8 ; PREFACE. 
11. On the first day of shifting, a sharp look-out should be kept for cater- 
pillars, which are apt to secrete themselves im flowers, and, if not at once re- 
moved, will quickly destroy the specimens under pressure. 
12. In fine weather the bundles of specimens, weighted or strapped, may 
be exposed to the strongest heat of the sun; but as this causes a rapid extrac- 
tion of moisture, in order to insure its passing away, the plants must, on bring- 
ing in, and while still warm, be shifted into fresh papers: otherwise mouldiness 
and decay, and not exsiccation, will ensue. Artificial heat, not greater than 
140°, may be substituted in wet weather. 
13. In drying plants within the tropics, and in all damp and hot climates, 
frequent shifting of papers is necessary ; if neglected, the specimens will either 
fall to pieces, or become mouldy and rotten. 
14. Succulent plants, heaths, and plants with compound leaves (such as 
Mimosee), should be dipped (all but the flowers) for a few seconds into boiling 
water, before being placed in the drying papers. This will Ail/ them, promote 
the drying of succulents, and prevent the heaths, &c., from shedding their 
eaves. 
15. Plants with delicate corollas (Iridee, Oxalidee, &c.), should be placed 
between single leaves of very thin and soft, unglazed paper (filtering or tissue 
paper). In shifting to dry papers the tissue-paper is not to be removed, but 
lifted with its contents to the dry layer. This will prevent the flowers from 
curling up or perishing. 
16. When the specimens are quite dry and stiff, a single sheet of paper is 
sufficient between each layer ; they may be placed still more closely on the 
sheets, but not piled one on another; and, finally, in sending specimens from 
a distance, great care must be taken to protect the bundles, by sufficient cover- 
ing, from the effects of external moisture, or from the attacks of insects. 
Correspondents in South Africa are informed that packets of 
specimens, intended for the author, will be forwarded, if sent to 
the Hon. Rawson W. Rawson, C. B., Colonial Secretary, Cape- 
town. They should be addressed on the outside, ‘* Dried Speci- 
mens of Plants, for Professor W. H. Harvey, Trinity College, 
Dublin,” and sent free to Capetown. If of moderate size, packets 
addressed from any part of the Colony ** To the Colonial Secretary, 
Capetown,” go free through the local post, as sanctioned by a Go- 
vernment Notice (No. 387, 1857). 
