FIXATION OF BLOOD FILMS. 



I6 3 



longitudinally. Paper which is decidedly ridged or 

 ribbed will not answer. 



3. Needle. 



Method. The patient is pricked and the first drop of 

 blood wiped away as before. One of the half strips of 

 cigarette paper is now 7 held in the right hand, the index 

 finger being placed above the strip and the edges held 

 between the thumb and index finger and the index and 

 middle fingers respectively ; this converts it into a 

 gutter, the convex edge of which is downward. The 

 edge of this gutter which points away from you (and 

 which is formed by a machine-cut edge of the paper) 



FIG. 28. Method of spreading films with cigarette paper. 



is now dipped into the drop of blood and a small 

 quantity picked up on its lower surface. This lower 

 surface is then placed on a clean slide parallel to one 

 of its shorter edges and about half an inch from it, 

 and pressed gently upon it so as to flatten out the 

 paper gutter ; as this flattens out the edge of the drop 

 of blood on its under surface will follow it. The strip 

 of paper is now drawn towards the other end of the 

 slide with a steady uniform movement, and in doing 

 so the drop of blood is spread out into a long uniform 

 film. In this way a film in. wide and 2 in. long can 

 be made on a single slide. A fresh piece of paper is to 

 be used for each specimen. 



M 2 



