Triple-stained Section of Tongue 233 



fixation, but even with good fixation the utmost attention must be paid to 

 the selection of dehydrating agent, clearing agent, and to the temperature 

 at which the embedding takes place. It has been the experience of the 

 author that the newer substitutes for alcohol in dehydrating tend to 

 harden or render brittle muscular tissue to a greater extent than does the 

 more old-fashioned method of using ethyl alcohol. There is little choice 

 in the matter of clearing prior to embedding, for it has been found by 

 numerous workers that benzene has less hardening effect on muscular 

 tissue than has any other agent. 



Unless very thin sections are to be cut, it is recommended that a wax of 

 no higher melting point than 52° C be employed and that embedding be 

 conducted exactly at this temperature. It is far easier to do this by the 

 method of an overhead heating light placed above a tube of paraffin than 

 by thermostatic control. It may be stated categorically that should the 

 temperature be permitted to rise above 56° C it would be better to throw 

 the preparation away than to waste time endeavoring to section it. Par- 

 affin sections are cut from the block by the standard method, stranded, 

 and caused to adhere to the slide by egg albumen. These sections, how- 

 ever, may be lost because muscularized tissues tend to absorb water very 

 readily when in paraffin section, so that, if the sections are flattened for a 

 prolonged period in contact with large volumes of warm water, they 

 will tend to expand more than the surrounding wax with the result that 

 they will arch away from the glass support and inevitably become de- 

 tached while being deparaffinized. Therefore, it is recommended that, 

 as soon as the sections are flattened, they should be pressed to the slide 

 with a piece of wet filter paper, rolled into position with a rubber roller, 

 and dried with the maximum possible speed. 



As soon as they are dried, the sections are deparaffinized by the usual 

 techniques and taken down to distilled water, where they can remain 

 until one is ready to stain them. Celestine blue B is selected as the nuclear 

 stain in this instance because the contrast of muscularized tissues is far 

 better brought out with the aid of a picro-contrast than by any other 

 method. These picro-contrasts are, however, so acid that hematoxylin- 

 stained nuclei are often decolorized in the course of counterstaining. The 

 sections are therefore passed directly into celestine blue B staining solu- 

 tions (Chapter 7) from the distilled water and allowed to remain 1 min. 

 After they are removed from the staining solution, they are rinsed in dis- 

 tilled water and accumulated in a jar of either distilled or tap water until 

 it is time to counterstain them. 



The solution of van Gieson should be used for counterstaining. This 

 stain requires little or no differentiation, so that the sections may be 

 placed in it and examined from time to time until the connective tissues 

 are seen to be stained a very bright red against a background of yellow 



