£6 INJEC 
thoracic duel near its infection into the angle formed be¬ 
tween the iubclavian and jugular veins on the left fide, 
or by tying thefe veins on both fides, we may diftend al- 
molt all the abforbents of the animal. Thus we are ena¬ 
bled to purfue thefe velfels in many parts where they have 
not yet been difcovered, where they can fcarcely be traced 
by injection, and even in fome parts where it is utterly 
impollible for the injections to reach them. 
Another method, fometimes fuccefsfuiiy ufed by our 
author, was firft practifed by Malpighi. In this the part 
is to be fteeped in water, and the liquid changed as long 
as it appears tinged with blood ; fuffering the parts after¬ 
wards to remain in the fame water till the putrefaction 
begins. As loon as this begins to take place, the air 
which is extricated will diftend the lymphatics, fo that 
they may be eaftly feen, and then injected with quickfil¬ 
ver. It is, however, remarkable, that this method will not 
in general anfvver fo well in the human fpecies as in qua¬ 
drupeds ; the air having never palled by putrefaction into 
the human ladteals in any of the fubjefts which Mr. Shel¬ 
don tried, though it will take place in thofe of the liorfe 
or afs, and many other animals; drawings of the lafteals 
may likewife be made in this method to very great ad¬ 
vantage. . In fome parts of the human body alfo this me¬ 
thod may be employed to advantage; as the liver, heart, 
&c. It may likewife be ufeful to make ligatures on the 
large trunks of the velfels previous to the maceration, 
that thus the air may be confined as foon as it is extri¬ 
cated from the coats by putrefaction. Our author adds, 
that if ligatures were made upon the wrifts and legs in 
articulomortis, or immediately after death, the lymph would 
be.Hopped, in the velfels, the latter would become dif- 
tended, and might be injeCled with the greateft facility 
by the common method after taking off the ligature. Mr. 
.Sheldon in fuch.a cafe recommends the tourniquet. “I 
have reafon (fays he) to believe, that abforption goes on 
as long as mufcular irritability remains; which lalt conti- 
aiues a confiderable time after the general life of the ani¬ 
mal is loft.” On this, however, we cannot forbear to re¬ 
mark, that making ligatures for fuch purpofes upon a 
human creature in articulo mortis, or even immediately af¬ 
ter death, favours fo much of barbarity, that we cannot 
think it will be often praftifed. In fome cafes, even in 
the dead fubjeCt, ligatures are ufeful; as when we are 
fearching for the lymphatics in the fingers and toes. In 
thefe it is ufeful to ftroke up the parts with the finger, 
by which means the fmall quantity of lymph remaining 
an the velfels will be forced upwards, and Hopped by the 
ligature; after which the velfels may be ealily injeCled 
•with quickfilver, as already mentioned. 
To inject the velfels, we muff open one or more of 
them, directing the point of the lancet almoft always to¬ 
wards the trunk or trunks of the velfels, and taking care 
not to carry the incifion through the oppolite fide. If 
the velfels happen to lie under the peritoneum as the lac- 
teals, or under the pleura as the lymphatics of the lungs, 
we may cut into their cavity through thefe membranes, 
in injecting thole of the extremities, however, and in 
many other parts of the body, it is abfolutely necelfary to 
dilfeCt the velfels we defign to fill away from the fat and 
reticular fubftance before we attempt to open them with 
the lancet. The tube with the pipe fixed to it is previ- 
oully to be filled with mercury; the anatomift then in¬ 
flates the velfiel by means of the blow-pipe, takes the tube 
from the afiiftant, and introduces the lmall tube into the 
punCture. In this operation it will be found necelfary 
not to carry the tube farther into the velfel than is fuffi- 
cient to give the mercury a free palfage ; for, if we intro¬ 
duce it farther, the palfage of the mercury will be im¬ 
peded by the pipe being pulhed again ft the fide of the 
velfel. Should not the liuid be able to effeft a paflage, it 
will then be necelfary to prel’s upon the furface of it in 
the tube with our fingers. If it defeend freely, and with¬ 
out any of it palling between the fide of the velfel and 
i'rtiall pipe, we have only to fill up the tube with msr- 
T I O N. 
cury as the latter defeends ; but if it gets out, we nruft 
then tie the velfel. This, however, Ihould always be 
avoided if poffible ; becaufe, if not very dexteroufly per¬ 
formed, the operator will be apt to feparate the tube from 
the velfel; and on this account the punCture ought always 
to be very fmall, no larger indeed than is necelfary to al¬ 
low the pipe to get in with difficulty. As the injection 
proceeds, the preifure upon the furface of the quickfilver 
muft be carried on higher and higher in the courfe of-the 
lymphatic, till we come near the glahd or glands into 
which the velfels terminate ; otherwile we (hall feldom get 
the cells of the glands, or the velfels emerging from the 
oppofite fide of the glands, w-ell injected. In injecting 
the lymphatic velfels of the extremities, it will be ufeful 
to raife the part where the pipe is inferted higher than 
the other end of the limb, and to make the afiiftant prefs 
with his hands along the fkin in the courfe of the velfels, 
which will favour the progrefs of the injection. When 
the velfels are fufficiently filled, which may be known by 
the fwelling of them, and by the refiftance the mercury 
meets with, the affiftant palfes a ligature about the velfel 
and ties it above the punfture before the anatomift with¬ 
draws the injeftion-pipe. 
The method of injefling the larger trunks or thoracic 
duft with the coarfe injection is exaftly fimilar to that 
already deferibed for the fanguiferous velfels. Mr. Shel¬ 
don, however, recommends the ufe of fome pipes of a par¬ 
ticular conftrudlion invented by himfelf. The improve¬ 
ment confifts in ffiaping the ends of'the pipes like a pen; 
taking care to make the edges and point blunt, to avoid 
cutting the velfel when we introduce them. Thus much 
larger tubes than thofe commonly in ufe may be admit¬ 
ted ; and there is no occafion to make any bulb or rifing 
near the extremity of thefe fmall pipes to prevent the 
thread from flipping off; for this will certainly hinder us 
from inferring pipes of fuch diameter as might otherwile 
be done. 
The difteftion being performed, the preparation is then 
to be preferved either in a wet or dry ftate, according to 
its nature. Preparations of the larger parts, as the trunk 
or extremities, Ihould be preferved dry ; and to dry them 
effectually, they Ihould be expofed to a free current of 
air, but not to the rays of the iun ; and the velfels ihould 
be difplayed in their natural fituation. When fully dried, 
they ought then to be varnilhed over with tranfparent 
fpirit or copal varnilh; which will not only preferve them 
from infedfts, but render them more beautiful, and the 
velfels more conl'picuous. They Ihould then be inciofed 
in glals cafes, where they are to be placed in a horizontal 
polition, and handled as little as poffible. 
Some preparations are the better for being dried and 
afterwards immerfed in phials full of oil of turpentine ; 
by which means the flefli will be rendered tranfparent, 
the velfels diftinvftly feen, and the velfels appear extremely 
beautiful. The only difadvantage of this method is, that 
the parts on which the velfels pafs, do not at all preferve 
their natural bulk, by real’on of their Ihrinking up; 'and, 
as the wet preparations are free from this incpnvenience, 
Mr. Sheldon does not liefitate at affigning them a decided 
fuperiority over the dry ones. Sometimes it is necelfary 
to fix the preparations upon ftiff paper or pafteboard, on 
account of their weight after being inje&ed with mer¬ 
cury. The paper oi pafteboard on which they are faf- 
tened ought to be of various colours, according to the 
nature of the preparation, in order to form a proper 
ground for Ihowing the lymphatic velfels. Such fmall 
preparations as are preferved in fpirits, or oil of turpen¬ 
tine, may be kept in bottles well clofed with Hoppers : 
and the larger in common preparation-glalfes. Our au¬ 
thor delcribes a fimple method of Hopping the mouths of 
thefe preparation-glafles, by which means the ftopper is 
rendered nearly as durable as the glafs itfelf: “ In order 
to execute it, let the anatomift: take care to have the 
upper furface of his bottles made plain, by defiring the 
workmen at the glafs-lioufe to flatten them in the making, 
i This 
