OF THE HERBARIUM. 195 



other of the numerous ills to which a ' Hortus Siccus' is 

 exposed ; because it is mainly due to neglect, to leaving 

 the specimens to take care of themselves, that insects are 

 encouraged in their depredations. The student may have 

 an intense affection for his botanical treasures ; he may 

 handle them tenderly, when extracting some much-prized 

 example ; he may see that the room is duly warmed to pre- 

 vent the admission of damp with its accompanying swarm 

 of minute Fungi ; but all his labour and love will be thrown 

 away, if he be not constantly on the watch, turning over 

 the sheets, and examining his favourites individually, 

 scrutinising their condition, and looking with an almost 

 microscopic eye for the first traces of the enemy. l Prin- 

 cipiis obsta ' should be the motto inscribed over the portals 

 of his cabinet. He must strive to prevent the fiend from 

 entering his paradise at all ; for if once he and his progeny 

 gain a footing there, it will cost him many a weary hour's 

 hard work to eradicate them. 



As a means to this end, no plant, whether dried by 

 himself, or communicated from some other source, should 

 be introduced into the herbarium without first undergoing 

 a strict investigation. Indeed, if a number 01 specimens 

 are received in bad condition, it is always as well to 

 1 sulphur ' them, according to the plan given below, to 

 prevent the possible infection of the whole cabinet. A 

 world of future trouble and vexation will be saved, by 

 taking care, in the first instance, that no ova or larva? are 

 concealed among the leaves or in the flower-heads. 



Another necessary precaution is to ' poison ' the speci- 

 mens before laying them by. Frequent experiments have 

 been made in this direction, with the view of discovering 

 some means of warding off the attacks of the insect world, 

 or at least of rendering them harmless. Not one of the 

 numerous methods, however, can be pronounced absolutely 

 certain in its operation. Many of the lower forms of 

 plants, the Algae, the Lichens, and the Mosses are, compara- 

 tively speaking, exempt from their ravages ; but they seem 



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