STAINING WITH BRAZTLIN. 469 



Staining with Brazilin. 

 By 



Sydney J. llickson, F.R.S., 



Beyer Professor of Zoology in the Oweiis College, Manchester. 



Brazilin is extracted from the wood of Cgesalpinia 

 e chin at a, growing in South America. Formerly, under the 

 name Brazil-wood, it was used commercially as a dye ; but 

 of recent years it has been superseded by other colouring 

 substances, and practically driven out of the market. 



Chemically it has considerable resemblance to hsematoxyliu, 

 which is also extracted from the wood of a tree belonging to 

 the order Leguminosge, but brazilin (CigHj^Oj) differs from 

 haematoxylin (CigHj^Oe) in having one hydroxyl less. Further 

 information concerning the chemistry of brazilin may be 

 found in the papers by Professor Perkin and Dr. Gilbody 

 published in the * Proceedings of the Chemical Society ' 

 during the past four or five yeai's. 



Brazilin has been tried as a stain for animal tissues by 

 Flechsig and Breglia, but apparently the results were not 

 vei'y satisfactory. Their methods, though mentioned in the 

 third edition of Lee's * Microtomist's Vade-Mecum,' are 

 omitted from the fourth edition, 



Brazilin is mentioned as a chromatin stain in Eawitz's 

 ' Leitfaden fiir histologische Untersuchungen,' p. 98, but it 

 is not mentioned in the elaborate ' Tabellen zum Gebrauch 

 bei mikroscopischen Arbeiten,' by W. Behrens, published in 

 1898, nor in Bohm and Oppel's ' Taschenbuch der mikro- 

 scopischen Technik,' published in 1896. 



My first experiment was to attempt to use brazilin instead 

 of hasmatoxylin in the method suggested by Heidenhain, 



