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 know by the name of “bullnose 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 interruption, 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, under which a lamp or gas flame may be placed to keep the temperature sufficiently high to insure the perfect fluidity of the mixture. The tin bath is, perhaps, most convenient when made like a small shallow cistern; but some close it on the top to place the pots upon it, and alter the shape to their own convenience. 8. We will now inquire into some of the materials which are needed in this operation; the first of which is _size_. This substance is often used in the form of _glue_, but it must be of the very best and most transparent kind. To make the liquid which is to receive the colours for the usual mode of injecting, take of this glue seven ounces, and pour upon it one quart of clean water; allow this to stand a few hours, and then boil gently until it is thoroughly dissolved, stirring with a wooden or glass rod during the process. Take all impurities from the surface, and strain through flannel or other fine medium. The weather affects this a little as to its stiffness when cold, but this must be counteracted by adding a little more glue if found too liquid.