THE MICMTOMIST'S VADE-MECUM. 



CHAPTER I. 

 INTRODUCTORY. 



1. THE methods of modern microscopic anatomy may be 

 roughly classed as General and Special. There is a G-eneral 

 or Normal method, known as the method of sections, which 

 consists in carefully fixing the structures to be examined, 

 staining them with a nuclear stain, dehydrating with alcohol, 

 and mounting series of sections of the structures in balsam. 

 It is by this method that the work is blocked-out and very 

 often finished. Special points are then studied, if necessary, 

 by Special Methods, such as examination of the living tissue 

 elements, in situ, or in " indifferent " media ; fixation with 

 special fixing agents ; staining with special stains ; dissocia- 

 tion by teasing or maceration ; injection ; impregnation ; and 

 the like. 



2. THE GENERAL METHOD. The first thing to be done with 

 any structure is to fix its histological elements. (This state- 

 ment applies equally to all classes of objects, whether it be 

 desired to cut them into sections or to treat them in any other 

 special way.) Two things are implied by the word "fixing;" 

 first, the rapid killing of the element, so that it may not have 

 time to change the form it had during life, but is fixed in 

 death in the attitude it normally had during life ; and second, 

 the hardening of it to such a degree as may enable it to resist 

 without further change of form the action of the reagents with 

 which it may subsequently be treated. Too much stress can 

 hardly be laid on this point, which is the most distinctive 



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