166 THE MICROSCOPIST. 



tinned pressure by the syringe drives it through the parietes of 

 the vessel into the cellular tissue. The large quantity of in- 

 filtrated blood the invariable concomitant of my process 

 characterizes this from all other modes of injecting, and is a 

 distinctive feature of these preparations/' 



Still another, and in some respects a more certain and con- 

 venient plan, has been employed by Dr. Goddard of Philadel- 

 phia. It consists in adding a quantity of sulphuric ether to 

 the finely levigated coloring matter, which is also first ground 

 or mixed with linseed oil, in the manner employed by painters. 

 Upon this plan (as well as upon the last named) I have suc- 

 ceeded in making some beautiful injections of the smallest 

 capillaries, yet I have sometimes failed, owing to the too rapid 

 evaporation of the ether, and the clogging up of the vessels 

 from the early deposition of the solid coloring matter. I have 

 also observed that after the ether has evaporated from the 

 vessels, the particles of coloring material cohere with too little 

 tenacity, so that on putting a section of injected tissue into" 

 turpentine, &c., the color has been washed out from the cut 

 ends of the larger vessels. Perhaps a solution of gum nias- 

 tich, &c., in ether, colored with fine vermilion, &c., will answer 

 the indications better. 



Whatever mode of injection be adopted, it is important that 

 the operator be supplied with sufficient material. The quantity 

 which can be used will surprise any one unaccustomed to the 

 process. 



A foetus maybe injected by the umbilical vein; a uterus, 

 by the hypogastric arteries; the head, by the carotids; the 

 liver, mucous membrane of the intestines, &c., by the portal 

 vein ; an extremity, by the principal artery ; &c. 



The liver, kidney, &c., may be well injected out of the body ; 

 and it is often desirable to use various colors for the different 

 sets of vessels. It will require some practice, however, to judge 



