Injection of Bloodvessels 167 



cannula, and tie the ligature firmly over the artery behind 

 the point of the cannula, into which put the stop-cock. 

 Fill the syringe with injection fluid, which must not be too 

 warm, and take care not to draw up any air-bubbles ; now 

 insert the nozzle of the syringe into the stop-cock and force 

 in a little fluid ; remove the syringe, so that the air may 

 escape, insert the syringe again, and repeat the process 

 until no air-bubbles come out of the stop-cock. You may 

 then proceed slowly with the injection. Half an hour is 

 not too long to take over the injection of an animal of the 

 size of a cat. The completeness of an injection may be 

 judged by looking at the vascular parts, such as the tongue, 

 eyelids, and lips. When the injection is complete shut the 

 stop-cock, remove the syringe and cannula, and tie the 

 ligature round the artery. Now place the animal in cold 

 water for an hour to set the injection- fluid. When quite 

 cold, dissect out the organs, cut them up into small pieces, 

 and place them in methylated spirit to harden, and change 

 the spirit every twenty-four hours for the first three days. 

 The hardening will be complete in ten days. 



Injection of Lymphatics (Puncture method). A small 

 subcutaneous syringe is filled with a watery solution of 

 Berlin or Prussian blue, and the nozzle is thrust into the 

 pad of a cat's foot. The injection is to be forced into the 

 tissues. Then rub the limb from below upwards. This will 

 cause the injection-fluid to flow along the lymphatics, and 

 find its way into the glands of the groin. 



To Inject Lymph-sinuses of Glands. Force the nozzle 

 of a subcutaneous syringe into the hilum of a lymphatic 

 gland of an ox, and inject a watery solution of Prussian or 

 Berlin blue until the blue appears on the surface of the 

 gland. Then place it in methylated spirit to harden. 



When blue injection-fluid is used, add a few drops of 

 acetic acid to the spirit while hardening the tissues. 



