METHOD OF PREPARING AND EXAMINING THICK-FILMS 357 



obtained from Dr. Karl Hollborn, Leipzig.) Stock solutions, 

 if kept in well-stoppered containers, remain in good condition for 

 months, even in the tropics. 



D eJiemoglohifiization previous to staining or fixation of films is 



Fig. 21. — A, placing pasteboard separators, between slides in slide-box. 

 B, Box inverted and raised, leaving slides and separators in lid. C, Assem- 

 bling slides and separators into a block. 



unnecessary. Neither alcohol nor any other fixing agent should be 

 allowed to touch the thick films before dehemoglobinization, and 

 are not used at all in the method described below. 



If only a few slides are to be stained, a Coplin jar or other con- 

 venient staining dish will serve. If a large number are to be 

 handled, the methods illustrated by Figs. 20, B., and 21, A, B, 

 and C, will be found very convenient. 



Place all slides in the slide-box with the blood-films on the 

 left and the wax-pencil numbers on the right. Pieces of pasteboard, 

 each about i" X i>4" X 1/20" thick (25 X 30 X 1.2 mm.), are 

 dropped between the numbered ends of the slides, one to each 

 interval. The lid is replaced, the box lifted and rotated clock- 



