Collecting and Preserving. 161 



Collecting and Preserving Plants, continued, 

 eunv A o use. But one species or variety should be placed on a 

 sheet. The species of a genus are collected into a genus 

 cover. This cover is a folded sheet of heavy manilla or other 

 firm paper, and the standard size, when folded, is 12x16^ 

 inches. On the lower left hand corner of this cover the name 

 of the genus is written. A label should accompany each 

 specimen upon the separate sheets. The specimens are now 

 ready to be riled away on shelves in a horizontal position. If 

 insects attack the specimens, they may be destroyed by fumes 

 of bisulphide of carbon or chloroform. In this case it is 

 necessary to place the specimens in a tight box and then insert 

 the liquid. Usually, however, specimens are dipped in poison, 

 and then dried, before being mounted. 



HERBARIUM POISONS, i. 120 grains of arsenic acid dis- 

 solved in a quart of alcohol. The arsenic acid is very deli- 

 quescent and the bottle must be kept tightly corked. This is 

 Dr. Gray's favorite preparation, and is used in the herbarium 

 at Harvard University. 



2. Place as much corrosive sublimate in alcohol as the 

 liquid will dissolve. If the poison is applied with a brush, 

 care must be taken to avoid one with iron trimmings, as the 

 sublimate corrodes the iron. 



3. Dissolve i^ oz. of corrosive sublimate in i pt. of alco- 

 hol ; add 2J^ fluid drams of carbolic acid and apply with a 

 paint brush. 



4. i Ib. of corrosive sublimate, i Ib. of carbolic acid to 4 

 gals, of methylated spirit. 



Camphor, frequently renewed in each cabinet, is often suffi- 

 cient to prevent the attack of insects. 



2. Preserving and Printing of Flowers and Other Parts of 

 Plants. 



To PRESERVE THE COLOR OF DRIED FLOWERS. i. Im- 

 merse the stem of the fresh specimen in a solution of 32 

 parts by weight of alum, 4 of nitre and 186 of water for two 

 or three days until the liquid is thoroughly absorbed, and then 



