24 MANUAL OF HISTOLOGY. 



added to water when required. Three grains to the ounce of 

 water will give a fluid that will stain alcohol-hardened tissue 

 in from ten to fifteen minutes. A solution containing ten 

 grains to the ounce will stain very quickly. If it is desired to 

 keep the solution, add f. j. of alcohol for each ounce. Hsema- 

 toxylin stainings are soaked in water for a few minutes to 

 wash out the alum, then transferred to alcohol, clarified in the 

 clove oil, and finally mounted in balsam or dammar. 



Klein } s formula for Ticematoxylin. Mix in a mortar 5 

 grammes of the officinal extract of hsematoxylin, with 15 

 grammes of alum, and pulverize carefully. To this add grad- 

 ually 25 c.c. of distilled water, and filter. To the residue add 

 15 c.c. of distilled water and again mix in a mortar, and filter ; 

 to this filtrate add 2 grammes of alcohol. Now mix the two 

 filtrates and keep in a glass-stoppered bottle. If the liquid 

 should at any time become muddy, filter again. Care must be 

 taken to prevent any acid from intermingling with the fluid. 

 Acids cause the hsematoxylin to turn red ; for this reason, sec- 

 tions which have been hardened in chromic acid should be 

 placed in a watch-glass and covered with distilled water, to 

 which add a drop or two of a 30 per cent, solution of caustic 

 potassa ; allow it to remain therein 10 to 15 minutes. To use 

 the hsematoxylin fluid, add a few drops to an ounce of distilled 

 water, so as to make a pale violet solution ; allow sections to 

 remain in this solution for 12 to 24 hours. Or, a stronger so- 

 lution may be employed which will stain specimens in 10 to 30 

 minutes, and still give good results. Mount in glycerine, ace- 

 tate of potassa, balsam, or better, resinous turpentine. 



Eosine solution. Eosine, first introduced by Fischer in 

 1875, is much used in staining fresh preparations. It is cus- 

 tomary to have a strong solution of one to ten or twenty on 

 hand. A few drops are then added to a watch-glassful of water 

 or alcohol. Fresh tissues are both stained and hardened. It 

 affects the body of the cells, together with the nuclei. It is apt 

 to diffuse, unless special care is taken, and long soaking, say 

 for twenty-four hours, is practised. 



Double- staining with cosine and other aniline colors. 

 Schiefferdecker first stains in an alcoholic solution of eosine 

 and then in a one per cent, watery solution of an aniline color 

 (dahlia, methyl violet, or aniline green). Care must be taken 

 not to extract the color when dehydrating the specimen in 



