88 METHODS OF MICROSCOPICAL RESEARCH. 



stained, made twenty years ago, which are as per- 

 fect as on the day they were mounted. 



Since xylol has been introduced anilin stains may 

 be used with even greater confidence, as that pre- 

 paration tends rather to preserve than to destroy 

 the anilin colours, which are undoubtedly adversely 

 affected by benzol. Xylol, therefore, should be used 

 to clear the specimens before mounting them, and 

 Canada balsam, which has been thoroughly hardened 

 and re- dissolved in xylol, should be used as the 

 mounting medium. If the specimens, having been 

 cleared in a mixture of equal parts of xylol and 

 absolute phenol, are mounted in " xylol balsam, 5 ' 

 brilliant clearness will result, and the preparations 

 will prove absolutely permanent. 



The author has found it most convenient to make 

 saturated solutions in alcohol of the anilin colours 

 given in the appended list, and to stain the specimens 

 slowly in weak solutions, either alcoholic, made by 

 adding a few drops of the saturated solution to 

 alcohol, or aqueous, made by adding a small 

 quantity of the stain to distilled water. The 

 advantage of using alcoholic solutions is that when 

 the dilute stain has been found to give the desired 

 tint it may be preserved for use over and over 

 again. It must be filtered each time, and as its 

 colour becomes lighter, must be restored to its 

 original tint by the addition of a few drops of the 

 " stock " solution. 



The following will be found the most generally 

 useful of the anilin colours and sufficient for all 

 purposes. 



Anilin Blue. 



Nicholson's Blue. 



