STAINING REAGENTS. 71 



9. Hamatein. It is well known that a solution of hsematoxylin 

 (C 16 H 14 O 6 ) after being prepared must stand some time to " ripen " 

 before it is ready for use. The substance ultimately formed chiefly 

 by the action of the air is hamatein (C 16 H 12 6 ), which occurs in 

 commerce in the form of a brown powder which is soluble in alcohol 

 or water. P. Mayer recommends the following solution of this 

 body in alum or Ham-alum : l 



(.) Hamatein . . . . i gram. 



Alcohol (90 per cent.) . . -5 cc - 



Dissolve by heating. 



(6.) Alum ..... 50 grams. 

 Distilled water .... 1000 cc. 



Mix the fluids (a) and (b). Allow the mixture to settle, and use 

 the clear supernatant fluid as a stain. If it be too strong, dilute 

 with distilled water, or, better still, with alum solution. 



I have used this extensively during the last year for staining in 

 bulk, and find it to be an excellent dye. 



Logwood. Staining solutions were formerly, and sometimes 

 are, made from logwood chips. 



10. Logwood (Mitchell's). The tannic acid is removed. 



Place finely-ground logwood (2 oz.) in a funnel; pack it well, 

 and allow water to percolate through it until it flows away with 

 but little colour. Allow the water to drain away ; spread the 

 logwood on a board to dry. 



Dissolve alum (9 oz.) in 8 oz. of water. Moisten the dry logwood, 

 pack it again tightly into a funnel, and pour on the alum solution. 

 Close the lower end of the funnel, and allow the alum solution to 

 extract the dye from the logwood for forty-eight hours. 



Allow the coloured fluid to flow off, and percolate 4 oz. of water 

 through the logwood in the funnel. Add a few drachms of glycerine 

 and rectified spirit. Dilute largely when using, so that staining 

 will take place slowly. 



11. Other solutions of hsematoxylin, including Weif/ert's, are 

 referred to in the text. (Lessons on Central Nervous System and 

 Salivary Glands.) 



General Statement regarding Hsematoxylin. Hsematoxylin is 

 specially useful for staining tissues hardened in chromic acid. 

 Ehrlich's haematoxylin is much to be commended. In all cases it 

 is better to clarify sections stained with hsematoxylin by means of 

 xylol not clove-oil before mounting in balsam. 



Haematoxylin and logwood are amongst the best nuclear stains 

 we possess, and the tissues which stain best are those hardened in 

 alcohol ; but those also from Miiller's fluid stain well. With those 



1 Zeitsch.f. wiss. Mik., viil p. 341. 



