34 Animal Micrology 



8. Next, place the sections in about 3 c.c. of Delafield's hema- 

 toxylin diluted with an equal volume of water, and leave them for 

 various lengths of time (3, 7, 12 minutes) to determine the time 

 for successful staining. 



9. Transfer the sections from the stain to tap water, and gently 

 move them about for from 5 to 10 minutes to wash out the excess 

 of the stain. If the sections are still overstained, place them in 

 5 c.c. of distilled water to which 3 drops of acetic acid have been 

 added. Leave for 5 minutes, or until they become lighter in 

 color, then wash in several changes of tap water until they have 

 again become blue. 



10. Remove the sections from the water and transfer them 

 through 35, 50, 70, 85, and 95 per cent, alcohol successively, 

 leaving them from 3 to 5 minutes in each, and lastly transfer 

 them to absolute alcohol for 10 minutes, and finally to carbol- 

 xylol for 10 minutes, or until clear. 



11. Select one or two of the best sections and transfer them to 

 the center of a clean glass slide. After straightening them out 

 properly, drain off the excess of the carbol-xylol, and before the 

 sections can become dry, add a drop of Canada balsam. Carefully 

 lower a clean cover-glass (for cleaning see memorandum 14, chap, 

 vi) on to the balsam. There should be just sufficient balsam to 

 spread evenly under the cover without exuding around the edges. 



12. Label, stating card number, name of the preparation, and 

 other data that it is desired to add (see chap, vi, i, step 10). 



13. Carry one of the pieces of stomach prepared in Gilson 

 through the same treatment. The sections should be transverse 

 sections of the stomach wall. 



14. Clean up all dirty glassware immediately. 



MEMORANDA 



1. The Thinnest Sections are not always the best. For a general 

 view of an organ, large, comparatively thick sections are usually better; 

 for details of structure, thin sections. 



2. Small Pieces of Tissue may be cemented to a cork if too small 

 to hold conveniently between thumb and forefinger. A piece of stout 

 copper wire is heated for a moment in the flame and touched to a bit 



