g2 PHLEBOTOMY. 



of the blade to be used depends upon the thickness of the 

 skin and other tissues covering the vein. If the vein is 

 opened, dark red blood escapes from the wound in a large 

 stream. If the operation does not succeed at the first effort, 

 one should select an undamaged portion of the skin for a 

 second attempt so that the opening into the vein may be 

 direct and clean. 



When the vein is opened lay the instrument aside. The 

 compression of the vessel must be continued in order to 

 insure the flow of blood, to prevent aspiration of air and 

 also to provide that the lips of the skin wound shall not be- 

 come displaced in relation to that of the vein by which the 

 escape of blood would be impeded or stopped. The flow of 

 blood may be favored by inducing masticatory movements 

 by the animal. The amount of blood withdrawn varies 

 between 3 and 8 liters, according to the size of the animal and 

 the object to be attained. 



The wound may be closed by an interrupted or a pinned 

 suture. For the latter, relieve the compression on the vein 

 and grasp the lips of the skin wound between the finger and 

 thumb and stick the pin perpendicularly through the middle 

 of them a few mm. from their borders. Apply a noose of 

 silk ligature, previously prepared, over the pin and close and 

 tie the loop. In applying the pin and loop, take care not 

 to elevate the skin from the underlying part, which tends 

 to the production of a hematome. 



b. With the lancet the operation is preferably performed 

 on the right side of the neck. Compress the vein as illus- 

 trated in Fig. 6, and hold the lancet between the thumb 

 and index finger in such a manner that it can only penetrate 

 as far as into the vein, and then push it in quickly just in 

 front of the compressing thumb through the skin, subcutem 

 and venous wall as deep as the fingers holding the lancet 

 will permit. 



Hold the blade perpendicular to the long axis of the vein, 

 and avoid directing the point dorsalwards, which would 



