86 Animal Micrology 



has cooled, the tube should be cut with a file at the proper place to make 

 two cannulae of it. 



9. If the Blue Color Fades in the gelatin mass in the tissues, it may 

 frequently be restored by treating the tissue or section with oil of cloves 

 or turpentine. 



10. A Cold Fluid Gelatin Mass has been used very successfully by 

 Tandler (see abstract by A. M. C. in Journal of Applied Microscopy, 

 Vol. V, p. 1625). To prepare the mass, dissolve 5 grams of finest gelatin 

 in 100 c.c. of tepid distilled water. Color to the desired shade with 

 Berlin blue, and then add slowly 5 to 6 grams of potassium iodide. The 

 mass remains fluid at ordinary temperatures, but when injected objects 

 are placed in 5 per cent, formalin, it sets completely and is thereafter 

 unaffected by reagents. The minutest vessels are injected, and sections 

 may be stained in the usual ways. Subjection to strong acids, such as 

 sulphuric or hydrochloric, does not affect the mass, hence it may be used 

 for injecting specimens that are to be decalcified afterward. To preserve 

 the fresh mass, add a few crystals of thymol and keep in a stoppered 

 bottle. 



11. Corrosion of Injected Vessels or Cavities is sometimes practiced. 

 A mass must be employed which will not be attacked by the reagent 

 used for destroying the surrounding tissues. One of the best masses 

 consists of white wax 5 parts and colophonium 6 parts, melted together 

 at a temperature of about 75 C. For fine vessels increase the propor- 

 tions of wax, for larger ones add more colophouium. Vermilion, Prussian 

 blue, or chromate of lead may be used for coloring. The part to be 

 injected should be placed in warm water and the mass injected at a 

 temperature of from 50 to 60 C. The injected part is left in cold water 

 for from 1 to 2 hours, and is then corroded in pure hydrochloric acid for 

 from 6 to 48 hours, according to the resistance of the tissue. Finally, 

 wash the preparation thoroughly in running water. For bibliography 

 and more detailed directions see Technique des Injections, par Her- 

 mann Joris, UNIVERSITE LIBRE DE BRUXELLES, 1903. 



