70 PRACTICAL HISTOLOGY. 



Dissolve the hsematoxylin in the alcohol, add the glycerine and 

 water, and then the acid. At first the solution is light-red, but 

 when it has been exposed to the air for 2-3 weeks it gets bluish. 

 It does not over-stain, and the tissues stained with it, when exposed 

 to the light, become violet or bluish tinted. It may be used either 

 for sections or for staining in bulk, and in the latter case it does 

 not tend to over-stain. 



Application. Sections from alcohol 



(1.) Stain (3-5 minutes). 



(2.) Wash in alcohol (90 per cent.). 



(3.) Alcohol, oil, balsam. 



Garbini finds it better to place the sections after staining in 



(2.) Distilled water. 



(3.) Solution of carbonate of lithia (.25 per cent.). 



(4.) Alcohol. 



6. Glycerine Hsematoxylin (Renaut). Saturate perfectly neutral 

 glycerine with potash-alum, and to it add drop by drop a saturated 

 solution of hsematoxylin in 90 per cent, alcohol, until a deep-violet 

 tint is obtained. About one-fourth part of the haematoxylin solution 

 has to be added. Let it stand exposed to the light for weeks, and 

 filter. 



7. Eosin Hsematoxylin (Renaut).- Add drop by drop a con- 

 centrated watery solution of eosin to 200 cc. of glycerine saturated 

 with potash-alum. Filter. Add drop by drop an alcoholic solution 

 of hsematoxylin. Expose to light for weeks, and filter. 



8. Heidenhain's Hsematoxylin. 



(1.) This is used for staining in bulk. Prepare J per cent, 

 watery solution of hsematoxylin, which must not be 

 kept too long. Boil the hsematoxylin in water and 

 allow it to cool. Place the hardened tissue in this dye 

 for 24-48 hours. 



(2.) Transfer it for 24 hours to .5 per cent, watery solution 

 of yellow chromate of potash (24-48 hours). This 

 causes dark clouds in the fluid, so that the chromate 

 must be frequently changed. 



(3.) "Wash carefully in water. The tissues are then hardened 

 in alcohol, and may be embedded in paraffin. It is best 

 adapted for objects hardened in absolute alcohol, e.g., 

 salivary glands, pancreas (Lesson XXIII.), or in picric 

 acid. Besides tinting the nuclei a greyish-blue, the 

 protoplasm of the cells has a fine steel-gray tint, but 

 the sections must not be too thick. 



