PREPARATION AND MOUNTING 79 



for botanical objects, and is often preferred before 

 balsam, as its use is simpler. It has been noted 

 that objects to be mounted in Canada balsam must 

 be completely dehydrated ; but the worker who 

 favours the use of glycerine jeUy must bear in mind 

 that objects mounted in it must have a previous 

 soaking in water or some watery solution. This 

 medium is readily prepared at home, but the be- 

 ginner had better buy a small quantity from a 

 dealer. 



Suppose we wish to mount some stinging hairs 

 of the nettle (p. 48) in glycerine jelly. We first cut 

 a short strip, bearing two or three hairs, from the 

 cuticle of the plant. We give this a good soaking 

 in water which has lately been boiled and allowed 

 to cool. Water which has been boiled is freer from 

 air than water fresh from the tap, and soaking in 

 water frees the objects from air-bubbles. Then 

 we transfer to a 1 in 3 mixture of glycerine and 

 water, and allow the object to soak in it for some 

 time before proceeding to mount. In mounting, 

 we place a clean glass slip on the mounting table, 

 transfer the object to the centre of the slip, soak off 

 excess of fluid with blotting-paper, place a suffi- 

 cient quantity of glycerine jelly on the object, light 

 the spirit lamp, and heat the table. As soon as the 

 jelly melts, which will be in a minute or so, the 

 lamp must be removed. Skim off air-bubbles, and 

 carefuUy lower a clean cover-glass over the object, 

 pressing it gently into position. After the slide 

 has set — say in eight or nine hours — excess of jelly 

 is removed with a knife-blade, and the slide carefully 

 cleaned with water and soft rag. 



