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V. — Double Staining of Wood and other Vegetable Sections. 
By George D. Beatty, M.D., of Baltimore. 
In my paper on vegetable staining in the April number of this 
Journal,* I said the only aniline colour I had used with success for 
staining leaves was the blue. The statement was based on the fact 
that this colour did not come out when the leaves were put into 
absolute alcohol, or into oil of cloves, provided certain brands of 
these chemicals were used. 
I have lately discovered that benzole fixes the anilines when 
they are used in staining vegetable and animal tissues. It not only 
instantly fixes any aniline colour in vegetable tissues, but also 
renders them as transparent as oil of cloves. 
Finding that benzole possessed this property, led me to try 
double staining upon sections of leaves and sections of wood. The 
results have proved highly satisfactory. I have found the follow- 
ing processes successful : A section, say of wood, being prepared for 
dyeing, is put for five or ten minutes in an alcoholic solution of 
roseine pure " (magenta), one-eighth or one-quarter of a grain to 
the ounce. From this it is removed to a solution of " Nicholson's 
Soluble Blue Pure," one half-grain to the ounce of alcohol, acidu- 
lated with one drop of nitric acid. In this it should be kept for 
thirty or ninety seconds, rarely longer. It should be frequently 
removed with forceps during this period, and held to the light for 
examination, so that the moment for final removal and putting into 
benzole be not missed. After a little practice the eye will accurately 
determine the time for removal. 
Before placing the object in benzole it is well to hold it in the 
forceps for a few seconds, letting the end touch some clean surface, 
that the dye may drip off, and the object may become partially dry. 
By doing this, fewer particles of insoluble dye rise to the surface of 
the benzole, in which the brushing is done to remove foreign matter.' 
The object should then be put into clean benzole. In this it may 
be examined under the glass. If it is found that it has been kept 
in the blue too short a time, it should be thoroughly dried, and, 
after dipping in alcohol, be returned to that dye. If a section of 
leaf or other soft tissue be under treatment, it should be put in 
turpentine or oil of junijper, as they do not contract so much as 
benzole. 
When haematoxylon is used instead of magenta, it is followed by 
the blue as just described. As neither of these dyes comes out in 
alcohol or in oil of cloves, the section may be kept in the former for 
a short time before placing in the latter. 
The hgematoxylon dye I prefer is prepared by triturating in a 
* ' Cincinnati Medical News,' June, 1875. 
