PIPETTES 



37 



done it without waking a sleeping child. The needle is then 

 laid down, and if the blood flows out in large drops (as usually 

 happens if the ear has been well rubbed) it is collected with- 

 out the slightest difficulty, and this is specially likely to be the 

 case if you puncture the ear of the side on which a patient has 

 been lying. If it does not flow readily, take the lobe of the 

 ear between the forefinger and thumb of both hands^ and 

 squeeze it gently so that all the blood in the lobe is forced 

 through the puncture, and collect the drop thus formed. When 

 this has been done the lobe of the ear will be full of blood 

 again, and a second drop can be milked out. Repeat this pro- 

 cess as often as necessary. There are few patients from whom 



B 



FIG. 14. 

 A, Before coagulation ; B, after, showing clot suspended in clear serum. 



several pipettes half full cannot be collected from a single 

 slight puncture. 



Many pathologists prefer the finger. In that case an excel- 

 lent needle can be made by softening a small piece of capillary 

 tubing in the flame and separating the two ends rapidly. This 

 will give two tapering tubes, which can be broken off so as to 

 leave a very sharp point, with which the skin at the side of the 

 nail can be punctured almost painlessly. The lig'ature is then 

 applied as in the figure, and the patient bends his finger for- 

 cibly, squeezing out two or three drops of blood. After these 

 have been collected the bandage must be removed and the 

 hand allowed to hang down, so that the finger refills with 



