BY DR. KLEIN. 117 



done, I make one push more with the piston, turn the stop- 

 cock of the nozzle, and take away the syringe. 



I will next describe the injection of a whole animal, such as 

 a rat or a small rabbit, with carmine gelatin mass. The animal 

 is killed by inhalation of chloroform. A window is then cut 

 out in the left wall of the chest, just large enough to expose 

 the heart and the roots of the great vessels, taking care not to 

 carry these incisions so near the middle line as to endanger 

 the internal mammary arteiy. A fold of pericardium having 

 been taken up with the forceps and divided, the apex of the 

 heart is raised out of the thorax and pierced with a threaded 

 needle through both ventricles. By the thread which has been 

 brought through, the apex is then drawn downwards by an 

 assistant, while the root of the aorta is cleared with the aid of 

 two pairs of dissecting forceps. A ligature is then passed 

 round it close to its origin, and looped. Thereupon the wall 

 of the left ventricle is opened near its base, and as soon as 

 blood has ceased to flow, the cannla is passed into the aorta, 

 to such a distance that its neck can be grasped by the ligature, 

 which is then tightened. The blood in the canula is then re- 

 moved with a capillary pipette, and filled with saline solution 

 with another pipette, and an opening is made in the right 

 ventricle. Up to this time the animal has been allowed to 

 remain on a plate. The plate is now placed on a support, at 

 a level which nearly corresponds with that of the WoolfFs 

 bottle, in which the mass is contained, which is kept warm by 

 immersion in a water-bath, heated by a spirit lamp. The noz- 

 zle having been connected with the discharge tube of the flask 

 by an India-rubber tube, and the syringe (the piston of which 

 has been drawn up) with the other opening in the Woolff's 

 bottle, an assistant injects a little air so as to fill the discharge 

 tube up to the orifice of the nozzle. The stopcock is then 

 closed, and the point of the nozzle inserted in the canula. 

 The stopcock having been reopened, the assistant pushes on 

 the piston. As soon as the syringe is emptied, the screw-clamp 

 between it and the injection bottle is tightened. Air is again 

 injected, if necessary, in the same manner. If, however, a full- 

 sized syringe is used, it is seldom necessary to repeat the pro- 

 cess. When the vessels are sufficiently full, the heart is 

 seized with strong clip-forceps, as near the base as possible, 

 care being taken not to include the canula. The stopcock is 

 then closed. 



As a third example may be taken the injection of the 

 abdominal organs of a rabbit. The animal is decapitated. 

 The whole of the left wall of the thorax is removed from the 

 flanks forwards as far down as the costal origin of the anterior 

 half of the diaphragm. The left lung and the heart having 

 been drawn aside to the right, the thoracic aorta is prepared 



