2 5 6 



CLINICAL BACTERIOLOGY AND FLEMATOLOGY 



Here, again, you find whether you have taken the right 

 amount of blood. If you have taken too little, the cover- 

 glasses will be very difficult to separate; it may, indeed, be 

 impossible to do so without breaking them. If you have 

 taken too much, they will separate with great readiness, and 

 the blood will spread in uneven smears instead of forming a 

 uniform film. 



I used formerly to recommend the use of forceps for hold- 

 ing the cover-glasses in making these films. The only advan- 

 tage is that it avoids "steaming" the cover-glasses by the 

 condensation of moisture from the fingers, which may distort 

 the corpuscles. Except when the operator's fingers are very 

 moist it is quite unnecessary, and perfect films maybe obtained 

 with the cover-glasses held in the fingers. 



FIG. 53. 



The blood may be taken by means of the platinum loop, and 

 this is a good plan, as all danger of smearing the cover-glass 

 upon the skin is avoided. If several films are to be taken, a 

 number of platinum loops should be provided, as the blood 

 upon them soon coagulates. The exact size of the loop can 

 only be learnt by experiment, and when one has been found 

 to deliver a drop of the right size it should be kept entirely 

 for this work and carefully protected from injury. 



II. METHOD WITH CIGARETTE-PAPERS. 



Requisites. i. Perfectly clean slides. 



2. Some fairly stiff cigarette-papers cut in half longitudin- 

 ally. Paper which is decidedly ridged or ribbed will not 

 answer. 



3. Needle. 



