The problem of preserving plant spe

The problem of preserving plant specimens in their natural colours is of particular interest to scientific workers who require specimens for demonstration or record purposes. The method of keeping specimens in formalin or alcohol is suitable for those who are more interested in the structure than in the colour of the specimen. For those who have to demonstrate the colour changes associated with disease, nutritional deficiencies, etc., it is imperative to have some method whereby the colour can be fixed and kept over long periods