224 FLORA OF WASHINGTON AND VICINITY. 



lected, which should only be done where the plant is in demand, all but 

 one, of course, are relegated to the duplicate department, and usually 

 without further ceremony. Siiecimens selected for the herbarium, how- 

 ever, require still another form of treatment. They must be poiso7ied. 

 Let no one think that this can be dispensed with. As certain as that it 

 requires the proper cycle of seasons for it to grow, so certain will the 

 time come when if left uupoisoned it will be devoured by the insect pests 

 of the herbarium. Neither lay the unction to your soul that this can 

 be done after mounting, and thus waste neat and costly glazed paper by 

 mounting them first. The insects naturally work on the under side of 

 the plant, where the poison cannot be applied after it is down. The 

 labor of poisoning is, perhaps, the least pleasant of all kinds of herba- 

 rium work, but its absolute necessity should at once dispel all hopes of 

 evading it. 



There is an almost complete uniformity among all botanists as to the 

 kind of i^oison to be used, the accepted substance consisting of corro- 

 sive sublimate and alcohol, the proportion being one ounce of the 

 former dissolved in one quart of the latter diluted fifty per cent. 

 The mode of applying it varies considerably. The use of the camel's 

 hair brush is slow and tedious, but consumes the least poison, and may 

 be defended on economical grounds, though not likely to be as thorough 

 as other methods. Probably the best way, all things considered, is first 

 to fill a trough or large j^latter with the x>oison and then dij) the entire 

 l)lants in the liquid, handling them with tweezers, and letting them drip 

 before laying them aside. After poisoning, they should be immediately 

 placed in dry papers ; otherwise all the pains taken to press them 

 nicely will be in vain, and their colors will vanish after all. This can 

 be prevented by care, and once changing will be sufficient. It is not 

 necessary to use regular driers for this purpose. ]!:^ewspaper is good 

 enough, and it will be found very salutary to use, for drying out the 

 poison, sheets of paper designed for the duplicate department or for 

 general use. The habit of the insects is to bore through the sheets on 

 which the ])lants are laid. They never go round the ends of them, but 

 eat circular tubes downward or upward through the paper until they 

 find a suitable habitat. If all the papers in the herbarium are saturated 

 with the poison, they find themselves greatly restricted in their opera- 

 tions, and as it is not usually deemed worth while to poison duplicates, 

 it is a great protection to them to have them in poisoned ])apers. The 

 temporary label should be kept with the plant throughout the poisoning 

 as throughout every other process. 



