ON THE STRUCTURE OF THE ROOT. 69 



cate looking and of a bright yellow colour. This is the growing 

 point of the root, and it is here that the cells are in their simplest 

 condition, and all new tissue has its origin. This root apex has to 

 force its way between the particles of soil, and lest the delicate 

 tissues of which it is composed should be injured, it is protected 

 by a rough-looking, brown covering, called the root-cap, which is 

 formed at the extreme apex. As the root-cap is worn away in its 

 progress through the soil, it is renewed from the young growing- 

 point. Behind the root-hairs the root is yellowish brown and 

 somewhat rough-looking. 



These are the only observations that can be made without the 

 dissection of the root and the use of the microscope. 



If we take transverse and longitudinal sections from various 

 parts of the root, we can observe and locate the internal structures. 

 For section-cutting, roots should be preserved and hardened in 

 methylated spirit. They should be placed in 70 per cent, alcohol 

 for at least twenty-four hours before cutting, or they may be pre- 

 served indefinitely in this solution. If pure methylated spirit 

 cannot be obtained, absolute alcohol, although expensive, must be 

 used. To test the purity of the methylated spirit add a little 

 water to a small quantity. The spirit is unsuitable if the mixture 

 turns milky. There are other methods of preserving and harden- 

 ing, but methylated spirit is necessary with all of them, and the 

 above is perhaps the best suited to a beginner. 



In order to cut and mount sections, the following apparatus is 

 necessary : — A sharp razor, three or four watch-glasses, two or 

 three camel-hair brushes, a dish containing methylated spirit or 

 absolute alcohol, a small bottle of a rather thin solution of Canada 

 balsam in xylol, xylol or oil of cloves, a stock of 3 x i glass slips, 

 thin cover-glasses, and a staining solution, such as Bismarck 

 brown. The process of preparation may be divided into five 

 operations : — 



I. — Sectionising. — Take a piece of root, including the tip, 

 about an inch in length. Hold this in a perfectly upright position 

 between the forefinger and thumb of the left hand, the cut end 

 slightly projecting above. Rest a sharp razor, well wetted with 

 spirit, in a horizontal position on the tip of the forefinger, and 

 draw it over the root so as to cut thin transverse slices. It is 



