40 Treble Staining. 



rosein solution, No. 18 dilute it with spirit, and im- 

 merse the sections for two or three minutes, remove 

 them to methylated spirit and wash off the excess of 

 colouring matter. Then place them in a dilute solution 

 of iodine green. Coming from spirit they will float on 

 the top of the watery solution, and this in many cases, 

 when the green stain is not required to be very deep, is 

 quite sufficient. When a deeper stain is required, im- 

 merse them altogether, and let them remain a minute 

 or two ; but it must be borne in mind that this colour 

 cannot be washed out again if too deep, which the 

 spirituous stain can, so that it is better to have a sec- 

 tion apparently over-stained in the rosein solution, 

 while it is even under- stained in the iodine green. 

 After washing, the sections are mounted in the usual 

 manner. It will be found, however, that a good deal 

 of the rosein will come out in the second immersion 

 in spirit, and it is necessary to change it until no 

 more colour comes away ; otherwise the oil of cloves 

 will become coloured, and from it the Canada balsam, 

 in which the specimen is mounted. 



With the above mentioned three colours, the most 

 beautiful effect may be obtained, but it will take some 

 time and practice to get the process exactly right, and 

 this is a matter which can only be gained by experi- 

 ence. The results will be found to vary with the 

 length of time the section is immersed in each of the 

 two last colours, and also with the strength of the 

 solutions. 



The section should be uniformly and deeply stained 

 with picro-carmine. The other two solutions should be 



