1 L8 Transactions of the Society. 



account of my results and to draw special attention to a structure, 

 not hitherto described, which it has helped me to disclose. 



In working with this process I have used several well-tried 

 aniline dyes, which in most cases have given satisfactory results, 

 but so far none have given such striking and gratifying results as 

 those obtained by the use of methyl-blue in combination with 

 Heidenhain's iron-luematoxylin. 



As yet, the method has been tried upon not very thin sections 

 of vegetable tissue only, and upon one subject {Lil. auratum). I 

 have repeated the process several times, but each time with equally 

 successful results, the new structure being so pronounced that I 

 feel sure if I had had other similar material of different species at 

 my command to be treated in a like manner, the same structure 

 would be brought into view. 



The following is a short description of my methods : — 



Paraffin sections (15/* to 20/x) of the above-mentioned material, 

 fixed in Flemming's strong solution, are made to adhere to the 

 slide or cover-glass (preferably the latter), either by the water, or 

 one of the modifications of Meyer's albumin process. I use six 

 drops of Meyer's albumin to one ounce of tap-water 



After the removal of the paraffin, the sections are brought down 

 to water in the usual manner, and finally washed in distilled water. 

 The sections on the cover-glass are now mordanted for about 

 fifteen minutes in a 1 per cent watery solution of permanganate of 

 potash, and then lightly rinsed in distilled water and placed in a 

 strong watery solution of methyl-blue, where they are allowed to 

 remain at least over-night — twelve hours or a little more will do 

 no harm. They should then be well washed for a few moments in 

 one or two changes of distilled water, mordanted in a 3 per cent 

 solution of iron alum and stained by Heidenhain's hematoxylin. 

 I give not less than six hours in the iron alum and from twelve to 

 twenty-four hours in a 0*5 per cent watery solution of haemat- 

 oxylin. 



The delicate part of the work now commences, that of differen- 

 tiation ; and it is not at all easy to lay down any fixed rules or 

 times to ensure the success of this, the most important part of the 

 technique. 



Carried too far, or insufficiently done, the particular section or 

 series on the cover-glass is spoilt and may be cast aside at once. 

 I am unfortunately bound to admit that although judgment must 

 be used in this matter, there is always a fair amount of chance in 

 hitting off the right degree of density. 



The black stain of the iron-hrematoxylin completely masks the 

 initial methyl-blue stain, and the difficulty of obtaining the correct 

 point of differentiation of the iron-hseniatoxylin stain when that 

 part of the process is nearing completion is greatly increased by 

 the deep blue coloration which soon comes into play as the black 



