STAINING, PRACTICAL AND THEORETICAL 



authors' original papers: the full references to these are given in 

 the bibliography of this book. 



The violet and blue obtained by using the basic Faviol tech- 

 nique are deeper than the corresponding colours obtained by the 

 Falg method. This circumstance would perhaps be of help in 

 determining a choice by workers after having had experience of 

 both methods. 



Among strongly erythrophile elements are the nucleoli of cells, 

 probably on account of their histone component; red blood 

 corpuscles, and neurokeratin. The oldest fibres formed by 

 fibroproteins (e.g. keratin and collagen fibres) are strongly 

 erythrophile, the youngest fibres being weakly erythrophile. In- 

 deed there appears to be a tendency for erythrophiha to increase 

 with age in all erythrophilic tissues. Much work remains to be 

 done upon the relative erythrophiha of various tissue elements, 

 both with regard to each of these two techniques separately, and 

 by comparison between them in this respect. As a general rule, 

 not yet entirely confirmed, the Falg method is preferable for 

 adult gland tissues. 



MODIFIED FALG AND FAVIOL TECHNIQUES 



It has long been known that some dyes (e.g. aurantia, nigrosin, 

 orange G, tartrazine, picric acid) decolorize certain tissues that 

 have been stained with certain other dyes. This matter is dealt 

 with in some detail on pages 10-16 of this book. However, it 

 should be mentioned here that orange G is a notable example of 

 this class of decolorizing or differentiating dyes. Its action can be 

 seen in the Mallory triple stain for connective tissues. In that 

 technique the red blood corpuscles, stained by the acid fuchsin, 

 become coloured orange by the subsequent application of orange 

 G. It was found accordingly that sections stained by the Falg 

 and the basic Faviol methods, then treated with an aqueous solu- 

 tion of orange G of appropriate strength, were completely decolor- 

 ized. If, however, the stained specimens are first immersed in a 

 dilute aqueous solution of acetic acid of appropriate strength, then 

 washed with water before the orange G is applied, the strongly 

 erythrophile elements retain their red colour. Thus it is possible 

 to obtain a picture of the strongly erythrophile elements alone. 

 This is called the Falgog method (pages 201-2). It has been 



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