238 Wisconsin Academy of Sciences, Arts and Letters. 
Either first or last term may then lead in Indian file; but 
only the mid-term can head a wedge, for the imparity of the 
mid-term and either remaining term, prevents the two from 
being sensed as evenly following the other; and only a Wedge 
can the mid-term head, for the structural parity of first and 
last terms (later emphasized) is pictured only by their even 
following of the mid-term. Accordingly, reverting to my il¬ 
lustration of page 236. 
(a) Suppose that, as central last term, I choose the lat¬ 
eral first term. In doing so I force the lateral elements 
to make their appearance, so to speak, in Indian file, not 
merely in order of time, but also in priority of structural 
rank, the first appearing “express” being built at once into 
the central portion of the growing mental edifice. “Express” is 
followed by “striking,” which takes a lateral position as its ad¬ 
junct, being followed in its turn by “freight” which, as the 
object of “striking,” is sub-lateral to “express.” 84 Thought 
being thus constructed, “striking” ranks as one of the verbal 
adjectives. 
(b) Again, as central last term, I may choose the lateral 
last term ; that is, the “freight” may be the first to enter cen¬ 
tral syntax as immediate object of “saw,” entailing as a rule 
the use of the passive participle, being followed accordingly 
in thought-construction by “struck,” which in turn is followed 
by “express.” 85 The lateral elements again appear in Indian 
file, but in reverse order, the lateral “struck” being also ranked 
as one of the verbal adjectives. 
(c) Also the lateral mid-term may be the first to enter cen¬ 
tral syntax, as immediate object of the central “saw,” being 
followed by its first and last terms (subject and object) “ex¬ 
press” and “freight.”* Accordingly “I saw an express train 
strike a freight.” Although the limitations of vocal utterance 
compel these two to make their appearance one before the 
84 For this stretching of lateral thought by the pull which brings its 
first term into central structure, compare pages 148-149. 
85 The investigation of the preposition “by”, in “I saw a freight 
train being struck by an express,” which may rank as the survivor of 
a make-shift means (one of several) of expressing reverse relation, I 
reserve for another publication. 
