ANATOMY. 
of the body. For there is no spot on the 
surface of the skin from which ointment may 
not be taken up, nor any internal part from 
which blood, when accidentally effused, 
may not be absorbed ; nay, the very matter 
composing the texture of our bodies, is un- 
dergoing continual removal and renovation. 
These vessels must therefore be supposed 
to begin by open orifices generally through- 
out the body, although the fact can be de- 
monstrated in the intestines only. On the 
inner surfaces of these organs they appear 
to the unaided eye fine and pointed tubes ; 
but by the microscope their mouths are 
discerned to be patulous, and like a cup. 
The beginning absorbents soon join toge- 
ther, and after some time form minute ves- 
sels, capable of being injected by anato- 
mists : these again conjoin, and form larger 
vessels, which are still discoverable with 
great difficulty. 
In structure and arrangement these ves- 
sels have great .similitude to veins : they 
have in consequence been named by some 
anatomists the lymphatic veins. Like the 
veins, their sides are thin and transparent, 
though of considerable strength: like the 
veins, they frequently communicate toge- 
ther, or, as it is technically termed, anas- 
tomose. The advantage derived from these 
communications is obvious: for by these 
means the dissimilar matters which they 
take up from various parts are mixed toge- 
ther, and blended with the lymph which 
they imbibe from the interstices of the body, 
and which serves as a vehicle for such hete- 
rogeneous particles ; they also prevent ac- 
cidental pressure made on a few vessels 
from obstructing the progress of the absorb- 
ed fluids, which are in that case conveyed 
forwards by collateral channels. Like the 
veins also, these tubes, by conjoining, form 
a tube of smaller area th;m the united areas 
of the vessels before their junction. The 
effect of this construction is the same as in 
the veins; that is, an acceleration in the 
currrent of the lymph in proportion as it 
comes nearer to the trunk of the absorbing 
vessels. The diameter of the thoracic duct 
bears but a small proportion to the united 
diameters of all the minute absorbents in 
the body, and when this duct has been 
opened, the lymph has flowed from it with a 
force and jet like that with which the blood 
issues from a large vein. Like the veins, 
the absorbents are furnished with numerous 
valves, which prevent any retrogade motion 
of their fluids, and also prevent any portion 
of the vessel from sustaining the weight of 
more fluid than is contained between its 
valves. The absorbents, however, differ 
from the veins in one very material circum- 
stance, viz. that they have a power of con- 
traction, and are able of themselves to pro- 
pel their contents. Whoever reflects on 
the phenomena of absorption, can scarcely 
doubt that these vessels have a contractile 
power, by which they refuse admission to 
noxious substances, whilst they readily im- 
bibe those that are salutary. If these ves- 
sels are observed in the mesentery, when 
turgid with absorbed chyle, their contents 
will disappear in a certain tract, and again 
become visible; a phenomenon that can 
only be explained by supposing the vessel 
to contract at that part, and urge forwards 
its contents. Haller found that the thoracic 
duct contracted when stimulated, so that 
there can be little doubt of these vessels 
being muscular throughout their whole ex- 
tent. 
The absorbents are found in considera- 
ble numbers under the skin of the extremi- 
ties; and, when they arrive at the groin 
and armpit, they pass through little bodies 
about the size of small beans, which are 
called lymphatic glands. The absorbent 
vessels, as they approach the gland, gene- 
rally separate into several branches, which 
terminate in that body : and again, about 
an equal number of absorbents emerge from 
the gland, conjoin, and form one or more 
principal absorbing vessels. The absorb- 
ents, which enter the gland, are usually de- 
nominated vasa inferentia, and those, which 
go out of it, vasa efferentia. If quicksilver 
be poured into the former vessels, the 
gland swells, and a great deal of quicksilver 
appears to be deposited in it ; and after- 
wards, if the power propelling the injection 
be continued, it is seen coming out of the 
gland, by the vasa efferentia. It seems 
therefore to follow, that the progress of the 
absorbed fluid is checked a little in these 
glands, and it is probable, that some change 
is effected in its progress through them. 
This opinion is confirmed by observing, 
that these glands abound with blood-vessels, 
which probably pour some fresh animal 
juices into those which are contained in the 
lymphatic vessels. 
The lymphatic glands are found in great 
numbers in the groin, armpit, and side of 
the neck, apparently serving like barriers 
to the absorbents of the head and extremi- 
ties, as they approach to the large veins of 
the trunk. The absorbents of the intes- 
tines, which contain the chyle, a scarcely 
