52 



preferable size. It is essential that this inner sleeve, when in 

 place, be approximately i cm. shorter than the outer one so 

 that when the units are full of heavy herbarium sheets and their 

 accompanying genus and species covers there shall be no sagging 

 at the front end; the inset front end or door prevents undue 

 sagging. The details of these units are best brought out in 

 the figure. 



To complete a unit, a slip of paper should be pasted in the 

 rear of each and a handful of flake naphthalene placed under 

 the flap to act as a repellent to keep out destructive insects; 

 if a small amount of paradichlorobenzine be mixed with the 

 naphthalene a thoroughly efficient repellent and disinfectant 

 is provided. The front flap of the door should be provided with 

 the proper knob or handle to facilitate opening and closing. 

 The pull clips supplied by the Globe Warnicke Co. for their 

 cardboard filing cases serve the purpose admirably, or a very 

 satisfactory one may be improvised by using an ordinary brass 

 curtain ring, fastened in place by means of a flat brass manu- 

 script staple about one and one-half inches long, the prongs 

 passing through a half-inch washer and spread on the inside of 

 the door. 



These cartons, when constructed of good grade corrugated 

 cardboard, are exceedingly durable if protected from moisture; 

 are strong enough to bear the weight of an average man without 

 breaking down; are as tight as any ordinary wooden case; and 

 when stacked in tiers and filled with botanical specimens have 



