176 PREPARATION AND MOUNTING 
that which will take a large pin. These sizes must always 
be at hand, as the vessels of some subjects are exceedingly 
minute. 
A, Stopcock.—This is a short pipe like a small straight 
tap, which fits accurately upon the end of the syringe like 
the pipes, and also takes the pipes in the same manner. 
The use of this is absolutely necessary when the object is 
so large that one syringe full of liquid will not fillit. If 
no preventive were used, some part of the liquid would 
return whilst the syringe was being replenished, but the 
stopcock is then turned as in an ordinary tap, and all 
danger of this effectually removed. 
5. Curved needles—These are easily made by heating 
common needles at the end where the eye is situated, and 
bending them with a small parr of pliers into a segment of 
a circle half an inch in diameter. . They are, perhaps, more 
convenient when the bent part is thrown slightly back 
where it commences. The pointed end is then thrust into 
a common penholder, and the needle needs no re-tempering, 
as the work for which it is wanted is simply to convey the 
thread or silk wnder any artery or vessel where it would be 
impossible to reach with unassisted fingers. 
6. A kind of forceps, commonly known by the name of 
“bulidog forceps,” will be. constantly required during the 
process of injecting. These are short, usually very strong, 
but not heavy, and close very tightly by their own spring, 
which may be easily overcome and the artery so released by 
the pressure of the fingers. When any vessel has not been 
tied by the operator, and he finds the injected fluid escaping, 
one of these “ bulldogs” may be taken up and allowed to 
close upon the opening. This will cause very little in- 
terruption, and the stoppage will be almost as effectual as 
if it were tied. 
7. When the ordinary mode of injection is employed, it 
is necessary that the preparations be kept warm during the 
time they are used, otherwise the gelatine or size which they 
contain becomes stiff, and will not allow of being worked by 
