216 INITIATIVE IN EVOLUTION 



human evertor of the foot concerned in the construction of the 

 plantar arch is " often absent or undeveloped " in African races, 

 which are well-kDown in some groups to have adapted themselves 

 to a form of foot which shows no plantar arch, being normally- 

 flat-footed. In this small field of observation, a mere plot of 

 lentils like that which Shammah defended of old, there is set forth 

 a mimic battlefield, and it is not difficult to see that the forces at 

 work can owe allegiance to one and one only of various commanders. 

 The problem as to the origin of the peroneus tertius would no more 

 attract the Mendelian than did the trousseau and approaching 

 marriage of Caddie Jelly by attract the far-away gaze of her mother, 

 fixed upon the world of Borria-boula-gha, and, for that matter, 

 de Vries would hardly pay it more attention — to him it would be 

 indifferent ; whereas Weismann would have as much to say about 

 it as about the little toe of man, which furnished for him and Herbert 

 Spencer such fruitful material for debate many years ago. This 

 muscle resembles the results of some of Michael Angelo's first 

 attempts at sculpture, thrown aside perhaps in his place of work 

 and from time to time taken up, rough -hewn again and again and 

 finally shaped into a form far from perfect, but with the value and 

 teaching of a failure for him who was some day to outshine all 

 modern rivals. If the history of this muscle be not one of initiative 

 in evolution through the factor of use and habit the Pan-Selectionist 

 must do the best he can with an incalculable number of " trials 

 and errors," and must suppose that, rather than allow this small 

 territory to the neo-Lamarckian, a long series of man's ancestors 

 have been making experiments for the benefit of man's walking 

 power under the guidance of selection with an insignificant muscle 

 whose only function is that of aiding in the eversion of the foot, 

 and that in the rudimentary condition described by Professor Keith 

 it had selective value. No one who was not committed to a domi- 

 nating theory could hesitate for a moment which of the two alter- 

 native views of the origin of the peroneus tertius he would choose. 

 Dr. Barclay Smith speaks in the paper referred to above of the 

 extensor brevis pollicis, or minor, as a muscle of extremely late 

 appearance, and as " peculiarly human," and says all the evidence 

 points to its being a segmentation product of the extensor ossis 

 metacarpi pollicis, its appearance being foreshadowed in the anthro- 

 poid by an extension of that muscle on to the proximal phalanx 

 of the thumb. 



It is not without interest to the thesis before us to read the 

 rather bewildering story of the early life of a very insignificant 

 muscle such as the small extensor of the thumb of man. 



