ANALYSIS OF MOUNTING METHODS 457 



apart from it l>y a spring, so as to close by the pressure of the 

 finger and to open of itself, will be found (if the blades be well 

 sharpened) much superior to any kind of knives for cutting through 

 delicate tissues with as little disturbance of them as possible. A 

 pair of small straight force] is with fine points, and another pair of 

 curved forceps, will lie found useful in addition to the ordinal y 

 dissecting forceps. 



Of all the instruments contrived for delicate dissections, however, 

 few are more serviceable than those which the mieroscopist mav 

 make for himself out of ordinary upprllf-s. These should be fixed in 

 light wooden handles (the 

 cedar sticks used for 

 camel-hair pencils, or the 

 handles of steel pen- 

 holders, or small porctl- Fir;. 388. Spring scissors, 

 pirte quills will answer 



extremely well) in such a manner that their points should not 

 project far, since they will otherwise have too much 'spring;' 

 much may lie done by their mere tear'uty action; but if it be desired 

 to use them as cuttimj instruments, all that is necessary is to harden 

 and temper them, and then give them an edge upon a hone. It will 

 sometimes be desirable to give a finer point to such needles than 

 they originally possess; this also may be done upon a hone. A 

 needle with its point bent to a right angle, or nearly so, is often use- 

 ful; and this may be shaped by simply heating the point in a lamp 

 or candle, giving to it the required turn with a pair of pliers, and 

 then hardening the point again byre-heating it and plunging it into 

 cold water or tallow. 



Analysis of Methods of Preparation and Mounting which 

 follow :- 



1. Descriptions of microtomes, and knife-kolders and knifp.- 

 position. 



2. Mounting objects in general. 



3. Preparation of soft tissues, under the following subtitles : 



Fixation. 

 Dehydration. 

 Clearing. 

 Staining. 



This last is further subdivided as follows : 

 Stains for living objects. 

 Stains for fresh tissues. 



Stains for fixed and preserved entire objects. 

 Nuclear stains for sections. 

 Plasma tic stains. 



Imbedding methods under the following subtitU- 

 Imbedding methods in general. 

 The paraffin method. 

 This last is further subdivided as follows : 



1. Saturation with a solvent. 



2. Saturation with paraffin. 



