MODERN METHODS OP EXAMINATION. 71 



most usual. Lieberkuhn used tallow, varnish, and tur- 

 pentine, colored with cinnabar ; and Hyrtl, whose prepa- 

 rations have been much admired, follows a similar plan. 

 He evaporates pure copal or mastic varnish to the consis- 

 tence of syrup, and grinds one-eighth as much cinnabar 

 and a little wax with it on a slab. For fine injections this 

 is diluted with ether. 



For a bright red, the cinnabar may be mixed with a 

 little carmine 



For a yellow color, the chromate of lead, prepared by 

 mixing solutions of acetate of lead (36 parts to 2 ounces 

 of water), and red chromate of potash (15 parts). 



White may be made with zinc-white or carbonate of 

 lead 4J ounces of acetate of lead in 16 ounces of water, 

 mixed with 3 J ounces carbonate of soda in 16 ounces. 



For gelatinous injections the coloring matter is com- 

 bined with jelly, prepared by soaking fine gelatin in cold 

 water for several hours, then dissolving in a water-bath 

 and filtering through flannel. 



By injecting gelatinous fluid solutions of various salts, 

 the coloring matter may be left in the vessels by double 

 decomposition. 



A red precipitate, with iodide of potassium and bichlo- 

 ride of mercury. 



A blue, by ferrocyanide of potassium and peroxide of 

 iron, etc. 



Dr. Goadby's formula for a yellow color is : 



Saturated solution of bichromate of potassium, . 8 ounces. 



Water, 8 " 



Gelatin, . . . . . . . 2 " 



Saturated solution of acetate of lead, . . .8 ounces. 

 "Water, ........ 8 " 



Gelatin, 2 " 



For gelatinous injections, both the fluid and the subject 

 should be as warm as may consist with convenience. 

 Camphor also should be added to prevent mould. 



