ON INJECTING BLOOD VESSELS, ETC. 71 



To INJECT AN ANIMAL WITH A GELATINE " MASS " 

 BY THE SYEINGE. 



Arrange so that they may be ready to hand 

 the necessary instruments and apparatus, viz., the 

 syringe, thoroughly cleaned and tested for work, 

 with its stopcocks and cannulae, scalpels of several 

 sizes, a large and a small pair of scissors, dissecting 

 forceps, " bull-dog " forceps (for clamping leaking 

 vessels), a curved needle threaded with silk or 

 thread for tying vessels, a wash-bottle of a capacity 

 of from half a pint to a pint. The injection mass is 

 to be melted by standing the vessel containing it in 

 hot water, and it is to be kept fluid in a water-bath 

 of a temperature from 40 to 45 C. 



Chloroform the animal (say a rabbit) which is to 

 be injected, and make an L-shaped incision into the 

 thorax so as to expose the heart and aorta. This 

 is done by cutting upwards along the middle line of 

 the sternum nearly as far as the root of the neck, 

 then making a second incision at right angles to 

 this, to the rabbit's left. A triangular flap is thus 

 made and the heart, enclosed in the pericardium, 

 exposed. Having cut through the pericardium, 

 seize the apex of the heart with a pair of forceps 

 and snip it off. The right and left ventricles are 

 thus opened, and the animal instantly bleeds to 

 death. The opening in the right ventricle, leading 

 to the pulmonary artery, has a crescentic, slit-like 

 appearance, whilst the opening in the left ventricle, 

 leading to the aorta, is circular. Insert the cannula 

 into the aorta and tie it in securely with a silk 

 ligature. Wash all blood from the cavity of the 

 thorax in order to ensure the cleanliness of the 



