A little practice will show what size the drop of blood 

 should be, at what angle the spreader should be held and 



at what rate it should be moved. 

 The film dries within a 



spreader 



/ 



drop of blood 



slide 



Fig. 3 



few seconds and 

 this process may be 

 hastened by waving 

 the slide to and fro. 

 Fixation should fol- 

 low immediately. 



B. Thick drops 



The slide is held against the drop of blood on the ear. 



The drop is thereby transferred to the glass 



and may have a diameter of about 5 mm. 



The slide is held in a vertical position so 



as to allow the drop to spread out. If the 



drop does not run of itself (as for example 



when it is not large enough) the lower edge 



of it may be touched by the needle with 



which the ear was pricked and the drop 



drawn out along the vertical slide to form a 



streak of blood about one inch in length. 



By this method a film that is neither too thick 



nor too thin is obtained, and one which after 



staining can be examined over its entire 



surface (fig. 4a), in contrast with the round 



Fig. 4 



drop which is too thick in the middle for staining and exam- 

 ination (fig. 4b). 



The film should be laid horizontally to dry in the air but 

 not in the sun. It dries in the course of a few minutes. 



THIN SMEAR OR THICK DROP PREPARATIONS 



Each of these two methods of examination has its own 

 advantages and disadvantages. 



