BRIEFER ARTICLES. 
A METHOD OF PRESERVING THE GREEN COLOR OF 
PLANTS FOR EXHIBITION PURPOSES. 
For many purposes, especially when intended for museums, classes 
in botany, pharmacy, etc., it is very desirable to preserve, as far as 
possible, the natural appearance of plant specimens. Where the pur- 
poses for which the material is to be used will permit its preservation 
in a dry state, the natural colors may generally be well preserved for 
some time by rapid drying. This is true of nearly all colors both of 
leaves and flowers. Such material, however, is likely to slowly fade, 
especially if it is not kept perfectly dry and well protected from strong 
light. Where the material is to be kept in fluid media, such as alco- 
hol, formalin, gelatin, glycerin, etc., it is impossible in most cases to 
preserve the natural colors except by resorting to special methods. 
The method about to be described will not preserve the colors of 
flowers. It is effective only in cases where some shade of green is to 
be preserved, that is, where the distinctive color depends on the pres- 
ence of chlorophyll in all or in certain cells. Usually it will also 
effectively preserve the browns, reddish browns, and yellows, such as 
occur in injured or diseased portions of stems, leaves, or fruits. 
The principle involved is to bring about a combination of the 
chlorophyll in the cells of the plant with copper. The resulting com- 
pound, copper phyllocyanate,’ is practically insoluble in any of the 
ordinary preserving media except strong alcohol, and is not destroyed 
by light. If the work be properly done the resulting green can 
scarcely be distinguished from the normal chlorophyll green. The 
amount of copper phyllocyanate in each cell will be proportionate to 
the quantity of chlorophyll which it contained, so that contrasts and 
shades due to this difference will be clearly brought out. 
The most difficult part of the process is to get the copper into the 
*TSCHIRCH, A., Das Kupfer vom Standpunkte der gerichtlichen Chemie, Toxico- 
logie, und Hygiene, pp. 27-55. 1893. 
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