USE OF AN HERBARIUM. S23 



a few transverse slips of paper, to bind them more firmly down. A 

 half sheet, of a convenient folio size, should be allotted to each 

 species, and all the species of a genus may be placed in one or more 

 whole sheets. On the latter the name of the genus should exter- 

 nally be written, while the name of every species, with its place of 

 growth, time of gathering, the finder's name, or any other concise 

 piece of information, may be inscribed on its appropriate paper. 

 This is the plan of the Linnaean Herbarium, in which every species, 

 which its original possessor had before him when he wrote his great 

 work, the Species Plantarum, is numbered both in pencil and in ink, 

 as well as named, the former kind of numbers having been tempo- 

 rary till the book to which they refer was printed ; after which they 

 were confirmed with a pen, and a copy of the book, now also in 

 my hands, was marked in reference to them. Here therefore we 

 do not depend on the opinion merely, even of Linnaeus, for we have 

 always before our eyes the very object which was under his inspec- 

 tion. We have similar indications of the plants described in his 

 subsequent works, the herbarium being most defective in those of 

 his second Mantissa, his least accurate publication. We often find 

 remarks there, made from specimens acquired after the Species 

 Plantarum was published. These the herbarium occasionally shows 

 to be of a different species from the original one, and it thus enables 

 us to correct such errors. 



The specimens thus pasted, are conveniently kept in lockers, or 

 on the shelves of a proper cabinet. Linnaeus, in the Philosophia 

 Botanica, exhibits a figure of one, divided into appropriate species 

 for each class, which he supposed would hold his whole collection. 

 But he lived to fill two more of equal size, and his herbarium has 

 been perhaps doubled since his death, by the acquisitions of his son 

 and of its present possessor. 



One great and mortifying impediment to the perfect preservation 

 of an herbarium arises from the attacks of insects. A little beetle, 

 called ptinus fur, is, more especially, the pest of collectors; laying 

 its eggs in the germens or receptacles of flowers, and other." of the 

 more solid 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, 

 Gentiana, Primus, the syngenesious class, and especially willows, 

 are preferred by these vermin. The last-mentioned family can 



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