, / A N I 
vorous and hei-bivorous ; and the winged, which 
include the bats, infe<?tivorous. 
Such are the general outlines of the moft famous 
fyftems which have been invented to facilitate the 
ftudy of natural hiftoiy. Buffon, however, with no 
lefs truth than vivacity, has expofed the abfurdity 
of fyftem, when applied to the works of nature; 
and, by the moft beautiful difplay of one great 
branch of natural hiftory, has taught us to con- 
ceive what pleafure might be expected from the 
ftudy of the whole, executed on a fimilar plan of 
elegance and precifion. 
In natural hiftory, of all other fciences, there is 
the leaft danger of obfcurity. In morals or in me- 
taphyfics, every definition muft be precife, becaufe 
thefe fciences are necefiarily founded on definitions; 
but it is far otherwife in fubjefts where the exhibi- 
tion of the objeft itfelf is capable of correfting any 
mifreprefcntation. Thus, by miftake, a creature 
may be ranked among quadrupeds, which belongs 
more properly to the fifh or infe6l claffes ; but this 
can produce very little confufion, as every reader 
will be able to form a fyftem confonant to his own 
judgment, on examining the figure and properties 
of the Animal. 
Animated nature, in general, is divifible into five 
clafles: quadrupeds, birds, fifties, infeils, and am- 
phibious Animals; but, though all thefe feem to- 
lerably diftinft from each other in their very na- 
tures, there are fome inftances where we cannot 
eafily decide whether it is a bird or a quadruped, 
a fifli or an infeft, which prefents itlelf to our ob- 
fervation. Nature is varied by imperceptible gra- 
dations; fo that no exaft line can be drawn between 
any two clafles of it's produflions, nor can any de- 
finition be framed to compiehend them all. 
Each clafs of quadrupeds may be arranged under 
one of the domeftic kinds, as a model on which to 
form an idea of the reft : thus we may fay, that 
a tiger is of the cat kind, and a wolf of the dog 
kind, becaufe there are fome rude refemblances 
between them; and one who has never feen wild 
Animals will be able to form at leaft a flight con- 
ception of their figures from his acquaintance with 
thofe which are tame. But we dare not aflert, with 
fome fyftematic v/riters, that a bat is of the human 
kind, or a hog of the horfe kind, m.erely becaufe 
there is fome trivial fimilarity in their teeth or paps. 
All references of this kind, however, are merely 
arbitrary; and, in many cafes, it muft be confefled, 
they are very uncertain. It is difficult to deter- 
mine, for inftance, whether the civet fhould be 
clafied with the dog or the cat kind ; but the exa6l 
hiftory of the civet being once known, it is of very 
litde importance to what kind the different con- 
jeftures of different perfons may judge it bears the 
greateft refemblance. 
Animals confift of folids or firm parts, fluids, 
and matter of an intermediate nature. The folids 
are mere earth, connefted together by fome oily 
humour, and reducible by fire into their original 
fubftance. Thus a bone,' being perfeftly purged 
of all it's moifture by calcination, is found to be- 
come pure earth, which the leaft force will crum- 
ble into duft; yet the fame bone, on being im- 
merged in water, will become firm and folid again 
after calcination, and confiderably more fo in oil 
than in water. Indeed, the cupels or furnaces of 
chymifts made of Animal earth will fuftain the 
utmoft eff^efts of fire. 
The fluid parts of Animals become more crude 
in proportion as they are nearer the lafteals and 
A N I 
abforbent veflels. Chyle, for example, is little 
more than a vegetable juice : but, in it's farther 
progrefsjit gradually lofes it's vegetable characters ; 
and, after a number of circulations, it becomes a 
perfe6l Animal juice, under the denomination of 
blood, from whence ail the humours are derived. 
Animal fubftances have been diftinguifhed from 
thofe of vegetables, by two circumftances : firft, 
that the former, when burnt, are found perfeftly in- 
fipid, all Animal falts being volatile and evaporat- 
ing with, heat; v/hereas the contrary is experienced 
in vegetables, which conftantly retain fome fixed 
fait in all their afties : fecondly, that no pure acid 
is contained in any Animal juice; nor can any acid 
fait be extracted from it, though thefe qualities are 
known to exift in all vegetables. Animals, how- 
ever, may be converted into their vegetable nature 
by putrefaftion. 
ANIMALCULE. An animal of fuch minute 
proportions, that it is fcarcely difcernible by the 
naked eye, though all nature teems with an im- 
menfe variety of thefe creatures. Of this humble 
fpecies are thofe innumerable hofts of infefts which 
people the water in the fumm.er months, tinging 
it fometimes with a pale or deep red colour, and 
fometimes with a yellow one. ' The Animalcule 
ufually exhibits fomething of the fhrimp ap- 
pearance, and the moft common one is called by 
Swammerdam, pulex aquatic a arborefcens. Their 
concoux"fe at this feafon. Dr. Derham obferves, is 
for the purpofe of propagating the fpecies ; and he 
adds, that thefe little infefts afford a comfortable 
iiibfiftence to many water animals. The green fcum 
on the furtace of ft"agnant waters is often folely 
compofed of myriads of another ftill fmaller order 
of Animalcules ; which may probably, in their turn, 
be deftined to fupply the pulices aquaticse with 
food. The invention of the microfcope has brought 
to light millions of Animalcules in almoft every 
kind of fluid ; and, in the Philofophical Tranlac- 
tions, we meet with obfervationr. on the Animalcules 
in rain-water, in feveral chalybeat waters, and in 
infufions of pepper, bay-berries, barley, oats, wheat, 
&c. Thofe, indeed, who have made the moft mi- 
nute refearches into the natures of the feveral ob- 
jects fubjefted to their fenfes, have difcovered that 
the fubftances on which they employed their curi- 
ofity were often totally different from what they 
were originally apprehended. From fuch invefti- 
gations it appears that the whole earth is replete with 
an infinity of Animalcules floating in the air we 
breathe, difporting in the liquois we drink, and ad- 
hering to every objeCt of the fight or touch. The 
conjectures and hypothefes relative to the produc- 
tion, generation, ftruclure, and ufe, of thefe Ani- 
malcules, invented by caprice, and adopted by cre- 
dulity, have been miOre various and contradidlory 
than it is eafy to conceive. Avoiding, therefore, 
thele inexplicable labyrinths, we fliall confine our 
obfcrvations to aftual difcoveries. By the afliftance 
of the microfcope, we not only perceive that fuch 
Animalcules really exift, but are enabled, in fome 
degree, to determiine their fliapes, and the various 
peculiarities of their miOtions. Indeed, the con- 
templation of known Animalcules has rendered the 
idea of infinitely fmall bodies extremely familiar 
to all mankind. A mice was formerly thought the 
utmoft limit of animated minutenefs; but our cre- 
dulity is not, at prefent, greatly alarmed, when we 
are told of animals even twenty-feven millions of 
times fmaller than a mite. Minute animals ap- 
pear to be proportionably ftronger, more aftive. 
