HERBORIZATION. 379 



bottom, if of thin boards, must be cleated, or compounded of 

 wood with the grain in opposite directions, or very stout binder's 

 board or trunk- board may be advantageously used. This should 

 be covered with coarse cotton or linen cloth, glued fast and well 

 painted. While stationary, the pressure may be given by means 

 of weights when more convenient. 



O 



802. The Wire press, now much in use, is a press of this porta- 

 ble kind, in which the boards are replaced by sheets of wire net- 

 ting, with wide meshes, and surrounded and strengthened by a 

 strong but light iron border. Straps with buckles are used to 

 hold the parts and contents together and to apply the pressure, 

 as in the ordinary travelling-press. Besides its portability, the 

 advantages of such wire presses are that, in a small wa}', the}' 

 may serve both as portfolio for collecting and as press for dry- 

 ing ; also that, as the drying takes place mainly by evaporation 

 instead of absorption, much less paper is required, and the trouble 

 of changing the driers is saved. 1 In fair weather, the press filled 

 with plants may be hung in the wind or sunshine, in foul weather 

 near a fire. The disadvantage is that specimens dried in this 

 way are apt to be brittle. To use this system advantageously, 

 the botanist should have at least two such presses in operation, 

 one for collecting, while the other is in use for drying. 



803. Poisoning. Dried specimens are liable to the depreda- 

 tions of certain insects, especially of their larvae. The principal 

 pest is a small brown beetle, Anobium paniceum, L. ; the perfect 

 insect does considerable damage, the larva vastby more. Plants 

 with milky juice, such as Asclepiadeae, Apocj'naceie, and Eu- 

 phorbiacese, those containing bitter principles, such as Gentians 

 and Willows, and generally such plants or such organs as con- 

 tain much protoplasm or azotized matter, are most subject to 

 attack. Ranunculaceae, Umbelliferae, and Composite are seldom 

 spared ; while Labiatae mostly escape, probably on account of the 

 volatile oil which they contain. Even Ferns are liable to have the 

 parts of fructification eaten away. To a certain extent, the im- 

 pregnation of the herbarium-cases with camphor, naphthaline, 

 or strong-scented oils, may exclude the vermin. But safety is 

 secured only by poisoning. 



804. The proper poison is corrosive sublimate, dissolved in 

 strong (95 per cent.) alcohol. Drop into the alcohol as much cor- 



1 Prof. A. Wood seems to have been the first to call the attention of 

 American botanists to this system, which he has earnestly advocated. 



An improved form of this wire press, well adapted both for collecting 

 and pressing in moderate quantity, is made and sold, at a small price, by 

 Paul Roessler, optician, at New Haven, Connecticut. 



