270 THE ENGINES OF THE HUMAN BODY 



active and daring. It will thus be seen that the mend- 

 ing of a broken connecting rod and the repairing of a 

 ruptured tendon are effected by very different means. 

 One is welded ; the other is healed. 



Let us take another example. The axle of a motor 

 car gives trouble ; there is a crackling noise in the bear- 

 ings ; on exposing the axle the mechanic finds it scored 

 owing to a broken ball-bearing. He removes the frag- 

 ments and replaces them by a new bearing, and all then 

 goes well. Now, in one of the main axles of the human 

 machine a somewhat similar accident is apt to occur, 

 particularly in strenuous young athletes. A cartilage of 

 the knee-joint becomes ruptured and displaced. The 

 knee cartilages serve as movable bearings to fit together 

 incongruous moving surfaces of the joint. The result of 

 such an accident is a sudden locking of the joint. Two 

 courses are open to the surgeon. He may open the 

 joint, just as a mechanic does the axle of a wheel, and 

 stitch the bearings back into their proper position, or, if 

 they are damaged beyond repair, he may remove them 

 and trust to Nature replacing them. If he opens the 

 joint his patient runs some risk, for a mistake may lead 

 to the introduction of germs and consequent inflamma- 

 tion and stiffness of the joint. That is a risk which the 

 skilled surgeon does not fear. But in this case, as in the 

 last, there are surgeons who maintain that as good and as 

 quick healing of the ruptured or displaced cartilages can 

 be obtained by first replacing the fragments by manipula- 

 tion of the joint. Having thus restored the parts to 

 their right places, they bind the limb to a splint and leave 

 the actual repairs to Nature. So equal are the results 

 obtained by either of these methods that it is difficult to 

 tell which is the better one. Certainly there are cases of 

 long standing in which repeated and skilled manipula- 

 tions fail to give relief and which can be set in the way 

 to recovery by a surgical operation. But whether the 

 surgeon succeeds by operation or by manipulation, in 

 either case it is Nature who actually effects the repairs ; 

 the surgeon is her skilled assistant. 



