HOMOLOGY AND ITS INTERPRETATION 51 



same time, a heeled hand equipped with a calcaneum, a talus, 

 a navicular, a cuboid, and all other structural elements requi- 

 site to ally it to the human foot and distinguish it from the 

 human hand. In fact, Mr. McCann's own photographs of the 

 gorilla skeleton show these features quite distinctly, though he 

 himself, for some reason or other, fails to speak of them. It is 

 to be feared, however, that his adversaries may not take a 

 charitable view of his reticence concerning the simian heel, but 

 may be inclined to characterize his silence as "discreet," all the 

 more so, that he himself has uncomplimentarily credited them 

 with similar discretions in their treatment of unmanageable 

 facts. In short, Mr. McCann's case against homology resem- 

 bles the Homeric hero, Achilles, in being vulnerable at the 

 "heel." At all events, the homology itself is an undeniable 

 fact, and it is vain to tilt against this fact in the name of 

 adaptational adjustments like "opposability" and "nonoppos- 

 ability." Since, therefore, our author has failed to prove that 

 this feature is too radical to be classed as an adaptive modi- 

 fication, our only hope of exempting the human skeleton from 

 the application of the argument in question is to show that 

 argument itself is inconsequential. 



Mr. McCann's predicament resembles that of the un- 

 lucky disputant, who having allowed a questionable major 

 to pass unchallenged, strives to retrieve his mistake by 

 picking flaws in a flawless minor. As Dwight has well 

 said of the human body, "it differs in degree only from that 

 of apes and monkeys," and "if we compare the individual 

 bones with those of apes we cannot fail to see the correspond- 

 ence." ("Thoughts of a Catholic' Anatomist," p. 149.) In 

 short, there exists no valid anatomical consideration whatever 

 to justify us in subtracting the human frame from the exten- 

 sion of the general conclusion deduced from homology. Who- 

 soever, therefore, sees in the homology of organic forms 

 conclusive evidence of descent from a common ancestor, can- 

 not, without grave inconsistency, reject the doctrine of the 

 bestial origin of man. He may still, it is true, exclude the 



