652 A N A T 
funis not being exaflly in the middle of the child’s body, 
for it is not fufpended by the funis: the reafon is, be- 
catife the fuperior parts are much larger, and heavier in 
proportion, than the inferior. When other parts prefent, 
it feems owing to the motion of the child altering its fi¬ 
gure when the waters are much diminifhed in quantity, or 
to circumvolutions of the cord : when the polition is once 
altered, it becomes confined or locked in the uterus, and 
cannot eafily refume its original pofrure. As the figure of 
the foetus is oval, and the head naturally falls to the moft 
depending part of the uterus, the vertex generally points 
to the os tincae, with the ears diagonally in the pelvis. 
The foetus is mechanically dilpofed to alfume this pofition 
from its peculiar figure and conftrtnftion, particularly by 
the bulk of the head and articulation with the neck, by 
the action of its muffles, and by the fhape and conftruc- 
tion of the cavity in which it is contained. 
When a child is newly born, and left unconfined, how¬ 
ever it may fling its limbs in ftarts, yet for tiie moft part, 
w hen quiet, it gathers itfelf. up into the oval form, as it 
lay in the womb. Were it not for art, this natural habit 
would be prefsrved, and man would take reft, like the 
quadruped, with ail hislimbs folded up. 
The fize and weight of a child’s body at birth is gene¬ 
rally over-rated, infomuch that we are often told of chil¬ 
dren weighing from fifteen to twenty pounds. So far is 
this from being true, that Dr. Hunter declares, he never 
knew an inftance of tt crhild that weighed twelve pounds, 
and the greateft number are but little above half that 
weight. Dr. Macaulay was at great pains to afcertain the 
O M Y. [Comparative. 
ordinary bulk of new-born children, by weighing feveral 
thoufands that were born in the Bntifli lying-in hofpital; 
the refult was, that the fmalleft weighed a little above four 
pounds, the largeft eleven pounds two ounces, but the great- 
eft number weighed from five to eight pounds, avoirdupois. 
To fliew the general pofition of the child in the womb atr 
or about its full time, Dr. Hunter has favoured us with an 
elegant diffeftion, which we have reprefented in Plate V. 
of the Gr avid Uterus. Indeed the four former of thefe 
plates reprefent dilfeftions of the fame fubjeft, an unfortu¬ 
nate female, who expired luddenly at nearly the end of the 
ninth month of her pregnancy. The arteries and veins, and 
moft of the different velfels, were injefted with wax, and 
are now in Dr. Hunter’s collection. Thefe engravings de- 
monftrate the different appearances of the gravid uterus, 
in the fame order that its different membranes were diffec- 
ted oft'; the laft of which being removed, exhibits, as in 
Plate V. a view of the child, of its full (ize, juft before 
birth. The navel-firing is cut, tied, and turned to the 
left fide over the edge of the womb. At the fundus the 
invefting membranes are likewife turned ovee the edge of 
the womb, that they might be more apparent. On open¬ 
ing the uterus, the body of the child was found covered 
with a white greafy mucus, which is commonly feen on 
children at their birth. This is reprefented at the upper 
part of its back, where it was interieded with line?,.from 
the wrinkles and motion of the child’s body. Every part 
is delineated juft as it was found; not fo much as one joint 
of a finger having been moved to (hew any part more dif- 
tindfly, or to give a more pitfturefque effect. 
COMPARATIVE ANATOMY. 
THE principal advantages of Comparative Anatomy 
are the following: Firft, It furnifhes us with a fuff.cient 
knowledge of the different parts of animals, to prevent 
our being impofed upon by fuch authors as have delineated 
and deferibed feveral parts from brutes as belonging to the 
human body. Secondly, It helps us to underhand feve¬ 
ral paffages in the ancient medical writers, who have taken 
many of their deferiptions from brutes, and reafoned from 
them : their reafonings have often been mifapplied, and 
confequently wrong explained, by the moderns. The 
third and great life we reap from this fcience, is the light 
it cafts on feveral functions in the human oeconomy, about 
which there have been fo many difputes among anatomifts. 
Thefe differences of opinion, by exhibiting the ftruCture 
of the fame parts in different animals, and by comparing 
the feveral organs employed in performing the fame aCtion, 
which in the human body is brought about by one more 
complex, will be in a great meafure done away. 
All quadrupeds have a covering of hair, wool, &c. to 
defend them from the injuries of the weather ; which va¬ 
ries in thieknefs according to- the feafon of the year, and 
difference of the climate. Thus in Ruffia and the nor¬ 
thern countries the furs are very-thick and warm; while 
the little Spanith lap-dogs-, and Barbary cows, have little 
or no hair at all. The cutis and cuticula in quadrupeds are 
cjifpofed much in the fame way as the human, but they 
are more elaftic. Immediately under this there is a very 
Ilyin cutaneous mufcular fubftance, called panniculus car- 
noj'us , which is common to all quadrupeds, the. porcine 
kind excepted; this principally covers the trunk, ferving 
to fhrivel the (kin, in order to drive off infefts, their tails 
and heads not being fufficient for this purpofe, vyhile their 
extremities are employed in their fupport and progreftion. 
It has probably been from obfervirig fome mufcles of the 
human body, fuch as the platyfma myoides, cremafter, 
and frontales, and the collapfed tunica celluiofa of the 
emaciated fubjeits, to refemble this thin mitfcle, that 
home of the older anatomifts reckoned fuch a panniculus 
among the common integuments of the human body. Moft 
of the quadrupeds want clavicles, whereby their anterior 
extremities fall upon their cheft, fo as to make their thorax 
proportionally narrower than the human. This frnall dif- 
tance of their anterior extremities is very neceffary for their 
uniform progreftion. Apes indeed, and fquirrels, have 
clavicles, to allow them a more full ufe of their extremi¬ 
ties in climbing; but they walk ill on all fours. 
ANATOMY of a DOG. 
We may firft obferve of this animal, as indeed of moft 
quadrupeds, that its legs are much fhorter in proportion 
to its trunk than in man, the length of whofe fteps de¬ 
pends entirely on the length of his inferior extremities: 
however, to balance this, the trunk of the animal is pro¬ 
portionally longer and fmaller, and his fpinemore flexible, 
by which he is able at each ftep to bring his pofterior ex¬ 
tremities nearer to his anterior. His common integuments 
are much like thofe of other quadrupeds ; only they allow 
little or no paffage for fweat; but, when he is over-heated, 
the noxious and fuperfluous matter finds an exit by the 
falivarv glands; for he lolls out his tongue, and flavers 
plentifully. We are not, however, to fuppofe, that be- 
caufe a dog does not fweat, he has no infeulible perfpira- 
tion. That a dog perfpires is evident, becaufe one of 
thefe animals can trace another by the feent of his foot- 
fteps; which could not happen, if a large quantity of 
perfpirable matter was not conftantly going oft'. We may 
alfo obferve, that the rabies canina is a dileafe peculiar to 
dogs, foxes, wolves, and others of that genus; for though 
the bite of other mad animals, fuch as cats, or hogs, and 
even poultry, will produce the difeafe, no fair inftance 
has ever been brought of any of thefe animals being ori¬ 
ginally' feized with this malady. 
The pyramidal mufcles are wanting in the dog; to flip- 
ply which, the redhis is inferted fleftiy into the os pubis. 
The omentum reaches down to the os pubis ; which, con- 
(idering the pofture of the animal, we (hall find to be a 
wife provifion, fince its ufe is to feparate an oily liquor for 
lubricating the guts, and facilitating their periftaltic mo¬ 
tion. So, in our eretl pofture, the natural gravity of the 
oil will determine it downward; but, in the horizontal po_ 
fttion 
