66 CLINICAL BACTERIOLOGY AND 



will remain compressed; if incomplete, it will gradually 

 become inflated. 



Again, beginners may find a difficulty in controlling the 

 fluid movements in the stem of the pipette. This with prac- 

 tice will soon be overcome, when the operator acquires that 

 delicacy of touch gained by practical experience, pro- 

 vided, of course, the end of the pipette has been properly 

 drawn out and squarely cut. 



When we expel the contents of the pipette containing 

 air-bubbles, of course we find the air-bubble question 

 troublesome when we begin to aspirate. To obviate this 

 condition, raise the glass slide, rest the end of the pipette 

 upon it, squeeze the teat, and allow the fluid to run away 

 from the point. 



When bubbles are in existence on the slide, we aspirate 

 from the far side of the drop; in this manner making a 

 kind of strainer. 



The contents having been thoroughly mixed, we now 

 aspirate the whole fluid ; suck in a column of air at the 

 point, and seal the end in the flame. 



The barrel of the pipette should be marked with the 

 grease pencil with the owner's name or number of patient, 

 and placed in the incubator at 37° C. for fifteen minutes, 

 making careful note of the time. 



Pipette No. 2 should be treated in exactly the same 

 way, save that the control serum takes the place of the 

 patient's serum, and incubated for fifteen minutes exactly. 



When the pipette has been incubated the proper time, it 

 is taken out. A teat is fixed on to the barrel, the pointed 

 or distal end of the stem is scratched and broken off, the 

 whole of the contents expelled on to a slide, and thoroughly 

 well mixed, as previously described. 



One or two drops should now be placed upon a clean, 

 grease-free, emery-paper-rubbed slide (on its convex face), 

 and the film made with a spreader. It is well to make 

 three slides in this manner, so that one may choose the 

 best film in the end, and air dried. The application of 



