CHAPTER IV. 



COARSE INJECTIONS. 



336. SPECIAL APPARATUS AND MATERIAL : Acid, Acetic, No. 8, mixed with an 

 equal volume of water Aniline Red (Magenta) Aniline Blue Beeswax Berlin Blue 

 (see 1449) Carmine No. 40 Chrome Yellow Chrome Green Cobalt Blue Dishes 

 (2) of 100 cc. capacity Magenta or Aniline Red Mixing Dish, 400 cc. capacity Pestle of 

 Wood or Porcelain Pins Plaster of Paris, Finest Dental Red Lead Sponge Syringe 

 with assorted Can ulse Thread, Linen No. 25-35, Cotton No. 20 Turpentine, Oil of 

 Varnish, Copal Vermilion, American or Chinese. 



337. The object of injections is to render the blood vessels 

 more apparent, and thus to facilitate their detection. The impor- 

 tance of a perfect familiarity with their position and relations cannot 

 be overestimated from the surgical and experimental standpoints. 



338. Syringe. A syringe is usually employed to force the injecting mass into tbe 

 blood vessels. It should have the following features : (A) Ample capacity, so that one 

 syringe full will fill the entire arterial or venous system of the animal to be injected. Of 

 course this does not apply to large animals like horses. One of 200 cc. is adapted to cats. 

 (B) The piston of the syringe should fit well and be leather packed (Fig. 35). (C) There 

 should be canulss of various sizes corresponding 1 to the different vessels to be injected. 

 The brass anatomical syringes (Fig. 37, 38) are best, but quite expensive. 



Care of the Syringe. As soon as an injection is finished, expel any remaining 

 plaster into the waste pail. Then fill the syringe several times with clean water and 

 expel it. Force a part of a syringe full through the canula, so it may be entirely emptied. 

 Finally, it is best to unscrew the top of the barrel and remove the piston, so that the bar- 

 rel may be entirely emptied. Wipe the piston with an old towel and oil the leather 

 packing before returning the piston to the barrel. 



If glue or wax mass is employed, the syringe should be cleaned with hot water. 



If the piston becomes so loose that the mass passes it instead of being forced out 

 through the canula, remove the piston, and make the leather packing flare slightly (Fig. 35). 



rf the canula becomes clogged, it may be easily opened by using a small knitting 

 needle. 



339. White-Metal Syringe (Fig. 35). Syringes of this kind are cheap and answer 

 very well for both coarse and fine injections. The metal canula is much too large to insert 

 in an ordinary vessel, but that difficulty may be easily overcome by the use of glass can- 

 ula? (Fig. 36) and a rubber tube for connection (Fig. 42). 



