96 PRACTICAL HISTOLOGY. 



15. After removing surplus alcohol, pour on a few \ Dehydra- 



drops of essential oil (origanum, xylol). V tion and 



16. Kemove oil and mount in xylol-balsam. j mounting. 



N.B. In making a balsam preparation, the sections must always 

 pass through four groups of fluids. 



Watery liquid Alcohol Essential oil Balsam. 



i __ _ 2 <-- - 3 - - 4 



Never take an object from one group to another of the series 

 without passing it through the intermediate group; it must be passed 

 from the ist to the 4th, and on the return from the 4th to 

 the ist. 



