178 Modern Microscopy 



and repeat the process until you have got rid of all the dis- 

 integrated vegetable fibre. Now pour the raphides into a 

 bottle, and if they are quite clean, pour off the water and 

 add methylated spirit, in which they may be preserved until 

 required for mounting. 



To mount isolated raphides, clean a cover-glass, fasten it 

 to a slide with the aid of your breath, take up some of the 

 raphides in a dipping-tube, place them on the cover-glass, 

 and spread them evenly over its surface with a needle. 

 Place the slide out of reach of dust until all the spirit has 

 evaporated, and the raphides are quite dry ; add a few 

 drops of Canada balsam, and put the slide away again for 

 twelve hours ; then add a few drops more balsam, take up 

 the cover with a pair of forceps, and mount it on a warmed 

 slip. When the raphides are very large, they must be 

 mounted in balsam that is rather thicker than is usually 

 used. 



Raphides in situ in Tissues. — Harden the stems, roots, 

 or leaves, in methylated spirit, and make sections in the 

 ordinary way ; dehydrate, clear in clove-oil, and mount in 

 Canada balsam. 



Raphides in Scale-leaves of Bulbs, such as Onion, 

 Garlic, Lily, Hyacinth. — Strip off a thin portion of the 

 cuticle, place it in methylated spirit for a few hours, and 

 when dehydrated clear in clove-oil and mount in Canada 

 balsam. 



Sometimes raphides are rendered too transparent when 

 mounted in balsam. When this is the case they must be 

 put up in glycerine jelly in the following way : 



Isolated Specimens. — Pour off the methylated spirit, and 

 add water ; pour off the water, leaving the raphides at the 

 bottom of the bottle. Clean a cover-glass and a slide. 

 Place a few drops of warmed glycerine jelly on the centre 

 of the slide ; take up a few of the raphides on the point of 

 a penknife, and place them in the glycerine jelly, but do not 

 stir them up. Now apply the cover-glass, and press it down 

 carefully with a needle, giving it at the same time a twisting 



