OF THE HERBARIUM. 
197 
disagreeable to the botanist in his study, than to the insects 
in his herbarium ! 
Should it be found, that the larvse, in spite of all pre- 
cautions, have established themselves in any part of the 
herbarium, the infected packets must be at once removed, 
and submitted to the fumes of sulphur. For this purpose 
let a box be provided — if made of iron or lined with tin, 
so much the better — large enough to hold two or three of 
the packets. An air-tight lid being requisite, let a shallow 
groove or channel be run round the upper edge of the box. 
to receive the lid when closed ; the groove itself is to be 
filled with water when the box is in use, thus rendering 
it air-tight. It is necessary to retain the fumes of the 
sulphur within the box, not only on account of their evil 
odour, but because they are apt to produce unpleasant, and 
even injurious, symptoms in the operator, if imbibed to 
too great an extent. For the same reason, the work should 
be carried on in an outhouse or in the open air, not in an 
inhabited room. A movable framework of iron fits loosely 
into the box, consisting of netting, or of a few cross bars 
sufficiently strong to support the packets, and resting on 
legs three or four inches high. 
Now let a shallow pan of burning sulphur be laid on 
the bottom of the box ; the framework with its packets 
placed over it ; the lid shut down ; and the whole left un- 
disturbed for about forty-eight hours ; and it will be found 
that at the end of that time not a single insect survives. 
I have had occasion to try this plan repeatedly, and never 
knew it to fail. [Another method, of which I can speak 
with approval, consists in placing the packets in an oven, 
and leaving them to bake for some hours. No form of 
animal life — at least of animals destructive to plants — can 
stand against the continued heat : it is especially useful in 
very damp climates. Care must be taken that the oven is 
not too hot, or the specimens will be rendered over-dry and 
brittle. — Ed.] The best season for making these experi- 
