AN HERBARIUM. 387 



herbarium has been perhaps doubled shice his death 

 by the acquisitions of his son and of its present pos- 

 sessor. 



One great and mortifying impediment to the perfect 

 preservation of an herbarium arises from the attacks of 

 insects. A Uttle beetle called Ptinus Fur is, more 

 especially, the pest of collectors, laying its eggs in the 

 germens or receptacles of flowers, and others of the 

 more soUd parts, which are speedily devoured by the 

 maggots when hatched, and by their devastations 

 paper and plants are alike involved in ruin. The most 

 bitter and acrid tribes, as Euphorbia, Gentianay 

 Prunus, the Syngenesious class, and especially Wil- 

 lows, are preferred by these vermin. The last-men- 

 tioned family can scarcely be thoroughly dried before 

 it is devoured. Ferns are scarcely ever attacked, and 

 grasses but seldom. — To remedy this inconvenience I 

 have found a solution of corrosive sublimate of mer- 

 cury in rectified spirits of wine, about two drams to a 

 pint, with a little camphor, perfectly efficacious. It is 

 easily applied with a camel-hair pencil when the spe- 

 cimens are perfectly dry, not before ; and if they are 

 not too tender, it is best done before they are pasted, 

 as the spirit extracts a yellow dye from many plants, 

 and stains the paper. A few drops of this solution 

 should be mixed with the glue used for pasting. This 

 application not only destroys or keeps off all vermin, 

 but it greatly revives the colours of most plants, giving 

 the collection a most pleasing air of freshness and 



2 c 'i 



