32 METHODS OF OBTAINING HUMAN AND ANIMAL BLOOD 



OBTAINING SMALL AMOUNTS OF HUMAN BLOOD 

 For obtaining small amounts of blood up to 2 or 3 c.c. for the 

 Widal reaction, complement fixation, and other tests, the following 

 method is satisfactory: 



1. Wash the last joint of the middle finger with alcohol. If the 

 hand is cold, it should be warmed by immersing it in hot water. Before 

 puncturing compress the finger and squeeze in such a manner as to 

 drive the blood toward the end of the finger. 



2. Prick deeply with a broad blood lancet, Hagedorn needle, or 

 scalpel (Fig. 10). 



FIG. 11. METHOD OF SECURING A SMALL AMOUNT OF HUMAN BLOOD. 

 By pricking the finger deeply across the lines of the skin with a broad lancet, 

 two or more cubic centimeters of blood are easily collected in a small test-tube. Do 

 not use a large tube, as blood may be lost on the sides of the tube. 



3. Collect the blood in a small test-tube, about 8 cm. by 1 cm., 

 such as is used in performing the Noguchi reaction for the serum 

 diagnosis of syphilis (Fig. 11). 



4. By squeezing the finger, sufficient blood can usually be obtained 

 from one puncture practically to fill a tube of the size mentioned. One 

 to two cubic centimeters of serum are easily obtained in this manner, and 

 this is sufficient for cond acting the ordinary serum reactions. When 



