OF THE HERBARIUM. 197 



disagreeable to tlie botanist in his study, than to the insects 

 in his herbarium ! 



Should it be found, that the larva?, 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- 



