BLOOD 195 



is to take it from one of the veins of the ear. An adult rabbit can easily be 

 bled to the extent of 20 c.c. in this way. 



1. Prepare a large Pasteur pipette with the pointed end short but strong 

 and bent at an obtuse angle to the shaft (fig. 133, p. 166). The point must be 

 sharp and have thin cutting edges. Sterilize the pipette by passing it 

 through the flame but be careful to allow it to cool before using it. In this 

 particular case a pipette is better than a syringe. 



2. Let the animal sit on the knees of the operator or of an assistant. Shave 

 the hair over the line of the marginal vein and cleanse the skin in the ordinary 

 way (p. 172). Compress the vein at the root of the ear between the finger 

 and thumb or with a pair of pressure forceps. 



3. "Holding the ear in the left hand, thrust the point of the pipette through 

 the skin and then into the lumen of the vein. . A flow of blood into the 

 pipette will indicate when the point is in the vein. The point of the pipette 

 should be directed towards the tip of the ear and must be held absolutely 

 parallel to the axis of the vein to avoid penetrating both walls. 



The flow of blood into the pipette is slow : sometimes it ceases, owing to 

 the formation of a small clot in the end of the pipette ; this, however, can 

 easily be displaced by aspirating at the plugged end of the pipette. 



It is a good practice to puncture the vein near the root of the ear so that if unsuc- 

 cessful at the first trial another attempt may be made nearer the tip. By bleeding 

 from the two ears in turn, blood may be collected at frequent intervals from the 

 same animal. 



4. When sufficient blood is collected remove the pipette and seal the point in 

 the flame. The blood can afterwards be aspirated into other Pasteur pipettes 

 through the plugged end, the plug being well flamed before being taken out. 



5. Clip the wound with a pair of pressure forceps for a moment to stop 

 any haemorrhage. After being bled the animal will be thirsty, and some 

 water should be left in its cage. 



B. Jugular vein. The anatomical data and the technique of the operation 

 are the same as in the case of the guinea-pig (p. 194). 



C. Carotid and femoral arteries. Here again the description given for the 

 guinea-pig is applicable (p. 194). 



D. Cardiac puncture. The technique is similar to that described for 

 cardiac puncture in the guinea-pig. C. Nicolle and Duclaux recommend 

 using a rather large needle, about 2 cm. long, fitted to a sterile syringe of 

 10-20 c.c. capacity. 



1. The animal is held down on its back and the skin over the heart shaved 

 and cleansed. 



2. The needle with syringe attached is driven in sharply to a depth of 

 17-18 mm. to the left of the sternum in the fourth intercostal space counting 

 upwards from the xiphoid cartilage. The needle must be inclined from below 

 upwards and slightly inwards. 



3. Aspirate the blood slowly into the syringe and then withdraw the 

 needle quickly. 



Dogs are most easily bled from the jugular or external saphenous vein 

 (p. 173), or from the carotid or femoral artery, the ordinary rules of asepsis 

 being observed. It is to be remembered that dogs' blood coagulates very 

 quickly. 



Birds. 



Bleed from the axillary vein (p. 173) adopting the ordinary aseptic 

 precautions. 



