8 PRACTICAL BOTANY 



The success of work in the laboratory depends very greatly 

 on due care in the direction of section, and on the condition of 

 the edge of the razor. 



All the sections required in the succeeding pages of this 

 book can be made by hand : elementary students are advised 

 to avoid the use of a microtome ; they should cultivate that 

 small amount of manual dexterity which will suffice for the 

 successful preparation of such objects as will be described 

 below. 



When cutting sections the razor is to be opened so that the 

 blade is in a line with the handle : the object to be cut may be 

 held in the thumb and first finger of the left hand, while the 

 razor is grasped firmly by the four fingers of the right : it may be 

 found convenient to rest the thumb of the right hand on that 

 of the left so as to regulate the movements of the right hand. 

 The edge of the razor is not to be rudely forced through the 

 tissues of the specimen, but a sliding cut is to be made, thus 

 using a considerable length of the edge of the razor : in this 

 way a smoother surface of section is obtained, and the tissues 

 are not displaced as they otherwise might be. 



Care must be taken to keep the object and the razor wet 

 during the process of cutting, in order to avoid the entrance of 

 air into the tissue, and to prevent adhesion of the section to 

 the razor. When fresh material is cut, water or very dilute 

 alcohol may be used for this purpose, but if material which has 

 been hardened is cut, it is advisable to use alcohol of the same 

 strength as that in which the material has been preserved. 



IV. Embedding. The objects are frequently so large that 

 they may be held in the hand whilst they are being cut. If 

 they are too small for this, it is convenient to embed them in 

 some substance. 



The simplest method is to fix the object into a slit in a piece 

 of pith. Dried elder-pith is the best, and it may be bought 

 ready prepared from the dealers. 



When the object to be cut is small, or easily damaged, it is 

 more convenient to embed in some easily fusible substance : 

 by this means also the form of the object is less likely to be 

 distorted in the process of cutting. Various substances, or 



