322 USE OF AN HERBARIUM. 



of books, or other paper, the smoother the better. If there be 

 plenty of paper, they often dry best without shifting; but if the 

 specimens are crowded, they must be taken out frequently, and the 

 paper dried before they are replaced. The great point to be at- 

 tended to is, that the process should meet with no check. Several 

 vegetables are so tenacious of their vital principle, that they will 

 grow between papers, the consequence 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 for 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 persever- 

 ance, till the plants are quite dry, and all their parts incorporated- 

 into a smooth flat mass. This renders them unfit for subsequent 

 examination, and destroys their natural habit, the most important 

 thing to be preserved. Even in spreading plants between papers^ 

 we should refrain from that precise and artificial disposition of their 

 branches, leaves, and other parts, which takes away from their natu- 

 ral aspect, except for the purpose of displaying the internal parts of 

 some one or two of their flowers, for ready observation. 



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

 of their flowers generally fade, nor are reds always permanent. 

 Yellows are much more so, but very white flowers retain their na- 

 tural aspect. The snowdrop and parnassia, if well dried, continue 

 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 willows, and most of the orchideae. The heaths and firs in 

 general cast off their leaves between papers, which appears to be 

 an effort of the living principle, for it is prevented by immersion of 

 the fresh specimen in boiling water. Nandina domestica, a Japa- 

 nese shrub, in troduced among us by Lady A, Hume, and Mr. 

 Evans, of Stepney, is very remarkable iu this respect. Every leaflet 

 of its very compound leaves separates from its stalk in drying, and 

 those stalks all fall to pieces at their joints. 



Dried specimens are best preserved by being fastened, with weak 

 carpenter's glue, to paper, so that they may be turned over without 

 damage. Thick and heavy stalks require the additional support of 



