484 APPENDIX III. 



Gum-arabic. For adhesive use on glass. 100 grammes gum-arabic in 250 c.c. 

 water, to which is added a solution of 2 grammes crystallised 

 aluminium sulphate in 20 c.c. water. 



H. 



Hcematin-ammonia. See Ammonia-hsematin. 



HoBmatoxylin (Logwood), Bohmer's. Dissolve 0*35 gramme htematoxylin 

 in 10 grammes absolute alcohol. This will keep indefinitely. For use 

 add this solution drop by drop to a second solution of O'l gramme 

 alum in 30 grammes distilled water until a beautiful blue-violet colour 

 is produced. Allow the mixture to stand for a few days, and filter 

 before using. See p. 146. 

 Grenadier's. Prepare 



(1) Saturated solution of heematoxylin in absolute alcohol. 



(2) Saturated solution of ammoniacal alum crystals in distilled water. 

 Take 4 c.c. of (1) and mix with 150 c.c. of (2). Allow it to stand in the 



light for a week, filter, and add to it 22 c.c. glycerine and 25 c.c. 

 methylated alcohol. Before use it is best to allow it to stand for 

 some time till any precipitate has time to settle. 



These hsematoxylin solutions stain best if old, and should be used 

 very dilute, i.e., a few drops in a watch-glass of water. Sections 

 of alcohol material, etc., must previously be placed in water to 

 prevent a precipitate being formed on the surface. All acids must 

 be avoided, though J per cent, hydrochloric acid is useful in case 

 of overstating. Logwood is invaluable for staining cell-contents, 

 nuclear figures, etc. 



Hydrochloric acid, % per cent, in 70 per cent, alcohol. Used in restoring over- 

 stained carmine preparations. See p. 249. 



10 per cent, in water. Sometimes used as a sterilising fluid to 

 keep utensils in. 

 concentrated. 



mixed with from three to five times its bulk of water can be 

 used for maceration. For method, see p. 159. 



I. 



Iodine, in alcohol. Otficinal tincture of iodine, diluted with alcohol to a 

 dark sherry colour. Or iodine dissolved in alcohol to the same tint. 

 in glycerine. Iodine dissolved in glycerine, and water added if 

 desired to dilute it. When undiluted, can be used to show minute 

 grains of starch by carefully heating the preparation in a drop. 

 in potassium iodide. Take 5 e.g. iodine, 20 e.g. potassium iodide, and 

 15 c.c. distilled water. 



and sulphuric acid (colours cellulose blue). Best obtained with 

 potassium-iodide iodine, and sulphuric acid diluted with half its 

 volume of water, i.e., 2 vols. acid to 1 vol. distilled water. 



