41 
SELECTION AND PEESERVATION FOE THE HEEBAEIUM. 
Ferns are amongst the best of all plants for preserva- 
tion in the form of an herbarium ; for, in addition to their 
elegant appearance when nicely dried and arranged on 
sheets of clean white paper, they are less liable than most 
plants to the attacks of the destructive pests in the shape 
of insects, which commit such havoc among dried plants 
in general. We must give our inexperienced readers a few 
hints on the selection of specimens for this purpose. 
The process of drying need not be described in detail. 
We shall merely remark, that the fronds should be dried 
quickly, under moderately heavy pressure, among sheets 
of absorbent paper, which are to be replaced daily, or every 
second day, by dried sheets as long as the plants continue to 
give out moisture. The thicker the bulk of paper placed 
between the specimens whilst under pressure, the better. 
Two or three changes will generally be sufficient, if the 
paper substituted is in each case perfectly dry. 
The smaller growing kinds should be gathered, if possi- 
