SECTION ONE 



and secondary. When, for example, we use the common haema- 

 toxylin-eosin stain, the haematoxylin is the primary stain and the 

 eosin is the secondary stain. In the Falg and basic Faviol methods, 

 the acid fuchsin is the primary stain and the hght green or viol- 

 amine is the secondary. But there is a difference between the 

 haematoxyhn-eosin method and the compound fuchsinic acid 

 methods. In the haematoxylin-eosin method the secondary stain 

 colours those tissue elements that have not been stained by the 

 primary stain (haematoxylin). As stated by the authors (Gurr & 

 MacConaill, 19606), we can regard the eosin in the haematoxylin- 

 eosin technique as a complementary secondary stain, while the 

 light green in the Falg technique can be regarded as a supple- 

 mentary secondary stain. Thus, it appears that there are two 

 types of counterstaining : (i) complementary secondary staining, 

 and (2) supplementary secondary staining. 



THE FAVIOL TECHNIQUE 



Practical details for carrying out this procedure are given on 

 pages 203-6. What has been written in the above paragraph 

 applies equally to the Faviol technique. 



RESULTS OF FALG AND FAVIOL TECHNIQUES 



The resalts of staining by the Falg or Faviol techniques are 

 most easily expressed in the terms of concept of erythrophilia 

 (MacConaill, 1949). A tissue element is said to be strongly 

 erythrophile when it has a marked affinity for acid fuchsin. 

 Tissue elements that have a moderate affinity for acid fuchsin are 

 stated to be moderately erythrophile, while those which exhibit 

 only a weak affinity for that dye are said to be weakly erythrophile. 

 Erythrophobe tissue elements are those which have no affinity for 

 acid fuchsin. As observed by Professor MacConaill, the Falg 

 and Faviol methods demonstrate these degrees of erythrophilia 

 by, in effect, transforming differences in monochrome intensity 

 (amplitude) into differences in colour (wavelengths). Strongly 

 erythrophile substances remain red, usually somewhat deeper 

 than the colour of acid fuchsin. Moderately erythrophile elements 

 become violet, and weakly erythrophile elements become blue. 

 Erythrophobe are unstained and remain transparent. For an 

 explanation of these phenomena, readers are referred to the 



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