372 APPENDIX. 



It is perhaps best to wash tissues or sections 'stained 

 ■with hsematoxylin in the diluting fluid (2); they 

 may however be washed with alcohol (best about 

 70 p. c); if it is desired to stain more particularly 

 the nuclei, the stained tissue may be placed for a 

 short time in a mixture of 2 parts alcohol (70 p. c.) 

 and 1 part 1 p. c. hydrochloric or nitric acid. 



If a section, which it is wished to preserve, has been 

 stained too deeply, the colour may be partially 

 extracted by placing the section in dilute acetic 

 acid. If the sections are washed with water, 

 distilled water must be used, otherwise alumina 

 may be precipitated. 



The hsematoxylin after it has been used should be put 

 aside in a separate bottle, since after filtration it 

 may be used again. If it has been mixed with acid, 

 it will have a reddish tint and will be useless ; the 

 acid may be neutralized with sodium carbonate, but 

 the mixture rarely stains so well as the original 

 solution. 



b. Alum-hmmatoxylin. To a "3 to "5 p.c. solution of 

 alum, add a few drops of a saturated solution of 

 hsematoxylin in absolute alcohol. 



c. Alum-logwood. Place in a mortar 5 to 10 grms. of 

 alum, 5 grms. extract of logwood, and 100 c.c. of 

 water, grind well, leave for a day and filter. 



To both (6) and (c) a little thymol or salicylic acid 

 should be added, both should be filtered before being 

 used; these solutions stain well the nuclei of sections 

 of most tissues, but they cannot be satisfactorily 

 used for staining pieces of tissue before sections are 

 made. 



