378 ANATOMICAL PREPARATIONS 
The fubftance employed for the inje€tion ought to be 
entirely melted over a moderate fire, and be heated to the 
exact degree that will not permit the cooling of it too faft, 
upon coming“into contact with the parts into which it is 
impelled, nor ought it to be fo great, on the other hand, 
as to burn or crifp the veflels; or prove troublefome to 
the operator in handling the fyringe or pipes, whilft he is 
making the injection. 
The inje€tion fhould be thrown into the part to be pre- 
pared, at one uniform impulfe, made flowly and evenly, 
with a fteady hand, and with folittle force as not to endanger 
a rupture of the veflels in the foft parts. When the in- 
jection is finifhed, the pipes fhould be corked or otherwife 
clofed, and the parts injected fhould be fuffered to cool by 
degrees. If they are plunged at once into cold water, 
before the fubftance’ of them has acquired a certain de- 
gree of hardnefs and firmnefs, a contraction in the elaftic 
coats of the veflels may be produced, fufficient to occa- 
fion a rupture, efpecially in the capillaries, which will 
always be followed by an extravafation of the injedted 
fubftance. 
Having expofed the injected parts to the air during an 
hour or two, it is proper to commit them to cold water all 
night, to cool and to harden them thoroughly. After 
taking them out of the containing veflel and abforbing the 
water from their furface with a fpunge gently applied, 
or fuffering it to run off by draining, they fhould be put 
into a fufficient’ quantity of the menftruum to cover the 
preparation entirely. 
The next confideration is how to make ufe of the men-~ 
ftruum for corroding the parts to be diflolved and remov- 
ed from the veflels. For this purpofe the operator fhould 
be furnifhed with a china bowl or a ftone veflel, on which 
the menftruum can make no impreffion; or what will an- 
{wer ftill better, a glafs veffel with a mouth fufficiently 
large to put in and take out the injected parts, without any 
difficulty. 
