Films that are old, or that have been subjected to the 

 action of light, are sometimes entirely or partly fixed and 

 hence unusable. They haemolyse. badly or not at all and 

 staining is likewise not successful. 



The above method is quite satisfactory for ordinary pur- 

 poses, but occasionally more rapid work is required, when 

 the object is not so much to obtain beautiful results and 

 when one is content if only one can discover a plasmodium. 



In such cases the following method is recommended: 



a. Dry the film well. 



b. Haemolyse for 10 minutes in a fluid consisting of 1 

 drop of stain in 2 c.c. of the 1:1000 solution of magnesium 

 sulphate. 



c. Flush carefully with water. 



d. Dry again. 



e. Stain for ten minutes with 3 drops of stain in 2 c.c. of 

 the solution of 1:1000 magnesium sulphate. 



/. Pour off stain, but do not flush. 



g. Dry by leaning slide against the wall. 



B. Thin film 



a. This is fixed by immersion in methylalcohol. Fresh 

 films should be left in the bath for 2 minutes. In the case of 

 older films drain off the fluid after 3 to 4 minutes. 



b. Flush directly in plenty of running water. 



c. Let it dry in the air until quite dry. 



d. Pour over stain: 2 drops of Giemsa solution in 2 c.c. of 

 water. The process of staining takes as long as in the case of 

 the haemolysed thick drop. 



e. Flush with plenty of running water. The metallic- 

 looking film on the stain must not be allowed to touch the 

 smear. Lean the slide against the wall to dry. 



A well made and well stained thin film shows the follow- 

 ing charactersitics: 



a. The erythrocytes lie next to one another and are col- 

 ored grey. If good stain is used and the staining has been 



