THE MICROTOMISrS VADE-MECU 



CHAPTER I. 

 INTRODUCTORY. 



1. The General Method. The methods of modern micro- 

 scopic anatomy may be roughly classed as General and 

 Special. There is a General 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 section* 

 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 ; dissociation by teasing or 

 maceration ; injection ; impregnation ; and the like. 



There is a further distinction, which may be made, and 

 which may help to simplify matters. The processes of the 

 preparation of tissues may be divided into two stages, Pre- 

 liminary Preparation and Ulterior Preparation. Now the 

 processes of preliminary preparation are essentially identical 

 in all the methods, essential divergences being only found 

 in the details of ulterior preparation. By preliminary pre- 

 paration is meant that group of processes called by German 

 anatomists Gonservirungsmethoden, those, namely, whose 

 object it is to get the tissues into a fit state for passing- un- 

 harmed through all the ulterior processes to which it may 

 be desired to submit them. Preliminary preparation com- 

 prehends the operations of (1) killing; (2) fixing; (3) the 

 washing and other manipulations necessary for removing the 



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