Preparation of the Color. 



Dry color, i vol. 



Glycerine, i " 



95 per cent, alcohol, i " 



To avoid lumps, which would clog the cannute, or small vessels, the 

 color is thoroughly ground with the liquid in a mortar. It is stored in a 

 well-stoppered bottle, and is prepared for use simply by shaking. 



Special Mass. 

 For the injection of brains, and, perhaps, for other rapidly perishing 

 specimens, it seems best, as suggested by Prof. Wilder, to use strong pre- 

 servatives in preparing the mass : 



Corn starch ( that used for food ) i vol 



5 per cent, aqueous solution of chloral hydrate, j^ " 



95 per cent, alcohol 54 " 



Color, , ^ " 



For convenience and economy, a considerable quantity of either of the 

 masses described above may be prepared at once, and kept in a wide- 

 mouthed specimen or fruit jar. A smooth stick in each jar is convenient 

 for stirring the mass, which should always be done just before using. The 

 syringe may be filled directly from the jar, and any mass remaining in the 

 syringe after the injection is finished may be returned to the jar. 



If it is desired to have the mass enter very fine vessels, some of the stock 

 mass, as given above, diluted with an equal volume of water or chloral so- 

 lution, may be injected first, and immediately followed by the undiluted 

 mass, or, for large animals, a mass containing twice the usual amount of 

 starch. In whatever form the starch is used, it is necessary to work some- 

 what expeditiously, because the exudation of the liquid in the smaller ves- 

 sels takes place so rapidly that the mass hardens very quickly in them. 

 The larger the vessel, the more slowly, of course, do the exudation and, 

 consequently, the hardening take place. It sometimes happens that large 

 vessels, like the aorta, are not fully distended after the exudation of the 

 liquid. In this case some mass containing double the ordinary amount of 

 starch can be advantageously injected in two hours or longer after the first 

 injection. 



Dry Preparations. 



Finally, if vessels injected with the starch mass are dissected free, soak- 

 ed a day or two in Wickersheimer's preservative, and then dried, they re- 

 tain their form, and, to a great degree, their flexibility. 



S. H. Gage, Cornell University, Ithaca, N. Y., April 25, 1884. 



