The HTS TORY of IN C.T's: 
Then the Loufe turns his head, which lies be- 
tween the two fore legs, to the fkin, and dili- 
gently fearches for fome pore of fweat: when 
he finds it, he fixes his aculeus, or fucker; there- 
in; a little after this, the blood is obferved, 
through the microfcope, to afcend to the head, 
in a very rapid, and; as it were, frightful 
fiream. 
The Loufe has at that time matter enough 
to feed on in any pofture, for if it finds any 
hairs on the hand, by which it does not defire 
to defcend, it ftays in that pofture; and fucks 
with its head down, and its tail elevated. I 
have likewife obferved that it fometimes fucked 
with its belly upward, that is, when the hair 
it took hold of was bent down; and then the 
motion of the {tomach, and pancreas, or {weet 
bread, might be feen moft beautifully by the 
help of a microfcope. 
But I fhould think the principal ufe of the 
claws, which I havedefcribed to be fituated at the 
end of the fheath or cafe of the aculeusor fucker, 
is to affift the creature in fucking, and that the 
aculeus ferves for this purpofe; for whilft thefe 
are ftrongly fixed in the fuperficies of the inner 
fkin, and in the extremities of the pores, they 
enable the Loufe to ufe its aculeus the more 
freely, and to move it at difcretion, when the 
end of its fheath is placed firm and immov- 
able. 
Sometimes, whilft the Loufe was fucking, 
I have ftrongly pulled the skin of my hand 
afide, that by this means the fheath, or rather 
its claws, together with the aculeus or fucker, 
might be bound faft in the skin, and the Loufe 
could not difengage itfelf. This affords indeed 
a very agreeable fight. This I did witha de- 
fign, that if I could thruft the Loufe out of 
its place, I might the more plainly fee the 
aculeus: but I could never accomplith my de- 
fire in this particular, though I had then almoft 
wifhed to have three hands, that I might the 
better find what I wanted. ‘There are fome 
{peculations and refearches in anatomy that will 
not bear writing, fince they almoft diftraé the 
mind, 
When the Loufe is employed in fucking, a 
very {mall rivulet, Fig. 111, % of blood im- 
mediately appears behind the aculeus or fucker, 
which is feen through the tranfparent head. 
Between and before its eyes, on the middle of 
the head, there is obferved alfo a confiderable 
dilatation x, for the jaws are there remarkably 
expanded, by the blood continually afcending. 
Thefe parts are fo {wiftly contracted again, that 
there {carce remains the leaft fign of blood after 
amoment, and both are performed with fuch 
velocity, that the dilatation can hardly be di- 
{tinguithed from the contraction ; wherefore I 
do not know how to explain this matter more 
properly, than by the fudden ofcillation of the 
pendulum of a clock. Behind the eyes, a {mall 
tivulet of blood is likewife obferved to run down 
within the head : this paflage may be properly 
called the cefophagus or gullet, fig. 111. 6 which 
lies behind the jaws, and grows wide again in 
43 
the Loufe’s neck as has been fhewn before g. 
I have chofen to exhibit all thefe as one conti- 
nued canal, that my defcription may be the 
miore clear. 
After the blood has afcended to the jaws, and 
comes to the gullet, we obferve that it is im- 
mediately conveyed to the ftomach, and that 
the bifurcated appendages, as well as the fto- 
mach itfelf, are at once filled with it: The 
motions of the ftomach are then remarkably 
increafed, its mufcular parts being diftended ; 
for as thefe mufcular parts are then ftretched; 
they have an opportunity of contra¢ting them- 
felves again. Wherefore it is immediately ob- 
ferved, that the excrements in the large guts 
begin likewife to move; nay, it ufually hap- 
pens that the Loufe difcharges them during the 
fucking: 
The food being thus received into the fto« 
mach, is agitated about in a wanderful man- 
ner; itis moved up and down, and by con- 
tractions and dilatations, which are not to be 
defcribed, then performed by the ftomach, is; 
as it were fifted. After this, it is feen, that 
the contents firft begin to divide into parts in 
the back or hinder portion of the ftomach, and 
they then appear like raifins preferved in jars; 
and are thus diftributed through the body. 
However, this is a falfe appearance ; it arifes 
from hence, that the skin being divided into 
many grooves, is not equally tranfparent every 
where, and that fome difference is in this ref 
pect feen through it, becaufe the grooves are 
not equally tranfparent with the intermediate 
parts. Nay, the particles of the internal fat 
not being uniformly vifible through the skin, 
and obfcuring the brightnefs of the skin, con- 
duce likewife to deceive the fight, as if the 
retreating blood entered into many peculiar 
veflels. ‘To this may be added, that the blood 
has not at that time a homogeneous ot equal 
colour, for its parts feparate from each other. 
From thefe appearances, before I had accu- 
rately examined things, I thought that the 
blood was diftributed out of the ftomach, 
through various veffels, into the other parts of 
the body; but I afterwards obferved that this 
phenomenon arofe, as well from the blood 
itfelf, as from the different colours of the parts 
through which it was feen, and which I then 
took to be veffels.. Perhaps others, efpecially 
doctor Hooke, who firft prejudiced me in fa- 
vour of this opinion, have {plit on the fame 
rock. Ihave not as yet made this experiment 
in the fmalleft Lice, in which more peculia- 
ia may probably be feen, than in the larger 
ind. 
I have likewife refolved to receive the blood, 
when changed in the ftomach, into a glafs tube, 
and then to view it in the open air, or in fome 
dark place by candle light ; but this I have not 
hitherto done, being hindered from making 
this, as well as many other experiments which I 
had a mind to try. In fome hours after feeding, 
the contents of the ftomach are obferyed to be- 
come infenfibly more brown or blackith, and 
to 
