpecies, called by M. D’Auben-
ton, the horfe-lhoe bat, from the circular line
upon the nofe.

Although the death of bats in vacuo was
fudden, it was under limitations. Four bats
confined in a clofe veffel, lived fcarcely an hour
and a half : one lived almoft three hours. The
water of the veffel in which were the four, af-
fcended an inch and feven lines ; that in the
veffel where there wrere two, an inch and three
lines; and in that with one, eleven lines.

I extended my experiments to feveral rep-
tiles, vipers, and fome land fnakes. Both
fpecies of animals having died in clofe veffels,
the water was elevated to a certain degree, as
their number was greater. The greateft eleva-
tion occalioned by three vipers, was an inch
and three lines ; and the leaft elevation by
the death of one viper, was fix lines. The
death of one fnake, raifed the water four lines,
and of five fnakes, an inch and feven lines.

There is the fame law writh fmall lizards and
fifhes. The elevation of the water is propor-
tioned to their numbers.

I have repeated all thefe experiments at all
feafons, and have always feen the water within
the receiver rife, with this fingle difference,
that the elevation is more accelerated in warm,

than

confined in stagnant aIr. 227

than in cold weather, as well as the death of
the animals upon which the experiments are
made. I have alfo conflantly obferved, that
the elevation of the water is fo much the lefs,
as the animals are fmaller. Vipers, fnakes,
and bats, raifed the water more than frogs,
newts, and lizards ; and lizards raifed it more
than leeches. The death of a barbel weighing
a pound, raifed it above an inch ; that of one
weighing two ounces, raifed it only two lines.
It feemed to me, that in confequence of this
proportion, the death of the fmalleft animals
fhould raife it very little, or hardly at all ;
which would happen, if their death was not
occafioned by the diminiffied elaflicity of the
air ; becaufe, the water within the receivers
remaining at its original level, would evince,
that the elaflicity of the air underwent no al-
teration.

To difcufs this fad, was of the greatefl im-
portance. I begun with the larvae of large
flies. Thirty were put into a very fmall receiv-
er. They were extremely minute, being new-
ly produced. I left them upon the flefh where
they had been depofited by the mother. They
lived only feven hours in the receiver ; and
the water afcended a line and a half. I re-
peated the fame experiment upon other fifteen
worms. After their death, I could fcarcely
perceive that the water was elevated above the

0^2 level j

228 ANIMALS AND VEGETABLES

level ; and it undoubtedly was not, when I re-
peated the experiment upon eight worms, al-
though the whole died.

The larvse of common flies exhibited nearly
the fame phenomenon. The water rofe a third
of a line, when the number was great ; when
it was fmall, the rife was not fenfible.

Seven earth worms dying, did not raife the
water.

The larvae and nymphs of gnats, had only
an inch of air, and died in lefs than a day.
They were to the number of fome hundreds ;
yet, after their death, the water in the receiver
flood at its original level.

The death of five rat-tailed worms confined
in a receiver, did not fenfibly alter' the level of
the water ; but the death of a greater number
occafioned a perceptible elevation.

Some flagnant waters are full of a fort of
minute animals, called by naturalifls, water-
lice or fleas. Thofe animals are in conflant
motion, darting through the water where they
are. Several thoufands. lived two days and
fome hours in a receiver, and died without a
fenfible elevation of the water.

I could perceive no elevation in water full
of animalcula, confined in a receiver, although
the whole died in two weeks.

The experiments I made upon feveral in-
feds undergoing no metamorphofis, as, fhell

and

CONFINED IN STAGNANT AIR. 229

and naked fnails, millepedes, &c. and even
upon others which do change, as, caterpillars,
chryfalids, and nymphs, demonftrated to me,
that the death of a great number raifes the wa-
ter a little in the receiver ; when the number
is fmall, there is no elevation.

We have now enough of fads to decide the
queftion in which we have engaged, efpecially
when they are compared with thofe of Signori
Cigna and Verati ; and I draw two principal
conclusions. Firft, That there are Several ani-
mals, which, dying in clofe veffels, do not di-
minifh the elafticity of the air : The Second,
That thoSe which diminilh it, do fo very little.
The firft refult is unfavourable to the opinion
of thofe, who attribute the death of animals to
the diminifhed elafticity of the air. We know,
that we cannot afcribe it to this : for if, in
many cafes, animals die, without the air lofing
its elafticity, we muft conclude that their death
has another caufe. The little diminution
which the elafticity of the air Suffers, makes
me doubt much, whether, in the other cafes,
it occafions the animals’ death. By Signor Ve-
rati’s experiments, it appears, that the baro-
meter fell little more than an inch at the great-
eft alteration. According to my experiments,
the water in the receiver Sometimes rofe a few
lines, fometimes near an inch, and at the great-
eft degree an inch and Seven lines, that is, one

fourteenth

230

ANIMALS AND VEGETABLES

fourteenth of an inch, and feven fourteenths of a
line of mercury. But we know, that, in the
changes of weather, there is a greater differ-
ence in the weight of the air. The mercury in
the barometer fometimes falls more than an
inch : it falls quickly, efpecially in ftorms,
without affefting animals : otherwife, both the
cold and warm-blooded animals would not live
in fafety on mountains, where the mercury
falls lower than in the barometers placed in
clofe veffels. Animals can not only live in
air which has loft its elafticity, to fuch a de-
gree that the barometer falls fome inches, as
upon the fummits of lofty mountains; they can
live in air which cannot be renewed, where the
barometer falls to lefs than half its natural
height. Such is the ingenious experiment of
Signor Cigna. This acute obferver confined
two fparrows in the receiver of an air-pump.
One was left at liberty ; the other was put in-
to a glafs veffel, around the neck of which
there was firmly tied a very large Florence
fiafk. Then he begun to exhauft the air, un-
til the mercury within afcended in the barome-
ter twenty-feven inches and a half, and fell
without, by the index, to nineteen inches. Af-
ter this, he let as much air into the receiver, as
depreffed it two inches within. In a little af-
terwards, he drew the fame quantity from the
er, which he foon returned ; and continu-
ed

CONFINED IN STAGNANT AIR. 33 t

ed this alternate exhauflion and return for half
an hour; and the two fparrows were always kept
in air rarefied fo much as to fupport eight inches
and a half of mercury, or at mod ten inches
and a half. Only the fparrow at liberty had
the benefit of refpiring renewed air ; while that
which was confined always refoired the fame.
This laft expired, foon after being taken from
its veflel ; w'hereas, the other came from the
receiver in perfect health. Boyle tells us, that
animals perifh in condenfed air rendered denfer
than the atmofphere. I often repeated this ex-
periment, condenfing the air fometimes twice,
and fometimes thrice, and even more, than the
natural air. I have obferved, with Boyle, that
the air become mod: elaftic, kills the animals
flower, but that they abfolutely perilh.

It is then demonllrated, by experiment, that
the diminiffied elafticity of the air, is not, and
cannot be, the efficient caufe of the death of
animals confined in veflels hermetically fealed.
It rernains to fee, whether their refpiration
contributes to their death ; which is the opini-
on to be difcufled, and will be the fubjecd of
the following chapter.

0.4

CHAP.

ANIMALS AND VEGETABLES

CHAP. III.

There are three things to be enquired into,
in an examination of the fir ft queflion, Whe-
ther the death of animals in confined air, is oc-
cafioned by their refpiration ? i. If we actual-
ly find exhalations in clofe veffels where ani-
mals have died. 2. If the exhalations are the
occafion of their death. 3. Suppofmg. they
are, how do they effeCt it.

I return to the firft article. Signor Cigna,
who has elucidated this theory, has proved the
reality of the influence of the exhalations of
refpiration, by the foetid odour we are fenfible
pf upon opening the veffels where animals have
died, and by a fort of pellicle of vapour cover-
ing the internal furface of the veffels. I fhall
here relate what I have obferved in my experi-
ments. I have almofl always feen this pellicle
over the internal furface of the veffels where
warm-blooded animals had died ; fuch as,
birds, rats, bats, &c. But I have never, or al-
mofl never, remarked it with cold-blooded ani-
mals. I have indeed felt fomething, upon o-
pening the veffels ; and the odour was certain-
ly foetid and cadaverous. I have felt it in all
my experiments, which have been very numer-

pus,

CONFINED IN STAGNANT AIR. 1$$

ous, and even in thofe made with the frnallefl
animals ; fo that the exiftence of this vapour is
not to be doubted, although it does not always
appear within the veffel, whether becaufe it is
not in fufficient quantity, or whether becaufe
it is of a dry nature. Both eafes may prevent
it being feen under the form of an aqueous
veil.

It appears, at the fame time, inconteftible,
that thofe exhalations are the real caufe of the
death of the animals. Signor Cigna endea-
vours to prove it by the refemblance we re-
mark, between the phenomena feen in liquids
which evaporate in confined air, and thofe ex-
hibited by animals refpiring in clofe veflels.
The evaporation in clofe veflels, as he has ob-
ferved, is proportioned in duration to thofe two
conditions ; namely, the fize of the veffel, and
the rarenefs of the air where it operates. Ani-
mals are alfo fubjeCt to thofe two conditions.
They live fo much longer as the quantity of
confined air is greater, and die fooner when
the air becomes more rare.

Collecting fome of the refults which I have
hitherto eftablilhed, and connecting them with
thofe which I fliall eftablifh hereafter, it feems
to me eafy to prove this fad. I have obferved
that the death of animals is accelerated by two
circumftances ; by the encreafed heat of the
atmofphere, and the number of animals confin-
ed.

2 3 4 ANIMALS AND VEGETABLES

ed. In thofe cafes, the exhalations are more
copious : reafon perfuades us of this, and ex-
periment confirms it, by the more foetid odour
exhaled upon opening the veffels. As we can-
not aferibe the death of animals to the dimi-
nifhed elafticity of the air, and as we fee no o-
ther caufes, why may not we recur to thofe
•exhalations which have become more denfe and
active ? And further, as we fhall foon fee, ani-
mals die fooner in clofe veffels, where there are
others already dead, becaufe there are in thefe
more exhalations. We comprehend by this
means, how animals confined alone, or in fmall
numbers, live much longer than when there
are many ; and alfo, why they live much long-
er in cold weather ; becaufe in the two hypothe-
fes, this leffens the afflux of the vapours. For
this reafon, the life of animals will be abridged,
in proportion to the fmallnefs of the veffels.
The vapours become denfer, from the little
fpace they have to fpread.

After all thofe facts, we cannot fay, that the
caufe of the death of animals in clofe veffels
muft be aferibed to the diminifhed elafticity of
the air, inftead of the exhalations of refpira-
tion ; and if the diminifhed elafticity of the air
does not contribute to it, fome great change
which the air undergoes, produces this effett :
particularly, as the confined air, by the infpira-
tions and expirations, will ceafe to be the fame,

which

CONFINED IN STAGNANT AIR. 235

which mu (I always happen when a free com-
munication "with the external air is interrupted ;
for then it fhould lofe the pabulum , which is a
fub fiance or quality known only by name, but
upon which we make the life of animals de-
pend ; fo that the air will be decompofed or
corrupted, and afluredly will become unfit for
refpiratioti. But the flender fupport which the
opinion, that animals die upon account of the
diminifhed elaflicity of the air, can receive, is
demonflrated by the animals themfelves dying
in fiuuations where the communication of the
external with the internal air is uninterrupted.
When feven frogs had expired in a receiver,
the higher part of which was open, and thus
the external and internal air preferving an e-
quilibrium : an hour after this, I confined o-
ther two frogs, the upper part or the receiver
remaining open ; but thefe two frogs died in
an hour and a half. I fhall further obferve,
the frogs in the receiver perifhed fooner, accor-
ding as the number of dead frogs was greater ;
although the diameter of the opening above
was at leaft twro lines.

Several birds, reptiles, and fmall quadru-
pedes, perifhed when put into a receiver where
dead animals were, although the receiver Was
open above. The conftant communication of
the external with the internal air, defiroys the
opinion which afcribes the death of animals to

the

23° ANIMALS AND VEGETABLES

the diforder or corruption of the air. But it
remains certain, that death is occafioned by the
exhalations of refpiration ; for I have obferved
that animals die later when the receiver is o-
pen above, as fome part of the exhalations e-
fcape.

I may remark, in patting, that the death of
animals, in veflels where the upper part is open,
is an argument which may decifively prove,
that they do not die from the diminished elafti-
city of the air.

Enlarging the opening of the receiver, fo
that the exhalations might more abundantly e-
fcape, I made an experiment, to afcertain com-
pletely, whether they occafioned the death of
animals. I thought of patting the exhalations
from the receiver into a vettel applied to the
opening, which was eafily accompliflied. I
confined two fwallows in the vettel, after per-
fectly fecuring the opening with a wooden (top-
per. Swallows were preferred, as eight had
died in the receiver. The influence of the ex-
halations was fuch, that eight fwallows died in
a quarter of an hour, although two confined in
a fimilar vettel lived two hours.

I varied the experiment, by collecting in
the vettel various quantities of the vapours.
The life of the animals has always been pro-
portioned in duration, to the quantity of va-
pour. Long after the vapours have been con-
fined

CONFINED IN STAGNANT AIR. 237

fined in veffels, they retain the power of de-
ftroying animals. It makes little difference in
their influence, whatever animals have afforded
them : they are equally fatal from all. The
exhalations from birds kill quadrupedes, and
thofe from quadrupedes are fatal to birds. It
is the fame with thofe of fifhes, with refpect to
reptiles, infects, and the reft. To finilh the
proof I had engaged in, I made the following
experiment. Several animals having expired
in a receiver, during very warm weather, I o-
pened the hole at the upper part of the receiv-
er, and prefented a bird to the very foetid va-
pour which efcaped ; fo that in its infpiration
it was forced to inhale the mephitic air. Every
bird treated in this manner died.

Although I believe it impoflible that any
animal can live in confined air, when the vef-
fels are very fmall, yet it is certain that fome
may live longer there than others. In general,
cold-blooded animals can fupport this fituation
better than warm. In the fame air where a
newt or a frog will live a day, a fparrow, a
bat, or a rat, will not live an hour. Among
cold-blooded animals, there is even a fort of
gradation. A newt lives longer than a frog,
and a frog fhorter than a leech. The fame is
the cafe with a number of infects. In the opi-
nion of fome, it is not difficult to afcribe a rea-
fon for the variety in fu.ch phenomena. Cold-
blooded

23^ ANIMALS AND VEGETABLES

blooded animals are not only more tenacious
of life, but they have alfo lefs neceffity to ref-
pire, than warm-blooded animals have.

A frog, a viper, a toad, will live longer in
vacuo than a bird : thofe animals fhould alfo
abforb a fmaller quantity of exhalations, from
not being obliged to refpire fo often as the
warm-blooded animals. It will not then be
furprifmg, that they live the longer of the
two. It is doubtlefs a reafon analogous, which
occafions the difference of time that we fee a
cold and a warm-blooded animal can live in
clofe veffels. Experiment proves that frogs
die fooner than newts, as I have myfelf found,
by keeping both immerfed in water. We may
reafon in the fame way refpefting infe&s, with-
out recurring to their ftronger or weaker con-
ftitution, which may likewife produce fnnilar
difcrepances.

It remains for me to explain, hour the ex-
halations of refpiration are noxious to animals:
and here, in particular. Signor Cigna has dis-
played his wonted abilities. The exhalations
of refpiration kill animals, according to this
obferver, by irritating the bronchise and the
lungs, forcing them to contract and become
rigid, thus preventing the entry of new air.
And, according to this author’s opinion, ani-
mals in infe&ed air, fhould die from fuffocatiom
He endeavours to fhew, that this is the aflual

caufe

CONFINED IN STAGNANT AIR. 2%$

caufe of their death, from the different fymp-
toms obferved in the refpiration of confined
animals. When the exhalations b^gin to col-
lect in the confined air, the refpiration becomes
more frequent and fainter, becaufe the air is
fcarcely infpired, before the animal is forced
immediately to expire it, from the quantity of
exhalations it contains. Thefe exhalations con-
tinuing to encreafe, the refpiration alfo con-
tinues frequent, but becomes more laboured.
The animal is foon exhaufled by this laboured
and frequent refpiration, when confined in air
where other animals have died. All this proves,
in the opinion of Signor Cigna, that the exha-
lations injure the animal, becaufe they irritate
and make rigid the organs of refpiration, and
obflruct the entry of the air.

In my numerous experiments, I have feen
the fame fymptoms of altered refpiration.
They manifefl themfelves in the warm-blooded
animals, and particularly in birds. They are
not fo evident in cold-blooded animals ; but,
at the fame time, they are feen, if we pafs the
animals from the open to confined air, which
has previoufly been vitiated by exhalations.
Signor Cigna had before experienced this in
feveral animals. He confined a frog in a re-
ceiver, where there were five or fix already
dead : the frog inftantly became agitated, and
leapt againft the fides of the receiver. The

refpiration

^40 ANIMALS AND VEGETABLES

refpiration was at the firft frequent and labour-
ed ; apparently becaufe it was more painful ;
and it, in a fhort time, ended with death. I
am, therefore, with the Turin Profelfor, fully
convinced, that the refpiration is affedted by
this air ; but I cannot agree, that there hap-
pens in animals that contraction of the organs
of refpiration which kills them by fuffocation.
When feveral frogs are confined in a capacious
veffel, they live a long time. If the weather is
not warm, they retain their vivacity for more
than a day ; but after this, they become flug-
gifh, and fwell exceffively. If they are males,
the two veficles upon the fides of the head en-
creafe ; and their inflation is fuch, that they
prevent the frogs from finking in the water j
but keep them upon the furface. After re-
maining fome time in this Hate, the frogs ex-
pire. When taken from the veflfel and opened,
we difcover that the fwelling proceeds from
the inflation of the lungs, which cannot pofli-
bly be more diftended. The fame inflation is
found in the lungs of toads and newts dying in
the fame manner : they alfo are neceflltated to
lwim. The lungs are fo far from being con-
tracted and become rigid, that they are much
dilated, and confiderably charged with air.
Tor this reafon then, and for others of which I
fhall afterwards fpeak, I cannot admit that a-
niraals die from the impeded refpiration. In

very

CONFINED IN STAGNANT AIR. 24I

very fmall veifels, where feveral animals were
already dead, I confined fome vipers and frogs ;
and at the fame time I put an equal number
of the like animals in vacuo. It is incredible,
how much fooner the former died than the lat-
ter. Some of them did not furvive a minute ;
but thofe in vacuo were alive at the end of fe-
veral hours. Therefore, it was not fuffocation,
or an obftacle to the air entering into the lungs,
that occafioned the death of the former ani-
mals, otherwife they would have lived much
longer, or at leaf! as long as thofe in vacuo.

At the fame time, I forced fome frogs to re-
main under water, preventing them from rif-
ing to refpire at the furface. In others, I have
tied the origin of the lungs in fuch a manner,
that the air could not enter. Others, I have
deprived of the lungs, and confined them with
other frogs in a fmall quantity of air become
very foetid by the exhalations of refpiration.
The laft expired in a few minutes, fometimes
in one, even in lefs ; while thofe deprived of
refpiration, by immerfion in water, having the
lungs tied, or cut away, have lived in vacuo for
feveral hours. I have found the fame with
toads and water-ferpents. Since the death of
all thofe fpecies, occafioned by deprivation of
refpiration, has been, without comparifon, la-
ter than the death of the fame animals killed
by the exhalations of their refpiration, we mull

R conclude.

242

ANIMALS AND VEGETABLES

conclude, that thofe exhalations do not occa-
fion death by the fufpenfion of refpiration ;
but that they are, with refpect to thofe ani-
mals, one of the poifons mod; fit to deftroy
life ; and that it afts as fuddeniy as any other
poil'on, and even kills almoft inftantaneoufly
when colletted in a great quantity. This poi-
fon penetrating the body by means of refpira-
tion, when animals infpire the air, will caufe
that laboured breathing they experience ; for
it is more than probable, that it will make, up- f
on the organs of refpiration, a violent and pain-
ful impreffion. At the fame time, the vefiels
of refpiration are not the only vehicle to con-
vey the poifonous vapours to the animal. Earth-
worms, leeches, and fome other infects, which
are not only without real lungs, but alfo with-
out fiigmata or trachea, die in like manner
with the reft in confined air. We mull fay
then, that the exhalations act upon them, ei-
ther by infinuating themfelves through the
pores of the fkin, by the channel of the ali-
ments, or by both: The deleterious quality of

the exhalations is fo formidable to every fpe-
cies of animal, that it extends to thofe which
never feel the lively impreffions of the air, front
their conftant abode at the bottom of the wa-
ter. This induced me to obferve fome of the
fnails and fnakes of ftagnant waters, put in an
open veftel with water. They crawled over

the

CONFINED IN STAGNANT AIR.

the bottom, without betraying any fign of un-
eafinefs ; but when confined in a very fmall
veffel, they were inceffantly agitated ; they a-
fcended the fides of the veffel, contrary to their
ufual cuftom, leaving the water, and foon ex-
pired. The influence of the exhalations thus
acts beneath the waters, which we cannot
doubt, from the foetid odour communicated to
the water within the receivers, as well as to the
external water, whenever the odour is to a
certain degree.

But fince thofe peftilential exhalations do
not kill animals by depriving them of refpira-
tion, how do they occafion the death of ani-
mated beings ? It is not by coagulating the
fluids, by diffolving them, or by deftroying
them. Immediately after the death of animals
killed in this manner the blood preferves its
original fluidity ; the ferum continues to flow,
and the minute globules retain their fize and
figure. Befides, did the exhalations coagulate
the blood, or contribute to make it more fluid,
this could not be the caufe of the fudden death
of animals killed by them : for they could effect
it only by interrupting the whole circulation, or
depriving the blood itfelf of fluidity a .

I have fufpe&ed that this poifon kills by de-
ftroying the irritability of the mufcles. The
irritability may be loft in two ways ; the muf-

R 2 cular

* Dc phenomeni della circolazicne, tom. i. c. 6.

244 ANIMALS AND VEGETABLES

cular fibre may either become too relaxed or
too rigid. The mufcles do not feem relaxed,
but rather too rigid, when the animals are
taken from the confined place where they have
died. Such were the phenomena I obferved in
frogs : their hind legs and thighs were extended
in a ftraight line, as if they had been dried.
If their pofition was changed, or if they were
bent, a refiftance was found, and when at
liberty they refumed their -original pofition:
the mufcular fubftance feemsd harder under
the finger, and under the knife : but I foon
difcovered thofe changes in the mufcular fibre
did not precede or attend upon the death of
the frogs, but that they followed it. If I took
from the veflel frogs dying, or fcarcely dead,.
I did not perceive their limbs extended, and
their mufcles preferved fufficient flexibility :
on the contrary, the extenfion and rigidity
only took place when they had continued fome
time in the veflel. I have obferved the muf-
cular hardnefs and the extenfion of the limbs
in dead frogs which had remained fome time
immerfed in water. Finally, this change in
the mufcular fyflem, by no means happens to
all animals.

The following facts have made me entirely
renounce the idea which caufed me fufpeft the
lofs of irritability. The mufcles of a frog’s
thigh difplay great irritability when cut or

pricked t

CONFINED IN STAGNANT AIR. 245

pricked : they vibrate and fuddenly contract,
not only where the point of the needle 01 the
edge of the inflrument touches, but far be-
yond it ; and the vibration continues during
forae time, although the caufe which occafions
it is fufpended. Having taken from a clofe
veflel a frog upon the point of death, I will
not fay that the mufcles retained their irritabi-
lity as in a date of health, or that the approach
of death did not weaken it ; but I will fay,
that the vibrations and contractions of’ the
thighs, when pricked and cut, re-appeared,
and even continued after the entire death of
the animal.

I confequently abandoned the idea of the
lofs of mufcular irritability : and, after matur-
ed reflection, it feems to me, that the nervous
fyflem is the part upon which the exhalations
aft. And here are the reafons which have fug-
gefled that opinion. I fubmit them to the
judgement of philofophic readers. Convul-
fions commonly precede, and attend the death
of our animals. They are clearly feen in
frogs : the whole body is fometimes convulfed,
but particularly, and more violently, the limbs.
In thofe convulfions they die. As in Winter
they longer refill death, the convulfions alfo
continue longer. If taken from the veflel be-
fore death, it appears that the feat of feeling
has fuftered. They are fluggifh, although vio-

R 3 lently

246 ANIMALS AND VEGETABLES

iently agitated : they do not change their place,
when ftimulated ; the convulfions re-appear ;
their lethargy augments, even when placed in
the open air ; and they generally die. Thofe
convulfions are doubtlefs the effeft of affected
nerves. The reafon feems natural ; but here
is a convincing proof. I wounded the mufcles
of a frog, which had not been expofed to con-
fined air : the wounding excited in them the
motions which ftimulating ordinarily awakens ;
but they were never convulfive motions. On
the contrary, if I touched the origin of the
crural nerves with the fame inftrument, which
was extremely fine, the limbs fuddenly became
convulfed ; and then, in the fame manner as
when in confined air, when I pricked the fpinal
marrow, or the brain, the convulfions became
univerfal over the body. I have never been
able to fee the convulfions partial or general in
frogs, but by wounding the nerves. It is on
this account, that the convulfive fpafms in ani-
mals confined in clofe veffels, make me fufpe£t
that the poifonous vapour a&s upon the ner-
vous fyftem.

I had (till one doubt to folve. I could not
reconcile the almofi: immediate death of frogs
expofed to the ftrong exhalations of refpira-
tion, with the prefervation of their life during
a long time, although deprived of the brain,
i have fhewn, in my work upon Circulation,

CONFINED IN STAGNANT AIR. 247

that frogs will live feveral days, although the
brain is taken away. But the doubt difappear-
ed, when I faw their death become fudden,
when, inftead of wounding the brain, I wound-
ed the fpinal marrow. If a pin was introduced
where the fpinal marrow unites with the brain,
the frog in a moment died convulfed. Ani-
mals as tenacious of life as frogs, die with the
fame fuddennefs, when the fpinal marrow is
injured. It is not therefore very extraordinary,
that death fo immediate is occafioned by the
peftilential exhalations infinuating themfelves
in quantities into animated bodies, and, not
affe&ing the other parts, attack the whole ner-
vous fyftem, and momentaneoufly deprive it of
the fenfitive faculty.

But, what can we fay of the death of thofe
animals in clofe veffels, if very fmall, in which
there is found no nerve, as in the eels of vine-
gar, and the multitude of infufion animalcula ?
I agree that thofe mod minute beings are kil-
led by the exhalations. The analogy of fo
many other animals which perifh from the fame
caufe, renders this conjecture very plaufible.
The exhalations can only deftroy them by con-
tact. We mull confequently fay, that they
a£t upon the organs of thofe animals, and there
produce an efted: fimilar to that they operate
upon the nervous fubflance of other animals ;
although their organic ftru&ure may be with-

R 4 out

24? ANIMALS AND VEGETABLES

out nerves, fo much at lead that we cannot
judge of it by the inicrofcope. But,, for this
reafon, they cannot evite the fatal influence of
the exhalations ; nor do I fee how they can e-
fcape it, when they cannot refill the effeCts of
the eleCtric vapour, and particularly of certain
odours.

Befides, I befeech the reader to view this o-
pinion as a conjecture. I have not made that
collection of faCts necefl’ary to give it authenti-
city ; but I have not had leifure to enter into
all the details, and to make the moft profound
refearches. I wilh that others would under-
take it ; and 1 fliall always have the fame re-
gard for thofe who attain their purpofe, whe-
ther they confirm or confute my conjecture ;
for I have no other view but the fearch of
truth.

In the firft chapter, I have fpoken of eggs
and feeds which did not germinate, when con-
fined with a fmall quantity of air. It is pofli-
ble, that this fterility may be occafioned by the
fame caufes that deftroy animals confined in
fmall veffels. A companion will help to con-
vince us. Butterflies, as we have feen, chap, i,
do not come from chryfalids confined in fmall
veffels. I find that M. De Reaumur has had
the fame refults, although the objeCt of his ex-
periments was very different from mine. In
glafs tubes four or five inches long, he herme-
tically

CONFINED IN STAGNANT AIR. 249

tically fealed chryfalids. Part of thefe were
from the cabbage caterpillar, and part of that
kind transforming to phalen®. They always
remained in their original Hate, although they
had been confined for feveral months. They
never developed ; for, as he obferved, they
perfpired ; and perfpiration is neceffary for
chryfalids to change to butterflies. Thefe two
fads he proved in a decifive manner. When
the chryfalids are in a very confined place, as
in a tube of feveral inches, the moiiture which
tranfpires cannot diflipate : on the contrary,
it falls back upon the chryfalids. Thus, in
fome days, we fee them moiffc ; and this hu-
midity, infinuating itfelf into their bodies, ren-
ders them difeafed. Therefore, the death of the
chryfalids happens nearly from the fame caufe,
as that of animals in flagnant air. What I fay
of chryfalids, may be applied to the eggs of
infe&s, and the feeds of plants. We know,
that eggs hatch only at a certain degree of heat,
which occafions perfpiration : if confined in a
fmall veil'd, they re-abforb the exhalations which
they have before tranfpired, and then they cor-
rupt. A proof of this, is the humidity which
after a certain time covers the eggs, and fome-
times, in confiderable abundance, the fides of
the veil'd.

The fame happens to vefifels confining veget-
able feeds. As I have been often wont to put

feeds

250 ANIMALS AND VEGETABLES, kc.

feeds in a little water, that they might germi-
nate ; upon taking them out, I faw the part
which had been expofed to the air covered by
a humid pellicle.

From oppofite reafons, we fee why eggs
and feeds are excluded in large clofe veflels.
They are always in fafety ; for the vacuity be-
ing great, the exhalations may difperfe. In
the fame way, butterflies come from chryfalids,
when the capacity of the veflfel is confiderable.

observa.

[ 251 ]

OBSERVATIONS and EXPERIMENTS

UPON

SOME SINGULAR ANIMALS WHICH MAY BE
KILLED AND REVIVED.

CHAP. I.

In the hiftory of the animalcula of infufions,
which I have treated fo much at large, it has
been faid, that when once thofe animals perilh-
ed from a defedt of water or humidity, they
could never again be brought to life, although
water was fupplied, and their immerfion conti-
nued long. Of this I have had the moft con-
vincing and repeated proofs, in the experiments
which I proceed to narrate. But there are o-
ther animalcula, which, notwithftanding they
are the inhabitants of infufions, are fo much
diftinguilhed and privileged by nature, as to
enjoy the advantage of refurreCtion after death.
Such, among others, are the Wheel-animal, the
Sloth, the Anguillse of Tiles, and thofe of
Blighted Corn.

A

252 ANIMALS KILLED AND REVIVED.

A microfcopic animalcule inhabiting the fand
of tiles and fevvers, is by naturalifts termed the
Wheel-animal. The abdomen is large, and fi-
tuated towards the middle of the body : in the
opinion of fome, there is an heart. The pof-
terior part of the animal is provided with a mi-
nute trident ; and the anterior part divides in-
to two trunks, bearing, at the vertices, the fem-
blance of two moll fmgular wheels. From
thefe it has obtained the name of the Wheel-
animal. One, magnified, is reprefented PI. 3.
fig. 1. If the fand I have mentioned is put in-
to water, the animalcule exhibits all its organs
to the obferver, provided the fand remains a
certain time infufed. If the water fails, the ac-
tion of the wheels, and that of the heart, ceafes;
the animal gradually lofes motion and life ; it
contrafts, becomes very minute, and afiumes
the refemblance of a dry and emaciated Ikin.
To revive it, it is fufficient to immerfe it in wa-
ter : then the body foon extends, the wheels
and the trident appear, the heart is re-animat-
ed ; motion is regenerated in the whole animal ;
it begins to fwim in the water, and exercifes all
the fun&ions of life. It is of no importance
that the animal has remained long dried in the
fand. Lewenhoek, the firft who had the good
fortune to difcover it, and from whofe works I
draw the chief part of what I relate, has feen
yi'lieel-animals re-animated, after being kept in

ANIMALS KILLED AND REVIVED. 253

dry fand almoft two continued years. With
this naturalift we muft obferve, that when the
animal revives, the trunks and the wheels are
not always completely difplayed, but are fome-
times exhibited as in fig. 2. A.

Such are the three figures of the wheel-ani-
mal which Baker has, after Lewenhoek, given,
in his treatife intitled, The Microfcope made ea-
fy. He contents himfelf with repeating only
what the Dutch naturalift had written before.

Although feveral naturalifts have treated of
the wheel-animal, they feem to me to have
done it but fuperficially, and all to have pro-
ceeded upon the relations of Lew'enhoek. I
thought it would not mifapply my pains to in-
veftigate this interefting fubjed, and to illuf-
trate it by additional fads : and I was parti-
cularly induced to this, by the relation between
that animalcule and the chief objeds of my
work. I have therefore compofed a fhort and
methodical hiflory of the animal, from the ma-
terials with which I have been furnifhed by ex-
periment and obfervation. But, what renders
it fo very remarkable is, the fingular faculty
of refurredion, pofleffed by the wheel-animal.
When upon the point of publi/hing the fruit of
my labours, another work of Baker, written in
Englifh, fell into my hands a : there, much is
faid of the wheel-animal. I perufed it rapidly,

and

* Employment for the Microfcope. London, 1764.

■254 ANIMALS KILLED AND REVIVED.

and feeing at once, that the author propofed to
treat the matter ex profejfo , I defigned to fup-
prefs in this work all that concerns the wheel-
animal ; becaufe it would have been ufelefs to
treat of a fubjeCt already difcuffed by a learned
obferver. I fhould certainly have done fo, had
I not perceived that Baker’s obfervations were
materially different from mine ; becaufe his
wheel-animals had been of a different fpecies.
I therefore refolved to publifh my treatife,
which was improved by that of Baker, its im-
perfections leffened, and new important mat-
ters added.

I proceed to recite my experiments and ob-
fervations, beginning with a faCl which may be
patent to every one. I examined the fand from
a fewer, about three hours after it had been
put into water. I had no trouble in finding
what I fought for. In the firfl drop prefented
to the microfcope, appearing like muddy water
and fand, I faw three living beings, which I
immediately recognifed as three of Lewenhoek’s
wheel-animals. Upon the anterior part of the
body was a horn : the fize of the body increaf-
ed towards the middle, and the pofterior part
was terminated by three points : but the ante-
rior part had neither trunks nor wheels, and
the animals were nearly as in fig. 2. A.

The body is tranfverfely annulated, and lon-
gitudinally radiated with fome parallel promi-
nent

ANIMALS KILLED AND REVIVED.

nent rays \ fig. 3. The indiftinCtnefs of the
rings and lines renders them difficult to find*
To be able to fee them, one mult be accuftom-
ed to obfervation, and have an excellent eye.
In the middle, there is obfcurely feen a little
longitudinal fafcia, covered with fpecks j and
above it, more vifible, a circle formed, as if by-
two C’s touching at the extremities. At the
upper part of the circle is feen the origin of a
little canal, A B, fig. 3.

The animal being very flexile, it aflumes
fome extraordinary lhapes in its progreffion.
Sometimes it extends, and becomes very {len-
der ; at other times it contracts, and becomes
very corpulent. Sometimes the anterior part
is contracted and concealed in the body, or the
fame happens to the pofterior part. One part
of the body will be inflated, while the reft; is
flaccid. In a word, its motions are as Angular
and eafy to fee, as they are difficult to defcribe
with precifion : and all thofe remarkable fi-
gures are exhibited, although the animal re-
mains ftationary.

The mode in which the wheeler tranfports
itfelf from one place to another, is this. It fixes
the tail to the plane which it means to traverfe :
the whole anterior part of the body is extend-
ed. When in this (late, the animal detaches
the tail ; and, contracting the pofterior part of
the anterior, it advances. The extremity of

the

256 ANIMALS KILLED AND REVIVED.

the tail is again fixed to the -plane ; the body
is extended as before ; the extremity is detach-
ed ; and, by the contra&ion of the anterior
part, a new ftep is made. This operation is
repeated, and the animalcule palfes along with
fuch agility, as foon to traverfe the field of the
mierofcope.

This method of progreffion, by means of
the contra&ions and extenfions of the body, is
common to feveral infe&s ; but, in particular,
to apodal vermes, which is generally . known.
A circumftance peculiar to the wheel-animal
is, that it fixes itfelf by the point of the tail ;
which is fo eifential to its regular progrefs, e-
i'pecially over a polifhed furface, that without
this precaution, it would conftantly go wrong.
When the animal has found fome point of fup-
port, and is fixed by the tail, it frequently (lops
for fome time, and extends the anterior part,
as if from a centre examining around, what
direction it fliould take : then, fuddenly de-
taching itfelf, it advances in a given line.

In Lewenhoek’s opinion, the wheel-animal
fixed itfelf by all the three points at the extre-
mity of the tail. At firft, I likewife thought
them neceflary ; but, upon examining them
with more attention, I perceived that the mid-
dle point only was ufed for that purpofe. To
fee it with precifion, the drop where the wheel-
animal is, muft be thin and transparent, and

free

ANIMALS KILLED AND REVIVED. 25/

free from fand : then it is eafily perceived, that,
fo far from the lateral points fixing to the plane
of pofition, they do not even touch it, but are
diftant a confiderable degree ; and that the
point in the middle is the only fixing one.
When viewed with a powerful magnifier, this
point feems to be compofed of a number of in-
finitely fine fimilar points, which are almoft
imperceptible ; Fig. 3. D. It is by means of
thefe points that the wheel-animal advances.

The three wheel-animals, which I then ob-
ferved for the firffc time, were not fwimming ;
they crawled along at the bottom of the drop.
I foon perceived, that this was their cuftom
when the wheels were not in action. Any one
may fatisfy himfelf of it, by putting a quantity
of fand, mixed with wheelers, into a watch-
glafs half full of water. He will immediately
fee, that thofe at the furface of the fand con-
ftantly crawl upon it, and do not commit them-
ielves to the water. The fame is the cafe with
thofe buried in the fand, when brought to the
furface.

The three wheel-animals moved with agility
in the drop which I firft obferved ; the ante-
rior party fearching among the fand as if for
food ; but they never left the fluid : they ap-
proached the edges of the drop, and inftantly
returned. As the drop begun to evaporate,
their motion became languid j and the languor

8 encreafed

2^8 ANIMALS KILLED AND REVIVED,

encreafed fo much, as to deprive them of power
to change their place. Although they remain-
ed upon the fame fpot, they turned around
and ftretched themfelves. Such motions were
particularly confpicuous in the head and tail,
which proceeded from, and re-entered the body ;
and they were hid when the whole drop had e-
vaporated. The appearance of the wheel-ani-
mals then changed, not only becaufe life was
gone, and they were completely motionlefs,
but alfo becaufe their fize was greatly diminifh-
ed. They became three minute corpufcula, fo
diftorted, that it was impoflible to recognife
them for what they had originally been.

They were an hour in this Hate of apparent
death. I then put upon them a drop of the
fame water that had evaporated. The reader
may well conceive my attention in obferving
this refurre&ion. the fuccefs of which happen-
ed as I had forefeen. In a few minutes, the
animals begun to fwell, a point appearing at
one end, Fig. 4. D. This pointed part then
begun to move, by extending and contracting ;
the part oppofite became pointed alfo, and be-
gun to move as the other. I perceived that
thofe points were the head and tail of the ani-
malcule, proceeding from the place where they
had been concealed upon the evaporation of
the drop. The tranfverfe annuli, the longitu-
dinal rays, the internal and external organs,

all

ANIMALS KILLED AND REVIVED. 2 5^

all re-appeared ; and the three wheel-animals
refumed their original figure and fize, which
they in a very fhort time effected. They tra-
veled the fand vigoroufly, and fhewed them-
felves to be as lively as ever.

Difcovering fome wheel-animals in the fand
of fewers, I repeated thofe experiments, and
found that they always revived, during what-
ever time they had been kept dry. There is
now before me a remarkable inftance. I have
ftill in my poffeffion fome fand, upon which I
made experiments near four years ago ; which
has been preferved dry in a fmall glafs veffel.
When moiftened, the wheel-animals in it in-
ftantly revive. This fad; agrees with what
I have related from Lewenhoek. Baker has
obferved a circumftance little lefs worthy of
notice. With water he wet the infide of a
glafs wherein wheel-animals had been kept dry
for fome months, and he faw them recover
their original vivacity. Here it matters little
to know whether they revive oftener than once.
Eleven times I have dried the fame fand, and
as often wet it ; and I have conftantly feen the
death of the wheel-animals attend the drying
of the water, but their life recommence when
the fand was moiftened.

However, thofe fads fhould be underftood
under fome limitations. Although the animals

S 2 do

<260 ANIMALS KILLED AND REVIVED).

do revive feveral times, and even after they
remain a long time dry, it is certain that the
Dumber revived always decreafes in proportion
to the times the fand continues longer dry,
and the times it has been wet, to revive the
wheel-animal's, ft is true, I have feen their e-
ieventh refurreftion. The firft times, they
were very numerous ; but the number after-
wards continually decreafed, and at laft be-
came very fmall. I fhould add, that, ftill wet-
ting and drying the fand, none revived the fix-
teenth time. It is the fame with refpeft to the
fand remaining dry. I took a portion numer-
oufly inhabited by the animals, and I have pre-
ferved it dry in a box for three years, only
moiftening it every five or fix months for my
obfervations j but the refurre&ions always be-
come fewer ; and now, at the end of the third
year, I do not exaggerate when I fay, that
one hundredth part does not revive. I have not
extended the experiment further : but it is un-
doubted, that if the wheel-animals remain long
dry, and if they continue to become rare in
proportion, a period will finally arrive,, when
they will revive no more.

The time necelfary to accomplifh their re-
furreftion, is unlimited. 1 have found, that in
four minutes after moiftening the fand, fome

begin to live $ life then extends to more ; and

in

ANIMALS KILLED AND REVIVED. z6 1

in an hour, all are reanimated a. I am igno-
rant what can occafion this difference in the
time neceffary for their refurrection. It may
happen, either becaufe fome parts of the fand
where fome of the animals are, may he better
moiftened than others ; or, although ail flhould
be moiftened in the fame time, it may hap-
pen, that all the wheel-animals are not of
the fame texture. In that cafe, the mare denfe
or confiftent will more ilowly receive the im-
preffion of the v'ater, and be longer in reviv-
ing ; or, fome may be difeafed, and lefs fit for
immediate refurreftion.

I have not perceived any very fenfible differ-
ence of time between the refurreflion of thofe
which have been dry for fome hours, and the
refurreftion of thofe which have been dry for
feveral days, feveral months, or even for com-
plete years.

As I knew the influence of heat in reftor-
ing the life of animals and vegetables, I fre-
quently moiftened the fand with warm water.
The wheel-animals then revived fooner than
when the fand was moiftened with water at the
heat of the atmofphere.

S 3 But

a Baker’s wheel-animals begun to exhibit Cgns of life
only in half an hour. It would appear, that he fpeaks of
thofe that were longeft of reviving. Perhaps his .experi-
ments were made upon a fpecies different from mine.

262 ANIMALS KILLED AND REVIVED.

Bat there is one condition effential to effeft
the refurre&ion of the animals. It is abfolute-
ly necefiary, that there fhould be a certain
quantity of fand. Let us enquire further into
this. One day, I had two wheel-animals tra-
verfing a drop of water about to evaporate ;
it contained very little fand. Three quarters
of an hour after the evaporation of the drop,
they were dry and motionlefs. I moiftened
them with water, that they might revive ; but
this was in vain, although they continued wet
during feveral hours. Their members fwelled,
and they became three times their original
fize : but they (till remained motionlefs. This
circumftance feemed to me the more extraor-
dinary, as it was among the firffc times I had
\vet the fand, and thofe two were the only ani-
mals that did not revive. To be certain whe-
ther the fadl was merely accidental, I took a
portion of the fand, and fpread it out upon a
piece of glafs : I waited until the numerous
reanimated wheel-animals fhould become dry,
in order to wet the fand anew, and learn whe-
ther they would revive or not. The fand was
carelefsly fcattered upon the glafs, fo as in
forne parts to be a thin covering, and in others
to be in a very fmall quantity. The animals
jn thefe parts did not revive ; but all that were
in thofe parts where there was abundance of
fand, revived. A difference fo remarkable,

Uoi> » * / ; . .

made

ANIMALS KILLED AND REVIVED. 263

made me fufpedl that this fpecies of beings in-
habiting fand, require a certain portion of it
to enable them to pafs from death to life.

However, to acknowledge the truth, I did
not at fird adopt this conjecture ; but I could
not dived my mind of it, as it feemed to be
confirmed by fadts : befides, upon recollecting
the experiments I had before made upon the
refurredtion of wheel-animals, I was certain,
that thofe reviving always had been among
fand. To certify or deftroy the doubt, it was
fufficient to repeat the lad experiment ; for, if
thofe which revived had been mixed w'ith fand
at the moment of their refurredtion, or if, up-
on the contrary, thofe then without fand did
not revive, there would be a complete demon-
ftration of what had been the caufe ; namely,
that the prefence of fand was efiential to their
refurredtion. Upon repetition of the experi-
ment, the confequence condantly was, that the
animalcula never recovered life, unlefs in pla-
ces where there was a quantity of fand.

One of my friends, an eminent philofopher,
and an excellent microfcopical obferver, con-
dantly has the fame relult from fiis experts
ments a.

Ihe Abbe Roffredi, a good obferver, when
incidentally fpeaking of the wheel-animal, in

S 4 the

* II. R. Padre D. Carlo Giufeppe Campi di Milan,

264 ANIMALS KILLED AND REVIVED.

the Abbe Rofier’s Journal de Phyfique, men-
tions the fame phenomenon b.

To thefe we may add the following fa£ts.
If we fpread out the fand with wheel-animals,
in fuch a manner, that there is a confiderable
quantity in fome places, and much lefs in o-
thers, and very little in the red; ; and then
moiden the whole : in the firft cafe, where it
is plentiful, the reviving animals will be nume-
rous ; in the fecond, where it is more rare,
fewer will revive ; and in the laft, very few,
fometimes none. If the mod abundant quan-
tity of the fand is dried and fcattered thinly
over any place, then there will appear only
fome animals revived, where they were before
very numerous. Befides, the refurrection of
the wheel-animals in this fatal 1 quantity of fand
is effected later than where the fand abounds ;
in this cafe, four minutes is enough : where
there is little fand, their refurre&ion will re-
quire nine, or eleven minutes, and fometimes
more.

But, have the animals which do not revive
from a defect of fand, and referable globules
floating upon the water : have they lofl the fa-
culty of refurre&ion, or do they refume it up-
on being fupplied with their native fand ? To
afcertain this circumdance, I have often taken
the thin furfaces of fand, wherein the wheel-

animals

b Journal de Fhyfique, 1776.

• - i / > » . v.r « *

ANIMALS KILLED AND REVIVED. 265

animals did not revive, and put them at the
bottom of a watch-glafs, with water upon
them ; but of twenty dead animals I favr
fcarcely one revive. It therefore appeared to
me, that privation of fand deprived the wheel-
animals of their innate faculty of refurrection.

How can the fimple defect of fand produce
fo important an effect ? What connexion,
what phyfical relation is there between the
prefence of fand, and the refurredtion of the
wheel-animals ? May not the caule which ef-
fedts this phenomenon be entirely different ;
and cannot we fay, that the fand may ferve
the place of fome very fimple external condi-
tion ? I fee that when the animals perifh from
want of fand, their bodies are expofed to the
influence of the air upon the evaporation of
the water ; but they do not experience this, or
at leaft in a far lefs degree, when they die co-
vered with fand. We may fay, this fuppofes
that the immediate adtion of the air, by irri-
tating and injuring the corpufcula, from its la-
cerating influence, while they are ftill humid,
and while they are at the fame time mod ten-
der and delicate, renders them incapable of re-
viving, from the alteration they undergo. The
conjedture hazarded is founded on a fadl, e-
vincing there are animals, whofe flrucfure is
fo delicate and fragile, that they are unable to
fupport the immediate impreflicn of the air,

and

266 ANIMALS KILLED AND REVIVED.

and always live under cover. Such are the
miners , a fpecies of infefts fo named from their
inhabiting the interior of the leaves of trees,
where they live almofl always concealed and
prote&ed from the influence of the air. My
conje&ure would perhaps require an experi-
ment, which I had not time to make. We
fhall immediately fee, that wheel-animals re-
vive in vacuo. One might put fome of thofe,
fwimming in water without fand, under an
exhaufted receiver, and then wet them, obferv-
ing whether they revived ; which they fhould?
according to my fuppofition ; becaufe, in that
fituation, they could fuffer nothing from the
motion of the air when the water evaporated.

I arrive at another enquiry, more important
than the preceding. I have hitherto fuppofed,
that the wheel-animals perijhed when the liquid
dried. It is true, they exhibit every appear-
ance of death ; the body is dry and disfigured ;
they lofe the ufe and motion of their members.
But I mean to examine this circumftance more
deeply, fince it prefents the mod paradoxical
truth hitherto found in the hiftory of any ani-
mal, and we cannot hefitate too much in dif-
trufting truths of a fimilar nature. Let us
therefore enquire, if it is not poffible that the
wheel-animals, dead to appearance, may pre-
ferve a fpark of life. To elucidate our en-
quiry, let us recur to the analogies between

ANIMALS XILLED AND REVIVED. 2 67

large animals. Cold, fo injurious to infe&s,
renders thofe it does not deftroy, lethargic
during winter : they are in fuch a degree
of torpor as to feem dead to the fight and the
touch ; their limbs fliff and contracted, their
wings deprefied, their bodies emaciated. They
have no external motion ; no mark of feeling
when flimulated, or when cut in pieces. This
we fee in the hundreds of infeCts which we
cafually find upon the coldeft days of winter,
in the earth, in the clefts of trees, in the holes
of walls. In this manner does cold operate
upon beings poffefiing the higheft rank in the
animal fcale. In the midfi of winter we have
found marmots, which are a fpecies of rat,
fo lethargic, that the flame of a candle burn-
ing their limbs could not awaken them, or re-
cal the fenfations of life a. Terreftrial apd am-
phibious animals, when kept long in water,
exhibit the fame appearances. Rhedi having
immerfed flies in water an hour and a half,
found them with all the femblance of death.
Reaumur made the fame experiment upon
bees. It is well known they are vindi&ivc
when injured. This naturalifl left a whole
fwarm in water, I know not how long, and
found them fo completely deprived of fenfa-
lion, that he handled them at pleafure ; he
took them from the water, put them upon a

table,

a BufFon, Invoke naturelle.

268 ANIMALS KILLED AND REVIVED.

table, and examined whether or not there
were feveral queens : they afterwards recover-
ed. i may fay the fame of the apparent death
of frogs and newts. After fome hours im-
merfion in water, their bodies became ftiff and
fragile, jufl as happens in death.

May not the apparent death of infers and
other animals be fimilar to that of wheel-ani-
mals among fand ? But thofe animals preferve
a real principle of fenfation and life, which
the concurrence of certain circumflances is re-
quired to unfold, and put in a date to animate
the whole fyftem. If the temperature of the
air is a little encreafed, motion and life re-
appear in animals rendered torpid by cold : if
the bees which have been immerged in water
are expofed in the funfliine, they foon begin
to move, walk, expand their wings, and fly.
In the fame way do frogs and newts recover
their natural vivacity, when they have remained
a fhort time in a dry fituation. Why then
cannot we fay the fame, that there is in the
wheel-animals fome latent fpark of life, which
the aid of water is required to difcover ?

Confidering thefe fafts, and allowing them
their juft value, I fee that we cannot deny that
there is a refemblance between the date of dry
•wheel-animals, and the ftate of the animals I
have named, with refpedl to their appearance,
their perfect immobility, and the complete in-

• action

animals killed and revived. 269

action of their members. But I remark a molt
fenfible difference, which muff: create a great
diftindtion between them. When animals are
torpid from cold ; whatever is the power of the
agent depriving them of fenfation and motion,
it only does this, by deftroying the harmony
between the fluids and the folids ; but it does
not derange them fo far, as to deprive them of
what conftitutes their fluidity or folidity. This
harmony exifts in the moft internal parts of
the body. I have often opened newts, frogs,
toads and lizards, when torpid from cold, and
apparently dead ; and I have found that the
blood did not circulate in the limbs, while it
continued to circulate in the large veflels, al-
though the circulation was languid. If a great-
er degree of cold has penetrated the folids, if
it has coagulated the blood, then, it is certain,
the animals perifti. This has already been ob-
ferved in many animals, by feveral naturalifts j
and I have myfelf found the fame in the toads,
frogs and newts, of which I fpeak.

I have found a remnant of motion in the
blood and in the heart of half-drowned ani-
mals ; and I doubt not that this motion conti-
nues in bees and flies. When all thofe ani-
mals remain long in water, the motion, what-
ever it is, is deftroyed, and all hope of reco-
very is loft. It is therefore very certain, that,
in the animals which revive, that quality which

conftitutes

ANIMALS KILLED AND REVIVED.

conftitutes the exigence of their folids and
fluids is not loft, and the harmony which
reigns between them is not totally deftroyed.
But, how many efiential differences are there
in wheel-animals ? While they traverfe the
fluid, they refemble gelatinous fubftances ; they
are lacerated and deftroyed when touched with
the point of a needle. When dry, the folids
are contra&ed and diftorted ; the whole body
of the animal is reduced to a hard fhapelefs
atom of matter : when pierced by a needle,
it breaks in pieces like a grain of fait. But
how does this atom of matter, where the folids
preferve no veftige of their former humidity
and pliancy, and where the fluids exift no
more : how can we believe that this dry and
disfigured atom retains a principle of life ?
Can we think that life exifts in a frog, a toad,
or a newt, when dry and rigid, as the wheel-
animals are among the fand ? Can we con- '
elude, and conclude with reafon, that in dry
and fhrivelled wheel-animals, we muft admit
the fame as in the reviving animals I mention-
ed before ? Can we conclude, I fay, that
their life is entirely gone, not only becaufe the
reciprocal aftion of the fluids and the folids is
deftroyed, but alfo becaufe the fluids are en-
tirely evaporated, and becaufe the drynefs and
rigidity has changed the natural ftate of the
folids ? If, when we put a (tiff and contra&ed

frog.

ANIMALS KILLED AND REVIVED. 27I

frog, toad, or newt, in water, we faw it gra-
dually become animated ; then, as we would
fay, it was a real and abfolute refurredtion : fo
may we call what Happens to the reviving
wheel-animals, a real and abfolute refurre&ion
alfo.

. But it is time to refume the hiftory of thofe
wonderful animalcula. We have already de-
fcribed their figure and their properties ; but
we have not yet examined their organs fepa-
rately, which is neceffary to make us well ac-
quainted with their ltru&ure and motions. I
mean to fpeak of the heart, the two trunks,
and the wheels revolving at the vertices. I
could not properly treat of them before, be-
caufe it would have prevented me from purfu-
ing the plan I intended to adopt, which led me
to relate fome fads, following the order of the
time when I learned them. In all my obferva-
tions, the wheel-animal has Ihewn me thofe
three organs only. Their appearance depends
entirely upon the will of the animal. While
animated, it is not unufual that it does not
fhew them at firffc, or difplays them very flow-
ly. This is what I have obferved in my wheel-
animals, and what fome of my friends have
obferved along with me. I did not obferve all
the three organs until after twenty-one days
examination. Let the reader reprefent to him-
felf a fnail proceeding from its fhell : it extends

itfelf.

ANIMALS KILLED AND REVIVED.

itfelf, and puts out its head and horns ; then
retiring within its habitation, contrafts itfelf,
and conceals the head and horns in its body : in
this way, he will fenfibly figure the motions of the
trunk and the wheels of our animalcula. The
wheel-animals I then examined, and thofe which
I afterwards faw, did not always at the fame
moment difplay both the trunks and the
wheels, but, like fnails, concealed fometimes
the one, and fometimes the other; which hap-
pened whenever they contra&ed themfelves ;
and when they remained long extended, the
trunks and wheels were kept out a long time
alfo. The wheels cannot receive this appella-
tion but in a very improper fenfe, and by
means of a fort of latitude or accommodation*
In the tra£l upon the Animalcula of Infufions,
I have treated at length of the minute, long,
and flender fibrils proceeding from the orifice
of the mouth of many of thofe beings : I have
laid, the fibrils were in conftant vibration ; that
they produced a certain vortex in the infufions,
which drew to the mouth of the animalcule the
corpufcula ferving it for food. The wheels
obferved in the wheel-animals, are only two
circular lines of thofe fibrillse conftantly in mo-
tion : they produce the fame effetl with the
vibrating points or fibres of infufion animal-
cula : they form in the water two great vorti-
ces, which convey to the animal the fubftances

tVhereon

ANIMALS KILLED AND REVIVED. 273

whereon it feeds. A wheel-animal is exhibit-
ed with the trunks extended and the fibrils,
whofe motion refembles that of two wheels,
and forms two vortices ; Fig. 5. pi. 3.

When I fay that the wheels of my animal-
cula are fuch only in appearance, I do not mean
to infinuate that this will extend as a general
rule to all. This optical illufion, indeed, has
been corrected by fome naturalilts, in particu-
lar by Meflrs Trembley and Bonnet ; but it is
alfo certain, that the opinion of celebrated ob-
fervers is different. Lewenhoek, that acute
obferver of the mod minute objects, actually
calls them wheels, which revolve like thofe
conflructed by mechanics. Baker, who is not
inferior to him in accuracy of obfervation, and
who has ftudied the wheels attentively, to dif-
cover whether they are truly fuch, or only vi-
brating fibrillas, is very much inclined to believe
them wheels. The obfervations of thefe two
illuftrious obfervers may very well agree with
mine ; for their wheel-animals have been dif-
ferent. A fingular aperture for a mouth, fitu-
ated between the wheels, a fort of ring beneath
it, a number of ferpentine veffels in the head,
the periftaltic motion of the inteftines, the ir-
regular agitation of a tranfparent fluid in every
part of the body, a particular undulation of
that fluid in the inteftines and the (kin, were ob*
ferved by the Engliih philofopher in his wheel.

T animals ;

27 4 animals killed and revived.

animals ; and although he has accurately de-
fcribed them, I have been able to find none fi-
milar in mine. There is no doubt, I might
have feen all thofe organs, both becaufe I ufed
Cuff’s microfcope, as Baker had done, and al-
fo fome microfcopes which were much fuperior.
With this different organization, it is not won-
derful that his wheel-animals exhibited another
organ -which I have not found in mine \ that
is, a pair of wheels proceeding from the two
trunks, the revolution of which produces the
fame effeft as the vibration of the fibrilke : a
rapid current is formed in the fluid, which car-
ries the food to the mouth of the animal. With
Baker we muff remark, that this apparent ro-
tation is not always made with the fame veloci-
ty, and in the fame dire&ion. Sometimes if
is quicker and fometimes flower, which alterna-
tives are executed momentaneoufly or by de-
grees. In the fame manner, we fee the animal
at one time turn to the right, and immediately
afterwards to the left. It frequently happens,-
that after it has moved long at one fide, it (tops
and turns diametrically oppofite.

Let us leave this digreffion, and return to
the animals. When their fibrillas appear, they
no longer crawl at the bottom of the water,-
but they fwim through the whole fluid with the
greatefl velocity. Examining them while they
fwim, I have often endeavoured to difcover,

whether

ANIMALS KILLED AND REVIVED. 275

whether they fwim by the undulations of the
body, or by the vibrations of the fibrillse, which
not only regulate the vortices, but, by their ac-
tion againft the water, may raife the animal.
This I have not been able fatisfadtorily to elu-
cidate 5 but I fhould think they fwim by the
vibrations of the fibrillae, fmce they fink when
thefe are drawn within the body.

I have already fpoken of a little circle fitu-
ated towards the head of the wheel-animals,
which is in appearance like the junction of
two C’s by the extremities. This part is in
conflant motion, by alternate contraction and
dilatation, while the animal forms the vortex,
and while the fibrils are extended. The part
has been obfcrved by Lewenhoek and Baker :
they have thought it the animal’s heart. The
fituation, the fhape, contracting and dilating
motion, concur, according to the Englilh natu-
ralift, in eftablifhing this opinion. But, if this
is a heart, it is a voluntary mufcle, which beats
at the pleafure of the animal ; that is, when it
protrudes the fibrillte and forms the vortex ;
and this voluntary aCt has, before me, been ob-
ferved by others. But, are there animals whofe
hearts beat by intervals, fo that the beating-
may ceafe when the animals chufe ? Befides,
the wheel-animals fometimes remain alive in
the water for feveral weeks, without making
the vortex, confequently without moving the

T 2 heart.

27^ ANIMALS KILLED AND REVIVED’.

heart. Is it poflible that any animal can live
fo long without the beating of the heart, the
animating fpring of the whole machine ? Thefe
are two paradoxes, which may be no lefs true
than there are others more wonderful : fuch as,
the refurrection of the wheel-animal itfelf. Al-
though it may be thought that this part is ac-
tually the heart, either from performing fimilar
functions, from its fituation in the region of
the bread, from its contraction and dilatation,
like a heart ; I cannot think thefe are convin-
cing reafons-; for it may be an organ deftined
for a purpofe completely different. I ought to
fay, as I think, that it is more natural to be-
lieve this organ ferves for the aliments \ fo that
it contracts and dilates to receive the nutri-
ment, and tranfmit it to the ftomach. Such an
hypothefis will eafily explain why it is in mo-
tion only while the vortex is formed : it is be-
caufe the aliment is then drawn to the mouth
and tranfmitted to the body. If the part re-
mains long motionlefs, it is becaufe no food is
taken, and this commonly happens while the
animals, in an unfuitable fituation, languifli
and die ; which is fometimes the cafe with
thofe revived in fand kept in clofe veffels. I
have feen, that although the fand fwarmed with
wheel- animals during the firfl days, the num-
ber decreafed ; and the decreafe was to fuch a
degree, that in twelve or fifteen days, the whole

were

ANIMALS KILLED AND REVIVED. 2 7J7

wise dead. They appeared motionlefs and
disfigured at the bottom of the veffel, and a
great many of them were even reduced to no-
thing. During this period of difeafe, the vor-
tex was feldom made ; but it is mod frequent-
ly formed by them when we find them in few-
ers, and in pits full of rain water.

The idea, that this moving particle is an or-
gan formed for the reception of the aliments,
in order to tranfmit them to the ftomach, is
not imaginary. It is founded, i. Upon ob-
ferving in my wheel-animals a kind of little
canal united to this part, Fig. 3. B, Fig. 4. E.
The canal rifing towards the head, has great
refemblance to an cefophagus. 2. This part is
furely deftined for that purpofe in other aqua-
tic animals, bearing a great relation to the
wheel-animals, and afford cogent evidence of •
the fact. Such is an animal often found in the
tremella. It is fhorter, and a little thicker,
than the wheel-animal. The pofterior part is
provided with two fmall diverging filaments,
with which it fixes itfelf to any fubftance. At
the anterior part, there are long (lender fibrils,
which being put in motion by the animal, oc-
cafion a vortex in the water, Fig. 6. There
is no vortex when the fibrils are at reft : while
they move, and during the continuance of the
vortex, there is fcen, almoft in the centre of
the animal, a particle, A, fimilar in figure to

T 3 tbu

278 ANIMALS KILLED AND REVIVED.

that part in the wheel-animal of which we
fpeak : it alternately contra&s and dilates ; but
the motion ceafes with the ceffation of the vor-
tex. This difference only is to be remarked :
the particle in the wheel-animal is formed by
two femicircular cavities ; whereas that in the
tremella animal, refembles a bladder or folli-
culus. The particle and canal towards the re-
gion of the head, are connected as in the
wheel-animal. There is a fhort duft, B, ter-
minating at the mouth of the animal, and at
the oppofite extremity : it enters another folli-
culus, C, which moves with alternate contrac-
tion and dilatation, undulating like a wave al-
raoft at reft. This folliculus is precifely the
receptacle of the aliments. It is always full of
a yellowifh green matter, which proceeds from
the pofterior part of the body, by means of
the undulating or periftaltic motion. But we
not only fee the food difcharged from, but we
alfo fee it enter the body : that is, we obferve
fragments of the tremella drawn by the vortex
to the animal’s mouth, infufton animalcula
of various fizes, and fragments of other fub-
ftances. .Some of the rnoft minute enter the
origin of the ccfophagus, traverfe the moving
particle, and arrive at the paffage we fee in the
receptacle of the aliments.

The fame thing is obferved in another ani-
mal of the tremella, which I have mentioned

ANIMALS KILLED AND REVIVED.

in the traft upon the Animalcula of Infufionu
The moving particle of this animalcule, for it
has one 2s well as the wheel-animal, contracts
and dilates, while the aliment collected by the
vortex pafles from the cefophagus to the fto-
anach.

In thofe animals, therefore, we fee this par-
ticle, which, in place, figure and motion, re-
fembles an heart, although it is not one, but
is an organ deftined for the ufe of the ali-
ments. For thefe reafons, I have afcribed the
fame ufe to that of the wheel-animal.

Should I be right the wheel-animal has no
heart, we fee no other part, no other organ,
that can merit this name. If we may judge of
this by the fenfes, I fay it has none, more than
the two tremella animals I have mentioned, a
number of infufion animalcula, the prodigious
abundance and variety of polypi vifible by the
microfcope and to the naked eye. I flop at
them, to fay no more of many other animals.
I have never feen the appearance of circulation
in wheel-animals, nor in the animalcula of in-
fufions, thofe of the tremella, nor in polypi.
Although Baker has obfervedin wheel-animals,
the irregular agitation of a fluid, he ingenuoufly
avows, that he never has perceived any trace
of a real circulation : yet all feed, encreafe
and multiply, as thofe animals which have a
heart and circulation. Neither are thefe ef-

T 4 fential

280 animals killed and revived.

fenlial to the life of many animals. For this,
it is enough that there is a juft equilibrium,
a correfponding harmony, between the fluids
and the folids. The ideas we have of a heart
and of circulation, are particular notions, ta-
ken from a definite number of animals, which
demonftrate the bounds of our knowledge and
intelligence, and which would ill apply, if we
meant to fit them to the iinmenfity of models
framed by nature.

The wheel-animals inhabiting the roofs of
hcufes, of ovens, or other buildings expofed to
the inclemencies of the weather, fnould. be of
a conftitution calculated to fupport the moft fe-
vcre influence of cold and heat. I put them to
the teft. From a fewer expofed to the fouth, I
took wheel-animals fand, which had for twen-
ty-nine days been fubje&ed to the heat of the
fun in the middle of Summer. The thermo-
meter in the funfhine ftood, during this time,
at 129, 1 3 1 , 1 330. The heat did not injure
the animals ; for, when the fand was wet, I
had a great number very vivacious.

I expofed a little of this fand in very thin glafs
tubes, without a fouth window, where the re-
fleclion of a neighbouring v'all excited an ex-
treme heat, and I left them there the whole
Summer. During forne of the hotteft days,
the thermometer rofe to 1420; but the heat
did not injure the wheel-animals : upon wet-

UnS

ANIMALS KILLED AND REVIVED. 23 I

ting the fand, they appeared with the fame
livelinefs and vigour, and in the fame abun-
dance, as in other fand from the fame place
expofed in a north window, and feldom or
never experiencing the folar rays. I have con-
cluded, that the powerful heat of Summer did
not deprive the wheel-animals of the faculty of
refurre&ion ; but, is it the fame when they
are revived ? Is this degree of heat then equal-
ly fupportable ?

I have alfo expofed thofe tubes with fand
and water, where there wras a number of wheel-
animals, in the warm fituation above men-
tioned. The effedt was very different : in half
an hour, the heat of the fun at 1350 killed the
animals. Thus, it is not the fame with wheel-
animals, when dry and deprived of life, as
when in life and motion.

I afterwards faw, that refufcitated wheel-ani-
mals died when expofed to a more gentle degree
of heat, when expofed in the funlhine at 1 13°.

The heat of the fire has the fame effeft as
that of the folar rays. But, while the revived
animals perifli at 1 1 1 and 1130; if expofed to
1 440 when dry, they do not lofe the faculty of
refurredlion. With common fire, I could ex-
tend my experiments farther than with the heat
of the fun. I railed the heat to above T44°»
to fee whether dried wheel-animals ceafed to
fevive ; for it was to be thought there were

limits

282 ANIMALS KILLED AND REVIVED.

limits here ; and I found thofe limits at 153®.
Sand expofed to this degree of heat, prefent-
ed few wheel-animals, and at 158° none. But
there is a circumftance here neceffary 10 be e-
lucidated. I made thofe experiments, as I
may fay, dry, keeping the fand for two or
three minutes expofed to the degree of heat I
fixed upon. The confequences were very dif-
ferent, when I ufed wet fand, and immerfed it
two or three minutes in water warmed to that
degree ; then, the wheel-animals did not re-
vive beyond 13 1°.

It is nor difficult to explain, why the deduc-
tion of re-animated wheel-animals is more eafy
than when in th,eir hate of deficcation. The for-
mer are a fort of jelly 5 of confequence, very
fragile. Their minute filaments are eafily brok-
en and deftroyed by the penetrating power of
the fire, which does not take place with fuch
facility when they are dry : then they are
hard, and partly concentrated in themfelves.
Befides, in this ftate, their globular figure pre-
fen ts lefs furface to the a&ion of the fire ; alfo
the heat afts alone upon dry wffieel-animals ; apd,
when they are alive, it acts along wdth the wra-
ter, vffiich powerfully concurs in lacerating
them, and deftroying their organization : and
the heat has rendered that lacerating power more
active and penetrating. It is for this reafon

that

ANIMALS KILLED AND REVIVED. 283

that drv wheel-animals can lefs refill the heat
of warm water, than of the fire itfeli.

Having feen the effeft of heat upon wheel-
animals, it was necefiary to fee the effect of
cold upon them. For this purpofe, I took the
fand of fewers, of bent and flat tiles, where
the animals are found during the moll intenfe
cold of winter, when the roofs are covered with
fnow and ice. The fand moidened with water,
by the cold became fo firm and connected, that
it was as hard as a done ; but this cold had not
injured the wheel-animals. After melting the
mixture of ice and fand, I faw a great number
foon revive, only their refurrection feemed to
me lefs immediate.

The greated cold in Winter was i6°: I
thought therefore of fubje&ing thofe wheelers
I found upon the roof, to a degree more in-
tenfe ; and, taking fome portions of frozen
fand from the bottom of a few?cr, I put them
in a little glafs veffel, which, for three hours,
I placed in a degree of cold n° below o, by
means of a mixture I have often mentioned :
But the animals revived when the ice melted,
which prove, that degree of cold had done
them no injury.

After being certain of this, 1 fought for the
refults of the experiment inverfed ; that is,
what will happen when we pafs wheelers from
the degree of heat at which they are ani-
mated.

284 ANIMALS KILLED AND REVIVED.

mated, to different degrees of cold, always
more intenfe. One morning I tranfported fome
fwimming in a watch-glafs to a north window,
where the thermometer flood at 270, obferv-
ing what happened when the water in the glafs
became fo cold that the hand could fcarcely be
kept in it. The wheel-animals flopped the
vortex, and fell to the bottom, crawling lan-
guidly along the fand. The water was foon
frozen ; then they moved with difficulty ; and
this motion in a fhort time ended. When the
water was more frozen, they contracted with-
in themfelves, forming into globules, which I
dearly faw from the tranfparence of the ice.
Thus, the wheel-animals paffed the whole day
and the following night, w'hich v'as very cold.
The next day 1 removed them to a warm a-
partment, to fee whether thofe in the ice, un-
der the figure of globules, vrould recover life
and motion v;hen the ice melted. This took
place even vrhen I made the globules remain
longer in ice : even when I encreafed the na-
tural, by means of factitious cold, to 1 1° un-
der o.

Reafoning from the experiments of cold,
as upon thofe of heat, it would appear, that
the revived wheel-animals fliould not fupport
the fame degree of cold as thofe which are
dead. If, upon the other hand, thefe laft faCls
do fhew, that when the cold begins to act

with

ANIMALS KILLED AND REVIVED.

with power upon revived wheel-animals, they
then pafs from life to death, as appears by the
ceffation of their motion, their contraction and
disfiguration, fo that they become precifely as
when the evaporation of the water leaves them
dry in the fand.

Befides, fuppofing that an extreme cold ex-
ercifes its influence upon living wheel-animals,
I know not if it could have the power of de-
priving them of life. It is certain it could not
deftroy animalcula, as delicate as fome of thofe
of infufions, and the eels of vinegar. But,
what is more furprifing, the animalcula of in-
fufions, and the eels of vinegar, perifh at a
lefs degree of heat than the wheel-animals.
They cannot fupport more than 1 1 1° above o.
At this degree of heat, feveral fpecies of bee-
tles, of chryfalids and caterpillars, perifh, as I
before obferved, although they fupport the cold
of 340 under freezing. By this we fee, that
feveral animals fupport cold better than heat.

Thofe faCts teach us, that there are two
principal caufes deftruCtive of the refufcitating
quality in wheel-animals. Thefe are, the want
of fand and of heat. But, are there alfo others
producing this effeCt ? I could not difcover this
but by conjectures, and by ufing the different
methods which are noxious to the production
and life of other animals, efpecially thofe that
have the greatefl analogy with wheel-animals;
iuch as the animalcula of infufions. It has

been

286 ANIMALS KILLED AND REVIVED.

been proved, that thefe are produced in vacuo.
This method of injury does not feem fufficient
to prevent the refurreftion of wheel-animals*
though we cannot deny that their refurrec-
tion is facilitated by the influence of the air.
The mean of the principal refults of repeated
experiment is, i. Wheel-animals revive fooner,
and in greater numbers, in the open air, than
in vacuo. 2. Thofe which do not revive in
vacuo, revive when put in the open air.

However much the air may promote the re-
furre&ion of wheel-animals, it is abfolutely ne-
ceffary for the prefervation of their lives.
When they revive in vacuo, or are put in an
exhaufted receiver, they die in a few days.

Although wheel-animals revive in vacuo, it
is not fo fuccefsfully as in the open air : it is
natural to think they would revive in confined
air, although this air prevents the production
of other animals, and kills them when con-
fined in very fmall veflels. But in the veflels
where I had the wet fand of thofe animalcula,
although hermetically fealed in fmall tubes,
they have always very foon revived, and in
abundance : they have even lived long in very
fmall veflels, where there was very little air.

Wheel-animals fuffer from different fluids,
what they do not fuffer from privation of air,
or from confined air. I fhall mention the li-
quids that do, and do not, injure them. Thofe

which

ANIMALS KILLED AND REVIVED. 1%*f

which are not noxious to them, are either
thofe in which they revive, or in which, after
refurredtion, they preferve life. Such is, pit,
river, ice, fnow, and rain water ; diflilled wa-
ter, that of ditches, marfhes, pools ; the foetid
water of mud and dunghills. RefpeCting the
fluids noxious to them, they are either thofe
impregnated with pepper, common fait, fal-
gem, vitriol ; thofe in which are exprefled the
juice of the onion, garlic, urine, ink, wine,
verjuice, oil of olives, of nuts, brandy, vine-
gar, &c. Having put in each of thofe fluids,
the fand of wheel-animals, I never faw one
revive ; like wife, when revived wheel-animals
were put into them, they all perilhed. Some
ftrong and penetrating odours have been e-
qually fatal to them. Such is the odour of
camphire. When revived, if they are long
fubjefted to it, all die, and do not revive when
dry. The oil of turpentine produces only the
firfl effeCt. But if this odour becomes more
active, as by melting or burning the turpen-
tine, the fumes prevent the revivifcence of
the animals. The fumes of burning fulphur
and camphire produce both effects : the fumes
of leaf tobacco only deftroy revived wheel-
animals.

Reflecting upon the experiments made by
means of heat, liquids and odours, I have
fometimes doubted whether thefe three agents

had

eSo ANIMALS KILLED AND REVIVED.

had deprived the wheel- animals for ever of tile
property of refurre&ion, or if there was any
place to hope it might be recovered. This
hope did not feem chimerical in a being like
the wheel-animal : it would not be wonderful
to fee it recover the faculty it naturally pof-
fefles. I have preferred fand which has been
expofed to heat ; I have from time to time
wet it with pure water, and have often obferv-
ed it. The fame has been done with fand ex-
pofed to liquids and odours, keeping it in the
air and wetting it with frefh water, that the
noxious qualities which injured the wheel-ani-
mals might be deftroyed. But thefe methods
have never re-animated the numerous dead
bodies.

The wheel-animals which fuggefted the opi-
nions I have laid down, were for the greater
part thofe found in fewers, the ridges of flat
and crooked tiles. In this matter, which for
brevity I. have called fand, though, to fpeak
more properly, it is a mixture of earth, fand,
and the fragments of tiles, (I fhall continue to
call it fand), is the dwelling of wheel-animals :
but we mud obferve, that in fome kinds they
are much more numerous than in others. If
the fand is red, it is almofl: a certain indica-
tion, according to Baker, of the prefence of
thofe animals : but they are always inanimate
when the fand is dry. By one who is ac-

cuftomed

ANIMALS KILLED AND REVIVED. 289

cuflomed to obferve wheel-animals in the date
in w'hich they are found, when by the eva-
poration of the water they are dry, they are
eafily recognifed when the fand is prefented
upon a Aider to the microfcope : then they are
feen in the lhape of minute dry globules, of a
reddifh yellow colour ; which, when moiden-
ed, extend themfelves to form the animals.

The animals are alfo found in certain wa-
ters of the earth. Both Baker and I have of-
ten feen them in ditches ; and I have taken
many from pools, marfhes, and even holes of
water.

The wheel-animals of the earth are, in my
opinion, the origin of thofe of roofs $ and it
feems to me that it cannot be otherwife, at
lead, that we cannot fay the wheel-animals of
one roof come from another, which fuppofes a
particular cafe : but to take the cafe generally,
and confider it as in its origin, I fhould derive
them elfewhere, and confequently recur to the
waters.

The manner in which they pafs from the
earth to roofs, may be eafily conceived : when
in their dry date the wind may effefr this, or
when the air has raifed the v'hole or part of
the wrater where they are.

While du dying thofe curious beings, I have
always reflected upon a mod important pro-
blem ; which was, to enquire into the mode

U of

290 ANIMALS KILLED AND REVIVES*

of their propagation. For this, I have ifolated
them in watch-glafles like infufion animalcula :
1 have put one in each, but I never could fee
them propagate, either by (hoots or divifions,
although both ways are very common among
aquatic animals. Neither was it by a foetus ;
but I had reafon to think, that it was by means
of eggs. Whenever the ifolated wheel-animals
had been fome days revived, I have feen, in
the body of the largeft, an ovular fubflance ;
PI. 3. fig. 5. N. When I happened to find the
wheel-animals dead, they had always this ovu-
lar body ; but in general it had paffed from
their own bodies into the glafs, without my
knowing how ; at the fame time, with an im-
portant Angularity. When entire, the ifolated
animal fwam alone in the fluid ; but when the
body was broken, there fwam another wheel-
animal, much fmaller, along with it. This
made me fufpeft that the new inhabitant had
come from the ovular fubflance ; efpecially as,
when the animalcula were excluded, the other
eggs were broken. It might likewife be fuf-
pefted that it had been carried thither by the
air : but to be fure of this, it was neceflary to
fee the animal’s departure from the ovular fub-
ftance ; which, notwithftanding all my care
and attention, I could never accomplifli.

My obfervations agree 'with thofe of Baker,
who has not been more fuccefsful than myfelf.

He

ANIMALS KILLED AND REVIVED. 2 gi

He thinks the wheel-animals are oviparous ;
becaufe he has often found, in the water along
with them, gelatinous eggs of a proportional
fize. Befides, he has in two fpecies of wheel-
animals, a little larger than the moll common
kind, difcovered an oval body, the figure of
which very much refembles the fubftance I
have defcribed ; but he has never feen one ex-
cluded : nor has he feen a wheel-animal come
from the gelatinous eggs, although he has kept
them three years.

The learned Padre RofFredi has enjoyed the
happinefs denied to Baker and to me. In the
Journal of the Abbe Rozier, he has given a fi-
nilhing ftroke to our obfervations. Speaking
of the wheel-animal, he incidentally fays, but
in exprefs terms, that he has feen it proceed
from the egg. “ Lewenhoek is miftaken in
“ thinking the wheel-animal viviparous ; and
<c what he takes for Ihapelefs excrements in
<c the inteftines, is really an egg which I have
e< feen it produce, and obferved it many rimes
<c until I faw it hatched.” If Signor Roffre-
di’s obfervation is correct, I cannot doubt the
fad:. By this means, a circumftance in the
hiftory of the wheel-animal is elucidated,
which fhould deeply intereft the naturalift.

The folution of this problem, added to my
obfervations, difcovers another important truth;
namely, that the wheel-animals undergo no

H 3 meta-

2g2 ANIMALS KILLED AND REVIVED.

metamorphofis. I have collected many mi-
nute ones produced in a watch-glafs, and kept
them with great care : they always continued
to encreafe : but when I killed and revived
them, their increment was flower than when
they were kept continually wet. When full
grown, each in general laid an egg, which
produced another wheel-animal. Thus, I
know, that from the time they arc produced,
until maturity, they undergo no metamorpho-
lis. We cannot fay it is a metamorphofis-
when they are produced ; for they have then
attained their greateft perfection. The infects
which metamorphofe, never propagate their fpe-
cies until they become winged animals, and
have acquired the laft degree of perfection to
which metamorphofis will bring them.

Finally, my obfervations have demonflrated
to me, that wrheel-animals are hermaphrodites
in the mod rigorous fenfe. I have had the
fifth generation, from many eggs ifolated in
■watch-glafles, making ufe of ifolation to take
away, all lufpicion of copulation..

CHAP-

ANIMALS KILLED AND REVIVED. 29J

CHAP. II*

The fand of tiles, the mud of ditches, and of
marfhes, which pafs in the vulgar eye for the
vileft of matter, are to the philofophic obfer-
ver a fource of wonder, from the fingular be-
ings they contain. To ditches and marches
we owe the armed, club, funnel, bulb, and
knotted polypus. It is there we find the frefh
water worm, the boat worm, and the fpring-
ing millepede. Thofe animals have confound-
ed the human mind, and have created a new
philofophy. When the fand of tiles does not
ferve for an abode to wheel-animals, it will not
for that reafon be lefs famous or remarkable.
An animal, which revives after death, and
which, within certain limits, revives as often
as we pleafe, is a phamomenon, as incredible
as it feems improbable and paradoxical. It
confounds the moft received ideas of animali-
ty : it produces new ideas, and becomes an
objefl no lefs intercfting to the refearches of
the naturalift, than to the fpeculations of the
metaphyfician. But the celebrity of this fand
will encreafe, when we learn, that it contains
Other animals, which, like the wheel-animal,

XJ 3 poifefs

Sg4 ANIMALS KILLED AND REVIVED.

poffefs the property of refurrection ; fo that
we may almoft fay, all the animals living in
fand are defined to be immortal. I have dif-
covered in fand two new fpecies of animals,
which I proceed to defcribe. I lament that
their rarenefs has prevented me from extend-
ing my obfervations as far as I could have
wifhed, or rather as far as the importance of
the fubjecf would have required.

Upon wetting the wheel-animals fand, I fe-
veral times obferved a yellowifh animal, three
or four times as large as a wheel-animal, with
fix legs ; but I paid no attention to it, as I
thought it was fome little terreftrial infeft that
had fallen by chance into the watch-glafs where
the fand was kept. The reafon inducing me
to think it fuch, was, becaufe I had always
feen it move obliquely, and very flowly, at the
bottom of the water : as if unable to walk, it
was frequently fupine, and always made efforts
to recover its natural pofition ; but thofe ef-
forts were in general fruitlefs, as happens to
many aerial and terreflrial infefls falling cafu-
ally into water. At the fame time, with a
more continued and careful obfervation, I re-
cognifed it as an animal really aquatic. I faw
that it walked in fo laborious and awkward a
manner, from the fmoothnefs of the glafs-flider
upon which it had been put for examination ;
and, when placed upon fand, it had a regular

progreffive

ANIMALS KILLED AND REVIVED. 29^

progreffive motion, flow indeed, and, compar-
ed with the wheel animals’ motion, refembling
the crawling of a rortoife. Thus, to defign it
by fome defcriptive name, I called it the Sloth.

The whole body is granulated ; the anterior
part is obtufe ; and the poflerior part terminat-
ed by four hooked filaments, which ferve to
fix it to any particular place. The limbs have
finall Aiming claws, which, as far as one can
judge, are of a corneous fubftance, the points
turned towards the body, as we fee in the re-
curved claws of feveral infedts. The corpu-
lence of the floth rendering it opaque, prevents
us from feeing the internal organization, it
only allows us to fee a fmall elliptical fpot in
the middle of the body, which I fufpedt to be
the refervoir of the aliments. The anterior
part is alfo marked behind with a lucid fpot,
fmaller, narrower, and longer than the other,
which I have fometimes fancied the cefophagus.
The figure of the body prefents nothing agree-
able ; it very much refembles the tefticle of a
cock. The floth is reprefented fupine, Fig. 7.
pi. 3. ; and the profile is feen. Fig. 8.

This animalcule forms no vortex in the wa-
ter ; which is not furprifmg, as it has neither
the wheels nor the vibrating fibrillse of the a-
nimals which perform this operation. It ap-
pears that the wheel-animal cannot advance a
ftep, without fixing the trident to fome adja-

U 4 cent

296 ANIMALS KILLED AND REVIVED.

cent fubftance. It is not the fame with the
floth ; fqr it does not make frequent ufe of its
hooked filaments. It never fwitns. It is fpe-
cifically heavier than the water. It turns
round upon the land, or walks among it.

The phenomena of its death from the want
of water, and of its refurre&ion when water
is fupplied, are precifely the fame tvith thofe
of the wheel-animal. The motion is gradually
loft ; the limbs are contracted and drawn info
the body ; the whole di mi nifties-, is completely
dried, and affumes a globular figure ; PI. 4.
fig. 1. The reverfe of this takes place, when,
upon fupplying new water, the floth recovers
life. As the wheel-animal can revive only a
certain number of times ; fo is it with the
floth. It feems, that although fand is neceffa-
ry for its refurre&ion, yet it is not fo effential
as for that of the wheel-animal. The degrees
of heat injurious to revived wheel-animals, are
alfo injurious to floths ; and it is the fame with
odours and liquors. Cold, however intenfe,
does them no harm. Such are its fimilarities
to wheel-animals.

Sloths are much more rare than wheel-ani-
mals. It is not common, for five-and-twenty
wheel-animals, to find above three or four floths.
All floths are of the fame figure, although not of
the fame fize. I have ifolated feveral in watch-

r

glafles, fometimes with fand, and fometimes

with

*•- is / '

ANIMALS killed and revived. 297

■with pure water, meaning to fee how they pro-
pagated ; but, inftead of multiplying, they all
perifhed ; in the firft cafe fooner, and in the
lecond later, never attaining the fixth day in
life.

The third fpecies of refurgent animals found
in fand, is that of minute eels, very like the
anguilla; of vinegar. This fpecies is much
more rare, and it is not found upon every
roof. The head and adjoining part of the bo-
dy is very tranfparent, of a finning filver co-
lour ; the tail is the fame ; but the intermedi-
ate part of the body is a little dark, and is gra-
nulated upon the furface. The greater part of
the tail is bent, and terminated by a very lharp
point. The head, on the contrary, is obtufe ;
and, a little below its extremity, there is a
mouth, which terminates a little canal ferving
apparently for an cefophagus, and running
through the length of the body ; PI. 4. fig. 2.

If the fand they inhabit is very dry, they
are feen motionlefs, dried up, and generally
rolled in a fpiral ; but, when moiflened, they
foon exhibit figns of life. The tail firft begins
a gentle motion, bending and turning in differ-
ent directions : then the head moves, and af-
terwards the reft of the body ; fo that the
whole animal quickly becomes animated. The
confequence is, that the fame degree of humi-
dity is not required to animate this fpecies as

-9^ ANIMALS KILLED AND REVIVED.

by the wheel-animal and the lloth, which do
not revive, unlefs completely immerfed in wa-
ter. The eels do not change their fituation
much ; they only extend, contract, turn, and
bend themfelves. If the fand is thoroughly
wet, their agility and rapidity of fwimming is
as great as that of the eels in vinegar. They
live a long time in watch-glades, providing
they have water ; and, if there is fand at the
bottom, they hardly ever quit it, always mov-
ing about the grains, and touching them with
the head, which would induce us to fuppofe
they do fo in fearch of food ; becaufe fome
more minute and delicate fubdances are taken
In by the mouth, and paffed to the cefopha-
gus. I never obferved them propagate, al-
though kept long in the glades.

When the water evaporates they die ; but
they redd death longer than wheel-animals
and doths. Sometimes a fmall degree of mo-
tion is preferved feveral minutes after evapora-
tion. When dead, the figure of the body is
changed ; the length is contracted, the breadth
is diminifhed. Upon being moidened, they
indantly refume their original fize, and their
animation re-appears.

There are conditions effential for their re-
furrection. When the eels are in fand, a quar-
ter of an hour is necedary to recall them to
fife -p but when in pure water, there is a great

difference,

ANIMALS KILLED AND REVIVED. 299

difference, according to circumftances. If it
is only the fir ft or fecond time they revive,
there is not much difference in the time re-
quired for their refurreftion : but, in propor-
tion as the number of refurre&ions encreafes,
the time neceffary for refurrection always be-
comes greater : an hour at lead is required,
and fometimes this hour is not enough, for the
fourth refurre&ion : for the fifth, there is dill
longer required ; and fo on for the reft. But
the frequency of refurrection in pure water, as
in fand, has its limits, like that of wheel-ani-
mals and floths. The eels die for ever at the
feventh, or eighth, or, at mod, at the ninth re-
furrettion ; and, although placed in a humid
fituation, revive no more. I may add, that at
each refurre&ion part of their agility is loft ,
fo that the laft is but a fimple change, from
immobility to languid contorfions of the mem-
bers.

There, then, are three fpecies of animals in-
habiting the fand of roofs, of which nature has
permitted the refurrection after death. Thofe
three are the only inhabitants of this fand ; at
leaft, I do not think I have ever feen other ani-
mated beings there, having a permanent abode.
They are not the only animals in the world
that enjoy the privilege of refurrection ; there
are alfo others which poffefs it. Among thofe
fire the celebrated eels of blighted corn. All

the

300 ANIMALS KILLED AND REVIVED.

the world knows that Mr Needham is the au-
thor of this famous difcovery. Examining the
internal furface of blighted corn, he faw, with
agreeable furprife, that it was compofed of mi-
nute eels, which, upon being wet, acquired
motion, and gave certain figns of life. This
fudden refurrection, as he has thought, takes
place when the ears are gathered hill frelh and
humid ; if they have been gathered for fome
time, and have loll their humidity, it is necef-
fary to macerate them, and this will not always
be fufficient for the refurre&ion ; it is even ne-
ceffary that the eels which have come from the
ear lhall remain for a given time in the water.
We alfo fee, that when allowed to dry, they
become motionlefs ; and wetting them again,
they recover motion and life. But, what chief-
ly furprifed the author of this difcovery was,
after having preferved the blighted corn for
two years and more, he obferved, anew, the
fame phaenomena upon wetting it.

The difcovery was too wonderful for others
not to endeavour to afcertain it. It has been
found real by feveral good obfervers, fuch as
the tranllator of Mr Needham’s work, who
fpeaks of this difcovery a ; by the Count Gin-
jiani b ; but particularly by the celebrated Ba-
ker, in his excellent difiertation upon the eels

of

a NouveUes obfervations microfcopiques.

^ Delle malattie del grano in erba.

ANIMALS KILLED AND REVIVED. 3<3I

of blighted corn 3. Among other things, he
has feen the refurredtion of eels, taken from
grain that had been dry during four years :
this obfervation he made before Mr Folkes,
then Prefident of the Royal Society, and other
friends. But he faw a refurrection much more
wonderful, of the fame eels, which was effected
after a far longer time. In 1771, he had fome
blighted corn, which he had got from Mr
Needham in 1744. He made fome experi-
ments upon this corn, and the refurrection of
the eels fucceeded perfectly, at the end of 27
years b.

In fhort, there is not at this day any profef-
for, any amateur of natural hiftory in all Italy,
who does not take pleafure in amufing himfelf,
and the learned curiofity of his friends, with
thofe admirable refurredtions. For this reafon,
I judge it needlefs to flop to prove, by new
fadts, their reality, and to fpeak of the origin
and generation of thofe eels ; for we know that
this, which is the molt effenrial part of their
hiftory, has been amply elucidated by the learn-
ing and labours of Italians. I fhall but relate
the refults of fome of my little obfervations,
which may not only ferve as proofs of their
hiftory, but are analogous to thofe we have re-
lated of other refurgent animalcula. The ex-
ternal

* Employment for the microfcope.

b journal de L’ Abbe Rozier,

'302 ANIMALS KILLED AND REVIVED.

ternal colour of a grain of blighted corn which
has been kept fome time, is like foot ; if bro-
ken, the internal fnbftance confifts of a dry
whitiih matter : when examined with the mi-
crofcope, its appearance changes into a mafs of
long corpufcula, fhaped like eels; but thofe eels
are not only very much dried, but feem life-
lefs, and are fo crowded and confounded to-
gether, that it is difficult to feparate without
breaking them.

If this grain has been infufed fome hours in
water, and the extremity adroitly cut off with-
out injuring the infide, and if it is preffed with
pincers, through the hole there is feen pafs a
parcel of minute eels, juft like a bit of pafte
drawn into a thread : when let fall into water,
they are fcattered about, and falling to the bot-
tom, appear extended as fo many ftraight lines,
or a little bent, and remain in this pofttion un-
til they recover life.

I have attempted to know how long was re-
quired for their refurredlion, computing from
the moment when the grain was wet ; but fo
many varieties have occurred, that I have never
feen the fame thing happen twice. In fome
grains, the eels were reanimated in three hours,
and even in lefs, and others in four or five
hours ; there were fome which required twenty
hours and even more, and fome, complete days.
The eels of the fame grain were not all reani-
mated

ANIMALS KILLED AND REVIVED* 30$

mated at once : it fometimes happened that two
days intervened between the animation of tne
firft and the laft. The whole eels of blighted
corn do not revive ; fome are disfigured and
lacerated : part of the whole are always of this
defcription ; but fome, apparently entire and
unhurt, preferve perfect immobility.

The heat and cold of the weather are not
indifferent to their refurre&ion : heat accele-
rates it, and cold retards it : but there are alfo
irregularities here.

There are fymptoms which announce the
animation of the eels ; thefe I fhall abbreviate.
The firft indication of life, is when the eels
ftretch themfelves entirely or partially ; they
are no longer ftraight lines, as when they are
dead, but the head and tail begin to curve,
though the reft of the body continues a mo-
tionlefs thread in a ftraight line. Sometimes
the two extremities do not bend ; the middle
of the body only becomes arched. Sometimes
the one gently ofcillates, while the other does
not move ; fometimes they approach each o-
ther until they touch at the extremities, and
form a circle ; fometimes one extremity refts
upon the other, or glides over it ; fometimes
the whole body is rolled in a fpiral, in wider
or narrower volutions. Thofe bendings, arcs,
ofcillations, circles, glidings, . volutes ; thofe
contortions, formed and deftroyed, are repeat-
ed

^04 ANIMALS KILLED AND . REVIVED.

ed at firfl with great languor ; then in a more
marked manner, and with more vivacity. This
aftonifhing variety of motion, with others which
it is needlefs to defcribe, continues in the wa-
ter during the whole time the eels live. Whence
it appears they have nothing that may be with
propriety called a progreflive motion, which
makes a difference between them and the other
refurgent fpecies of animals. During life they
never rife in the water, nor do they crawl up-
on the fides of the veffel, but always remain
at the bottom, where they are feen under the
appearance of a nucleus, of a darker or lighter
colour as they are more or lefs numerous.

If the water gradually fails, whether by e-
vaporation or by taking it away, they gradu-
ally become lifelefs ; and when there is no
more water, they no longer move. The three
other kinds of refurgent animals have the pru-
dence to fly the places where the water dries ;
but the eels continue in the fame place without
moving.

In forne hours, they become very dry, and
tenacioufly adhere to the bodies applied to
them, fo that it is difficult to feparate them
without breaking ; but, when wet, they fepa-
rate eafily, efpecially with the point of a needle.
They foon lbften, and twift themfelves, when
it is feen they are of a gelatinous fubflance ;
and they cannot be touched with an iron in-

flrument.

ANIMALS KILLED AND REVIVED. 305

ffcrument, without being broken or injured.
This at lead happens when they are in life.
When they have been dead feveral days, they
are dill very fragile, yet have more cohefion
than one would think. They refill the point
of a needle, and do not even fuller from a
drop of water let fall from a height upon them.
When they have been dry for a quarter of an
hour, they are reanimated by the contact of
water, and become as vivacious as before. U-
rine, fait water, and vinegar, produce the fame
effect, although thofe liquids are fatal to them
in other circumflances, as we lhali fee. When
they have been dry fome days, they require a
full hour to recover life. If one has patience
to wet, and let them dry, their death and re-
furrection will be feen in this important limit ;
which is, that the oftener the hu mediations are
repeated, the lefs the number of refufeitants
vdll be, and the longer the time required for
their refurre&ion. I had a number of livelv

J

eels in a watch-glafs the firft time they reviv-
ed : the thoufandth part did not revive the e-
leventh time ; and the feventeenth there was
not one. I have often repeated this obfer-
vation, but always with the fame fuccefs ; ex-
cepting that the reviving eels either went be-
yond the feventeenth refurreflicn, or died be-
fore attaining it.

X

Wheel-

306 ANIMALS KILLED AND REVIVED.

Wheel-animals, floths, the minute eels of
roofs, and of blighted corn, poffefs the proper-
ty of refurr edition, circuinfcribed within cer-
tain limits, beyond which it is loft. The body,
to revive, mull be entire. Eels cut into two
pr more parts, although often wet, and re-
maining long in water, never exhibit any fign
of motion. When divided in two, they lofe
all fenfation, after a flight univerfal vibration
or convulfion of the body.

Like wheel-animals, 1 have fubjedded the eels
to different experiments, and frrft to electrici-
ty, ufmg Bevis’ battery : thofe alive died in-
flantaneoufly, and thofe dead at the time loft
the property of refurreddion. This did not fur-
prife me ; almoft all were broken or disfigured
by the traverfmg electric fliock. In the blight-
ed corn they have been fubjected to the fame
experiment, but there was a difference in the
refults. When the grains had been previoufly
macerated, few revived; if the grains were dry,
many recovered life.

The eels are revived by fait water, urine,
-vinegar, when they have been a fhort time dry ;
neither are they fo immediately killed by thefe
liquids as other animalcula, for they will move
ill them feveral hours after immerfion.

A vacuum does not affedd their refurrection,
whether the firft time after proceeding from
the grain, or after fome refurreddions ; only the

refurreddion^

ANIMALS KILLED AND REVIVED. 307

refurre&ions are not fo foon accomplilhed as in
the open air.

The heat of the fun or of the fire, at 140°,
kills them in fome hours : when raifed to 1440,
they are almoft immediately deprived of motion
and life. Heat more powerfully affeds wet
grains than dry. Sometimes the obferver will
have a number of eels from grains that have
been expofed to 138° of heat ; and fometimes
the greater part are killed at that degree.

When freezing water becomes folid, the mo-
tion of the eels ceafes. Cold 8° below o does
not take away the property of refurreclion ; and
when the ice melts, life re-appears.

Thofe who have never feen the eels of blight-
ed corn, will find them defigned, fig. 3, 4, 5,
pi. 4, as they appear, when examined not by
a very powerful magnifier, while fwimming in
the fluid. Seven blighted grains are reprefent-
ed of their natural fize and figure, fig. 6, and
three are magnified, fig. 7.

Plants are a kind of beings fo analogous to
animals, that we may excufe him who has de-
fined them ramofe animals. In the works of
Vallifnieri, Buft’on, Bonnet, and, laltly, of the
Abbe Cord, may be feen the numerous and va-
rious traits of analogy between the two kinds
of organifed beings. The fubjed which I treat,
prefents a new analogy ; for, as different ani-
mals revive after death, fo do many plants

X 2 lpring

308 ANIMALS KILLED AND REVIVED.

fpring again after they have perifhed. I fhould
depart from my plan, did I mean to fay as much
of them as I have faid of animals ; and I fhall
content myfelf with mentioning two, the Noltoc
and the Tremella. The Nofloc, thus named

1

by Paracelfus, is a terreflrial plant, which, from
its fudden appearance in places where there was
no mark of it before, was viewed by the an-
cients rather as a prodigy of heaven or of earth,
than as a plant. So they have denominated it,
heaven’s flower, and earth’s flower. It is feen
in all feafons, but particularly in Summer, after
heavy rains. Although it fprings in every foil,
It prefers meadows, arid lands, and fandy val-
leys. It is of a brownifh green colour, and of
an irregular figure, refembling a leaf carelefsly
folded. When feparatcd with the fingers, fome
refiflance is felt, fuch as when one tears a young
leaf. If a fudden drought happens, the nofloc
contradls and dries, remaining only a fine thin
fkin. If a fudden and heavv rain falls, it be-
comes green again, and refumes its original
fize. The nofloc is then, as Reaumur obferves,
•who has furnifhed me with this intelligence, a
plant of a Angular kind, fince it recovers life
after being in a flate which to others would be
permanent death.

The Tremella is an aquatic plant, which en-
joys the fame privilege. Botanifls have placed
it in the clafs of Confervia. If in a veffel where

* “ ' : ’ the

ANIMALS KILLED AND REVIVED. 309

the water fails, it dries and lofes its verdure ;
but if water be fupplied, it foon recovers its
original date. Nature does the fame with art.
I have feen, from the beginning of July till the
end of October, a ditch for watering land, co-
vered fifty times with the beautiful verdure of
the tremella, and feen it as often difappear,
when there was no water : I faw only at the
edges and at the bottom, colourlefs hairs*
which, the microfcope fhewed me, were the
tremella dry and dead.

But, w'hat can be the reafon why thefe fpe-
cies of animals and plants are thus privileged,
in companion with a very confiderable number
of others, which, perifhing once, perifh for ever?
Shall we perhaps repeat what we have faid up-
on the fimplicity of the ftrutture of thofe be-
ings ? But this does not feem to me well found-
ed. There are many animals which do not re-
vive, whofe ftrudlure is as fimple, and even
more fo, than that of the reviving animals.
Several fpecies of the animalcula of infufions,
which feem compofed of a fimple aggregate of
vehicles, enveloped by a fine membrane, are
certainly more fimple than wheel-animals, which
are provided with veflels, wheels, inteftines,
and ovaries ; yet they do not recover life when
once it is loft. The fimplicity of their ftruc-
ture would thence appear an obftacle to their
refurredlion ; for, vrhen the infufion has evapo-

X 3 rated,

310 ANIMALS KILLED AND REVIVED,

rated, the fimple membrane of feveral fpecies
burds : then they are diflipated, and each is re-
duced to a mafs, without order or connexion.

The armed polypi are no lefs fimple than
the animalcula of infufions, being compofed
but of a granulated gelatinous 1km. If, there-
fore, fimplicity of organization influenced the
refurreclion of animals, the armed polypi would
certainly be of the number. They feem fo
much the better adapted for it, as they conti-
nue in life, notwithlfanding every method ufed
to deprive them of animation. It is demon-
drated, that they receive no injury after being
turned feveral times outfide in, like a glove, or
when cut afunder. If the head is cut off",
there arifes a fort of hydra with many heads,
each of which receives food by a different
mouth. If thefe new heads are cut off, there
fpring new hydras ; and each head creates a
polypus fit for the formation of new hydras.
In fhort, every particle of a polypus, the fmall-
efl fragment,, develcpes and becomes a new
polypus. If an animal fo lacerated or man-
gled does not die, will it not appear very cre-
dible, that, only letting it remain dry, it will
fiill retain the faculty of redirection ? But
fa£ts prove the reverfe. When the water eva-
porates, the armed polypus always dies, which
happens equally, whether it is immediately ex-
pofed to the air, or concealed in aquatic herbs.

When

ANIMALS KILLED AND REVIVED. 3 1 I

When the water is almoft exhaufled, the arms
are drawn within the polypus : it contracts
within itfelf, and then lofes motion and life ;
which it never recovers, although afterwards
copioufly wet with new water. I fpeak of the
armed polypus : it is the only kind I have been
able to find, and it is the fmalleft of Mr Trem-
bley’s armed polypi.

After polypi, and the animalcula of infufi-
ons, according to my defcription, the organi-
zation of the floth appears the mod fimple.
We might fay the fame of the eels of tiles and
blighted corn, which are two fpecies of eels,
eafy to clafs from organization with fo great a
number of the inhabitants of fluids. Under
the tremella, in the water, are often found mi-
nute eels, very like thofe of tiles in fize, fhape,
and fimplicity of organization. I have fre-
quently had the curiofity to let them dry by
the evaporation of the water : they all endea-
voured to conceal themfelves where the fila-
ments of the tremella were thickeft ; and,
when the evaporation was completed, they pe-
rilhed, remaining partly twilled among thofe
filaments, and partly heaped upon each other.
If immediately wet, they revive ; but if a few
minutes elapfe, they do not.

The eels of vinegar give the flrongefl evi-
dence of their vigour. Although they continue
motionl'efs when the vinegar fails, and are ap-
X 4 parently

312 ANIMALS KILLED AND REVIVED.

patently dead, they recover life and aCtion if
wet after a full quarter of an hour. Some-
times I have fucceeded in reviving them after
half an hour. I do not call this a refurrec-
tion ; for, if it was fuch, I do not fee why it
fhould not take place anew, when wet' with
vinegar, after even a longer time. I fhall ra-
ther fay, they do not lofe life fo foon as the
eels of the tremella. and feveral other aquatic
infeCts, when left dry : when life is fuppreffed,
it is preferved, and appears upon being wet
with water.

I cannot find a greater fimplicity in the tre-
mella and the noltoc, than in many plants
that do not revive. Let us throw a hafty
glance upon the Truffle. That vegetable is
more fimple : no roots, tendrils, or fibres, in-
ternal or external, throughout a fubltance e-
qually compact and uniform, only interrupted
by veins fimilar to thofe winding upon fome fpe-
cies of marble. In refpect to other plants, not
only terreftrial but aquatic, it has no analogous
organization : yet truffles, after once drying in
the air, do not revive when put in water.

Thefe united facts fhew how fallacious are
the opinions of thofe who attribute the refur-
reCtion of animals and vegetables to the fimpli-
city of their organization. To what principle
then can we recur, fince here we mull proceed
■upon conjecture, rather than evidence, and the

vie w

animals killed and revived* 315

view of truth ? I ftiall fugged an hypothecs,
without engaging to fupport it. The experi-
ments of Haller demondrate, that the vital
principle of animals which have a heart, re-
Tides in the irritability of this mufcle. His ex-
periments are too well known, to need repeti-
tion. In animals which have no heart, it is
almod probable, that the principle of their life
refides in the irritability of their mufcles ; which
being the cafe, if the date of animals is fuch,
that the irritable nature of the heart and
mufcles is dedroyed, fo as to leave no hope of
it being repaired, it is clear that the animal
not only dies, but mud always remain dead :
but if the irritability is fuch, that, either by
nature or art, it may be re-excited, it is cer-
tain that the animal diould pafs from death to
life. It will not matter that it remains dead
a long time, even for an age. The reader
comprehends my idea. When wheel-animals,
floths, and the eels of tiles, are deprived of
water, their irritability is lod, as is evinced by
fatts, and they die : when other animals have
once lod this irritability, they never recover
it ; but wheel-animals, floths, eels of tiles,
&c. refume at once their original life.

This theory explains why, in certain cafes,
our animalcula lofe the property of refurrec-
tion when expofed to powerful heat, to pene-
trating odours 5 or when certain liquids, or e-

ledricity.

\

314 ANIMALS KILLED AND REVIVED,

ledricity, ad upon them. Thofe agents injure
the mufcular ftrudure, which appears by the
deftrudion of the body, and from the irritat-
ing force refiding there.

This perhaps is the reafon why frequent hu-
medations injure refufcitant animals. I have
particularly feen, in the eels of blighted corn,
that the frequent humedations injured and al-
tered the members.

We muft thence conclude, that as irritabili-
ty refides in the glutinous part of the mufcle,
this part has, in refufcitant animals, qualities
very different from the irritable parts of other
animals, although we are ignorant of this dif-
ference, becaufe we are ignorant of what the
difference in the gluten confifts.

I am a friend to fincerity. From my expe-
riments may be deduced a conclufion againfl
this hypothefis. Irritability is recognifed by
its appearance ; that is, when the mufcular fi-
bre is touched by any fiimulant, it contrads
and becomes rigid. I have often ftimulated
the mufcles of the eels of blighted corn and
of tiles, with an extremely fine iron point, at-
tentively obferving what happened. It always
appeared, that the mufcular fibre contraded a
little when touched ; but I muff acknowledge,
that I faw the fame thing in the eels of vine-
gar, and in other analogous animals which have
not the privilege of refurredion. There are

even-

ANIMALS KILLED AND REVIVED. 3J5

even minute aquatic and terredrial worms, com-
pletely as irritable as the eels ; fince, if touch-
ed, however gently, they contratt and fw.ell,
till they become twice as thick and Ihort.

The objection is therefore confined to this ;
There are fome animalcula which do not re-
vive, although they are as irritable, and even
more fo, than thofe that do. This does not
affedt my hypothefis ; for it does not place the
principle of refurredtion in the greatefl and
mod perfedt irritability, but in an irritability
which, after ceafing, may be renewed by means
of certain circumftances, although it would o-
therwife appear to be lefs adtive than in other a-
nimals. If this hypothefis does not entirely
feem applicable to plants, at lead in what con-
cerns irritability, fince we know, that, except-
ing a very fmall number, they have not this
property, it is dill poffible to apply it to their
organization. In general, dried plants do not
recover life ; probably becaufe, in drying, they
are fo much injured, as to become incapable
of imbibing the juices furnifhed by the earth,
and of converting them to their own fubdance.
Such is the caufe of their perifhing, and of
their total dedrudtion. If the drying of plants
does not occafion this diforder, and if the ac-
tion of their organs revives, when foftened in
■water, and they refume their original form, it
is undoubted they will here recover their for-

mer

3l6 animals killed and revived.

mer verdure and natural frefhnefs. This may
be the phyfical caufe, why the tremella, the
noftoc, and other vegetables revive.

I (hall end this diflertation with fome reflec-
tions upon thofe beings which we may, at plea-
fure, pafs from life to death. When this idea
is prefented to the mind, we are allonifhed,
becaufe they are ifolated beings : they form a
feparate clafs, and are adverfe to the receiv-
ed ideas concerning animated beings. But,
when it is proved by a train of innumerable
fadls, that all is gradated in nature, that thofe
beings are connected to other beings, and con-
fequently, the inflations exifl but in the gene-
ral fyftem, our wonder fliould ceafe, or at
leaft diminish, fmce it only arifes from our ig-
norance of the relations which afford us the
connexion of the clafs of beings poflefling the
prerogative of refurre&ion, with the other
claffes of animals. This is not the only ifolat-
ed fact that has exifted, and, at firft, been viewed
as an exception to general laws. To be ac-
quainted with many, it is neceflary to read the
works of Reaumur, Trembley, and Bonnet.
Thofe exceptions appear Angular at firft, be-
caufe they are feen only in a fingle inftance.
A plant, an animal of a new genus, or which
poflefled peculiar properties, was the origin of
thofe exceptions ; but farther obfervation, and
folid experiment, have fhewn them adapted to

fltveral

ANIMALS KILLED AND REVIVED. 317

feveral cafes, either in the Jame circumstances,
or under fome modifications, and proportioned
as people have applied themfelves to diverfify
the number of fubjects which have verified it.
Some are fo extenfive, that it is impoffible to
call them exceptions. This wonder, which af-
feCts the mind from fomething new or extra-
ordinary in the faCts which occafion it, gradu-
ally diminishes, and vanifhes entirely. One or
two examples will corroborate and elucidate
my reflections upon refufcitant animals.

One of the moft efficacious methods of de-
stroying animals, is, to cut them into pieces.
The experiment is common, and known. To
fay, that this was a method of multiplying fome,
would be to affirm what had a fabulous appear-
ance. Yet it is the cafe with the armed po-
lypus. And Shall we fay the dilcovery is bound-
ed by this animal ? lhe fcalpel need only be
applied to other animals, to prove the difcove-
ry extenfive : the reproductions of the earth-
worm, the boat-worm, the freffi water worm,
fome leeches, fea-ftars, fea-netiles. Sec. While
art effects prodigies upon thofe fpecies, nature
prepares fimilar in lilence ; I fpeak of the na-
tural divifion of the dart millepede, of fe-
veral fpecies of club, funnel, and bell polypi,
and a great number of infuficn animalcula.
We alfo find, that nature forms not only two
animals from one only, but even four, and a

multitudq

3 i S ANIMALS KILLED AND REVIVED.

multitude fo prodigious, that there are as ma-
ny fimilar animals as there may be atoms in
the generating animal. But the wonderful
progrefs of the difcovery of the polypus, does
not end there. It is a chain paffing from ve-
getables to animals, and leads to man. The
tremella is the link conne&ing animals and ve-
getables ; it is a real zoophyte. It has been
difcovered, that the filaments of which it is
compofed, fpontaneoufly divide, and that a
complete plant fprings from each divifion.
The polypus is joined to the tremella, and is
united to a number of fpecies dividing like it-
felf, which in the fame manner are linked with
other fpecies. But reproductions are not ef-
fected in the fame way in all thofe beings.
One may reduce a polypus, a frefh water worm,
a fea ftar or nettle, to the fmallefl fragments,
and be certain that each fragment will repro-
duce itfelf. The earth and boat worm cannot
be cut into pieces fo fmall, and reproduce it-
felf. If a fnail is decollated, a new head will
germinate ; but the head cut off, will not ac-
quire a body. Water-newts, and frogs in the
figure of tadpoles, recover their tails and limbs
when deprived of them ; but, if mutilated in
other parts of the body, they perifh a. No
warm-blooded animal is known, which repro-
duces itfelf when cut in pieces : but animals

recover

* Treatife upon animal reproductions.

ANIMALS KILLED AND REVIVED. 319

recover large pieces cut away. Duhamel has
feen a ring of flelh cut to the bone, reproduced
in the thigh of a chicken.

Similar reparations are every day obferved
in wounds, in the cicatrices of wounded
animals ; and we have certain evidence of
the reparation of the tibia in a man b. It is
thus that the difcovery of the polypus, which,
at fir ft, feemed to revolt fo much againft rules
thought general, extends to fo many links in
the animal chain. But, has this fuccefs fo ra-
pid, this advance fo great, exhaufted the fub-
jeCt of reproductions ? No, certainly ; it will
appear but liitle known, if we confider how
bounded the number of animals is upon which
our experiments have been made, compared
with thofe upon which we may make them.
The element of water is molt favourable to re-
productions. How many infeCts, worms, rep-
tiles, zoophytes, are there inhabiting the briny
waters of the fea, or the frefli waters of rivers,
pools, marfhes and ditches, upon which there
was never made an experiment, and which,
from the great refemblance they have, whether
in the modes of life and propagation, or in
fhape and external appearance with the repro-
ducing animals, are doubtlefs calculated to re-
produce themfelves ?

The

i> This faft is related by the celebrated Bernard M«f-
£?ti, furgeon at Mil^n.

520 ANIMALS KILLED AND REVIVED.

The idea of hermaphrodifm, until the be-
ginning of this age, has been viewed as a
thing more chimerical than true. Nature
feemed to depofe againfl it ; but in how many

hundreds of animals have not the cares of mo-

,

dern naturalifts found it ? This admirable pro-
perty has palled by degrees from one fpecies
to another. The polypus is a perfect herma-
phrodite, without fex ; it multiplies not only by
divifions, but by Ihoots. The puceron of plants
is lefs an hermaphrodite \ it has a fexual di-
ftinCtion : and although, during Summer, it
multiplies without copulation, at the end of
Autumn, it is obferved to copulate. Earth
worms, Ihell fnails, naked fnails, and many
fpecies of Ihell fifh are more or lefs herma-
phrodites. They are, at the fame time, male
and female, but infufficient alone. They give
and receive, they fertilize and are fecundated.
The difcovery of refufcitant animals is far from
being as extenfive as that of reproduction, and
of hermaphrodites ; but this ariles lefs from
the paucity of thofe beings, than from the few-
ness of philofophers who have entered upon
that branch of natural philofophy. Lewen-
hoek was the firlt who drew the curtain from
before thofe wonderful objects, by his wheel-
animal. He feems furprifed at a fact, unique,
and unexampled in nature ; and indeed no
one thought that there was in all the animated

world

ANIMALS KILLED AND REVIVED. 321

world another animal pofleffing this prodigy.
But, fince the profound refearches of more mo-
dern naturalifts have made others appear, I
doubt not that the number of thofe wonderful
beings will encreafe as the ftudy is cultivated.

The (hades feen in hermaphrodites are not
obferved in reproducing animals, and cannot
be expe&ed in the refufcitant. There may be
a greater or lefs degree of reproduction : an
animal may reproduce more or fewer organs :
an animal may perhaps be more or lefs an her-
maphrodite, if hermaphrodifm is taken in a
comprehenfive fenfe : thus, both poffibilities
have been realifed, as we fee in the fa£ts I have
mentioned. But we cannot reafon thus upon
the animals reviving after death : we cannot
fay that an animal dies more or lefs, or that its
refurre&ion is greater or lefs : death and re-
furre£tion are two indivifible afts ; fo much,
that neither has any gradation in the animals
hitherto known, and it cannot be expedited in
thofe we fhall afterwards dilcover. It is not
becaufe thofe animals have no particular gra-
dations, and are not connefted with others of
the fame kind ; but becaufe thofe gradations
are difficult to be obferved. We have feen the
flate to which cold reduces fome animals ; we
cannot call it death. There is then a thread
of life, a leffer life, to connect refufcitant ani-
ptals with the reft. The greater part of plants

Y . lofe

322- ANIMALS KILLED AND REVIVED..

lofe their verdure during winter : they have
little lap, and it is motionlefs : they ceafe to
take nutriment, to grow, to multiply ; all which
produce complete ina&ion. How many ani-
mals befide infedts do we fee with a lefs degree
of life, even without excepting warm-blooded
animals, which have a fimilar degree, and, a-
mong them, birds ! I am far from thinking
with Guagin, in his defcription of Mufcovy,
Populos quofdam in Lucomonia regione Rul-
tc fiae habitantes, quotannis vigefima feptima
cc Novembris die, ut folent hirundines et ra-
<c nos, fic et ipfos frigoris hyemalis magni-
“ tudine mori, poftea redeunte vere vigefima
t£ qua-rta Aprilis die denuo revivifcere. ”

We cannot at the fame time deny, that man
may fometimes be in a fimilar fituation with
animals overcome by cold : when immerged in
water, we may fay he hardly appears to be in
life. I will not affirm with fome phyfiologifts,
becaufe there is neither pulfation nor refpira-
tion found in the body, the pulfation of the
heart, and the circulation of the fluids, are
fufpended ; but I would rather think with Hal-
ler, that thofe motions are only too faint and
obfcure, to appear or be externally perceived.
Examples of this we have in fome animals
half-drowned, where a degree of motion is
perceived in the heart and in the blood. Be-
fides, the life of man and animals, when half-

drowned

ANIMALS KILLED AND REVIVED. 32J

drowned or ftrangled, cannot be more faint ;
and we may regard it as another point in the
paflage from the refufcitant, to thofe animals
which do not revive.

There are other two Hates which are very
fimilar to the death of our animals. The one,
the Hate of the embryo in a fecundated egg
which has not yet experienced the heat necel-
fary for its expanfion ; life is incomplete ;
there are but the rudiments or principles of
life. The other Hate is that of a chryfalis.
Among infefts, when the caterpillar has loft
its natural form, it affumes that of a fhapelefs
mafs, without the veflige of feet or of wings :
it ceafes to feed ; indeed to eat would be im-
poffible, for the organs are wanting : it has no
longer loco-motion ; and we would really be-
lieve it dead, but for foine inflection and con-
tortion of which the pofterior part is fufcepti-
ble. The appearance of death is Hill more
fenfible in the nymphs of many worms ; they
exhibit no fymptom of motion or fenfation.

Thus there are in nature fituations a little
fimilar to the Hate of refufcitant animals when
they are dry. We fee in the refufcitant ani-
mals, that this Hate may be protra&ed or a-
bridged at pleafure. That torpid animals may
never awaken from their lethargy ; that the
embryo may never expand in the egg ; that
flies and butterflies may never proceed from

Y 2 the

3^4 ANIMALS KILLED AND REVIVED.

the nymphs and the chryfalids, it fuffices to
keep them continually expofed to cold. The
reverie will happen when they are expofed to
heat. Probably there are gradations of con-
nexion, more immediate and more direct, be-
tween the animals that revive, and thofe that
do not. Life, however feeble and obfcure, is
always life ; between it and death there is a
diftance as great as between entity and non-
entity. An animal, whofe life is fufpended
from an impediment to the mutual afticn of
the folids and the fluids, and which is devoid
of fenfation, would be the link connecting the
leaffc degree of life with death. Such an ani-
mal is yet unknown : but we ihould not de-
fpair of finding it, fo many being found which
better link the chain of life. Let us only re-
member, that natural hiftory is ftill in its in-
fancy, and that what we have hitherto dis-
covered, is nothing, compared with what is to
difcover.

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1

EXPERIMENTS and OBSERVATIONS

UPON

THE ORIGIN OF THE PLANTULjE OF MOULD.

The mould which I have examined, and in-
tend fimply and briefly to defcribe, is that
which fprings upon apples, pears, melons, and
gourds, beginning to fpoil. It may be confi-
dered as of two kinds ; the one very fimple,
eafy to obferve and defcribe, the other complex
and involved, which can only be explained by
a generic del'cription. Let us begin with the
former.

One fpecies of this mould is without branch-
es ; each filament bears at the fummit a globule,
pi. 5. fig. 3. Another is ramofe, but with this
difference, fome plants have a globule at the
vertex of each branch, while others have it not,
fig. 2. Thofe globules I fhall always term the
minute heads of mould. There is one obferva-

v

tion neceffary to be made concerning them.
Without the microfcope, they appear fpherical,

Y 3 and,

3^6 ORIGIN OF MOULD.

and, even with it, they have the fame appear-
ance when viewed from above ; but when ex-
amined below, that is, where the ftalk is inferr-
ed in the head, we obferve that all, or the
greater number, are fhaped like mufhrooms ;
or, to fpeak more philofophically, they are real
mufhrooms. Two filaments are reprefented
with the globules, fig. 7. ; the globules highly
magnified, fig. 8. On pears there fometimes
grows a kind of mould, which is a real tree in
miniature, univerfally adorned with fpherical
heads or mufhrooms. A ftalk of this mould is
reprefented, fig. 6. We muft remark, that ra-
mofe mould is very often attached to vegetable
fubftances, without any root : but the mould
without branches, almoft always has roots, ori-
ginating from a round corpufcle, whence the
filaments forming the ftalks of the mould are
detached. It is a fmgular circumftanee, that
as every root of mould has a greater number
of ftalks, the filaments from the root are pro-
portionally more numerous. Upon tearing, the
mould from the fubftance where it fprings, a
degree of refi fiance is felt, which arifes from
the roots being well fixed : when torn up, they
appear very crooked, while the ftalks, if they
have not fuftered from the impreflion of the
air, are very ftraight. Many of the ftalks are
©f an equal thicknefs, at leaft they do not be-
come

ORIGIN OF MOULD.

327

come much fmaller towards the top. Fig. 3.
will perhaps render this defcription more plain.

Mould is at fird of a mod beautiful white ;
it then acquires a yellowifh tint, and at lafl
blackens ; but the heads grow much blacker
than the (talks and branches. The origin and
encreafc of mould is almoft proportioned to the
heat of the atmofphere : it is never more apt
to appear and vegetate fuddenly, than during
the heat of Summer: a fubdance which at night
exhibits but a fingle (talk, will frequently be
covered in the morning, and then the mould
has attained its full fize and maturity. The
height does not encreafe fo much as the thick-
nefs : the heads already black, are always of a
larger fize than thofe dill young and white.

Mould is never fo beautiful and vigorous as
when it vegetates under forne veflel or receiver,
providing the communication of the external
with the internal air remains. The reafon is
evident. As the dalks are very fine near the
fummit, and bear at the vertex a round cor-
pufcutum, ofcillating by its own weight ; each
filament ofcillates, as the ear of corn occafions
the ofcillation of the dalk. Thus we may eafily
perceive, that every breath of air, however gen-
tle, will bend, break, and dedroy thofe mod
delicate filaments; which does not take place,
when the fubdances to bear mould are put un-
der a receiver. Befides, the humidity of the

Y 4 fubdance

J28 ORIGIN OF MOULD.

fubftance is better preferved, which is a circum-
ftance moil effential for the production and in-
crement of mould. In the courfe of thefe ob-
servations, I have always made ufe of receivers.
The injurious influence of agitated air is feen,
fig. i, which reprefents two quantities of mould
with heads, as feen with the naked eye, when
taken from under the receiver, and expofed for
a fhort time to the aCtion of the open air : their
natural direction is loft, and they turn to oppo-
site fides.

Several fubftances put in a Situation to ac-
quire mould, diflolve into water, by which the
adjacent plane is wet in proportion as they
Spoil ; and it is precifely upon this place the
mould hitherto mentioned fprings. From the
fame fubftance, there likewife exhales a leffer
degree of moifture, which adheres to the in-
fide of the receiver, forming a pellucid aqueous
veil 5 and the encreafe is fo considerable as to
form large drops, which run down the Sides of
the receiver in ftreams, meandering among the
moiftened places : the fame quantity of mould
grows upon the ftreams, as may be feen, if the
receivers be tranfparent.

The other kind of mould we have defcribed,
is very complex, and always fprings upon the
vegetable fubftance itfelf, particularly upon
gourds and moiftened bread. When the pu-
trefaction of thefe vegetables commences, a

white

ORIGIN OF MOULDv

325

white thick covering of mould appears upon
the furface, and in a few hours is a line high.
When ripe, it is three lines high, or more.
This is a fpecies very different from that of
which I fpoke before, which, at complete ma-
turity, is fcarcely half a line high. We have
already faid, that each plant of this mould may
be obferved feparately, and without confufion,
and that the obfervation may be continued, di-
flingifhing each until maturity : but it is other-
wife with the mould of which I now fpeak j
fuch an obfervation would there be impoffible.
The immenfe number of plants when the mould
begins to fpring; the interweaving of the Items,
and bending of the branches ; the entangling
and interlacing of the whole in an hundred
different ways, completely prevent it : the fight
is confounded among a multitude of flender fi-
laments, which become in a greater or lefs de-
gree a whole, deranged and confufed as the
vegetation of the mould advances : the fub-
ftance can only be torn afunder to fee its pro-
grefs. When the ftalks of this mould are pull-
ed from the fubftance upon which they fpring,
it would appear they have no roots. From
each of the numerous ftalks, many twigs and
branches proceed ; but we Ihould obferve, that
thofe fubaltern productions are frequently of as
great a diameter as the parent ftalks from
which they originate.

While

33®

ORIGIN OF MOULD.

While the ftaiks vegetate and extend, there
appear feveral groups of fmaller (talks fpring-
ing laterally, with minute heads at the vertex.
Thefe heads refemble mufhrooms, partly glo-
bular, and, as the (talks rife, the heads en-
creafe, until they blacken and arrive at maturity.
New (talks with heads, are, befides thefe, feen to
rife, and the multiplication continues while the
mould vegetates. This little foreft is full of
ftaiks ; and its fkirts are terminated by delicate
points and black globules.

In this manner does mould fpring, ripen,
and die. We need not afk whether it is a real
vegetable ; it appears to be fuch too evidently,
by the obfervations I relate. But thefe veget-
ables or microfcopic plants, do not poffefs two
properties common to other plants. Ligneous
and herbaceous plants, when expofed to natu-
ral light, always tend to take a direftion per-
pendicular to the horizon. They endeavour
to attain it, and even to recover it, when taken
away. The experiments of M. Bonnet are ex-
cellent, as may be feen in his work Sur /’ ufage
des feuilles. In mould, we do not fee this ten-
dency to perpendicularity ; for, although many
ftaiks are perpendicular to the horizon, this is
not effential to their nature, and there are at
the fame time many other in a different direc-
tion. If a plant grows in the rent of a wall,
although its firft appearance is in a horizontal

dire&ion.

ORIGIN OF MOULD.

33*

direction, it in a very fhort time rifes perpen-
dicularly towards the heavens. It is not fo
with mould. I have often cut a piece of me-
lon, gourd or bread, into a cube : mould ve-
getated upon the four lateral furfaces, and the
ftalks had conftantly every other than a per-
pendicular direction.

The other property which was difcovered by
the celebrated Genevefe naturalift, is, the ten-
dency of plants to turn towards the light. Be-
fide the facts he relates, which are fufficient to
afcertain the property, I have frequently ob-
ferved it in legumes growing in infufions I kept
fhut up in a prefs. The plants always bended
towards a chink, through which a very fmall
ray of light penetrated : and, if I fhut up this
chink, and opened another in a different part
of the prefs, the plants abandoned their origi-
nal direction, to take this new one. I have
endeavoured to learn whether this happened to
mould, but could never difcover that light had
the leaft influence upon it. If ripe mould is
fhaken, a fort of black duff falls from it, which
the celebrated botanift Micheli has thought to
be the feed of the plant ; but Dr Monti fenior,
a very eminent botanift likewife, has doubted
the truth of this obfervation, and he rather in-
inclines to think, that mould fprings by a fpon-
laneous generation.

Before

33* ORIGIN OP MOULD,

l

Before difcuffing this queflion, the object of
which is fo interefting, I think it proper for us
to examine the place where the dull is found :
to accomplish which, it is neceifary to make a
brief analyfis of the heads of mould : this we
can do only by examining and feeing it ripen.
Before the heads are ripe, they are of a whit-
ifh or yellowifh colour, the Surface very Smooth :
upon being broken with a fine iron inftrumentj
they feem to be membranaceous, and full of a
granulated fubftance : if, inftead of being bro-
ken, they burft, fometimes a number of minute
round feeds come out. Thefe are found both
in the Spherical and fungiform heads.

When the heads blacken, the appearance
changes ; the furface feems unequal ; it is la-
cerated in Several places, and refembles a par-
cel of black rags. When opened, a number
of feeds is feen ; but young mould has white
feeds, and old or ripe mould has black. When
the heads are moiftened, the feeds are feen
more diftinctly, and in greater abundance.
Upon contaft with the fluid, or a little after-
wards, the heads burft, and fcatter around a
cloud of feeds j fo that I may affirm, without
danger of exaggeration, there is a million in
each head. The unripe heads do not open in
this manner upon being wet ; they remain en-
tire. It muft be remarked, the ripe heads are
not totally decompofed. Where they are round

like

ORIGIN OF MOULD.

333

like mufhrooms, there is a little head in the
centre, which continues to adhere to the ftalk :
this is cinder-coloured, with a degree of tranf-
parency, and does not appear black like the
exterior : it is difficult to detach it from the
ftalk ; but, with a fmall degree of preffure,
a little jet of feeds is raifed from it, refembling
thofe I have defcribed : the central head then
becomes a dry and empty (kin.

If the heads, when black and ripe, are o-
pened by means of water, fuch a quantity of
feeds ilfues forth, as'to adhere in great num-
bers to the plants, in particular to the ftalks ;
fo that one would fuppofe the exterior compof-
ed of feeds alone, were they not feen in a dif-
ferent ftate before. One of thofe deceitful
appearances is feen, Fig. 9, : it is intended to
reprefent two plants of mould, one of which
is entirely covered with feeds ; the head is tu-
mid, and likewife in a great meafure covered
with feeds. Fig. 4. reprefents two ftalks of
mould with heads : the whole feeds of the one
are expofed, and another is perfectly covered
by the integument ; the third is entirely co-
yered.

A quantity of thofe minute feeds conftitutes
the powder blackening the hands, when the
mould is manipulated ; and they are confulered
as real feeds by the celebrated Florentine bota-
nift. To afcertain the truth, he had rccourfe

to

334

ORIGIN OF MOULD.

to a method apparently decifive, which was,
to fow the duft. He ftrewed it upon fome ve-
getables, and faw them covered with plants of
mould. But the Bolognefe profeffor has re-
peated Micheli’s experiment, without finding
it fo conclufive ; the vegetable fubftances being
equally covered, although no dull was put up-
on them. Thus, the queftion remained unde-
cided ; for I do not know that any other per-
fon has attempted to refolve it.

Perhaps I fhall be taxed with prefumption,
when I fay I have been able, by means of ex-
periments analogous to thofe of Micheli, to af-
certain the fa£t ; but experiments much more
numerous, more diverfified, and more con-
nected with each other. The confequences I
fhall venture to publifh. I took two pieces of
moiftened bread, as fimilar to each other as
poffible, and from the fame loaf, fo as to be
perfectly equal. I endeavoured to attain the
fame equality in all the reft of my experiments.
I ftiewed one of the pieces with duft taken
from a quantity of ripe mould heads, fo that
the furface was flightly blackened by it : the
other piece was untouched, in order to com-
pare the production upon each. This was done
in Summer. Upon the following day, the fown
fubftance , but, for brevity, I fhall obferve,
that by this expreffion I mean, the fubftance
of whatever nature covered with duft, and

ORIGIN OF MOULD,

335

by the word unfown, the other vegetable fub-
fiance not covered with dull : upon, the fown
fubftance, I fay, next day appeared a fhade or
mould ; whereas upon the unfown, there ap-
peared none. Before the third day, both fub-
flances were covered with mould ; but the
mould of the fown fubftance was almoft double
the height and thicknefs of that upon the o-
ther. Both fpecies of mould were of the fame
kind, and perfectly fimilar to that which had
produced the duft. Upon the fourth day, the
mould of the unfown fubftance, although pre-
ferving the original thicknefs, was equal to that
of the other in height : it was ftill higher up-
on the following day, but afterwards continued
to become thinner. I repeated thofe experi-
ments eleven times upon moiftened bread, and
the effect was, that the mould twice became e-
qually high and thick upon both fubftances, and
nine times it was higher upon the unfown fub-
ftance, than upon the other : it conftantly
fprung firft upon the fown fubftance.

Having collected a great quantity of ripe
duft, I thought of varying the quantities,
by fcattering different portions upon moif-
tened bread : the confequences were new.
When the quantity of the duft was very fmall,
there was almoft no difference in the height
and thicknefs of the mould ; but the thicknefs
encreafed, if a greater quantity was fown. It

was

33^ ORIGIN OF MOULDS

was never fo thick as when liberally fcattered
over the bread ; but, in proportion as the thick-
nefs encreafed, the height diminilhed. Thofe
experiments were repeated again and again,
upon apples, pears, and gourds ; and the re-
fults were all, in a certain degree, more or lefs
fimilar to what I relate.

The confequences that may be deduced from
thofe experiments, are thefe. i. Sowing the
dull accelerates the production of the mould :
2. The thicknefs is encreafed : 3. The height
is lefs. Confidering thefe facts with refpeCt to
my objeft, it feems to me, that the fecond
proves the dull to be the real feed of the mould ;
fo that fcattering the dull occafions the more
abundant production of the mould. If the
thicknefs encreafes with the encreafe of the
quantity fcattered, it is natural to think, that
the fuperabundance of mould upon fown fub-
ftances is an effeCt of the duft, or rather of
the minute feeds fown, and that all, or molt
part of the mould, originates from them. This
being the cafe, it is not furprifing that the
mould upon fown fubftances is not fo high as
upon the unfown ; for, the plants being more
numerous, each cannot imbibe the fame degree
of nutriment from the fown fubflance, as may
be derived from that which is not fown, where
the plants are lefs numerous ; which is alfo the
cafe with other plants, as they are fmaller and

Ihorte^

ORIGIN OF MOULD.

537

fhorter in proportion as they are crowded.
The firft confequence deduced from the fa£ts
demonftrates, that the production of fown
mould is more early than that of unfown. I
have thought that this might happen, becaufe
the fown fubftances fooner fpoil ; fince it ap-
peared that the duft germinated earlier, if the
corruption of the fubflances advanced, as I be-
fore remarked.

I diverfified thofe experiments. Sometimes
I covered an half, fometimes two thirds, or
one, of a flice of bread, an apple, a pear, or
a gourd, without touching the other half : the
half, two thirds, or one third, were juft in the
fituation of the fown fubftances. I likewife
made another experiment. After covering
half a flice of bread, an apple, or a gourd,
with duft, I applied the furface fown to ano-
ther furface frmijar, but unfown, leaving both
in this ftate for feveral days. Upon the whole
fown furface was feen a veil of mould, the ve-
getation of which had ceafed, becaufe it was
fpoilt by the fubftance applied ; but there
was no veftige of mould upon the unfown fub-
ftance.

Thefe laft facts concur in corroborating the
idea, that the duft is the real feed of mould,
becaufe the mould produced upon the places
fown, was exa&Iy of the fame fpecies with
that which produced the duft. Notwithftand-

Z in<j

33^ ORIGIN OF MOULD.

ing all thofe plaufible and repeated experi-
ments, I was not Satisfied. Is it not pofiible,
faid I to myfelf, that this duft only renders the
foil more fertile, fo that it will produce a great-
er quantity of mould, as the earth, fertilized
by foreign matter, will produce a greater num-
ber of plants ? This was certainly not impof-
fible ; and, wifhing to proceed with philofo-
phic ftridnefs, I judged myfelf obliged to real-
ize or deflroy the poffibility : for which pur-
pofe, I thought that I Should cover the fubftan-
ces where mould Springs, with duft taken from
different vegetables, different earths, and o-
ther matter volatile from the extreme minute-
nefs. It appeared to me, that if this duft could
contribute to render the fubftance more fit to
produce mould, it did not alone poffefs this
advantage. The roots, ftalks, and green heads
of mould, were not fpared. I dried and re-
duced them to a very fine powder, but with-
out effed. The greater part, inftead of giv-
ing that abundance of mould, deprived the
fown fubftances of the faculty of producing
it ; and thofe which did not prevent the
production, diminifhed the quantity of what
the unfown fubftances ufed to produce. All
thefe united fads Seem to prove, that the mi-
nute grains proceeding from the heads of ripe
mould, are real vegetable feeds.

During

ORIGIN OF MOULD.

3 39

During thofe experiments, I was curious to
learn, whether the feeds would germinate when
fown upon fubflances that did not mould. I
fowed a certain quantity upon hard bodies, as
glafs, metals, flones, &c. ; alfo upon biot-lheet
and writing-paper ; upon cotton, fponge, &c.
All thofe fubflances were kept moift, to fee
whether they would mould ; but there appear-
ed no mark of it, excepting fome filaments I
faw upon fponge. To expand, certain cir-
cumftances are required by the feeds of mould,
and thofe are only found in certain fubflances.

The minute feeds, or dufl of mould, pof-
fefs the peculiarity of refilling a degree of heat
which no other feeds can fupport, without lof-
ing the faculty of germinating. After boiling
the feed in water, I poured out the water, then
become black, upon fubflances that mould,
and where the mould, according to cuftoin,
grows thicker than upon the fubflances un-
moiflened. I did the fame with fome dufl ex-
pofed to a much greater heat, fuch as that of
a hot chafing-difh, and have found, that as
this heat does not deprive the feeds of the pro-
perty of reproduction, neither does it alter
their fize and figure ; as I have convinced my-
felf by examination with the microfcdpe, be-
fore and after expofing them to the heat.

But, does the mould, which fprings with-
out being fown, and by the care of nature a-

Z 2 lone.

34° ORIGIN OF MOULD.

lone, upon an infinity of tub fiances difperfed '
here and there, alfo derive its origin from the
duft we may fuppofe difleminated through the
air, and upon terreftrial fubftances ? If natu-
ral and artificial mould are of the fame fpecies,
and if the artificial is produced by the dull of
the natural mould, I cannot fee why the laft
fhould not derive its origin from the fame prin-
ciple, efpecially fince it is demonftraied, that
no other part of the mould, as the roots and
(talks, aid the reproduction. The hypothefis,
fuppofing that this duft is invifibly fcattered
through all, and gives exifience to a great
quantity of natural mould, is one of the molt
reafonable hypothefes in philofophy. If each
head of ripe mould can furnifh a million of
feeds, as we have feen, and if each fpot of
mould contains a prodigious number of heads,
it is clear, that in fome years, the duft fhould
be extremely multiplied ; particularly, from
its levity and finenefs, it may be univerfally
fpread.

We have certain evidence that feeds maybe
kept a long time, without lofing the faculty of
germination. My illuftricus friend M. Bonnet
told me a fingular fad. In 1748, corn was
carried from Sicily to Geneva, and lodged in
the magazines of the republic. Some indivi-
duals fowed part of it in a walled garden,

^ 77 1 . Notwithfianding the length of time,

"“V" " it

ORIGIN OF MOULD.

34*

it vegetated very well, and nearly as thick as
in common with this grain. The wonderful
minutenefs of the feed of mould, feems to ad-
apt it well for long prefervation ; but I have
given a cogent proof of this. Heat is un-
doubtedly one of the mo ft powerful agents in
depriving feed of its germinating faculty. In
my trad upon infufion animalcula, it has been
feen, that the number of feeds that can fup-
port the heat of boiling water, is very final I :
and, if the very fingular cafe of M. Duhamel
is recolleded, where feeds germinated after
experiencing 2350 of heat in a ftove, it is de-
monftrated, that thofe of mould are not de-
ftroyed by a degree infinitely greater. This
being the cafe, it is not abfurd to think, that
feeds which refill the injuries of weather, may
preferve their fecundity for ages. It is thus
very eafy to comprehend how immenfe the
quantity of this vegetable Ihould be, fince its
feed multiplies fo much, and is preferved fo
long, and that it Ihould be fo largely dilfemi-
nated over all terreftrial fubftances, as always
to be ready to germinate, when the circum-
ftances, effential for this, occur.

Thus, the firft of Signor Mofcati’s doubts
concerning the univerfal generation of mould,
is refolved, which induced him to think it was
produced by a fpontaneous generation. The o-
ther doubt is equally removed, from which he

Z 3 deduced.

342

ORIGIN OF MOULD.

deduced, that he had feen moulding fubftances-,
mould the lame after being boiled : but, if the
feed does not lofe its virtue of germinating,
after being expofed in a burning chafing-difh,
it is not furprifing that it is preferved at a de-
gree of heat fo far inferior as that of boiling
water.

Although the fubftances upon which I made
my experiments, were conftantly kept under
receivers, which was done with the view of
having more luxuriant and beautiful mould,
the communication of the external with the in-
ternal air was not interrupted. I wiflied to
difcover what would happen if the communi-
cation was cut off ; and, firft, what would be
the confequence of leffening it. Moulding
fubftances were put into very large glafs vef-
fels : the necks of the vefiels were then drawn
to a point, by means of the blow-pipe ; and
the point could be made of any degree of fine-
nefs. I had vefiels, into which a ftream of
air no larger than a hair could be admitted ; a
little more in fome, and ftill a little more in
others.

All the confined fubftances moulded in a
certain time. In the veffels with a very fmall
aperture, I remarked two circumftances ; that
the vegetation was flower, and the mould did
not grow fo high, as when the aperture was
larger.

The

ORIGIN OF MOULD.

343

The vegetables within, always perfpired fo
much, that the vapour colle&ed at the aper-
tures, and obftru&ed them, particularly when
they were very fmall. This inconvenience
may be corrected by fucking out the moifture ;
but, if this is not obferved, mould will not
grow, or hardly at all, in very fmall veffels.

My curiofity being fatisfied with regard to
this, I palTed to another thing. I excluded the
external air entirely, which was eafily done by
an hermetical feal. All the veffels were not of
an equal fize ; fome would contain fix pounds
of water, fome only one, and others but a few
ounces. This variety of fize affe&ed the mould.
In the largeft, although of the fame capacity
with thofe in which the mould was expofed to
the air, it did not germinate in the fame abun-
dance, and was later of appearing : the mould
in thofe of a middle fize was ftill later, and
more rare : its Hate was word in the fmalleft
velfels ; none appeared in fome, and in others
a flight lhade was fcarcely feen.

After velfels of three different fizes, contain-
ing vegetable fubllances, were hermetically feal-
ed, I put them during feveral hours in boiling
water. In the fmalleft veffels there was no
mould, in the middle-fized a little, and plenty
in the largeft.

I put moulding fubftances in vacuo : the re-
fult of feveral experiments was, that during the

Z 4 time,

244

ORIGIN OF MOULD.

rime, which was always feveral days, the fub-
ftances were there, if by chance a portion of
air infinuated itfelf into the receiver, a quanti-
ty of mould appeared, which came to maturity
without rifing high. When the air was entire-
ly exhaufted, none ever appeared. Some plan-
tuhe of mould are reprefented, fig. 5. pi. 5. j
they were produced in a receiver upon an air-
pump, where the vacuum w'as not complete.

Thefe three different experiments prove, that
the plantulse have the fame relation with air as
other plants, only it feems to me that air is not
fo neceffary to them ; for, when a thread of air
entered the receivers, fome mould vegetated,
though the leguminous feeds within could not
vegetate in that fituation. Neither do feeds
germinate in veffels hermetically fealed, al-
though, as I have faid, vegetables will mould
there. The fimplicity of mould undoubtedly
contributes to render the prefence of air lefs
effential : in the fame way as animals, that are
lefs compound in the fcale of organization, may
be produced, and exifl: in a lefs quantity of air
than is neceffary for us.

M. Bonnet, in his judicious reflections upon
mould, queftions, whether we are fure that all
mould belongs to the vegetable kingdom, and
whether there may not be fome fpecies ap-
proaching the mineral, or may be the connexi-
on between the two kingdoms. This is not

impoflible.

*

«

✓

ORIGIN OF MOULD.

34$

impoffible, when, we confider how prodigioufly
diverfified this clafs of beings is, and how little
its fpecies are hitherto known, if we efteem
that foffils occupy the loweft place of the vege-
table kingdom.

Befide the mould defcribed, I have not ne-
glected to throw a glance upon many different
fpecies ; and l mud fay, that I have found in
all, very decided charaCteriftics to judge them
real vegetables. I muft likewife fay, that the
various kinds of mould I have obferved are ve-
ry few, compared with the immenfe number
yet remaining to be examined ; for there is al-
moft no fubftance, animal or vegetable, which
is not in certain circumftances liable to mould.
Thofe who attach themfelves to this branch of
Botany, will have fufficient ufeful practice j and
perhaps they may fucceed in difcovering the
link connecting vegetables with minerals, which
will do Philofophy a moft important fervice.
For my own part, I fhall be content if, among
other things, I have refolved the queftion con-
cerning the real origin of the moft common
mould. The fubjeCt has not before been com-
pletely difcuffed ; and it has led fome perfons
into the ancient and dangerous error of Spon-
taneous Generation.

EXPE-

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.

EXPERIMENTS

UPON THE

REPRODUCTION OF THE HEAD

OF THE

TERRESTRIAL SNAIL .

BY

CHARLES BONNET

IHTpTT. ~ ‘

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[ 349 ]

EXPERIMENTS

UPON

THE REPRODUCTION OF THE HEAD OF THE
LAND SNAIL.

MEMOIR I.

I publish my experiments upon the repro-
duction of the head of the fnail, only to afford
an additional confirmation 10 the Abbe Spal-
lanzani's beautiful difcovery. It is well known
how much this difcovery has been difputed be-
yond Italy, and particularly in France. There
are naturalifts of my acquaintance, who, after
decapitating hundreds of fnails without fuccefs,
have thought themfelves at liberty to conclude,
that the Italian obferver had allowed fallacious
appearances to impofe upon him. One of thofe
naturalifts, writing to myfelf, did not hefitate
to reproach me for having inferted an account
of the imaginary difcovery in the Palingenefie ,
and for reafoning upon it, as upon a fa£t the
bed afcertained. It will be thought with juf-

tice.

3’5° heads of snails reproduced.

tice, that thofe reproaches did not weaken the
confidence with which the ability and the found
reafoning of the celebrated naturalift of Reggio
had infpired me. Befides, he had communi-
cated to me, in a courfe of correfpondence, the
interefting hiftory of his experiments at length :
and it was eafy for me to judge, only by a trial
of the fa£ts that the judicious obferver had feen
and reviewed, the new wonders he laid be-
fore me, and which, in a fhort time after, he
prefented to the public in an Italian tract,
which appeared 1768, and was, the fame year,
tranflated into French. But, fince the author
did not detail, in that treatife, the precautions
he had taken to fecure his difcovery againft all
difpute, I requeued him to publifh an account
of his method, which he did in a letter from
Modena, 11 September 1769, and it was print-
ed in the Avant Coureur , 30 O&ober. This
letter, fo well calculated to deftroy every doubt,
has only done fo in part ; fome remain, and
people continue to oppofe to the experiments
of Padua, others which they judge contradiftory
to, or apparently confuting them. This con-
flict of experiments, which has continued nine
years, induced me myfelf to repeat the experi-
ment of the learned profeffor of Padua. I
proceed to give an account of it ; the impar-
tial public will judge, from the details,' of the
confidence it dderves,

The

HEADS OF SNAILS REPRODUCED. 351

The fpecies of fnail upon which I operated,
is of a middle fize, and frequent in the fields,
or in gardens, after a rainy day : then, numbers
abandon their dark retreats, and in a (hort time
one may collect hundreds. The (hell of fome
is yellow, or yellowifh : upon that of others are
circular black or brown fafcias.

It is not an eafy matter to decapitate a fnail.
The moment it feels the inftrument, it fudden-
ly contracts into the fhell. Thus, it will eafily
be feen, that it may happen we think it is de-
capitated, when only a portion of the integu-
ments is taken away. To avoid being deceiv-
ed, I have ufed more precautions than one.
The fnail is allowed to extend as much as
poffible ; and an additional extenfion is procur-
ed, by immerfing the animal in water. The
inftrument is prefented to the origin of the
head, feveral times before ftriking the blow ;
and I only efteem the operation completely
performed, when the head is obtained entire,
with the four horns well dil'played, and the
mouth, which may always be recognifed bv
the lips marking the opening. The head, as
it appears fome inftants after reparation from
the trunk, is reprefented a little magnified.
Fig. 1. pi. 6. The two large horns, gg, are a
little contracted. The fmall horns, p p , are
entirely contracted within themfelvcs. The

mouth.

3S2 HEADS OF SNAILS REPRODUCED.

mouth, b , is clofely Shut. The lips are very c«
vident.

A fharp-edged knife feems to me more fit
for this operation than a fcalpel. Sciflars are
flill lefs convenient than a fcalpel. I always
have made the cut perpendicular to the axis of
the trunk.

Immediately after the operation, the fnail
retires far within the fhell, and in general does
not appear again. At this time, a large por-
tion of that vifcous humour, of which it has fo
much, is diffufed. If, at the fame time, the
fevered head is viewed, fome motion is per-
ceived in the horns, chiefly in the large ; but
the motion very foon ceafes, and I have in vain
tried to renew it, by flimulating the head neay
the origin with the point of a fcalpel. The
four horns contract themfelves to a certain de-
gree, immediately after the operation; the finall
contracting more than the large.

By a very Ample method, one may ascer-
tain whether the operation is complete. This
is, to immerfe the decapitated fnail in water.
It is not long of leaving the fhell : it extends
as much as before the decollation ; and then
it is eafily feen whether the trunk is entirely
deprived of the head 3. The anterior part of

fuch

* However, it may happen that it does not extend fo
puipfl as one may with, or as is neceffary to judge of the

progrefs

HEADS OF SNAILS REPRODUCED. 353

fuch a trunk, drawn from the life, is repre-
fented, fig. 2. ; and the profile, fig. 3. It may-
be remarked, that the flefh is flrongly con-
trafted, to clofe the enormous wound.

The vifcous matter copioufiy diffufed by the
mail after decapitation, produces at the open-
ing of the fhell an operculum, which complete-
ly flops up the entry : it is very thin, and of a
whitifh colour. Frequently, two of thofe oper-
cula are formed, one fituated above the other.
Sometimes there are three : the exterior is
near the edge of the fhell, the interior more or
lefs within it.

The decapitated fnail can reproduce feverai
of the opercula ; but the vifcous matter is by
degrees exhaufled, and the fhell remains open,
or nearly fo. As the animal has no method
of feeding while deprived of its head, it can-
not continually repair the lofs of this kind of
varnifh. It infenfibly becomes emaciated,
which is feen by the diminution of fize, and a
fort of tranfparency to be remarked in its inte-
rior. I have fometimes been aflonifhed at
the number of opercula that have fucceffively

A a been

progrefs of the reprodu&ion ; but it is only necelTary to
take the fhell between the fingers, after the animal has been
taken from the water, and it will foon extend as much as
pofiible. Great care mull be obterved to avoid touching the
fnail ; becaufe, upon the moii gentle contact, it retires into
the (hell.

354 heads of snails reproduced.

been reproduced by decapitated fnails. All
fnails do not produce opercula ; but the num-
ber of thole whofe fhells continue open is very
final 1.

I have included my decapitated fnails in
boxes. Some remained at the bottom ; others
reached the Tides, againfl which they applied
the opening of the fhell ; others afcended
higher, and attained the covering, where they
fixed themfelves in the fame manner. Thefe
were apparently the molt vigorous, or had
fuffered leaft from the operation.

When I wilhed to learn from week to week
what was the real Hate of my decapitated fnails,
I had only to take away carefully the opercu-
culurn or opercula flopping up the opening of
the fhells, and then immerfe them in very lim-
pid water. They are thus forced to proceed
from the fhells fooner or later. It has happen-
ed oftener than qnce, that they did not appear
till feveral hours after immerfion. This me-
thod, to which I have always had recourfe to
know the ftate of my fnails, feems to me the
befl. They extend to the utmofl limits in the
water ; and the anterior part is then fo com-
pletely expofed, that nothing can efcape the
eye of the obferver. They endeavour to leave
the watei: ; and gradually attain their purpofe,
if the depth is not too great. They crawl
{lowly over the bottom, and along the Tides
> 1 ’ of

HEADS OF SNAILS REPRODUCED. 355

of the -vefiel, and advance until they reach a
dry part. Then they fix themfelves ; and, to
force them to appear again, it is neceflary
to re-immerge them in the water. Although
abfolutely deprived of a head, they advance
forward as if they had one, only their progrefs
is a little flower.

At firft, I decapitated only a dozen of fnails.
This was 8 May 1777. I repeat, and I can-
not too often repeat it, for I with to anticipate
the moft trivial doubts, that I have efteemed
the decapitation complete, only when l had up-
on my tablet the head entire, or attended by
all its appendages. All the heads, in this
manner fevered from the trunk, have been
ranged together upon one fide of my tablet,
and remain there at the moment I write this a.

I now proceed to give a fketch of the won-
derful reproductions which were elfe&ed by the
fnails before my eyes. I will not enter into a
mintute detail : it is unneceflary : my purpofe
only is, to prove the reality of the reproduce
tions, againfl the detractors of the famous dif-
covery of my celebrated friend the Abbe Spal-
lanzani.

The reproduction of the head of the fnail
does not obferve fo uniform a rule, as that of
the head of thofe aquatic worms which I mul-
tiplied by feCtions 1741, and of which I pub-

A a 2 liihed

a July 14.

35^ HEADS OE SNAILS REPRODUCED.

liflied an account a few years after b. The re-
productions of the fnail prefent a number of
varieties, which it would be tedious to de-
fcribe. Some inftances Signor Spallanzani has
given in his Programma, and after him I have
mentioned them in La Palingenefie , part 9. I
refer to thofe two works. Here I fhould con-
fine myfelf to my own cbfervations.

A profile of the anterior part of a fnail, de-
capitated 8 May, and delineated 21 June, is
reprefented a little magnified. Fig. 4. The
two large horns, g g, begin to extend : the
left is further advanced than the right, the
origin of which is juft vifible. A brown and
rather blackifh line, L proceeds front the large
right horp : this is the optic nerve and its
mufcle, the various motions and ftrucfure of
which, Swammerdam has expofed to our admi-
ration. A degree of tranfparency is feen in the
flefli ; and as it encreafes greatly in the fnails
that have failed a month or two, the optic
nerve and mufcle are alfo rpuch more evident.
A white line, /, runs along the back : I am yet
ignorant whether it is a veffel. The anterior
part of the fame fnail, viewed from before, is
reprefented from the life, Fig. 5. Only the
higher extremity of the large horns is feen,
and at the extremity there appears a minute
black point : this is the eye of the fnail, in

which,

fc Traite d’Infcctologic, Paris 1745.

HEADS OF SNAILS REPRODUCED. 357

which, Swammerdam allures us, he has found
the three humours of our eye, and two tunics,
the uvea and arachnoid. Here the eye is al-
ready vifibfe, although the horn only begins to
grow. I have perceived it in horns that had
made ftill lefs progrefs, as I lhall immediately
obferve. The fmall horns do not yet appear.
We know they have no eye at the extremity ;
neither are the new lips of the mouth, b , vifible.
This fnail I lhall defign by the letter A.

The anterior part of another fnail, drawn
23 June, is reprefented a little magnified,
fig. 6. The reproduction is a degree advanced.
One of the finall horns, />, is very evident, and
appears to be completely regenerated. The
correfponding horn, has not begun to extend.
Above the fmall horn, we perceive the origin
of the large horns, gg, which has made but
too little progrefs. Here is a ftriking example
of the varieties to be feen in the regeneration
of the head of the fnail. One of the fmall
horns has made the greatell advance, while the
correfponding horn is not yet feen, and the
large horns only begin to be obferved. A
profile of the fame fnail is feen, Fig. 7. The
tranfparence allows the optic nerve, t , to be feen
proceeding from the origin of one of the large
horns : the eye of this horn is diftin&ly ob-
ferved : the lips of the new mouth, b, are like-
wife vifible. This fnail I lhall defign by the

A a 3 letter

35$ READS OF SNAILS REPRODUCED-.

letter B. The anterior part, drawn 2 July,
is reprefented a little magnified, Fig. 8. The
plan is feen. Fig. 9. The mouth, b, cannot be
miftaken. The large horns with their eyes, g g.

Another fnail, which, upon 23 June, feem-
ed to be completely repaired, lhall be defigned
by C. The four horns were perfect, and had
acquired the natural fize of the horns of this
fpecies, "I he mouth appeared to be repaired :
the opening complete, and the new lips very
diftindt, were of the figure and proportions they
ought to be. In a word, this fnail fo much
refembled other fnails of the lame fpecies
which had not been mutilated, that I could
diftinguilh it only by the tranfparence and the
diminution of fize. It is reprefented, drawn
from the life, Fig. 10. The fedtion of the
anterior part of the fame fnail is reprefented,
Fig. 1 1 . The new mouth and its lips are dif-
tindlly feen. Above it, at a little diftance,
there is feen, from the tranfparence of the flefh,
an oblong fpot, t : this is the teeth of the fnail,
which the lips can approach or recede from.
Thefe two figures were not drawn till towards
the middle of Summer. After the 23 of
June, I began to fupply the fnail with young
vind and lettuce leaves ; but it did not touch
them. After traverfing the leaves and the
Tides of the velfels for fome time, it commonly
fixed itfelf to the covering, and remained there

for

riEADS OF SNAILS REPRODUCED. 3^9

for whole weeks. Notwithdanding it faded
more than two months during Summer, it al-
ways feemed to be in good health, and is dill
well when I write this, 21 July.

1 have faid, the eyes appear, although the
large horns only begin to repair. This I faw in
one of my fnails decapitated 8 May, the head
of which, feparated from the trunk, is repre-
fented. Fig. 1 . The regeneration had made
very little progrefs, 6 July : this day I caufed
it to be defigned. Fig. 12, the plan of the
anterior part. The origin of the large horns
is feen ; they do not yet begin to extend, and
their place is indicated only by the eye, which
is already perceptible : it appears like a black
point, as frnall as it is pollible to make with
the fined pen. The fnail has been defigned at
the moment when extended to the utmod ;
and I have taken the fame precaution with
refpedt to all the fnails defigned. In that of
which I now fpeak, neither the finall horns nor
the mouth yet appear.

When the fnail retra&s the large horns
within, the black point or eye is ealily perceiv-
ed through the flefli. Oftener than once I have
difcerned it with the naked eye, and even in
thofe fnails whofe reproduction is very little
advanced.

I fliould not neglect to obferve, that, of the
twelve fnails decapitated 8 May, only one

A a 4 died.

360 HEADS OF SNAILS REPRODUCED.

died. All the reft feem to be well while I
write this, 27 July ; but the progrefs of re-
production is very various. In fome, it feems
to be but begun : in others, only the large
horns are repaired, the origin of the fmall is
not yet perceived, and the mouth is not well
defined. The large horns of fome of thefe are
only half, or two thirds of a line long ; while
there are others, whofe large horns are a line
in length. Such are thofe of the fnail, which
I have hitherto defigned by the letter A, the
anterior part of which, as it appeared 21
June, is reprefented fig. 4. ; and the anterior
part of the fame fnail, as it appeared 26 July,
is feen fig. 13. Something fingular is prefent-
ed by the large horns. They are thicker in
proportion to their length, than thofe of un-
mutilated fnails. At the extremity, we remark
a kind of deformity, which feems produced by
a certain plication of the flefli, giving the horns
the appearance of being monftrous. The eye,
however, is very diftinCt. The colour of the
horns tends to violet, and is generally fo in re-
produced horns. It tends greatly to that of
the nerve running through the flefli. The
anterior part of another fnail is feen, fig. 14.
The mouth is not perceptible, but under the
appearance of a little prominence, b. It ieems
awry.

HEADS OF SNAILS REPRODUCED. 362

I have in general, with Signor Spallanzani,
remarked various confpicuous irregularities in
the reproduction of the double parts of the
fame fnail. I fee a large horn, of only half, or
of two thirds the length of the correfponding
horn : at other times, this one is fcarcely vifi-
ble. I likewife fee a fmall horn completely re-
generated, while its fellow is barely percepti-
ble, or not at all. I fee a mouth, one lip of
which is only half reproduced, while the other
feems completely repaired.

I confine myfelf to thefe few examples : they
will fuffice to give an idea of the varieties pre-
fented by the regenerating head of the fnail.
It feems to me, that they infer the reproduc-
tion of one part to be independent of the re-
production of another : for, how can we reject
this deduction, when we fee one horn com-
pletely reproduced, while the reft are invifible,
or only begin to grow ? This fact will not fail
to be confidered as moft important in the theory
of thofe admirable reproductions. But I will
not touch upon it now, as I have endeavour-
ed to guefs at it in part io. of the Palin -
genefie.

I had, upon 12 May, decapitated thirty
fnails, of the fame fpecies, treating them pre-
cifely in the fame manner as the firft : more
than two thirds have perifhed. Thofe ftill a-
live, regenerate with various degrees of flow-

nefs.

3^2 HEADS OF SNAILS REPRODUCED.

nefs, preferring the fame, or varieties analo-
gous to thofe already defcribed.

I fliall obferve upon this occafion, that the
months of May and June, and the beginning
of July, have been very frefh and rainy. On
fome days of the firft week of July, Reaumur’s
thermometer, at funrife, flood at 4, 5, and 6°
above freezing a.

At prefent, I will not enlarge the difcuffion
of my experiments upon the reproductions of
fnails farther : I intend to refume the fubjeCt
in another memoir.- I think enough has been
faid to prove, that nothing is more certain than
this wonderful reproduction. I know not what
to fay of the fruitlefs attempts of fome philo-
fophers, and particularly thofe of Meff. A-
danfofr, Cotte, and Bomare. Perhaps they
have too foon declared the date of their expe-
riments, or they have taken for an equivocal,
what was a real reproduction ; or perhaps they
have thought to be dead thofe fnails ftill alive.
In this cafe much patience is requifite, and, a-
bove all, to defpair of nothing. I do not fpeak
of the diverfities which the difference of fpe-
’ cies might occafion, in the confequences of the
experiments made by thofe celebrated perfons ;
for I have reafon to think, that among the
great number of fnails upon which they have
operated, there were fome of the fame fpecies

as

a About 41, 43, and 46° of Fahrenheit’s thermometer.

HEADS OF SNAILS REPRODUCED'. 363

as mine. Neither do I fpeak of the diverfities
that might arife from the difference of climate ;
for the climate of Paris is very little diderent
from ours* I therefore entreat thofe able na-
turalifts not to be difcouraged, and to examine
again a fubjeft fo pregnant with new truths ;
a fubje£t which cannot be too deeply invefti-
gated. They poffefs far more intelligence, ta-
lents and ability than are neceffary to fucceed in
experiments of this nature ; and I may predict
the mod complete fuccefs, if they will not be
difcouraged, and if they will proceed in the
manner I have done.

M. Adanfon wrote me concerning his own
experiments, 30 July 1769.

“ I begin to have a philofophic doubt con-
44 cerning the regeneration of the head, the
44 horns, and the jaws of fnails. My experi-
<c ments, diverfified to infinity for more than a
44 year upon between fourteen and fifteen hun-
44 dred fnails of ditferent fpecies, have convin-
44 ced me that my doubt has foundation. I
44 have, as every one has had, reproductions,
44 even very fudden ones, of horns, heads, lips,
44 and other parts, but thofe were reproduc-
44 tions of parts which had not been complete-
44 ly cut away : for all the heads, (I fay the
44 real heads), all the horns, all the jaws, and
44 the other parts that have been completely
44 cut away, and only a quarter of a line from

44 the

364 HEADS OF SNAILS REPRODUCED.

“ the origin, never have exhibited any kind of
“ reproduction, far lefs a regeneration. Let us
<c be ftriCl, and feek for reality. All thofe
<c who have rirutilated fnails, and firft Signor
“ Spallanzani, feem to me to have been de-
“ ceived : they have thought they had decok
u lated the head, when the cap only has been
“ cut off: they have believed they have cut
cc away, or eradicated, the horns, or the jaws,
<c while the origin of them always remained ;
tc whence it is not wonderful there were re-
“ productions. Thefe, you will candidly ad-
ci mit, are not reproductions, or rather rege-
“ nerations, fuch as you, Meff. Trembley, and
ec Reaumur, had feen in frefh-water worms,

“ the polypus, and in the claws of crabs

et How many well credited operations have
“ deceived perfons, lefs familiarifed than we
“ are, wuth fimilar operations, and the anato-
“ my of (helled animals ! They have imagined
<£ they had cut off, completely below the ori-
“ gin, fo many heads, horns, and mouths,
“ which they have, in every journal and peri-
(i odical paper, fo liberally regenerated ! I
“ know well, how deficient we are in the
“ greater part of nice experiments. Notwdth-
<s {landing my great experience, I may almoft
<c prefume to fay dexterity, in the anatomy of
ci the fmallefl: animals, I always diffruft my-
t£ fdf. For this reafon, I have an hundred

“ and

HEADS OE SNAILS REPRODUCED. 365

“ and an hundred times repeated the fame ex-
{C periments, before hazarding the refults to
the public. I have laboured the firft, or a -
“ mong the firft, to corroborate all the expe-
“ riments of Signor Spallanzani, and to make
“ additions to what might have efcaped him.
“ I have operated upon a greater number of
“ animals, and diverfified my experiments
“ more than any other perfon, to judge by
ec all that has been read before the academy
• c or printed, and I am the only one who has
“ read nothing upon the fubjeft which I in-

veftigate with the greateft affiduity - It

“ is nearly the fame with the reparation of the
?c parts of newts, feveral fpecies of frogs,
“ toads, tadpoles, See. I have feen fenfjble
“ reproductions to the tails and feet partially
cut away ; but no regeneration, when thole
“ parts were cut off dole at the origin. Confi-
“ der well my expreffions, regeneration and
“ origin , upon which your principles reft fo
much, and there is no aCtual regeneration :
<c and I hope you will do the juftice to my
“ doubts, as to acknowledge with me, that
“ Signor Spallanzani and his followers have
^ too far extended their expreffions of rege-
<{ nerations, which were only reprodu&ions of
portions of parts ” ------

To the numerous expediments and doubts
pf my celebrated correfpondent, I fhali oppofe

only

3^6 HEADS OF SNAILS REPRODUCED.

only the letter written to me by the Abbe Spal-
lanzani, cited at the beginning of this treatile,
wherein he details the precautions he ufed, to
avoid error. I fent a copy of this letter to M.
Adanfon ; but it did not produce upon his
mind the effeCt I expeCted ; and he dill perfid-
ed in his doubts, when he wrote me, 20 July
1 775 — “ The various parts cut or taken away,
“ not only from different fpecies of fnails, but
“ alfo from feveral other aquatic animals, as
<c frogs, toads, newts, have produced no or-
“ ganized reproduction to me, as the part cut
<c did according to Signor Spallanzani. I have
“ fo much diversified the experiments which
ei my friend Mr Needham, and fome other ob-
<e fervers of this rank, have witneffed, that
tc we all effeem it certain, that whenever the
“ operation has been complete, the reproduc-
“ tion is but a dump, that is, a mafs of flefh
“ unorganized, or differently organized : and,
“ Signor Spallanzani fhould know, that the
cc obfervations of our mod celebrated anatom-
ts ids have proved, that the reproduction of
(i the tails of lizards, fo common, although
<c externally well formed, prefent no regular
tc offification as the red, nor any vertebrce in

ce the interior ”

M. Adanfon is, as we fee, one of thofe
philofophers who dart difficulties upon faCts,
pad who wiffi themfelves to fee prodigies again

and

HEADS OF "SNAILS REPRODUCED. 367

and again, before admitting them to be true.

I cannot blame fuch a degree of referve ; but
I confefs, that in this cafe it appears to be ex-
treme, efpecially after evidence fo ftricUy de-
monftrative as the Abbe Spallanzani has given
of his difcovery. May I therefore hope, that
the experiments I now publifli, will triumph
over the incredulity of our learned academi-
cian ? Doubtlefs he will not fafpect that I
have only deprived the fnails of the cap, to ufe
his expreflion ; for the head, fo complete and
fo perfectly feparated from the trunk, repre-
fented Fig. i, will not permit the remainder
of the leaft fufpicion. I requefl M. Adanfon
to eftimate all the details of my experiments,
and to attend to the defigns of my able artift,
which reprefent fo admirably well the regene-
rations which I have witneifed. 1 could with
facility have extended them further ; but I do
not confider it as ellential to the purpofe I have
in view. If it lhould be objected, that the
fnail, drawn from the life, Fig. io. and n,
had not then touched the young vine and let-
tuce leaves with which it was fupplied, I may
anfwer, that it has given the molt indifpu table
evidence of being provided with very good
teeth : 27 July, it begun to eat the paper
covering over the mouth of the velTel where
it was confined, and voided fome well formed
excrements, the colour and confidence of

which,

368 HEADS OF SNAILS REPRODUCED.

which, exaCtly like paper, indicated that they
were the remains of it.

M. Adanfon alfo doubted the reproduction
of the limbs of the newt, fo perfectly ascer-
tained by the numerous experiments of Signor
Spallanzani ; the principal refults of which, he
mentioned in his interefting Programma , pub-
lished 1768. In his letter of 20 July 1775,
above tranfcribed, M. Adanfon fays, “ When-
“ ever the operation upon the newt has been
cc complete, there has only appeared the flump
<c of a reproduction, that is, a mafs of flefli
ce unorganized, or differently organized and
he cites the teftimony of Mr Needham, and
fome other observers. But, what will M. A-
danfon himfelf fay, when I inform him, that
this pretended flump, or imagined lump of
unorganized flelh, is the member itfelf, per-
fectly formed, concealed under thofe deceitful
appearances, and which has been completely
developed before my eyes, as I had formerly
feen the deveiopement of the heads and tails
of thofe aquatic worms I multiplied by cutting
in pieces ? I have actually in my cabinet,
newts completely repaired, of which I Shall
publiSh a hiftory in a future memoir, accompa-
nied by excelle?it drawings. Our celebrated
academician has therefore been precipitate in
his opinion, when he thought he only fufpend-
ed it. He has decided, that the newt repro-
duces

Heads of snails reproduced. 369

duces but a flump, while this flump was the
member itfelr, where there was nothing eiTen-
tial defective, and had only to acquire the fize
of that which it replaces.

M. Adanfon was thus deceived concerning
newts, as concerning fnails ; and the miftakes
of fuch a naturalifl, are a good leffon to thofe
who have neither his knowledge nor his abili-
ty. I am perfuaded that he will acknowledge
his error ; for I know him to be a fincere
friend to truth, and I have not to fear that he
will reproach me for having laid it open in this
little treadle.

M. De Bomare, no lefs a friend to truth,
and whofe experiments had been as unfuccefs-
ful as thofe of M. Adanfon, was, in confe-
quence, equally incredulous. I had referred
him to the fame letter of the Italian obferver,
printed in the Avant Coureur , 30 October 1769 ;
and he wrote to me 5 November 1 77^ — “ You
“ afk me, why I have not anfwered one of the
“ articles of a former letter, concerning the
“ reproduction of the head of the fnail. I af-
ec fure you, that all the experiments I have at-
“ tempted upon this fubjeCt, feem adverfe to
“ thofe of the Abbe Spallanzani. You will
“ fee at the article Lima^on of my Dictionary,

“ edit. 1776, what I have faid upon this fub-
“ je£t, which I before mentioned in 1768.”

1 fhall tranfcribe from the Diftionairc d’Hiftoire

B b Naturelle ,

37° HEADS OF SNAILS REPRODUCED.

Naturelle, the paffage to which I am referred
by M. de Bomare.

“ I acknowledge that, not being able to cre-
44 dit the reproduction ; while at the Chateau
44 de Chantilly during Autumn 1768, I made
44 many experiments upon the fubjeCt, which I
44 have communicated to the public : the refult
44 follows. Of fifty-two land fnails, whofe
44 heads I cut off, (all, whenever they felt the
44 cutting edge of the inftrument, fuddenly and
44 very powerfully contracted themfelves : the
44 feCtion finifhed, the part retiring precipitate-
44 ly into the fhell, appeared wrinkled and
44 contracted, like the extremity of the reCtum
44 of a hen), nine were in motion for twenty-
cc four hours, and only thofe where an imper-
44 feCt cut wras made upon the neck, between
44 the large horns and the organs of genera-
44 tion, the edge of the knife being fo blunt,
44 that I had evidently feen all the horns retraCt
44 and retire into the interior of the animal. I
44 remarked, that in this way I had only cut
cc away the {kin and the jaw of the fnails, fo
“ that in ten or twelve days they proceeded
te from the {hells, crawling about with mutilat-
<c ed horns. The fnails from which I had cut
<c only the diagonal half of the head, difplayed
46 only two horns ; but thofe which I had fud-
44 denly decapitated entirely (which were by
44 far the molt numerous) all died in a few"

44 days.

Heads of snails reproduced. 371

cc days, excepting two which remained alive
u five months fixed to a wall, and died in
“ Spring, without any indication of the repro-
“ duction of a head. I have taken other fnails,
“ and made a longitudinal incifion in the head,
<c between the four horns. Nature employed
cc more than a month in reuniting the twro
“ parts, the animals appearing very languid.
“ I repeated thofe experiments 1769, and all
“ were unfuccefsful. Many perfons have writ-
“ ten to me from different countries, that
“ their attempts have been precifely fimilar to
“ mine.”

It is lingular, that I have fucceeded with on-
ly a dozen of fnails, while M. de Bomare has
failed with more than fifty, and M. Adan-
fon with more than fourteen hundred. But it
is poffible that thofe gentlemen were too anxi-
ous to believe their experiments failed, or they
did not pay fufficient attention to the progrefs
of the regeneration, always more or Iefs tardy,
more or lefs difguifed, and of confequertce more
or lefs difficult to recognife.

I have named another valuable naturaliff,
who has not been more fortunate than MefT.
Adanfon and De Bomare : I fpeak of F. Cotte,
curate of Montmorency. He has narrated his
unfruitful attempts in a letter to the Abbe Ro-
zier, publifhed in the Journal de Phyftque , May
1774. He denominates the reproductions of

Bb 2 'ifie

372 HEADS OF SNAILS REPRODUCED.

the heads of fnails, imaginary. He fays,
that from 1768 until 1774, he decapitated a
great number of fnails : that almoft the whole
died foon after the operation, which had been,
performed with a fharp knife, not by drawing,
but by a fingle blow : and he concludes with
three confequences, which he affures us were
attendant upon all his experiments and obfer-
vations. 1. He has obferved that fnails have
the property of contracting theinfelves very fud-
dcnly, to proteCl the head from the inftrument,
in fuch a manner as to efcape with the lofs of
only part of the horns, or, at moft, the fkin of
the head. 2. When it happens that the head
is aftually cut off, it is not reproduced ; at
lead, he declares that he has never feen repro-
ductions, not even of the parts of horns cut a-
way. 3. Snails can live a very long time with-
out eating, and without the head.

I know not whether Meff. Adanfon, de
Bomare, and Cotte, have continued their expe-
riments, or what has been the confequence.
But I can fay, that I am not the only natural-
id who has fucceeded in corroborating the dis-
covery of Signor Spallanzani : that has been
already done by the celebrated Signora Baffi of
Bologna, by Meff. Lavoifier and Schafffer.
M. Senebier, pallor and librarian of our Re-
public, who has given public teftimony of his
{kill in philofophy and natural hiltory, has had

the

HEADS OF SNAILS REPRODUCED. 373

the fame fuccefs with myfelf in experiments
upon fnails. I would here tranfcribe what he
has written to me concerning them, did he
not inform me that he has fent his obferva-
tions to the Abbe Rozier, to be publifhed in
his Journal.

Although the head of the fnail is a very
complicated little machine, as I have elfewhere
fhown, by the ftruclure a ; it is indubitable,
that the gelatinous quality of the flelh greatly
promotes its wonderful reproduction. I have
enlarged upon this remark, when treating of
the polypus. However, I do not mean that
one fhould infer that all gelatinous animals,
and all animals in their firft ftate of jelly, may
reproduce themfelves, or repair the lofs of
their members, as the polypus and the fnail.
Experiment alone can difcover the limits of this
admirable property : and, what we have already
learned concerning the extent of its dominion,
fhould excite natural ifts to diverfify to the ut-
moft their attempts upon a fubjeft fo fertile in
wonders. I cannot too much exhort them ro
defpair of nothing, not even in the mod; un-
common experiments.

B b 3 ME-

a Paltngenefie Pbifafopbique, part. 9. New edit, of J.a
Contemplation cle la Nature, part. 3. chap. 21. note 4. 5.

374 heads of snails reproduced.

MEMOIR II.

Having myfelf beheld fome of the wonders
which the regeneration of the head of the fnail
prefents, I wifhed to know what M. Adanfon
thought of the refults of my experiments ; and
I requefted him to read the preceding treatife
which I had publifhed in the Journal de
Phyfique , September 1 777. He did fo, and
wrote me 10 January 1778.

44 I have read your excellent memoir upon
44 the reproduction of the head of the fnail,
44 with all the attention it deferves ; and the
44 perufal only tends to confirm me more and
44 more, of what a courfe of experiments,, con-
44 tinued nearly ten years, fince 1768 until
44 the prefent day, upon feveral thoufand
44 fnails, has informed me, namely, that the
44 integral parts of the fnail we fpeak of, whe-
44 ther the head entire, the eye, or the ocu-
44 lated horn, the upper jaw radically extir?
44 pated or cut below the origin, are not re-
44 produced, either under the fame form, or
44 with the fame organization as before. You
44 have decollated two or three dozens of fnails,
44 8 and 12 May 1777* I believe it. You

44 cut

HEADS OF SNAILS REPRODUCED. 375

“ cut them as I did myfelf, two lines below
“ the origin ; that is, towards the opening of
“ the parts of generation. You have, as I
have done, taken from each fevered head,
<c the upper jaw entire, and the oculated horn
“ entire ; and then, at the end of two or three
“ months, in June and July, you have feen
“ a third of the fnails reproduce themfelves,
“ even eleven of the twelve fird decapitated,
ec a complete head, with the eye-horns, the
“ upper jaw formed like a horfe fhoe, with
“ the ferrated teeth. You mud permit me
<{ dill to retain my philofophic doubt con-
“ cerning the three lad adertions, until you
<c have repeated the following experiments up-
<c on which it is founded ; experiments which
“ have ferved to confirm the accuracy of my
“ operations, and certain proofs that my fnails
“ were completely, and not apparently, decapi-
(t tated. To have the fame certainty, take
“ the greated number of fnails you pleafe,
<c (that is, hundreds, to provide againd the
“ great mortality that will follow), not of
“ the fmall fpecies, called the Lacquey, which
“ you have made ufe of, and which is mod
“ deceiving, from its great lubricity and agili-
“ ty in evading the knife, an agility propor-
“ tioned to its fmallnefs, which mull; have de-
ceived you ; at lead, that happened to me
“ in my fird attempts, which obliged me to

B b 4 “ relincjuifii

376 heads of snails reproduced.

“ relinquifh it : take, I fay, the large yellow-
tc ifh fnail of the vine, named Pomatia, or ra-
<c ther the brown garden fnail, called by us
“ the Gardener, which is almofl as large, and
“ the mofl common of all : after having kept
<c the whole, immerged one or two days more
cc or lefs in water, under a prefs, to diminifh
<c their vivacity and lubricity, tear away the
•c upper jaw, which is formed like a horfe
“ Ihoe, and edged with five or fix teeth, the
cc lower palate, which is a membrane dentated
“ like the tongue of a cat or a file, and era-
ee dicate the two large oculated horns, ufing
<c for thefe laft little pincers, with thread or
ct flax, to take away any edge, and preferve
tc them from flipping, or indeed prefling the
<c neck of the animal with two fingers, to era-
<c dicate the jaws : avail yourfelf of this forced
<c fituation, to cut away, with a fine and fharp
<£ botanical fcalpel, the twro oculated horns,
<c with the bulb below the eyes ; or only one
of the horns, to have an object for compari-
ec fon : cut the head entirely off others, ob-
ferving whether the fevered heads have the
“ jaws and eyes complete : preferve the heads,
<{ jaws, and eyes, to be certain that you have
“ as many as fnaiis operated upon. The fnails,
iC thus deprived of teeth, eyes, or heads, will
for the mofl part live fix months, even one
^ or two years, without eating ; they gradual-

(C

HEADS OF SNAILS REPRODUCED. 2)77

££ ly become emaciated unto perfect extinction:
“ if, during this time, they recover new eyes,
££ new jaws, a new head, which I have never
££ had the good fortune to fee in thofe identi-
££ fled after the operation : if this experiment,
££ made with all the precautions I have taken,
“ and which I believe it neceffary to ufe, fuc-
££ ceeds in your hands, and in thofe of the
££ Abbe Spallanzani, I fhall efteem it a fact,
££ that the parts entirely feparated are repro-
‘£ daced in thofe animals. But take care,
££ would you defire to make thofe contradictory
££ experiments, without which you cannot be
££ certain of the real reproduction of a jaw, an
££ eye, or a head? I abridge the fubjeCt, becaufe
££ the confequerices deducible are in my letter
££ 30 July 1769, which I thank you for having

££ reminded me of in your treatife

££ I pafs to newts. I have not yet been able
££ to procure the perufal of your memoir : but,
££ excepting the tail, to judge by the obferva-
££ tions I have made upon that of lizards, it
££ does not feem to be capable of reproducing
££ offeous vertebrae ; and although I have
££ only had reproductions of flumps of the
££ feet cut off feveral fpecies of thofe animals
££ and of frogs, becaufe I have not been able
££ to profecute my experiments with fo much
£C conveniency, or fo long, upon them as up-
££ on fnails, I very firmly believe the poffibili-

37$ HEADS OF SNAILS REPRODUCED.

“ ty of the reproduction of the fingers and of
“ their bones, whenever the anterior or pofte-
u rior part of the arm is not cut off.”

I want words to exprefs all the furprife ex-
cited in me, by this letter of my learned cor-
refpondent ; and I doubt not, that the reader
will partake it along with me. What M. A-
danfon defires me to do, is precifely that which
would occafion the failure of the experiment :
for how could one tear out, or eradicate with
pincers, the different parts of a fnail, without
caufing the greatefl diforder within ? How,
in this way, is it poffible to fucceed in eradi-
cating all the parts ? And, fuppofing it to be
poffible, would not we endanger the fources of
reparation ? Is it not fufficient, that I am cer-
tain, by the moft attentive examination of the
heads I have cut from my fnails, that they con-
tain all the parts that charaCterife a head, fuch
as the four horns, the mouth, the jaws, &c. ?
Was it neceffary to cut out the large horns
with a botanic fcalpel, in order to be fure that
the fnail would produce new ones ? Was it not
enough that I had feen, and many times feen
again, the origin and progrefs of the new ocu-
lated horns, that I had feen the new eye and
the optic nerve appear the firft in this wonder-
ful reproduction ? It is improper here to en-
creafe, as M. Adanfon has done, the agility
with which the fnail retraCts its head the mo-
ment

HEADS OF SNAILS REPRODUCED. 379

racnt ir is touched by the inftrument ; for the
agility is not to fuch a degree as to prevent one,
with a little addrefs, from performing complete
decapitation. I can even fay with truth, that
I have very feldom failed to effect it, at leaft
when I have taken the precautions mentioned
in my memoir.

M. Adanfon feems to reproach me with ha-
ving employed fnails of too fmall a fize : he
fays, the fmall fpecies I have ufed mult have
deceived me, from their great agility in eluding
the edge of the knife. Neverthelefs 1 can af-
firm, that I have operated upon the fmall fpe-
cies with as much facility as upon the middle-
fized, and even upon the largeft. But, we x>
aggerate the quicknefs of fnails in faving their
head from the inftrument ; for, an abftinence
feveral days, and the water in which they are
immerfed, weaken them more or lefs, and to a
certain degree diminifh the celerity of their
motions. Befides, if I made ufe of fmall fnails,
it was only becaufe I reafonably prefumed, that
the wonderful reproduction I wilhed to behold
would be performed more eafily, or in ftiorter
time, than in the largeft fnails. I have not ne-
glected alfo to operate upon thofe of the largeft
fpecies, and I (hall relate the effect.

To terminate the anfwer to the objections
of our celebrated Pyrrhonian, I (hall here fub-

lom

280 heads of snails reproduced.

join an extract from a letter I wrote to him,
21 January 1778.

cc If it was in my power, my dear and illuf-
cc trious friend, I would make the experiments
<c you defire upon fnails. But in truth, I do
not think that any thing can be done more
4t ftridtly demonflrative, than what has been fo
t£ well executed by my friend Signor Spallan-
“ zani, and what he narrated at length in the
<c letter of 1 1 September 1 769, a copy of which
I fent you, but upon the fubjedt you have
“ never replied a fingle word.

e< What is required ? To afcertain whether
“ the head is completely cut off', and whether
cc the head reproduced has all the organs of the
“ natural head. What muff be done, to af-
“ afcertain thefe two facts ? It is neceffary to
“ diffedt, with care, the head cut off ; to exa-
44 mine the interior with attention ; and to be
ct convinced that the head contains all the or-
cc gans belonging to it : then, it is neceffary to
44 diffect the reproduced head with the fame
te care ; to be fure, by an exadl examination of
<c the interior, whether it actually contains all
cc the parts belonging to the head of the fnail.
44 This has been frequently done by Signor
44 Spallanzani : and I now afk you, whether
44 there is any foundation, in ffridt rhetoric,
44 for doubting an experiment made with fimi-
44 lar precautions ? Yet you write me, 30 July

44 1769,

HEADS OF SNAILS REPRODUCED. 2$t

“ 1769, that the Abbe Spallanzani muft be
“ deceived ; that he thought the whole head
££ was cut off, when the cap only was taken a-
<£ way. You perfift in the fame affertion, 20
££ July 1 775. Certainly you have not attend-
££ ed to the letter of the Reggian obferver, to
££ which I referred you. Permit me to refer
£C you to it again.

££ I have fet apart all the fevered heads : I
££ have obferved the whole with attention : I
£C have feen the two large horns with their eyes,
££ the fmall horns, the mouth, the lips, &c. I
“ have then feen new horns protruded ; I have
“ feen the eyes of the horns, the optic nerve of
“ the eyes : I have feen a new mouth, new lips,
££ and new teeth appear in the fnails, in the
££ fame fnails whofe former heads I had fet a-
££ part : I have feen fnails that gnawed with
££ their new teeth the covering of a veffel, and
££ I have feen them void excrements, in which
££ was found the matter they had confumed.
££ What more would you defire, my worthy
££ friend ? And how can you write me, after fo
££ many united proofs, that you ftill retain your
££ philofophic doubt ? Can fuch a doubt, ex-
<£ tended fo far, and challenging the molt ac-
££ curate, reiterated, and demonftrative experi-
££ ments, be termed truly philofophical ?

££ Confider, that the Abbd Spallanzani and
££ I, are not the only obfervers who have our-

££ felves

382 HEADS OF SNAILS REPRODUCED.

“ felv.es beheld the wonders feen in the repro-
“ du&ion of the fnail. The celebrated Signora
£C Baffi, Meff. Lavoifier, Schaeffer, Muller, See.
44 have feen and deferibed them alfo. Are you
44 willing to think that all thofe obfervers have
44 been impofed upon, they who have given fuch
44 ample evidence of their ability and accuracy?

14 With refpeft to the reprodu&ions of newts,
44 you tell me, you firmly believe the poffibility
44 of the reproduction of the fingers and their
44 bones, fo long as the anterior or pofterior
44 part of the arm is not cut away. I am forry
44 that you fhould have written this, before per-
44 ufing my memoir upon the Reproductions of
44 Newts. There you would have feen, that I
44 have cut away the fingers, the hands, the
44 fore-arm, whole arms, feet, legs, and thighs,
44 complete ; and that all thofe members were
44 perfectly reproduced by the animal. This
44 would have induced you to bellow more con-
44 fidence in the beautiful difeoveries of Abbe
44 Spallanzani upon fnails and newts. My me-
44 moir was printed in Rozier’s Journal , for lafh
44 November ; and I wonder that you, who re-
44 fide in the fame place where it is printed,
44 have not procured it. The figures added to
44 the memoir are very accurate, but the defigns
44 were fuperior to the engravings. It will
44 prefent you with fadts which I hope in a fhort

44 time

HEADS OF SNAILS REPRODUCED. 383

<i time you will not oppofe. See, therefore, and
“ believe.”

The letter written to me by Signor Spallan-
zani upon the mode of operating, and to which
M. Adanfon had not paid the attention it de-
ferved, is fo well adapted to convince natural-
ids of the reality of the ingenious difcovery of
which it treats, that I cannot difpenfe with tran-
fcribing it here, as the bed refutation that may
be oppofed to the detractors of this difcovery,
and as a model of the method that one ought
to purfue in refearches of this nature.

“ Modena, 11 September 17 69.

“ I thank you, Monfieur, for the intelli-
<c gence you have given me concerning fnails.
“ Confidering the different refults of natural-
“ ids, and particularly of French naturalids. I
ct am of opinion, that befide the little dexteri-
£c ty in the art of experiment, the diverfity of
“ the fpecies of the fnails upon which they
“ have tried to repeat my experiments, has in
cc a confiderable degree occafioned a differ-
cc ence in the refult of their experiments. I
“ am certain, that all the fnails of Modena
u reproduce more or lefs ; but I do not urar-
“ rant the reproduction of foreign fnails : fome
C£ among them perhaps do not poffefs this re-
“ fource.' Upon this point you will fee great-
“ er detail in the preface I (hall prefix to my

tc Italian

384 HEADS O? SNAILS REPRODUCED.

Italian tranflation of your Contemplation de la
“ Mature, which will appear this year. It is
“ very probable, that the fnails which have ex-
“ ercifed the induftry of the learned anony-
<c mous Frenchman of whom you fpeak, are of
“ the number of thofe where the property of
“ reproduction does not refide in the higheft
“ degree. I might fay the fame of the fnails
“ upon which M. de Bomare and F. Cotte
te have operated. But does it thence follow,
“ that I am deceived ? To fay I am, would be
<£ a ralh opinion, to call it no more. If any
“ one attempts to confute me, I will try to de-
“ fend myfelf ; and my very circumftantial de-
<e tails, and thofe of my friends, will prove
“ that I am not deceived.

“ You obligingly afk, whether the fevered
“ head truly contained all the organs pertain-
“ ing to the head of a fnail ? To anfwer this
<c important queflion, I will mention what I
cc did in making the experiment. When I
<c faw that fnails enjoyed the prerogative of
<c reproducing themfelves, I begun to dilfe£t
cc them, on purpofe to obtain a perfect know-
<c ledge of the anatomy. I wifhed to make
<c myfelf mailer of all the organs of which
<c the head was compofed. M. Lyonet’s ana-
£C tomical work has always been my model ;
“ and I was provided with all his apparatus.
“ I killed in water the fnail I propoled to dif-

<c fed: :

HEADS OF SNAILS REPRODUCED. 385

r,: fefl : -it then proceeds from the {hell, the
££ four horns are difplayed, and it dies in this
£{ pofition, which is the mod; favourable for
cc diffeflion. It is by this trivial expedient
“ that I have been able to convince myfelf,
££ that the head cut off truly contained all trie
“ parts Swammerdam has defcribed in his trea-
£C life upon fnails.

££ It was only after having ftudied well the
£C ilruclure of the head, and having afcertain-
“ ed the fituation of each part, that I begun
££ to mutilate the animal ; and I proceeded in .
<£ this manner : — -Before cutting off the head
££ of the fnail, I waited until it had come out
£c of the {hell* and the horns were completely
££ difplayed : then the operation fucceeded
££ wonderfully well : and it often happens
££ that the fevered head will keep the horns
C£ nearly as much extended as before the ope-
££ ration, only they fink down and appear
££ feeble : the head itfelf contracts or concern
£t tres very much. I have foaked it in water,

£C and in forne hours it dilates, and becomes
££ foft ; in which ftate it is eafy for me to
££ anatomize it.

££ I begun the diffeftion clofe to the cut;
t£ and after dividing the integuments, I had the
<£ pleafure to obferve very diffin&ly the fepa-
££ ration or diftribution of ten nerves, pro-
cceding to the eyes and the other parts of

G c £{ the

386 HEADS OF SNAILS REPRODUCED.

“ the head : I obferved as didin&ly the dif-
“ tribution of the nerves of the oefophagus,
and the mufcles ferving for the different mo-
“ tions of the head. Sometimes, inflead of
“ the nerves, I examined the whole or part
6i of the brain of the fevered head.

<c Continuing the direction, and extending
“ it farther, it was eafy for me to trace the
cc different parts, even to the places where
<c they were inferted in the head. Without
“ the lead difficulty I found the throat of the
“ animal, its tongue, lips, mouth, teeth, the
lc four horns, with their nerves, mufcles, and
“ other appendages. If I chofe, I could retract
“ the horns into the head : I had but to pull
“ the ends of the divided mufcles.

“ Thefe are, my dear correfpondent, the
<c mod remarkable parts that prefented them-
“ felves to my view in the fevered head. I
te fay the mod remarkable, for I difcovered
c< many other lefs important, of which I fhall
“ fpeak in my large work.

cc I now afk you, If this affemblage of all
ce the parts compofing the fevered head ; if
<c this affemblage, which I have feen and re-
<c viewed an hundred times, is fimply the inte-
ce gument of the head, or part of this integu-
“ ment, as the French obfervers, whofe opi-
<c nions or experiments you have communicat-
u ed to me, imagine : is it not the mod fa-

“ tisfaidory

HEADS OF SNAILS REPRODUCED. 387

££ tisfadory evidence, that I have been under
££ no illufion, and that this fevered head con-
“ tained complete all the organs which com-
££ pofe it ?

££ I pradifed nearly the fame method with
££ regard to the head reproduced. It would be
££ fuperfluous to give you a detail of the or-
“ gans compofing it. I could only repeat,
££ word for word, what I have juft faid of thofe
<£ we difcover in the original head cut eft. It
££ is true, that, oftener than once, this decol-
<£ lation gives place to various monftruofities
££ of the parts reproduced : but this does not
££ affed the elfence of my difeovery.

££ I have taken care to meafure the fevered
££ head, and to compare it with that repro-
£C duced. I have taken many other precau-
£C tions, which I now pafs in ftlence, but fliall
££ mention them at large in my work.

££ I may flatter rnyfelf, that my treatife up-
££ on the reprodudions of fnails, will be lb
££ rich in experiments, and that thofe experi-
££ ments will be fo accurately described, and
££ fo well detailed, as to convince the molt ob-
££ ftinate infidels. ”

The reader may now judge, if I had any
foundation for reproaching the excefs of M.
Adanfon’s pyrrhonifm concerning the difeovery
upon fnails. It is in truth inoft fmgular, that
he perfifts in his doubts, after the perufal of a

letter

388 HEADS OF SNAILS REPRODUCED.

letter fo ftriCtly demonftrative as that I have
juft tranfbribed. How many phyfical faCts are
admitted by philofophers, and by M. Adanfon
himfelf, which are not better attefted than that
of which we fpeak ! Shall I fay more ? M.
Adanfon {till retained his doubts, 9 October
1779, as I learned from himfelf, during a vi,
fit he then paid me, after a journey made for
the recovery of his health. At that time, I
had not fnails in complete reproduction ; but I
had the fatisfaction of convincing him, by the
teftimony of his own eyes, of the realitv of
the wonders prefented by the reproduction of
the members of the water newt. I {hewed
him newts in various ftages of reproduction.
I (hewed him arms, hands, thighs, legs, feet,
perfectly well formed. He yielded to fo many
accumulated proofs, and was convinced that
what he had erroneouily fuppofed Ample flumps,
wrere in faCt real members, which would be
completely regenerated,

I return at prefent to the experiments I have
made upon the reproductions of the head of
fnails. Thofe whofe progrefs I mentioned in
the firft part of my treatife, died before finifh-
ing the reparation of the head. They became
much emaciated, and affumed a tranfparence
that is unnatural to fnails in the country. One,
whofe anterior part is reprefented fig. 12, re-
produced only one of the large herns, about a

line

HEADS OF SNAILS REPRODUCED. 3S9

line in length, but much thicker than the large
horns are when they begin to extend. This
lingular horn, which feemed to be formed like
a fort of fpindle, had two eyes, y y, very dif-
tindt, and each eye had its optic nerve. Fig.
15. reprefents the whole magnified, where,
flightly fhaded, the part reproduced is indicat-
ed, which is always of a clearer colour than
the original flefh. The horn being clofely ex-
amined, it was eafy to difcover that it was
formed by the union of two horns, which were
ingrafted in each other, as in a manner by
uniting. There was no trace of a mouth, nor
of the fmall horns, perceptible in this fnail :
how then can a complete decapitation be doubt*
ed ?

I refumed thofe experiments upon different
fpecies of fnails, Spring 1778. Their various
reproductions prefented varieties fnnilar or a-
nalogous to thofe I had obferved in the fnails
decapitated the preceding year. There was a-
mong thofe varieties, one like that of which I
have juft fpoken. Two eyes at the extremity
of the left horn, were very diltinCtly feen in a
fnail that had begun to reproduce the mouth
and the two large horns, fig. 16. The anteri-
or part of the fnail is here reprefented larger
than life.

I continued to attend my fnails during the
whole courfe of the year 1778. The progrefs

of

39 ° heads of snails reproduced.

of regeneration was as ufual very unequal, and
none repaired the whole head.

I decapitated twenty-four fnails of the fame
fpecies 26 May 1780, confining them in veffels
after the operation. Several reached the fum-
mit of the veffel, and attached their fhells to
the Tides, or to the paper covering over the
mouth. The greater part fliut up the fheli
with a very thin operculum, at different de-
grees of depth within.

Having immerged fome of the decapitated
fnails in water, 9 September 1780, that I
might judge of the date of the reproduction,
there were two among them that prefented a
remarkable monftruofity. In one, I obferved
only one large horn, very like that of fig. .1 5,
and evidently appeared to be formed as if by
the union of two horns. At the extremity,
were two fmall fhining black eyes, each pro-
vided with an optic nerve perfectly vifible
through the tranfparent flefh. This mcnftrous
horn, which was about a line long, appeared
thicker in proportion than that of fig. 15. It
greatly refembled a fpindle, being cut even at
the extremity, and being all nearly of the fame
thicknefs. But it was different from the other,
by a more important diflindtion. On the left
fide was feen, a little under the eye, a very mi-
nute tubercle, which feemed to be a fecond
fiorn growing out of the large horn. In this

fnail,

HEADS OF SNAILS REPRODUCED. 39!

fnail, I fought in vain for the parts conftitut-
ing the mouth. I could difcover no trace of
it : nor was there the leaft veftige of the two
fmall horns.

The fecond fnail prefented a monftruofity of
another kind : only one large horn had pro-
truded. At the extremity I thought I could
perceive three black eyes, but fo clofe to each
other, that they feemed confounded together.
Fig. 17. 18. the figures are magnified. Upon
the fuperior part of the horn were feen, very
diftinftly, three parallel optic nerves, only one
of which proceeded to the three minute eyes.
Under this horn, and at a little diftance from
the origin, a very fmall one is difcovered,
which feems only beginning to expand. In
this fnail, as in the former, no mark of the
parts forming the mouth were vifible.

I obferved again, both -with the naked eye
and a magnifier, the two fnails, 25 O&ober.
They had made a very fenfible progrefs. Up-
on this day, only eight of my fnails remained
alive : all, of that fpecies whofe lhell is yellow
or yellowifh. The other fixteen had perifhed ;
fome fooner, fome later.

I immerfed in water the fix fnails whofe re-
production I had not yet examined. The
greater part had made but little progrefs, and
fiiewed only the origin of a fingle horn. One
alone had protruded two eye-horns, at leaft a

line

392 HEADS OF SMAILS REPRODUCED.

line and a third in length ; the optic nerves fo
large or fo vifible, that they feemed to darken
the greateft part of the horns ; but the fmall
horns, the lips, or the other parts of the
mouth, did not yet appear. This fnail perfift-
ed in remaining in its Ihell, although immerged
in water more than two hours. SufpeCting it
to be dead, I had taken it out, and, only after
the lapfe of feveral hours, it agreeably furpriz-
ed me, by proceeding from its Ihell of its own
accord, and difplaying to my eyes its new pro-
ductions.

In another Memoir, I will give the hiftory
of my eight fnails.

After making experiments upon fnails of
the fmalleft fpecies, it was proper to make them
alfo upon thofe of the largeft fpecies. This I
begun to put in execution 24 May 1780, upon
twelve of the largefl fnails of our country.
We may judge of their fize, compared with
that of the fnails which have been the fubjeCt
of this and the preceding Memoir, when I fay
the diameter of the opening of the Ihell of thofe
was at lead nineteen lines, and that of the Ihell
of thefe but four or five.

In fome weeks, the half of my fnails died,
and exhaled an exceflive fcetid odour. Upon
1 3 Augufl, I immerged the fix furviving fnails.
They proceeded from the fhells, and I faw that
the large wound was perfectly cicatrized, but
could perceive no indication of reproduction.

Towards

HEADS OF SNAILS REPRODUCED. 393

Towards the middle of October, other two
fnails died. Upon the 18, I immerfed the
four remaining fnails in water, where they
were more than three hours without appear-
ing. I fcratched with my nail the laft volute
of the fpiral of the fhell in vain : all my at-
tempts were fruitlefs, and the fnails obftinately
concealed the anterior part : they were then
taken from the water, and fhut up in their vef-
fel. I will ingenuoufiy confefs, that I had lit-
tle hope that the fnails had made new produc-
tions. What then was my furprife, wdien they
next morning proceeded from their fhells of
their own accord, and exhibited unequivocal
evidence of reproduction, and even of repro-
duction pretty far advanced ! One, which be-
gun to repair the head, had two large horns
about a line in length, fig. 19. The left horn,
c , was thicker than the other, had two diftinCt
and black eyes at the extremity. The right
horn, on the contrary, appeared to have none.
I could as yet difcover no indication of the re-
generation of the fmall horns, and of the
mouth.

Another fnail, fig. 20, had likewife begun
to reproduce two large horns, nearly of the
fame fize as thofe of the preceding : but the
right horn appeared monfirous ; it feemed to
terminate by three fmall foft points, which are
drawn from the life.

Dd

The

394 heads of snails reproduced.

The reprodu&ion of the head of a third
fnail was announced by four or five very fhort
protuberances, where the large left horn only
could be diftinguifhed, prefenting three black
points, or three very minute eyes. The whole
is magnified, fig. 21. The three eyes, a , b , c :
two, inftead of being fituated at the extremity
of the horn, are fituated upon the fide : the
eye, a , is more apparent than the eye, b ;
the third, c , is a little below the other two.
It was impoflible for me to fee the optic nerves
through the flefli : the reproduftion had (till
made but little progrefs. Under the horn are
feen two protuberances, p, the nature of which
cannot yet be known.

I fhall continue my obfervations upon thofe
large fnails, and give the fequel in another
Memoir.

FINIS.

1.

EDINBURGH •’

MINTED BY DAVID 'WILLI JON; M.DCC.XCIE.

✓

Ale'S

ST)-*** I