ON MOUNTING. 141 



instead of balsam, and for such preparations Mr. 

 E nock's capped cells will be found invaluable. 

 Insects mounted in glycerine must, of course, be 

 previously prepared by dehydration, in spirit, after 

 the potass, process, and subsequent prolonged 

 immersion in glycerine until complete saturation 

 results. 



The Preparation of Vegetable Sections. 



Whensoever possible, stems, leaves, roots, petioles 

 and wood should be cut fresh and sectionised as 

 soon as may be ; all such specimens should be kept 

 in a mixture of equal volumes of alcohol, glycerine, 

 and water. Sections also may be stored in this 

 mixture. Nearly all vegetable sections require 

 bleaching before being stained ; very delicate 

 tissues may be bleached by means of alcohol ; hard 

 and deeply-coloured stems and woods must be 

 bleached in a liquid thus prepared : 



To one pint of water add two ounces of fresh 

 chloride of lime ; shake this up thoroughly two or 

 three times, and allow it to stand until the lime 

 shall have settled. Make a saturated solution of 

 common " washing soda." Pour off the supernatant 

 fluid from the chloride of lime, and, by degrees, add 

 to it the soda solution, until all precipitation ceases. 

 Filter the solution, and keep it in a stoppered bottle 

 in the dark. No fixed time can be given for the 

 bleaching process, the colour and density of tissues 

 being so variable. Experience, however, will be 

 rapidly gained, and over-bleaching easily avoided. 

 The sections being bleached, must now be washed in 

 distilled water, several times changed, and allowed 



