116 PREPARATION AND MOUNTING 



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 the unassisted 

 fingers. 



6. A kind of forceps, commonly known by the name of " bull- 

 nose 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 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 closed upon the opening. This will cause very little inter- 

 ruption, 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 the syringe. 

 For this purpose we must procure small earthenware or tin pots of 

 the size required, which will differ according to the kind of work 

 to be done ; and to each of these a loose lid should be adapted 

 to protect it from dust, &c. These pots must be allowed to stand 

 in a tin bath of water, nnder which a lamp or gas flame may be 

 r>laced to keep the temperature sufficiently high to insure the 



