CASES. 73 
of the case. The pin bearing the insect is passed through 
both sheets of paper until its point penetrates the wood. 
Thus three points of support are obtained. Other substitutes 
for cork have been proposed, corn stalks elder pith f7Za, etc., 
but their use is attended with this disadvantage, that the sap 
which they centain produces by fermentation an acid which 
corrodes a pin. 
Storage cases for insects are usually made in pairs, and 
we ae ? “A 
\ 
|| a Saeed 
Fic. 26. 
should have the two parts fitted together by tongue and 
groove. ‘This will be very effectual in excluding vermin. 
A large proportion of the alcoholic specimens of any col- 
lection will be kept in what are known as homeceopathic vials 
and various ways for arranging and keeping these have been 
devised. The common method is by laying them down in 
shallow drawers, but this has the disadvantage of injuring the 
cork by keeping it constantly soaked with alcohol. Mr. 
Emerton has suggested a handy form which is well adapted 
