AND HOW TO USE IT. 109 



allow them to soak for awhile ; transfer them to a solution of 

 anilin violet i part, dissolved in 300 parts of acetic acid (com- 

 mercial), leave them till sufficiently stained ; which may be 

 determined by removing the solution to clean water. Return if 

 not stained enough. Mount after staining by transferring them to 

 a clean glass slide, drawing off any excess of fluid, and add a drop 

 of a solution of acetate of potash of the following strength : — 

 Acetate of potash, i oz ; Water, J oz. Cover and fasten it 

 with a ring of varnish, if it is desired to preserve it. The advan- 

 tages are the simplicity and beauty of the results obtained ; it is 

 also good for exhibiting the structure of cartilage. 



Heidenham's Hsematoxylin : — A. — ^ to i per cent, aqueous 

 solution of HaematoxylJn, and B. — \ to i per cent, solution of 

 Bichromate of Potash. Small pieces of tissue well hardened in 

 alcohol are placed in 8 to 10 c.cm, of A., and after from 8 to 10 

 hours for a similar length of time, in a nearly equal quantity of B. 

 After they have taken a black colour throughout, the excess of 

 Bichromate of Potash is removed by water. Then dehydrate with 

 alcohol, imbed, etc., cut the sections extremely thin. A blue stain 

 is obtained if, instead of treating the tissue with Bichromate of 

 Potash, a i per cent, solution of alum is used. The nuclei are 

 mostly black ; the tissue elements more or less of a dark grey or 

 black colour, but so that different elements take an entirely different 

 shade of grey. In epithelial tissue the outlines of cells are ex- 

 tremely sharp, the protoplasm darker, so that a richness of different 

 cells in protoplasm and its distribution in separate cells is well 

 shown. Nerve fibres and markings of primitive bundles are also 

 well shown. 



A good stain for Spinal Cord, etc:— A solution of H^ematoxylln 

 prepared with water and alcohol. The sections are kept immersed 

 in it during an hour, and the temperature is maintained between 

 40° and 50^ C. =^ 104° to 122° Fahr. They are then removed 

 from the solution, washed and placed for 3 hours in a 2 per cent, 

 alkaline solution (Borax), or in one of potassium ferricyanide. 

 Afterwards they are submitted to the influence of alcohol, xylol, 

 and Canada balsam, in the usual manner. 



