PRESERVATION OF AN HERBARIUM. SSS 



cd to is that the process should meet with no check. 

 Several vegetables are so tenacious of their vital princi- 

 ple, that they will grow between papers, the conse- 

 quence of which is a destruction of their proper habit 

 and colours. It is necessary to destroy the life of such, 

 either by immersion in boiling water, or by the applica- 

 tion of a hot iron, such as is used fqr linen, after which 

 they are easily dried. I cannot however approve of the 

 practice of applying such an iron, as some persons do, 

 with great labour and perseverance, till the plants are 

 quite dry, and all their parts incorporated into a smooth 

 fiat mass. This renders them unfit for subsequent ex- 

 amination, and destroys their natural habit, the most 

 important thing to be preserved. Even in spreading 

 plants between papers, we should refrain from that pre- 

 cise and artificial disposition of their branches, leaves, 

 and other parts, which takes away from their natural as- 

 pect, except for the purpose of displaying the internal 

 parts of some one or two of their flowers, for ready ob- 

 servation. 



After all we can do, plants dry very variously. The 

 blue colours of their flowers generally fade, nor are 

 reds always permanent. Yellovvs are much more so, 

 but very few white flowers retain their natural aspect. 

 The Snowdrop and Parnassia, if well dried, contin- 

 ue white. Some greens are much more permanent 

 than others ; for there are some natural families whose 

 leaves as well as flowers turn almost black by drying, 

 as Melampyrum, Bartsia, and their allies, several Wil- 

 lows, and most of the Orchide^. The Heaths and 

 Firs in general cast off" their leaves between papers^ 



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