IN THE REPAIRING SHOPS 271 



The two instances just cited were selected from surgical 

 practice ; we shall now take a case which may be described 

 as'being of a medical nature. A motor car is brought to 

 the repairing garage because its driver complains of a lack 

 of speed and power, especially in taking hills. In fact, 

 the car becomes breathless on going up a steep incline. 

 The repairing mechanic finds that the valves of the 

 engine leak ; he. grinds and resets them, and all trace of 

 breathlessness disappears from the engine. A patient 

 comes to a medical man complaining of breathlessness, 

 especially on going upstairs. Now, such a breakdown 

 may arise in human as in motor machines from many 

 causes, but the skilled physician looks first to the state of 

 the valves of the heart. He listens over the position at 

 which he knows the great stem of the heart — the aorta — 

 comes to the surface of the chest ; he notices that as the 

 heart throws its charge of blood into that vessel there is a 

 rough sound which should not be heard there, and that 

 the sudden click which marks the closure of the valves 

 and prevents the blood flowing back into the aorta is 

 almost lacking. He concludes, therefore, that the breath- 

 lessness does not lie in a deficiency of the lungs, but in a 

 defect of the body pump. The aortic valves, he knows, 

 have become shrunk from disease. What is the physician 

 to do in such a case ? What can Nature do ? Neither 

 the physician nor Nature can open up the pump and 

 replace damaged valves with new ones. Living valves 

 cannot be ground and reset. Nature comes to the rescue 

 in this way. She brings into operation her compensating 

 mechanism ; the muscular engines of the ventricle have 

 now to do double work or more, because part of the dis- 

 charged blood falls back upon them. The muscular engines 

 of the ventricle become thick and strong and are able to 

 do twice their usual amount of work. The physician's 

 duty is plain. He has to assist Nature as much as lies in 

 his power. Such a patient has to nurse his heart — under- 

 take only such physical work as lies easily within the 

 effective capacity of his heart. If strict regulations are 

 observed such a patient, as Sir James Mackenzie has 



