CH IX~\ ISOLATION OF HISTOLOGIC ELEMENTS 



259 



the surface. Then a drop of the resinous medium is put 011 the object, and 

 finally a cover-glass is placed over it, or a drop of the mounting medium is 

 spread on the cover and it is then put on the object. 



ISOLATION OF HISTOLOGIC ELEMENTS 



I 357. Isolation, General. — For a correct conception of the, forms of the 

 •cells and fibers of the various organs of the body, one must see these elements 

 isolated and thus be able to inspect them from all sides. It frequently occurs 

 also that the isolation is not quite complete, and one can see in the clearest 

 manner the relations of the cells or fibers to one another. 



The chemical- agents or solutions for isolating are, in general, the same as 

 those used for hardening and fixing. But the solutions are only about one- 

 tenth as strong as for fixing, and the action is very much shorter, that is, from 

 one or two hours to as many days. In the weak solution the cell cement or 

 connective tissue is softened so that the cells and fibers may be separated from 

 one another, and at the same time the cells are preserved. In fixing and hard- 

 ening, on the other hand, the cell cement, like the other parts of the tissue, 

 is made firmer. In preparing the isolating solutions it is better to dilute the 

 fixing agents with normal salt solution than merely with water ($ 399). 



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Fig. A. 



Fig. B. 



Fig. 206 



Fig. 205 A. B. Preparation Vials for Histology and Embryology, 

 represents the two vials, natural size, that have been found most useful, 

 ■are kept in blocks with holes of the proper size. 



Fig. 206. Block with holes for containing shell vials. 



This 

 They 



