AND HORSEHAIR AS A DRAIN iOR WOUNDS 443 



lateral ligaments remaining of normal shortness, while the articular portion 

 of the femur is abnormally lengthened, the tibia becomes locked against the 

 femur when extension is attempted, and the application of violence for the 

 purpose could only lead to backward dislocation. Accordingly we found that 

 after free division of all the hamstrings, together with all tight bands of popliteal 

 fascia, the tibia did become locked in the way I had anticipated, when we tried 

 to straighten the limb. 



The abnormal length of the end of the femur being presumably the essential 

 obstacle to extension, I proceeded to reduce it, opening into the joint with a 

 semilunar incision anteriorly without dividing the lateral ligaments, and paring 

 away successive portions of the articular part of the femur until, some super- 

 fluous fibrous tissue of new formation having been also removed from the surface 

 of the tibia, I was at length able to effect complete extension, but not without 

 a degree of pressure of one osseous surface against the other which I should 

 not have felt justifiable without antiseptic means. 



The manner in which drainage was provided is a point worth\^ of your 

 attention. Next to the importance of the avoidance of putrefaction in wounds 

 is the prevention of tension by providing a free escape for effused blood and 

 serum. This we have hitherto generally done by means of the caoutchouc 

 drainage-tube of Chassaignac. But in the present case such a tube would have 

 been unsuitable, because the natural position for the drain was that it should 

 run between the ends of the bones which, as we have seen, were pressed together 

 so that the calibre of a caoutchouc tube would have been altogether obliterated, 

 and the drain in a most important part of its course rendered useless. Under 

 these circumstances I used a drain of horsehair, because such a drain operates 

 by capillary attraction through the interstices between the hairs, and those 

 interstices cannot be obliterated by pressure, seeing that the hairs are not 

 individually compressible. 



The drain was introduced in a manner which }-oii will often find useful. 

 It may frequently happen that the most dependent part of a wound may have 

 no opening in the skin to correspond with it : thus after excision of the mamma 

 it may turn out, when the operation is concluded, that the wound presents 

 a pocket extending considerably further back than the outer angle of your 

 incision. Under such circumstances it is desirable to make an opening for tlie 

 exit of the drain at the most dependent part. Now, if this were done by a punc- 

 ture with the knife, some arterial branch of considerable size might be wounded, 

 involving the necessity of freely enlarging the wound to secure the bleeding- 

 point. But if you take a pair of dressing-forceps, and bore steadily from within 

 outwards, the conical extremity of the instrument will slip past an}- arterial 



Gg2 



