DILUTION OF SERUM BY MEANS OF A TEAT PIPETTE 383 



2. Take a Pasteur pipette, nick the capillary stem 

 just above the sealed end with a glass cutting knife, and 

 snap off the sealed end with a quick movement so that 

 the fracture is clean cut and at right angles to the long 

 axis of the capillary stem cut "square", in fact. 

 Prepare several, say a dozen, in this manner. 



3. Fit a rubber teat to the barrel of each of the 

 pipettes. 



4. Make a mark with the grease pencil on the stem 

 of one of the pipettes about 2 or 3 cm. from the open 

 extremity. 



FIG. 193. Filling the capillary teat pipette. 



5. Compress the teat between the finger and thumb 

 (Fig. 193) to such an extent as to drive out the greater 

 part of the contained air. 



6. Maintaining the pressure on the teat pass the 

 stem of the pipette into the capsule holding the 

 saline solution, until the open end of the pipette is 

 below the level of the fluid. 



7. Now cautiously relax the pressure on the teat 

 and let the fluid enter the pipette and rise in the stem 

 until it reaches the level of the grease pencil mark. As 

 soon as this point is reached, check the movement of 



