82 



ANATOMY AND PHYSIOLOGY OF 



the vessels at which the injection is to 

 enter. Plaster of Paris (to which some 

 of the preceding dry coloring materials, 

 suitable to the fancy, can be added) must 

 be put in a mortar and rubbed with a 

 pestle in order to pulverize it completely ; 

 water is then to be added until the mixture 

 is of the consistence of cream ; the syringe 

 being in readiness, it is to be filled and im- 

 mediately injected into the vessels. In the 

 author's opinion, this injection is only suit- 

 able for injecting first-class vessels, for it 

 coagulates or "se^s" so quickly that it 

 cannot be used as a minute injection. It is 

 said that a small quantity of olive oil, in- 

 corporated with the liquid plaster, retards 

 its coagulation ; yet if too much were 

 added it would spoil the preparation. 



The moment the parts are injected the 

 syringe should be washed out in cold 

 water, and when the injection "sc^s" in 

 the veins, the pipes must be removed and 

 likewise cleansed. 



FORMULiE FOR COLD INJECTIONS. 



Dr. Parsons recommends, for coarse cold 

 injections, the following formula : Take 

 coloring matter and grind it in boiled lin- 

 seed oil, on a painter's marble, until it has 

 acquired the consistence of common white 

 lead, as sold at the stores. After being 

 finely legivated, a little lime-water, in pro- 

 portion of two table-spoonsful to a pint, is 

 to be incorporated by stirring. At the mo- 

 ment of filling the syringe with the injec- 

 tion, there should be added to it about one- 

 third of its measure of Venice turpentine, 

 which should be stirred in briskly and used 

 immediately, as it very soon hardens. 



For a temporary cold coarse injection, 

 white lead ground in oil answers every 

 purpose ; it requires no addition of lime- 

 water, because the lead is generally adul- 

 terated with carbonate of lime, which 

 hardens the mixture, and it can be colored 

 to suit the taste, or the vessels can be 

 colored with a pencil brush, before varnish- 

 ing. 



For filling the arteries, to dry and pre- 

 serve, red lead is the best and cheapest 



material ; vermilion, however, resembles 

 more the color of arterial blood. 



Whatever part we expect to inject with 

 warm injections, must be immersed in water 

 very hot, — not hot enough, however, to crisp 

 the vessels. Attention to this matter is 

 highly important, in view of successful in- 

 jection. 



THE COURSE OF INJECTIONS. 



Injections must follow the course of the 

 circulation ; the arteries, however, having 

 no valves, are easily injected in any direc- 

 tion ; but the veins are furnished with nu- 

 merous valves, which prevent the flow of 

 injection from the heart. Sometimes it is 

 necessary to break these valves by means 

 of a small whalebone probang. In the 

 region of valves are often found coagula- 

 tions, which must be washed out before the 

 injection can be introduced ; and this, also, 

 must be performed in the direction of the 

 circulation. Small pipes are to be intro- 

 duced, and warm water must be thrown in, 

 which can be made to escape through an 

 incision made with a lancet in a region ap- 

 proaching the right auricle. The incision 

 can afterwards be closed by suture, or 

 otherwise. Many of the veins of the 

 horse, however, are destitute of valves, and 

 therefore admit of injection in a direction 

 contrary to their circulation. 



To inject a portion of the animal, — the 

 knee or hock, for example, — it is necessary 

 to secure all the branches of the vessels that 

 have been divided where it is separated 

 from the body. The part is then to be in- 

 jected in the same manner as if we were 

 injecting the whole body. 



QUICKSILVER INJECTION AND PREPARATIONS. 



The fluid specific gravity and beautiful 

 metallic lustre of quicksilver render it val- 

 uable for displaying minute vessels. Dr. 

 Parsons remarks that the principal objec- 

 tion to its general use is the continuance of 

 its fluidity, which renders dissection, after 

 injection, almost impracticable. Yet there 

 are some very fine specimens of quicksilver 

 injections of glands and deep-seated lym- 



