The BOOK. of 
a vat number of orbicular particles, of a flat 
oval but regular figure. Thefe particles feemed 
alfo to contain another fluid: but when I viewed 
them fideways, they refembled cryftalline clubs, 
and feveral other figures; that is, according as 
122 
NMeACT: U RIBS: \ or, 
they were turned about in various diretions in 
the ferum of the blood. I obferved befides, 
that the colour of objects always appeared the 
more faint, the more they were magnified with 
a microfcope. 
Experiments on the particular motion of the mufcles in the Frog; which may be 
alfo, in general, applied to all the motions of the mufcles in Men and Brutes. 
How important and difficult it is to ex- 
plain the real caufes of mufcular motion, 
is fufficiently evident from numerous experi- 
ments; which though made by very ingenious 
men, yet have not hitherto difcovered its true 
nature. The great utility and foundation of 
further knowledge, which we fhould acquire 
from that difcovery, lie yet involved in the 
thickeft clouds of obfcurity. ‘This is the rea- 
fon which now induces me to publifh the ex- 
periments I made concerning the matter ; 
which, as they feem to me to have great weight, 
and to contain fome ufeful confequences, I 
would therefore advife my readers to confider 
ferioufly, and examine them by the touchftone 
of truth. 
In the conftruction and motion of the muf 
cles, it merits particular confideration, in what 
manner the nerve is actually joined to the 
mufcle; how it is conftructed in the mufcle ; 
what is its courfe, entrance, middle, diftribu- 
tion, and end; as alfo how it communicates 
with the moving fibre, and what effect it pro- 
duces in it; alfo what that very fubtle matter 
properly is, which is’ undoubtedly conveyed to 
the mufcle through the nerve. The know- 
ledge of all thefe particulars is not fufhcient for 
our purpofe: one muft likewife know the con- 
ftruction of the membranes, that inveft both 
the furface of the mufcle and its inward parts, 
and the delicate leffer fibres that reach from 
one moving fibre to the other, and, like a very 
fine web, diffufe themfelves through the inter- 
tices of the latter. It would be likewife ne- 
_ceffary to know the ftructure of the vein and 
artery belonging to the mufcles, and their real 
conftitution or difpofition in the mufcle, and 
to underftand accurately what belongs to the 
compofition of the moving fibres. But all 
thefe things are ftill obfcure and unknown, 
and will not be probably difcovered till we 
employ all our time, and the greateft diligence, 
in inveftigating them: but all difficulties are 
conquered by induftry, and an unwearied ap- 
plication. As to myfelf, I candidly confefs, 
that I have not brought every fubject, which I 
have advanced, to the greateft perfection pof- 
fible ; for, in order to attain this, I fhould have 
fpent my whole life in difcovering one thing, 
and this courfe is not agreeable to me: for I 
am thoroughly perfuaded, that, if I came to 
the utmoft-extremity, I fhould at laft difcover 
nothing but my own ignorance. For this rea- 
fon, I thought it better to employ my time 
rather on various things than on one; left, 
whilft I was too intent on a thorough know- 
ledge of one or two particulars, many of God’s 
work fhould lie hidden from me: for, indeed, 
a 
all the knowledge we are capable of, confifts 
only in this, to love God as we ought. 
With refpeé&t therefore to all the fubjects 
hitherto recited, I ftill find many indiffoluble 
difficulties. And though the excellent ana- 
tomift, Dr. Steno, hath difcovered many cu- 
rious things relative to this matter, yet he ftops 
alfo in the middle of hiscourfe. Befides, how 
far are we from knowing the motion and effect 
produced by the fubtle {pirit, that continually 
pafies through the nerves into the mufcles! 
This matter lies buried in impenetrable dark- 
nefs. Since I have made many experiments, at 
different times, on the motion of the mutfcles, 
I fhall now, however, fet forth the chief of 
them, and fubmit them to the examination of 
the learned. 
It is a matter eternally certain, and of great- 
eft moment, that whenever the nerves of living 
bodies are handled, there is immediately ob- 
ferved a confiderable motion in the mufcles to 
which they are fent, and this motion does not 
at all differ from the contraétion of thofe muf- 
cles. If we lightly pinch or prick the nerves 
of the diaphragm in a living dog, opened for 
the experiment, with the point of a very fine 
needle; or if we ftimulate them by putting 
them near the fire, or by pouring acrid liquors 
into them; we immediately fee the diaphragm 
performs its natural function : it contracts itfelf, 
from being arched becomes fmooth, raifes itfelf 
from the thorax, pufhes out the vifcera of the 
abdomen, and the cavity of the thorax is en- 
larged in proportion as the diaphragm contracts 
itfelf and becomes more fmooth, and is more 
ftretched out of the breaft. 
This experiment is very fine and elegant, 
fince the motion alfo, which is then obferved 
in that compound mutfcle, appears admirable ; 
and the fame experiment may be often re- 
peated in the fame fubject, if the nerves of the 
diaphragm be firft irritated, where their begin- 
nings run near the pericardium, In order to. 
irritate them a fecond, third, and fourth time, 
we mutt defcend by degrees, and choofe a lower 
part of them, until we come to the very place 
where they are inferted in the diaphragm. 
This experiment on the nerve may alfo be 
very eafily made, not only inthis but all the 
other mufcular parts of the animal’s body, with 
the farfie fuccefs. Hence we often obferve, on 
diffecting living animals, that when the nerves 
are wounded with a knife, confiderable motions 
arife in the mufcles to which they belong. 
This the celebrated Steno hath likewife ob- 
ferved in his Myolog. Specim. p. 78 and 79, 
after Thad fhewn him my old and common 
experiment on Frogs. This is obferved to 
happen, 
