SECTION ONE 



NATURAL COLOURING MATTERS 



The most important of these, as far as the histologist is con- 

 cerned, is haematoxylin. 



HAEMATOXYLIN 



Michrome No. 304. Molecular weight 302. An acid colouring 

 matter, pH 67*. Solubility at 15° C: water 10%, absolute alcohol 



10%. 



HO- 



OH OH 



This is obtained from the wood of a species of tree, the Haema- 

 toxylin campechiafium, Linn., which is indigenous to Mexico, but 

 is cultivated in the West Indies. Haematoxylin is not itself a dye. 

 It owes its tinctorial properties to the formation of one of its 

 oxidation products. 



HAEMATEIN 



Michrome No. 360. Molecular weight 300. An acid colour, 

 pH 6-05*. Solubility at 1^° C: water i -5 %, absolute alcohol, i -5 %. 



OH o, 

 HO—, 



HO O 



* 1% in neutral distilled water; see pages 17 and 29. 



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