V] STAINING UN-IMBEDDED SECTIONS 37 



95 p.c. alcohol on a lifter instead of on a glass rod. 

 Arrange the section flat on a lifter, hold it in place by 

 touching it lightly with a needle as the lifter is raised 

 from the fluid ; wipe dry the bottom of the lifter, drain 

 excess of fluid from it (taking care that the section does 

 not become dry) ; and then lower the lifter gently into 

 the next fluid. 



Take a section from picro-carmine and treat it in 

 the same way as the section from hsematoxylin. If, 

 after washing with water, it is only faintly red, put it 

 back in the picro-carmine. 



2. Clearing the section and mounting it in 

 Canada balsam. Take it up on the glass rod, gently 

 touch the edge of the watch-glass, or a piece of blotting- 

 paper, with it to remove excess of alcohol, and place it 

 in clove oil the clearing agent for 2 or 3 minutes. 

 In the clove oil the folds in the section will usually 

 disappear. 



With a lifter transfer the sections in this case with 

 plenty of fluid, from the clove oil to a slide, and examine 

 them under a low power of the microscope. They 

 should be transparent throughout. If either has any 

 opaque spots, put it on the warm bath for a few minutes. 

 If the opaque spots which are caused by the presence 

 of water do not disappear, the section should be thrown 

 away 1 , and another passed from the staining agent 

 through the alcohols, especial care being taken to 



1 The section may be dehydrated by transferring it from the clove 

 oil to 95 p.c. alcohol (or better, absolute alcohol) for about 10 minutes 

 and then replacing it in clove oil ; but the beginner is recommended 

 to take a fresh section. 



