12 APPARATUS AND METHODS. 



sharp knife or rough-work razor, also prepare the surface 

 whether transverse, radial, or tangential of the stem 

 or other solid specimen by cutting off a slice and thus 

 exposing the right surface from which sections are to be 

 cut with your good razor. 



At first you will find that the sections are rather thick 

 and often obliquely cut. Thick sections are sometimes 

 useful for the general arrangement of the tissues, but 

 oblique ones are generally quite useless. With practice 

 and care, extremely thin sections can be cut, along exactly 

 the desired plane. 



After the sections have been cut, they must not be 

 allowed to become dry. If you do not at once mount 

 them on a slide, transfer them from the razor by means 

 of a wet camel-hair brush, or a jet from a wash-bottle to 

 a watch-glass of weak alcohol. For Mounting see 14. 



1O. Razors. In section-cutting, success depends so largely on 

 having good razors that it is important to select these judiciously, 

 use them carefully, and keep them clean and in good cutting 

 condition. It is advisable to have several different razors for 

 different purposes ; in each case, it is false economy to select 

 inferior razors on account of initial cheapness. 



(1) For rough work, such as cutting off pieces of stem, trimming 

 off the surfaces from which thin sections are to be cut, etc., have 

 one or two strong razors ground flat on one side or on both sides. 

 These rough-work razors should be kept sharp and free from 

 notches ; rub them on a hone moistened with water, alcohol, or 

 olive oil. 



(2) For cutting sections of somewhat hard tissues, such as those 

 of a woody stem, and also for cutting somewhat thick and large 

 sections so as to see the general arrangement of the tissues in a 

 fairly stout herbaceous stem , etc. , use a finer razor, preferably with 

 both sides only slightly hollow-ground. 



(3) For very thin sections of soft tissues, use a thoroughly good 

 quality hollow-ground shaving razor, taking care not to cut a section 

 of large area. Only small sections must be attempted with this 

 razor, otherwise the sections will be curved, and there will be serious 

 risk of ruining the razor by having bits broken out of its edge. 



Keep the three kinds of razor separate above all, never use the 

 hollow-ground razors for rough work. 



The hollow-ground razors must be kept as sharp as possible. 

 The razor should be able to clip across a hair at a single touch ; 

 if it will not do this, it requires either stropping on leather or 

 honing on a stone and then stropping. Moisten the ball of the left 



