60 PRESERVING AND PREPARING PATHOLOGICAL SPECIMENS. 



5. Place iii a oiie-per-cent aqueous solution of phosphoinolybdic acid 

 for one minute or longer (use glass or platinum). 



6. Wash in two changes of water. 



7. Stain in the following solution for five to twenty minutes. 



Auiline blue soluble in water (Griibler) . . .- . 0.5 



Orange G. (Grii bier), . ... . . 2.0 



Oxalic acid . . . . . . . . 2.0 



Water, ..... . . 100.0 



8. Wash in water. 



9. Dehydrate in ninety-five per cent alcohol. 



10. Blot on the slide, and clear in xylol, or clear in oleum origani 

 cretici. 



11. Xylol balsam. 



.METHYLENE BLUE is a useful stain for many purposes. The tissues 

 may be hardened in Zenker's or Orth's fluid. Unna's polychrome methy- 

 lene blue is made by adding one part each of methylene blue and potas- 

 sium carbonate to one hundred parts of water. This should stand for 

 several weeks before use. The section is overstained and then decolor- 

 ized as follows : Stain for fifteen minutes or longer; rinse in water, de- 

 colorize in one-half -per-cent acetic acid or in alcohol ; clear in xylol. 

 Tliiouin or toluidin blue gives similar results. By the use of these stains 

 the bodies of plasma cells (see p. 103) are colored bluish-violet, the 

 nuclei blue. The granules of "mast cells" are stained red if the tissue 

 be hardened in alcohol or Zeuker's fluid, bluish if hardened in Orth's 

 fluid. 



Methods of Preserving Specimens for Gross Demonstration 

 and for Museums. 



When specimens of abnormal tissues or organs are to be preserved 

 entire for exhibition in jars in a museum, the superfluous parls are first 

 removed and the requisite dissections made. Then they are carefully 

 placed in the position and form which it is wished to preserve, by stuff- 

 ing with- horsehair or absorbent cotton and by the use of thread. When 

 thus carefully adjusted they are either suspended or laid on a wad of 

 absorbent cotton in sixty to eighty-per-cent alcohol, or in five-per-cent 

 formalin solution. In this they usually become hard, and finally, after 

 the removal of the temporary stuffing and braces, are transferred for 

 permanent exhibition to fresh, clear, eighty-per-cent alcohol, or in case 

 of formalin hardening to a fresh solution of the formalin, to which, if 

 the jar is likely to be exposed to cold, a little glycerin is added to pre- 

 vent freezing. This description applies especially to such specimens as 

 have cavities to distend or display. 



The more simple specimens, such as the solid A r iscera, tumors, etc., 

 may be washed and hardened in sixty-per cent alcohol or in formalin 

 solution. 



