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. 



4. 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 fill it. 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 pair 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 under 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 

 " bulldog 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 



