A Short Explanation of the TA B LES. 
Arachnorides, on account of its extreme 
finenefs. The cavities of the ventricles of 
the brain are united together merely by 
means of the faid coat, which likewife ferves 
to keep firm in their proper fituation the ar- 
teries adhering to the bottom of the brain. 
As therefore the ventricles of the brain have 
no other coat to enclofe and connec them, 
but this very delicate one, which gives way 
to the flighteft impreffions, we may eafily 
fee, that the faid ventricles are by no means 
fuited to contain the animal fpirits, which 
no doubt are continually pafling and repafling 
through the whole fubftance of the brain, 
marrow, and nerves, in order to contract 
the mufcles. It is therefore the pid mater 
alone that can be fuppofed to contain the ani- 
mal fpirits. But I abfolutely deny, that, as 
fome people think, thefe fpirits pafs in great 
quantities through the faid coat, as there are 
not to be found in the brain or origin of the 
marrow any ventricles ; or any great quantity 
of fpirits, that we may fuppofe to be driven 
backwards and forwards in fuch a manner. 
Befides what power fhould drive them. 
There are no mufcles at hand for that pur- 
pofe ; and as to the opinion of fome, who 
attribute fuch a motion to the heart, experi- 
ence fufficiently proves, that the juices fe- 
creted from the blood move flower than the 
blood itfelf. It would be more agreeable to 
experience to fuppofe, that fome juices are 
fecreted from the blood into the nerves, in 
_ order to move the mufcles; nor would a 
great quantity of fuch juices beneceffary, as 
appears plainly in the cafe of the {malleft 
tumours, 4 
In Frogs, the Wray-fith, and other animals, 
after the nerves have been feparated fome 
hours from the {pinal marrow, and all mo- 
tion has ceafed in the mufcles, I can not- 
withftanding reftore the faid motion, by on- 
ly any how irritating the nerves fo cut off. 
And this makes me believe, that the blood, 
that continually fows through the arteries 
into the marrow and nerves, produces in the 
mufcles, by means of the nerves, fuch a 
conftant irritation, as muft keep the mufcles 
in a ftate of perpetual contraction. To ex- 
plain the mechanifm of this motion; The 
food we take in, after paffing through the 
heart, increafes our blood : the blood drives 
to the brain, irritates the mufcles to con- 
traction, by fecreting fome few fubtile par- 
ticles, which are moved towards the tierves, 
and penetrate them. The mutfcles will, in 
their turn, put their contents in motion, and 
thus a perpetual and uninterrupted motion 
muft of courfe be produced in all the parts of 
the animal machine. It would certainly be 
worth while to demonftrate, by a due courfe 
of experiments, thefe operations of the blood, 
{pirits, nerves, and mufcles. What I have 
here faid of them is only by way of paren- 
XMM 
thefis, and therefore J think I have faid 
enough. 
J11/ Some very beautiful inofculations of the 
nerves. 
mmm The reft of the nerves iffuing from the 
‘lower part of the medullary nodules. 
ann &c. Some parts of the fpinal marrow, 
where its divifions are not fo confpicious, 
as more particularly appears in three places 
near the breathing-hole, or refpiratory 
points. | 
123, &c. Nine breathing-holes, which I 
here reprefented, to fhew the fituation of the 
fpinal marrow, with refpect to the annular 
incifures of the body. | 
0 In this place I have reprefented the fpinal 
marrow with agreater cleft, than it really has, 
the better to fhew the nerves //, 
The remaining part of this Jigure reprefents 
the genital parts of the Male Silk-Wornm 
Butterfly. 
p p Two branches of the laft and greateft pair 
of nerves, which branches, proceeding from 
the loweft part of the marrow, are cleft neat 
their extremities, and form a flit for the paf- 
fage of the vafa differentia r r. 
gq Vhe tefticles of the Silk-Worm Butterfly, 
already difcernible in the Silk-Worm itfelf, 
rr The vafa differentia. 
ss Places at which the faid veffels run in a fur- 
prifing manner through the nerves of the 
marrow. I leave others to judge whether or 
no this difpofition contributes to increafe the 
titallation. 
¢ A proftata, or fomething analagus to that 
glandule. 
uu The faid bags, fupplied with thei# feminal 
matter from two diftinG tubes. ‘Thefe bags 
are not only feparated from the vafa differen- 
tia, but have not the leaft communication 
Withthemiy sg. Me 
x « The body of the penis, with a perforation 
from end to end for the paflage of the feed. 
yy Two nails or hooks growing near that part 
of the penis, which is of a fubftance between 
bone and horn. It is by meansof thefe nails 
or hooks that the male fixes itfelf againft the 
vulva of the female, and draws her towards 
him, the furer to penetrate her with his pe- 
nis. The fame contrivance appears in the 
horned Beetle, and other infeés, 
% Part of the penis, confifting of a horny 
bone. The bone ferves as a preputium or 
fheath; from whofe fore end the penis pros 
jects. ; 
Pre. TV; 
4n oval nef, hollowed out under ground by the 
Coffus, in which it changes to a Nymph, 
@a@ The earth in which the Coffus had formed 
its oval neft. 
I & The 
