294 ROBKRT B. MONTGOMERY. 



a summary of his method is as follows: The pattern bearing 

 area on the ball of the foot is divided into two parts, one proximal 

 to the great toe (hallucal) and the other proximal to the smaller 

 toes (plantar). \Yhen three ridges meet to form a "Y" it is 

 called a delta of which there are three in the hallucal area, one 

 distal (just below the great toe), one medial, and one lateral. 

 If all three of them are present the pattern is a whorl (W), if 

 the distal one is absent the resulting pattern is a loop opening 

 toward the great toe and is designated as an "A" pattern, if 

 the medial one is absent and the loop opens medially a "B" 

 pattern is formed, and if the lateral delta is not present a "C 

 pattern results. When no pattern is present it is called an open 

 field (O). The plantar area contains three places in which a 

 pattern may be found. These lie in the three interdigital spaces 

 proximal to the four smaller toes. Four general types of patterns 

 are found in these areas: the open field or no pattern, designated 

 by an O, a loop opening distally (U), a loop opening proximally 

 (Q), and a whorl (W). To illustrate the application let us turn 

 to the right foot of twin 8 (Fig. i). The hallucal pattern is a 

 loop opening distally and is described as an 'A' pattern. The 

 first plantar area also contains a loop opening distally but is 

 designated by a 'U,' as is the second plantar area. In the third 

 area there is no pattern (O). Bringing the various symbols 

 together we have AUUO. To simplify matters, Wilder has 

 proposed a table in which each combination of plantar patterns 

 is given a number: O O O = i, O O U : 2, O O .1 : 3, etc. 

 The combination here is 21, and the formula is thus abbreviated 

 to A2i. Proximal to the plantar areas there are frequently- 

 found other deltas which are designated by the symbol 'd,' and 

 as there are two in this print, we arrive at the formula A2idd. 

 To formulate the left foot we proceed in the same manner except 

 that the plantar patterns are still read from left to right, giving 

 the formula A6dd. The formula of the right foot is placed as 

 the numerator of a fraction and the left foot as the denominator: 

 A2idd 

 A6dd 



In order that a set might be called identical the following 

 conditions must be met: (i) either all four patterns, or both 



