CHAPTER XII 

 INJECTION OF BLOOD AND LYMPH VESSELS 



Red Injection Mass. 1. Rub up 4 grams of carmine thor- 

 oughly with 8 c.c. of distilled water in a mortar and add ammo- 

 nium hydrate drop by drop until a transparent red color results. 



2. Soak 50 grams of best French gelatin in distilled water 

 until it is swollen and soft (18 hours) , then remove it to a porce- 

 lain evaporating dish and melt it at a temperature of about 45 C. 



3. While the gelatin is yet fluid, slowly add the coloring mat- 

 ter, stirring constantly until a homogeneous mixture is obtained. 



4. Before the mass cools add also some 25 per cent, acetic acid 

 solution drop by drop, stirring thoroughly until the mass becomes 

 slightly opaque and the odor of ammonia gives place to a faint 

 acid smell. Watch for this change closely, for a few drops too 

 much of the acid will spoil the entire mass by precipitating the 

 carmine. If the ammonia is not completely neutralized, on the 

 other hand, the coloring matter will diffuse through the walls of 

 the injected vessels and stain the surrounding tissues. Just 

 before using, the mass should be heated and strained through 

 clean flannel. 



With a large animal it is advisable to keep animal and appa- 

 ratus submerged in warm normal saline during the operation of 

 injection, but with a small animal this is unnecessary if the 

 operator works rapidly. 



Blue Injection Mass. Prepare a gelatin mass as directed above. To 

 the warm mass add sufficient quantity of saturated aqueous solution 

 of Berlin blue to give the desired blue color. If the blue does not dis- 

 solve, add a little oxalic acid to the mixture. The blue mass need not 

 be made for the present practical exercise unless the student wishes to 

 undertake a double injection as indicated in memorandum 2. 



INJECTING WITH A SYRINGE; SINGLE INJECTION 

 A common method of injection and one which proves satisfac- 

 tory in many instances, is by means of a metal or glass syringe. 



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