36 METHODS OF OBTAINING HUMAN AND ANIMAL BLOOD 



5 c.c. ampule with arm drawn out to a capillary tip and sealed after a 

 vacuum has been created by heating (Fig. 16a, B). A short piece of rubber 

 tubing connects the needle and the capillary portion of the ampule. A 

 needle of No. 25 gage is fitted tightly into the free 

 end of the rubber tubing. A slender glass tube 

 closed at one end and flaring slightly at the other 

 serves as a protection for the needle, which it covers 

 when the apparatus is sterilized. The apparatus is 

 sterilized in a hot-air oven at 150 C. for one hour. 

 To obtain a specimen of blood the needle is inserted 

 into a vein, and the capillary end of the ampule 

 crushed with a hemostat through the rubber tubing, 

 blood flowing into the ampule and replacing the vac- 

 uum. The protecting glass tubing is then replaced. 

 Not infrequently, especially in children and in 

 obese adults, one fails to enter a vein. Several 

 attempts to do so may result in ruining one or more 

 of the tubes. My colleague, Dr. Alfred Reginald 

 Allen, has devised a useful modification in the 

 technic of using this handy tube; this consisting 

 in detaching the bulb from the rubber tubing and 

 needle, inserting the latter into the vein, and, when 

 the blood appears, quickly attaching the bulb and 

 breaking the neck with a hemostat, in the usual 

 manner. By this method the bulb is not broken 

 until one is sure he has entered a vein and secured a 

 specimen of blood. 



(b) Wet Cupping. 1. This method is partic- 

 ularly applicable for securing blood from infants. 



2. Cleanse an area over the back just below the 

 angle of the scapula. 



3. Scarify with a few superficial linear incisions 

 or with a special scarifier. 



4. Apply a cup and exhaust the air with special 

 syringe. The vacuum produces marked congestion 

 of the skin with a ready flow of blood. 



5. Carefully release the cup and pour blood into a tube. 



6. The apparatus devised by Blackfan, and shown in the accom- 

 panying illustration (Fig. 17), is quite satisfactory and collects blood 

 in a sterile tube. 



FIG. 16. THE KEI- 

 DEL TUBE FOR 

 COLLECTING 

 BLOOD. (Manu- 

 factured by the 

 Steele Glass Co., 

 of Philadelphia.) 



