MOUNTING FLUIDS, AND METHODS. 8/ 



If the section is to be mounted in glycerine or Farrant's solution, 

 add a drop of either of these reagents and apply a cover-glass. 



// the section is to be mounted in balsam, remove as much as 

 possible of the surplus water or dye, as the case may be, and pour 

 methylated spirit upon the section. Allow it to remain on the 

 section for a minute or so, and drain it off at one end of the slide. 

 Apply fresh methylated spirit again, and finally absolute alcohol. 

 This is done to secure complete dehydration. The frequent and 

 prolonged application of strong spirit removes all the water. 



Remove as much of the spirit as possible, but do not allow the 

 section to dry. It is now ready to be cleared up. 



With a brush insinuate a drop of the clarifying reagent clove- 

 oil or xylol uwler one corner of the section, and allow the xylol to 

 How under the whole of the section. It will gradually diffuse into 

 the tissue ; and if the process be watched under the microscope 

 with a low power, the section will be seen to become gradually 

 more transparent, while the spirit will be seen os fine globules 

 driven out into the essential oil. The success of the process 

 depends on complete removal of the water by spirit, and the complete 

 removal of the latter by the essential oil used as the clarifying re- 

 agent. If any opacity remains, and it looks milky or like an 

 emulsion, there has been either water or spirit, or both, left in the 

 section. 



More of the essential oil is placed on the section, so that it is 

 completely bathed in it and rendered quite clear by it. Pour off 

 the superfluous oil, remove the surplus close up to the edge of the 

 section, add a drop of balsam, apply a cover-glass, and the process 

 is complete. 



In some cases it is convenient to put the drop of balsam on the 

 cover-glass, and then to invert this on the clarified preparation. 



In all cases where it is directed to mount in balsam, this process 

 must be gone through, viz. 



(1.) Stain the section. 



(2.) Wash it in water. 



(3.) Treat the section with strong alcohol (96 per cent.) to remove 

 water (3-5 minutes). 



(4.) Absolute alcohol (3-5 minutes). 



(5.) Clarify with an essential oil to remove all the alcohol. 



(C>.) If the section be not on a slide already, place it on a slide by 

 means of a lifter. Remove surplus oil with blotting-paper. 



(7.) Add balsam, cover the section with a cover-glass. 



(8.) If desired, the hardening of the balsam may be hastened by 

 gently wanning the preparation on a water-bath. 



Sometimes it is not convenient to stain, dehydrate, and clarify a 

 section on a slide. In this case the sections are stained, dehydrated, 



