071 Dotihle and Treble Staining. Bij Heneage Gibhes. 391 



water and filtered ; a portion of this solution is then added to 

 some methylated spirit until it has attained a moderately deep-blue 

 colour ; this must then be filtered to remove the colouring matter, 

 a good deal of which is precipitated ; it will then be fit for use. 



A small quantity is placed in a watch-glass, and the sections 

 allowed to remain until they have a distinctly blue colour. 



I have found this process very useful in pathological investiga- 

 tion, especially in the Carcinomata ; and in specimens hardened in 

 chromic acid it does away with the tedious process of passing them 

 through a solution of bicarbonate of soda. 



This method is modified from one mentioned in the ' American 

 Quarterly Microscopical Journal ' by Dr. Seller. 



I next come to the anilines ; and of these, after a large number 

 of experiments, I have found roseine, aniline violet, aniline blue, 

 and iodine green, give the most satisfactory results. The principle 

 I worked on was to make a spirituous solution of one colour and 

 a watery solution of another, and in this way I could depend on 

 the result. 



I made solutions of roseine and aniline violet in spirit, and of 

 aniline blue and iodine green in distilled water. A few drops of 

 one of the spirit solutions being placed in a watch-glass and 

 diluted with spirit, the sections were immersed for a short time 

 (this will depend on the strength of the solution and the tissue 

 itself, as some stain more quickly than others) ; they ought to 

 be taken out of the stain and examined in clean spirit, and 

 a little practice will soon show when they are stained enough. 

 They are then washed in methylated spirit until no more colour 

 comes away from them. A little of the aqueous solution is now 

 placed in a watch-glass and diluted, the section is removed from 

 the spirit to it ; the spirit causes the section to spread itself out 

 and tioat on the watery solution, and it may be seen taking on the 

 D(^w colour. For a light stain this is sufiicient, and it need not be 

 wholly immersed. It is then well washed in plain water and 

 placed ill spirit, when more of the first colour generally comes out. 

 When it is quite clean, it is ready for mounting in the usual way. 

 This is a very good process for double staining, and if the section 

 is of the same thickness throughout, the staining will bo perfectly 

 even, and each colour will have j)icked out those tissues for which 

 it has a special aOinity. 



To stain with more than two colours is much more diflBcult, as 

 they 80 often combine and produce an entirely ditl'ereut colour 

 uniform thi-oughout. I have obtained the best results from chloride 

 of gold or picrocarmine with the anihues just mentioned. 



The sfiecimen of rat's tail was first stained with chloride of 

 gold in the iLsual manner, and then submitted to the uniliue 

 process I have already described. 



