FIXATION OF FILMS 113 



before staining to submit films of blood l or pus or smear 

 preparations to the action of some chemical fixing agent, 

 unless the film is stained with Leishman's solution, which 

 both fixes and stains. The simplest method of doing this 

 is to immerse the films, after air-drying, in a mixture of 

 equal parts of absolute alcohol and ether for ten to thirty 

 minutes. In hot countries a saturated aqueous solution 

 of corrosive sublimate (five to fifteen minutes) is perhaps 

 as satisfactory as anything. Another method, combining 

 both fixing and staining, is to immerse the films as soon 

 as they are prepared and without drying for a few minutes 

 in the following solution : 



Absolute alcohol, saturated with eosin . 25 c.c. 



Pure ether . . . . . . 25 c.c. 



Alcoholic solution of corrosive sublimate 



(2 grm. in 10 c.c.) ,. . . 5 drops 



The specimens are then removed with a forceps and 

 well rinsed in water, stained for not more than a minute 

 in a saturated aqueous solution of methylene blue, washed 

 quickly, dehydrated in absolute alcohol, cleared in xylol, 

 and mounted in xylol balsam. This solution may be 

 used for fixing blood, pus, sputum, etc., if the eosin be 

 omitted, and the preparations may then be stained or 

 otherwise treated in any desired manner. 2 



Scott 3 recommends the following as giving the most 

 perfect results with blood films, etc. : 



(1) Hold the freshly prepared and still wet film in the 

 mouth of a wide-mouthed bottle half filled with the 

 ordinary formalin solution, film side downwards, for five 

 seconds. 



(2) Drop, while still wet, film downwards, into absolute 



1 For the method of preparing blood-films see the section on " Malaria," 

 Chapter XVIII. 



2 Gulland, Brit. Med. Journ., 1897, vol. i, p. 65. 



3 Journ. Path, and Bact., vol. vii, No. 1, p. 131. 



M.I',. g 



