BLOOD 193 



3. With a sterile pin or small lancet [or a straight surgical triangular 

 needle] prick the skin sharply and deeply. 



4. Wipe away the first drop or two of blood which issues with a piece of 

 sterile paper and collect the remainder. 



As a further precaution the skin of the finger after being washed and dried 

 may be painted over with a very thin layer of collodion. The finger is then 

 pricked through the collodion and in this way the blood is prevented from coming 

 in contact with the skin. 



B. Cupping. A larger volume of blood can be obtained by cupping, but 

 otherwise the method is open to the same objections as the foregoing. 



1. Asepticize about 10 sq. cm. of the skin of the thorax, back or sides. 



2. Apply a sterile cupping-glass over the part. 



3. When the glass has fixed itself, raise it (the operator's hands having, of 

 course, been already sterilized), scarify the skin with a sterile razor and apply 

 the cupping-glass again. 



4. When sufficient blood has collected put the patient in such a position 

 that the blood will not be spilt, then lift the glass and cover it at once with 

 sterile paper. 



C. Bleeding from a vein at the bend of the elbow. By this method all 

 danger of contaminating the blood is avoided, and it should be adopted in 

 all cases when cultures have to be sown. It is attended by no danger and is 

 less painful than the foregoing methods. 



1. Procure a sterilizable syringe of 2-20 c.c. capacity according to the 

 amount of blood to be collected, and adjust a sharp and clean-bored needle. 

 Test its efficiency and, if satisfactory, sterilize it with the needle attached, by 

 boiling it in water for 15 minutes or by heating in the autoclave at 115 C. 



2. Lay the patient's forearm flat on the bed, and get an assistant to com- 

 press the middle of the arm or put a tight bandage round it as in the operation 

 for bleeding. 



3. Wash the skin over the bend of the elbow with soap and rinse with 

 sublimate or oxycyanide, then with alcohol and finally with ether. As 

 the result of the combined compression and friction the veins at the bend 

 of the elbow will stand out prominently. 



To make certain of asepsis it is sometimes advised to lightly touch the point 

 through which the needle is to be passed with a cautery ; but in the great majority 

 of cases it is sufficient to wash the arm in the manner described. 



4. Select the largest vein, push the needle through the skin and then into the 

 vein. The vein lying, as it does, immediately beneath the skin is generally pene- 

 trated at the same time as the skin. The needle should be held parallel to the 

 long axis of the vein and at a very acute angle to the surface. When the vein 

 is entered, by gently withdrawing the plunger, blood will flow into the syringe. 



Notes. There is nothing to be gained by pointing the needle towards the hand ; 

 on the contrary, it is easier to point it towards the arm and the calibre of the vein 

 is such that it flows just as easily into the needle whichever way the latter is directed. 

 The alternative method which consists in first making an incision through the skin 

 and exposing the vein should never be practised. 



5. When the syringe is full, withdraw the needle from the vein, relieve 

 the pressure and apply a drop of collodion to the needle prick. Be careful 

 not to let the blood clot in the syringe but squirt it at once into a sterile 

 test-tube ; then wash the syringe in cold water and sterilize it. 



Horses, asses and cattle. 



In these animals the jugular vein is the most convenient from which 

 to bleed. The method has already been described in dealing with the 



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