186 BOTANICAL WORK. [SECTION 19. 



566. Poisoning is necessary if specimens are to be permanently pre- 

 served from the depredation of insects. The usual application is an almost 

 saturated solution of corrosive sublimate in 95 per cent alcohol, freely ap- 

 plied with a large and soft brush, or the specimens dipped into some of the 

 solution poured into a large and flat dish; the wetted specimens to be 

 transferred for a short time to driers. 



§ 2. HERBARIUM. 



567. The botanist's collection of dried specimens, ticketed with their 

 names, place, and time of collection, and systematically arranged under 

 their genera, orders, etc., forms a Hortus Siccus or Herbarium. It com- 

 prises not only the specimens which the proprietor has himself collected, 

 but those which he acquires through friendly exchanges, or in other ways. 

 The specimens of an herbarium may be kept in folded sheets of paper; 

 or they may be fastened on half-sheets of thick and white paper, either 

 by gummed slips, or by glue applied to the specimens themselves. The 

 former is best for private and small herbaria; the latter for large ones 

 which are much turned over. Each sheet should be appropriated to one 

 species ; two or more ditferent plants should never be attached to the same 

 sheet. The generic and specific name of the plant should be added to 

 the lower right-hand corner, either written on the sheet, or on a ticket 

 pasted down; and the time of collection, the locality, the color of the 

 flowers, and any other information which the specimens themselves do 

 not afford, should be duly recorded upon the sheet or the ticket. The 

 sheets of the herbarium should all be of exactly the same dimensions. 

 The herbarium of Linnaeus is on paper of the common foolscap size, about 

 eleven inches long and seven wide. This is too small. Sixteen and three 

 eighths iuches by eleven and a half inches is an approved size. 



568. The sheets containing the species of each genus are to be placed 

 in genus-covers, made of a full sheet of thick paper (such as the strong- 

 est Manilla-hemp paper), to be when folded of the same dimensions as the 

 species-sheet but slightly wider: the name of the genus is to be writ- 

 ten on one of the lower corners. These are to be arranged under the 

 orders to which they belong, and the whole kept in closed cases or cabi- 

 nets, either laid flat in compartments, like " pigeon-holes," or else placed 

 in thick portfolios, arranged like folio volumes. All should be kept, as 

 much as practicable, in dust-proof and insect-proof cases or boxes. 



569. Fruits, tubers, and other hard parts, too thick for the herbarium, 

 may be kept in pasteboard or light wooden boxes, in a collection apart. 

 Small loose fruits, seeds, detached flowers, and the like may be conven- 

 iently preserved in paper capsules or envelopes, attached to the herbarium, 

 sheets. 



