INJECTING APPARATUS. 249 



wires are for securing them tightly with thread to the 

 vessels, into which they may be inserted. In addition 

 to the syringe, two or three tinned vessels, to contain 

 size, injecting fluid, and hot water, are necessary. 



The size must be kept hot by the aid of a water bath ; 

 if a naked fire be used, there is danger of burning it. 

 A convenient form of apparatus for melting the size, 

 and afterwards keeping it at a proper temperature, is 

 shown in fig. 143?;?.. 



A pair of strong forceps, for seizing the vessel, and 

 a small needle, fig. 143#, is also necessary for passing 

 the thread round the vessel into which the injecting 

 pipe has been inserted, completes the list of apparatus. 

 To prepare the material for opaque injections : Take of 

 the finest and most transparent glue one pound, break 

 it into small pieces, put it into an earthen pot, and 

 pour on it three pints of cold water ; let it stand 

 twenty-four hours, stirring it now and then with a 



FIG. 143n,. Artery Needle. 



stick ; set it over a slow fire for half an hour, or until 

 all the pieces are perfectly dissolved ; skim off the 

 froth from the surface, and strain through a flannel 

 for use. Isinglass and cuttings of parchment make 

 an excellent size, and are preferable for particular 

 injections. If gelatine be employed an ounce to a pint 

 of water will be sufficiently strong, but in very hot 

 weather it is necessary to add a little more gelatine. 

 It must be first soaked in part of the cold water until 

 it swells up and becomes soft, when the rest of the 

 water, made hot, is to be added. The size thus prepared 

 may be mixed with finely levigated vermilion, chrome- 

 yellow, blue smalts, or flake white. 



To prepare the subject, the principal points to be 

 aimed at are, to dissolve the fluids, empty the vessels 

 of them, relax the solids, and prevent the injection 

 from coagulating too soon. For this purpose it is 

 necessary to place the animal, or part to be injected, in 



