and vivacious, than larger ones. How infinitely 
does the leap of a flea exceed any thing of which 
greater animals are capable ? How amazingly fafter 
than the bed race-horfe does a mite run, in pro- 
portion to their refpeilive fizes ? M. De Lifle has 
given the computation of the velocity of a fmall 
creature, fcarcely difcernible by the naked eye, 
which he found to run three inches in half a fe- 
cond : now, fuppofmg it's feet to be the fifteenth 
part of a line, it muft make five hundred fteps in 
travelling three inches j that is, it muft fliift it's 
legs five hundred times in a fingle fecond, or the 
ordinary pulfation of an artery. 
Sir John Hill has arranged Animalcules under 
three cialTes; namely, thofe which have no tails, 
nor any vifible limbs; thofe which have tails, but 
no vifible limbs; and thofe which have vifible 
limbs: each of which claffes he fubdivides into 
feveral diftinft genera. 
Animalcules, how;ever, may be more properly 
reduced to vifible, invifible, and microicopical. 
Vifible Animalcules are fuch as are perceptible by 
the naked eye; of which kind we may enumerate 
mites, with feveral fpecies of infefts, reptiles, and 
other vermin. Invifible Anim.alcuies are a race of 
beings neither perceptible by the natural eye, nor 
even by the beft microfcopes; concerning which 
naturalifts, of courfe, form many ftrange conjec- 
tures. Reafon and analogy, indeed, give fome 
fupport to our idea of the exiftence of an infini- 
tude of imperceptible Animalcules. The naked 
eye is adapted to the infpe£lion of all animals not 
lefs than the mite ; there a new order of beings com- 
mences, referved for the m.icrofcope, and compre- 
hending all defcriptions of creatures, from the mite 
to fuch as are twenty-feven millions of times fmaller: 
nor can this laft order be confidered as compleatly 
limited, till we fuppofe the microicope arrived at 
the higheft degree of perfe6tion. 
Microfcopical Animalcules are fuch as are only 
perceptible by the aiTiftance of a large m^agnifier; 
and thefe, according to fome naturalifts, fall moft 
properly under the laft clafs of invifibles. The ex- 
cefiive minutenefs of thefe Animalcules conceals 
them from the naked eye ; and one of the moft 
confiderable improvements in modern phiiofophy 
is the invention of thofe inftruments v/hich brinfj 
fuch creatures under our cognizance and infpec- 
tion. An objeft a thoufand tim.es too minute to 
afFeft the optic fenfe, might have feemed wholly 
excluded from our obfei-vation; but human i'asfa- 
city has contrived means to extend the faculty of 
fight inconceivably farther. Indeed, moft of our 
microfcopic Animalcules are fo extreiricly minute, 
that, through a lens, the focal diftance of Vv^hich is 
the tenth part of an inch, they leem only like fo 
many points : that is, their figures cannot be dif- 
tinguiflied; fo that they appear, from the vertex 
of that lens, under an angle not exceeding a mi- 
nute. If we farther inveftigate the real magnitude 
of fuch an objeft, it will be found nearly equal to 
—rj:^ of an inch in length. Suppofing, therefore, 
thefe Animalcules of a cubic figure, (that is, of the 
faine length, breadth, and tliicknefs) their mag- 
nitude will be expreffed by the cube of the frac- 
tion that is, by the number 
and fo many parts of a fquare inch does each Ani- 
malcule in that cafe equal. 
Strange as it may feem, it is undoubtedly true, 
that many thoufands of thefe Animalcules would 
have fufficient room to dance on the point of a 
common needle : and, indeed, fome liquids abound 
A N I 
with fuchamazingly minute Animalcules, that the 
magnitude of the whole earth is not large enough 
to be a third proportional to thefe diminutive float- 
ing animals, compared with a fingle whale. 
Animalcules are found of various kinds; fome 
formed like fifli, others like reptiles, fome hexape- 
dal, and others horned. In feveral kinds, however 
minute, it is eafy to difcover the form of their 
moutlis, their probofcides, and horns, with the mo- 
tions of their hearts, lungs, and other parts. Every 
Animalcule being an organized body, how deli- 
cate and fubtle muft be the feveral parts which 
conftitute fuch a creature, and preferve it's vital 
funftions 1 It is difficult to conceive how, in fo 
narrow a compafs, there can pofiibly be contained 
a heart, the fountain of life; muicles neceflfary 
to the creature's motions ; glands for the fecre- 
tion of it's fluids ; a ftomach and bowels to di- 
geft it's food; and other innumerable members, 
without which the minuteft Animalcule could by 
no means fubfift. As eveiy one of thefe members, 
hov/ever, is alfo an organical body, they muft ne- 
cefi^arily be compofed of parts, adapted to their re- 
fpeftive aftions. They confift of fibres, mem- 
branes, veins, arteries, nerves, and coats, with an 
almoft infinite number of fine fmall tubes, the mi- 
nutenefs of which exceeds every efibrt of human 
imagination. But there are ftill other parts which 
muft of neceflity be even lefs than thefe : and fuch 
are the feveral fluids permeating thofe fine tubes, 
as the blood, lymph, and animal fpirits; the fub- 
tlety of which, even in large animals, is almoft be- 
yond conception. Lewenhoeck calculates, that 
a thoufimd millions of thofe Animalcules which 
are difcovered in common water, do not collec- 
tively exceed the dimenfions of a fingle grain of 
land ! This author, likewife, on examining the male 
Iperm of various animals, difcovered in many an 
infinitude of Animalcules, not larger than thofe 
juft mentioned. In the milt of a fingle cod-fifli 
there are more Animalcules than miCn on the whole 
earth. The foul vv^hitifli matter which fticks to 
the human teeth abounds with Animalcules of va- 
rious figures, to v/hich vinegar is fatal ; and yet vi- 
negar itfelf fupports a fpecies of Animalcules 
which are ftiaped like eels. In flrort, if we give 
full credit to this penetrating naturalift, every 
corruptible fubftance produces it's various Animal- 
cules; and to thefe muft v/e afcribe the original 
caufe of m.any difeafes. The itch, it is well known, 
from repeated experiments, is a diforder arifing 
from the irritation of a fpecies of Animalcules 
found in the puftules of that malady; whence the 
communication of it by conta6t is eafily conceiv- 
ed, as well as the reafon why a cure is effefted by 
means of cutaneous applications. To the fame ra- 
dical caufe, fome have alfo attributed the fmall- 
pox, the meafles, and other contagious difeafes. 
Some, indeed, go farther, and pretend to reduce 
all difeafes in general to this principle : and a late 
writer, in particular, has ventured not only to ac- 
count for all difeafes, but even for the operations of 
all medicines, from the hypothefis of Animalcules. 
Thus the m.oft beneficial or curious difcoveries in. 
natural phiiofophy have laid the foundation for 
vifionary theories, and have been introduced to 
fupport the moft chimerical fyftems. 
ANIMAL FLOWER. A name given by 
moft naturalifts to an Animal bearing fome diftant 
refemblance to the Flower of the marigold, but of 
a paler yellow. This name, however, feems well 
adapted to the Animal; for it's claws, or tentacula, 
beinCT 
