PALM AND SOLE STUDIES. 



217 



and the ridges consequently escape in both directions through 

 the points naturally held by a and c, that is, distally between the 

 great toe and the second, and proximo-laterally towards the 

 region of the fourth interdigital area and the outer edge. As 

 shown in the actual prints, or in the tracings from them, here 

 presented, the b triradius, which is necessary to the full under- 



FIG. 30. Print of right sole of Mary (Component B). 



standing of the relationship, is not shown, but there is no question 

 but what it is present, beyond the tread-area, as indicated by the 

 dotted triradius drawn into each figure. 



The difference shown in the aberrant hallucal pattern of Mary's 

 right foot consists in the presence of the c triradius, thus closing 

 up all escape for the ridges in that direction, so that consequently 

 they curve around the core and open with the others between the 

 great toe and the next. The essential aberrancy of this pattern 

 consists thus in the presence of a triradius absent in the other 

 cases. 



The other difference in this aberrant foot, that affecting the 



