REPAIR IN EVOLUTION 73 



the functions of another, and some evolutionary rem- 

 nants long survive without function. I was, indeed, first 

 led to take this general view of the variational value of 

 pathological conditions by observing that the heart, when 

 laid open from any aspect, powerfully suggested an 

 organized or cured aneurism. By this I do not mean 

 that it is now in any way aneurismal, or that the heart is 

 descended from such a large and definite breakdown. The 

 view put forward is that the complex machinery of the 

 chordcB tendinecB, the columncB carnece, the papillares 

 musculi, the moderator band and the valves generally, 

 gives it the appearance of a repaired organ, and inevitably 

 suggests that, during its evolution, fibrosis and the reactions 

 of stressed tissues moulded and re-moulded it on the 

 general lines of mechanical construction, breakdown, and 

 repair. Many must have made the same observations, 

 even if they have not come to similar conclusions. The 

 anatomist and pathologist perhaps know their subjects 

 too well, and are necessarily greatly dominated by current 

 theory. The general adaptation of the heart to the work 

 it performs may well delight the anatomist as he studies 

 its machinery. His main business is not evolution. The 

 pathologist, on the other hand, observing its many failures, 

 is scarcely likely to discern that by failure itself may come 

 eventual perfection, and while the physiologist considers 

 its functions rather than its apparatus, he studies it as it 

 is, not as it was. In each case the observer may not see the 

 forest for the trees. Yet when we look at the partially 

 repaired aneurism with its fibrous growths, and turn to the 

 opened heart, the essential likeness of the chordce tendinecr, 

 for all their definite functions, to the rude fibres of an 

 aneurism, is obvious. Is such a likeness an accident of 

 evolution and pathology, or are we to consider the he;irt 



