374. ANATOMICAL PREPARATIONS 
eleven or twelve ounces, to procure a proper confiftence 
to the injeCtion. 
The method of afcertaining the due confiftence and the 
neceflary firmnefs of the injection, is by taking up any 
quantity of it, whilft melted, with a {mall wooden fpatula, 
and then letting it fall drop by drop on the furface of cold 
water. This immediately fpreads and forms into a 
thin plate. By rolling it between your thumb and fin- 
ger firft moiftened, or in the palm of one hand with the 
fingers of the other, both previoufly made wet to prevent 
fticking, turn it into the fhape of a cylinder or {mall blood- 
veffel, then throw it into a bafon of cold water, and let it 
remain till it is quite cold. If it is then of fuch a confift- 
ence as not to yield to a very flight force, when prefled be- 
tween your thumb and finger, and yet fo foft as to be ca- 
pable of bending readily without breaking, it has the due 
medium of firmnefs and flexibility which is defired. -If 
it appears to be too foft, a further quantity of wax and 
rofin are to be added in the above mentioned proportion, 
till it acquires the wifhed for confiftence. If, on the other 
hand, it is too hard, a proportionably larger quantity of 
the Venice turpentine is to be added. The fame precau- 
tion is to be obferved, 1f we make ufe of rofin, wax and 
{pirit of turpentine, as directed in the firft receipt. 
Operators feldom are at the trouble of weighing the 
ingredients; they generally judge of the refpective weights: 
and proportions of each by the eye. This method of de-. 
termining them will anfwer very well for perfons who have: 
acquired experience; for the different feafon of the year 
when the injection is made, and the different confiftence 
or purity of the wax and rofin, with other little circum-. 
ftances which fometimes happen, occafion fome little va- 
riation. In general there is not fo great danger of fpoil- 
ing the preparation, by making the compodlition a little 
fofter than is required, rather than harder, becaufe it 
grows fome what harder by time, and alfo by fteeping 
the 
