176 Modern Microscopy 



LESSON VIII. 



THE PREPARATION OF VEGETABLE TISSUES 

 FOR MOUNTING IN GLYCERINE JELLY, 

 ACETATE OF COPPER SOLUTION, ETC. 



Epidermis for Stomata. Take a leaf, remove the edges 

 with a pair of scissors, and then cut the remainder up into 

 small pieces of about J inch square. Place these in a 

 test-tube, add nitric acid, and boil gently over a spirit- 

 lamp for about a minute, then add a few grains of chlorate 

 of potash, and bring to the boiling-point again. Pour away 

 the acid and add water, which must be changed several 

 times until all trace of acid is removed. The epidermis 

 will then be found quite clean, and it may be stained and 

 mounted at once, or be placed in spirit and kept until 

 required. 



Another Way. Some epidermal tissues are very delicate 

 and will not stand the acid treatment. When this is the 

 case cut the leaf up as directed above, place the pieces in 

 a jar of water, and put aside for a week or two. The 

 action of water will rot the cellular tissue and set the 

 epidermis free. Then wash well in water, and should any 

 particles of debris adhere, they can be removed by brushing 

 with a camel's hair brush. 



The epidermis of some plants will not stand either of the 

 above processes. When this is the case, the only plan is 

 to strip off a small piece of the cuticle, lay it on a slide, 

 inner side uppermost, and with a scalpel carefully scrape 

 away cellular tissue that may be adhering. Then wash in 

 water, and proceed with the staining. 



To Stain the Epidermis. Make a 1 per cent, solution 

 of methyl aniline violet in distilled water and immerse the 

 specimen for about five minutes. Then wash in a J per 

 cent, solution of glacial acetic acid to remove excess of 

 colour, wash away all trace of acid with water, and mount 

 in glycerine jelly in the following way : 



