XX INTRODUCTION 



inch long, to connect the nozzle of the syringe with the 

 cannula, both of which they must fit rather tightly. 



4. Two or three glass plugs to fit the india-rubber tubing. 



5. A dish of water or salt-solution, in which aU the cannulse 

 and india-rubber connections are laid to displace the air from 

 them. 



6. Fine plaster of Paris. 



7. A mortar and pestle. 



8. Colouring matter, such as carmine previously rubbed 

 up with water : it must be well shaken before use. 



9. A piece of muslin to strain the injection through. It 

 must be weU wetted before use. 



10. A jar into which to strain the injection. 



11. Ajar containing about half a pint of salt-solution (-76 

 per cent.), at a temperature of 100° F. 



12. Dissecting-board, pins, scalpels, scissors, two pairs of 

 forceps, seeker, thin string or thread, and two or three pairs 

 of ' bull-dogs.' These last are very short spring-forceps, the 

 spring being so arranged as to close the forceps. They are 

 convenient to stop the escape of blood or injection from any 

 vessel that may have been cut. 



The injection should be performed close to a large sink, 

 over which is a water-tap with a foot or two of wide india- 

 rubber tubing attached. 



When everything is ready, kill iihe animal, and as soon as 

 it is dead, lay it open, cutting as few blood-vessels as possible. 

 Expose the root of the aorta or other vessel from which it is 

 intended to inject the animal ; choose a cannula of the right 

 size ; fit it with an india-rubber connection ; fill it with salt- 

 solution, and stop the end of the connection with a glass plug. 

 Pass a ligature around the vessel : make a longitudinal slit in 

 the vessel ; insert the cannula ; tighten the ligature upon it, 

 and tie it with a bow. If the ligature be too tight it will cut 

 the vessel. FiU the syringe with the warm salt-solution: 

 remove the plug from the cannula: press the body of the 

 animal sHghtly, to remove some of the blood from its vessels, 

 and to get rid of any clot that may have formed close to the 

 cannula. Inject the salt-solution, to force the remaining blood 

 om the vessels before it can coagulate ; and wash or sponge 



