Collecting and Preserving. 159 



Collecting and Preserving Plants, continued. 



cover iho uame of the genus is written. A label should accom- 

 pany each specimen upon the separate sheets. The specimens 

 are now ready to bo filed away on shelves in a horizontal position. 

 If insects attack the specimens, they may be destroyed by fumes 

 of bisulphide of carbon (see p. 9) 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.— 1. 120 grains of arsenic acid dissolved 

 in a quart of alcohol. The arsenic acid is very deliquescent 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 cor- 

 rodes the iron. 



3. Dissolve \% oz. of corrosive sublimate in 1 pt. of alcohol: 

 add 2)^3 fluidrachms of carbolic acid and api)ly with a paint-brush. 



4. 1 lb. of corrosive sublimate, 1 lb. of carbolic acid to 4 gals, 

 of methylated spirit. 



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

 cient to prevent the attack of insects. 



2. Preserving and Printing of Flowers and Other Part* 

 of Plants. 



To Preserve the Color of Dried Flowers.— 1. Immerse 

 the stem of the fresh specimen in a solution of 32 parts by weight 

 of alum, 4 of niter and ISO of water for two or three days until 

 the liquid is thoroughly absorbed, and then press in the ordinary 

 way, except that dry sand is sifted over the specimen and the 

 packet submitted to the action of gentle heat for twenty-four 

 hours. 



3. Make a varnish composed of 20 parts of powdered copal and 

 500 parts of ether, pov.'dered glass or sand being used to make 

 the copal dissolve more readily. Into this solution the plants are 

 carefully dipped ; then they are allowed to dry for 10 minutes, 

 and the same process is repeated four or five times in succession. 



