124 
Laboratory Notes. 
It might be supposed that mounting in the paraffin in this way would tend 
to obscure the tissues through the staining of the paraffin itself. If, however, 
the excess of stain is drained off thoroughly and the sections gently pressed 
down with blotting paper, very clean preparations are obtained, the wax being 
stained hardly appreciably. If the slides are warmed after mounting, the 
rather liquid Canada balsam (in xylol) dissolves the wax almost entirely, if not 
quite. 
If the sections do not shew a tendency to wash off the slide, the following 
method is preferable. 
Method II. Sections which adhere to the slide and do not wash off. 
The process described under Method I is followed as far as the “blotting 
down” of the ribbon. The slide is then gently warmed until the paraffin has 
melted and the wax is removed by treatment with xylol. If necessary the 
staining can be controlled at this stage by rinsing in absolute alcohol ; clearing 
with xylol follows and the preparation is completed by mounting in Canada 
balsam. 
Equally good results are obtained in Method II by mixing the Haematoxylin 
and Safranin (equal parts) and floating the ribbon on the mixture, for any 
overstaining can be controlled by washing in absolute alcohol after removal 
of the wax. 
Various other stains have been tried, with the following results : 
1. A saturated solution of Safranin in 50% alcohol, followed by a satsrated 
solution of Lichtgriin in clove oil gives exceptionally good preparations for 
details of structure, For example, in a transverse section of the root 
of Ceplialotaxus stained in this way, the thickenings on the walls of the assise de 
soutien are stained red, the cell-walls greenish red, and the protoplasmic lining 
to the cells bright green. 
2. An alcoholic solution of Safranin followed by Methyl Green gives 
fairly good differentiation. 
3. Methyl Green followed by Delafield’s Haematoxylin is less satisfactory. 
4. Gentian Violet followed by either Bismark Brown or Vesuvian Brown 
gives poor results. 
The preparations made by these methods are quite as good as those 
obtained by the means commonly employed in double-staining processes. 
The methods have the great advantage that the whole process of double- 
staining and mounting a slide can be carried out in from 5 to 10 minutes 
hence the time-factor, which becomes of such importance in investigation, 
involving the anatomical examination of much material, becomes very 
considerably lessened by the double-staining of microtomed sections in the 
ribbon. 
E. de FRAINE. 
University College, London, 
February 13th, 1913. 
