Undertakers will find it to their advantage to possess instruments of
the best materials and make; they are always cheaper in the end, as
they will resist the wear and tear to a greater extent, and will not
be liable to get out of order when most needed.
Especially in injecting apparatus should a great amount of care be
exercised about the selection. The greatest danger to be guarded
against is corrosion, as all injecting fluids which are now in use
contain more or less of either acids or metallic salts, all of which
will attack and corrode, to a lesser or greater extent, the metals
and other substances with which they come in direct contact.
Any injector, therefore, so constructed as to be free from danger
to its mechanism from the corroding effects of the liquids above
mentioned, will be the one to be chosen. According to the statements
above given, any part of an apparatus which is required to operate
with a certain degree of nicety must be kept from the corrosive
effects of the fluids, and this result is to be gained only by the
peculiar construction of the apparatus.
In the greater part of the injecting pumps now manufactured and in
use in this country, the body of the pump, which contains the working
part of the apparatus, is also filled with the liquid while in use;
and, therefore, this part, which ought to be protected from injury,
is constantly immersed in the strong corrosive solution during all
the time that the injector is being worked.
The result of this constant corroding action upon the apparatus will
soon show itself in the working of it, and constant repairs will be
found necessary to keep it in order or in a state of comparative
effectiveness.
It must be well remembered, that upon the working of the apparatus
depends, to a great extent, the good or poor success of embalming;
also, that upon the manner of using an apparatus, of whatever
description it may be, the length of its duration and its
effectiveness will be in the same ratio.
The automatic apparatus of Girard, for injecting purposes, is a
marvel of simplicity and durability; there is no piston or force
pump, which is liable at any moment to get out of order; no valves,
which will wear out by friction, or leak from the effects of the
liquid used.
The force used in ejecting the fluid is that of a gas, highly
antiseptic in its nature, and which, being generated inside of
a cylinder, saturates the injecting fluid (itself an antiseptic
solution), and by its expansive force propels it into the arteries of
the body.
All the appliances necessary to the perfect working of the apparatus
are condensed into a small compass. The amount of gas generated can
be increased or diminished at will. A pressure gage indicates the
force of expansion acquired by the gas. A glass tube, similar to
the water tube in use on some boilers, and with a graduated scale
attached, shows both the amount of liquid used and also the quantity
remaining in the apparatus; while a relief-cock insures safety to the
operator against too rapid an accumulation of gas.
This last danger need scarcely be apprehended, as, after the
pressure gage indicates the force of expansion required, the further
generation of the gas can be entirely stopped, until the vacuum
created by the outflow of liquid needs to be replaced by a new supply
of gas. For it is a fact well understood, that the force of expansion
of the generating power decreases in the same proportion as the
volume of the liquid is diminished, thereby causing a greater vacuum
in the apparatus.
The inside of the apparatus is thickly coated with lead, as that
metal is not sensibly acted on by either muriatic or sulphuric acid,
except at very high temperatures.
The jet or stream of liquid can be regulated by a screw cock,
attached to the neck of a metallic tube reaching to the bottom of
the apparatus, inside, and provided at its inner extremity with a
perforated bulb, which, acting as a filter, prevents any impurity or
sediment from finding its way into and stopping the circulation of
the fluid through the arterial system; at the same time it prevents
any excessive amount of pressure upon the rubber tube five or six
feet in length, which is connected with the delivery tube outside,
and at the end of which the nozzle is attached.
The nozzle or cannula itself is a very important part of the
apparatus, and is of a peculiar shape; it consists of a thin copper
tube about eight inches in length and a little over an eighth of an
inch in diameter; it is to be inserted at full length, or nearly so,
into the artery to be injected, as by doing so it meets a point where
the walls of the artery are strengthened by the surrounding tissues.
The shape of the apparatus is that of an elongated cylinder, rounded
off at both ends, resembling somewhat a soda fountain; it stands
upright, upon four curved legs about four inches in height, and
possesses a symmetrical and substantial appearance.
The other apparatus—Ronsard’s—is about similar in construction, but
the power exerted in forcing out the liquid is not gas, as in the
former apparatus, but compressed air, forced into the body of the
reservoir by means of a pump.
The body of the apparatus consists of a cylinder holding about five
gallons; this constitutes the reservoir containing the liquid to be
injected. Outside of this cylinder and running alongside of it is the
body of the pump. The pipe communicating the air forced inside the
cylinder above the liquid enters the bottom of the reservoir, and,
passing through the liquid, runs along the inner side of the vessel
until it has reached a point almost to the top of the cylinder. In
the center of the apex at the top of the cylinder is a small funnel
connected to a pipe running inside of the apparatus; this pipe, which
is furnished with a cock, is intended to conduct inside the apparatus
the liquid poured in at the funnel; it will act also as a relief
cock, should it be found necessary to relieve the pressure on the
liquid.
This apparatus is not provided, like the other, with a pressure gage,
from the fact that the pressure being the result of a mechanical
cause, the operator will soon be able to judge the amount of pressure
by the number of strokes of the piston.
The delivery pipe is similar in every respect to the one in the
apparatus described formerly; the graduated tube outside showing the
quantity of liquid inside the apparatus is also the same; in fact,
the similarity between the two is striking. But the principal feature
of the apparatus, and that which recommends it to the profession, is
the perfect isolation of all the working parts of the apparatus from
direct contact with the liquid injected. The greatest objection in
this case, as in the other, is removed, as the most important part of
the work, namely: that of compressing the air, is performed without
any danger to the generator.
Another apparatus—that of Waldon—combines the two systems in one, and
can be operated with equal facility either by means of compressed
air or by means of gaseous expansion.
Still, these instruments require a certain amount of familiarity in
the handling before they can be operated with efficiency, as, to a
person not fully conversant with their mechanism, they may prove
awkward.
The instruments of Messrs. G. Tiemann & Co., of New York, which I
have employed so far very successfully, could be rendered perfect by
adopting some modifications in their make.