78 METHYLEN BLUE, AND OTHER ANILINS. 



CHAPTER IX. 



METHYLEN BLUE, AND OTHER ANILINS. 

 A. Methylen Blue. 



113. The Uses of Methylen Blue. This colour seems to be 

 in a fair way to become one of the most important reagents 

 in the histological laboratory. Its importance as a stain for 

 micro-organisms in tissues is well known to all pathologists. 



As a histological reagent, it is used for sections of hardened 

 central nervous tissue, in which it gives a specific stain of 

 medullated nerves (post. Part II). It is a valuable specific 

 reagent for plasma-cells (for which see also Part II). It 

 possesses the property of washing out the stain of certain 

 other anilins, with which it gives valuable double-stains (post, 

 Chapter XIII). It stains a large number of tissues intra 

 vitam, with little or no interference with their vital functions. 

 And last, not least, it can be made to furnish stains of nerve- 

 tissue, intercellular cement-substances, lymph-spaces, and the 

 like, that are essentially identical with those furnished by a 

 successful impregnation with gold or silver. The results are 

 quite equal in most cases to those of gold or silver impregna- 

 tion, and are obtained with far greater ease and certainty. I 

 call especial attention to these processes, which seem to be 

 effecting a revolution in histological technique. 



114. Staining in toto during Life. Small and permeable 

 aquatic organisms may be stained during life by adding to 

 the water in which they are confined enough methylen blue 

 to give a scarcely perceptible or at least very light tint to the 

 water. If transparent organisms be taken, they may be 

 examined alive without further manipulation at any desired 

 moment. Microscopically examined, they will be found after 

 a time to be partially stained that is, it will be found that 

 certain tissue** have taken up the colour, others remaining 



