386 PRACTICAL ANATOMY. 



it will allow the injection to move in a greater column, therefore faster, 

 and will prevent stagnation. 



Where a vessel is cut too short to fix a pipe in, in the common way, it 

 is proper to pass a couple of pins through the mouth of the vessel, in- 

 troduce the pipe hetween them, and tie the ligature below the pins. 

 This also becomes more necessary where the vessel bears a large size in 

 proportion to the pipe, as in the vena cava hepatica of an ox, ele- 

 phant, &c. Also, where we are obliged to inject cavities from the side 

 of the cavity itself, — as the urinary and gall-bladders, vesiculse seminales, 

 often the heart, and sometimes a large artery that has only been par- 

 tially filled, — pins may be used, as in the case of vessels which are cut 

 too short to be tied up in the common way. Also, where there is a hole 

 in a cavity, as in the bladder, or in an artery or vein, the pins can be 

 used with advantage. 



Of Syringes. — They should not be too long and small, as they will 

 cool the injection too fast ; nor too short and thick, for they are then 

 very inconvenient for many purposes, as injecting small parts, &c. There 

 should be two sets of syringes, one for oily, and the other for watery 

 injections. Syringes are, in general, too large. In injecting minutely, 

 care should be taken that no air gets before the injection ; to prevent 

 which, before you fix the syringe into the empty pipe, pour some of the 

 injection into the pipe till it is full, and then fix the syringe. Push the 

 injection pretty quickly at first, until the vessel is full, and then gently, 

 to prevent extravasation. 



Of Injections, Sfc. — First, injections, with regard to subtleness, should 

 always be fitted for the purposes intended ; secondly, the nature of the 

 injection to answer the design ; and thirdly, its consistence should be 

 considered, both when it is hot and when cold. As we generally make 

 more at once than is used at one time, heating thickens and hardens it, 

 and therefore its consistence must be tried every time before it is used. 



Some injections require much more exactness in this respect than 

 others ; in corroded preparations we cannot be too nice in this respect, 

 as the injection is to support itself afterwards without any coats of 

 vessels. 



Common Injection. — The corroding injections are too hard for many 

 purposes, and the fine ones too soft: therefore we need something 

 between them ; e. g. — 



R. Eesin, ^ij. — Tallow, gij. 

 Colour q. s. ft. Injectio. 

 These we generally use for parts to be dissected, as legs, arms, &c. 



Oily Injections. — These are made of many kinds, as 01. Terebinth., 

 hog's lard, tallow, &e. The 01. Terebinth, is rather too thin of itself; 



