APPENDIX 329 



Just before the end of the injection, the vein or veins should 

 be tied, and the pressure of injection kept up for a few minutes, 

 the arteries tied, and the injected organs placed in cooled alcohol 

 (about 80 p.c.); the vessel is kept cool either by surrounding with 

 ice, or putting under a stream of water, for half-an-hour. 



Injections are best made by using a pressure apparatus, in 

 which the pressure is kept constant and the fluids warm, but 

 very good injections can be made by hand with an injection 

 syringe. 



d. Injections which require a small amount of fluid only 

 may be made with the following mixture ; this can be injected 

 cold. 



The white of an egg is cut up and beaten, small pieces of 

 camphor are added, and it is filtered through a dry filter (^ to 1 

 day). A stick of Indian or Japanese or Chinese ink is rubbed 

 up with a few drops of the egg-white on a ground glass plate, till 

 a drop on a thin filter paper does not make a grey ring round 

 a central black mass. This is put aside and more prepared and 

 added to it, and so on till sufficient of the mixture has been 

 obtained; it should not be too thick. In the preparation care 

 must be taken not to let the egg-white dry on the Indian ink. 



The tissues can be preserved in most hardening agents ; but 

 formol by itself is said not to give good results. 



e. A 2 p.c. aqueous solution of soluble Prussian blue may be 

 used for the injection of lymphatics, or injection of blood vessels 

 when it is only required to determine their general distribution. 

 The tissue is preserved in alcohol. 



