19G OF THE HERBARIUM . 



to revel in the destruction of the Ferns, the flowering 

 plants, and the Fungi, especially the two last named. 

 Strange to say, certain orders of the Phanerogamia are 

 more liable than others to the visits of these l pests of the 

 herbarium.' I may mention the Willows, the Umbelliferae, 

 and the Composite plants, as among their favourite haunts. 

 The Composite especially are greedily attacked by Ano- 

 bium, Dermestes, &c, possibly because the large flower- 

 heads, with which many of the species are furnished, 

 afford them such admirable hiding-places. These, then, 

 must be thoroughly impregnated with some poisonous 

 substance, before they are finally deposited in the cabinet. 



The best preservative medium with which I am ac- 

 quainted, is a solution of corrosive sublimate in alcohol. 

 To apply it, the specimen should be laid on a smooth 

 surface of glass or tin, and well painted with the mixture, 

 by means of a broad soft hair pencil. As the alcohol 

 evaporates, a deposit of sublimate is left behind. In the 

 case of very delicate plants or flowers, which are en- 

 dangered by the touch of even a soft hair pencil, it is 

 better to apply the solution through a glass syringe, 

 thoroughly sprinkling every part. The specimen may be 

 replaced in its wrapper as soon as it is dry, which takes 

 place very speedily on account of the volatile properties of 

 the spirits of wine. This poisoning process, be it under- 

 stood, is by no means permanent : it is of service for a time, 

 but only for a time, and must be renewed at stated intervals. 

 My own experience leads me to suggest, that the herbarium 

 should be carefully inspected twice a year, in the spring 

 and autumn, and a coating of poison laid on to every plant, 

 or, at any rate, on those which are most liable to the 

 attacks of insects. 



Camphor, oil of turpentine, and other strong- smelling 

 substances, have been recommended from time to time, but 

 I confess I have but little faith in them as preservatives. 

 Indeed I have generally found, that they are far more 



