38 KNIGHT DUNLAP 



spend no time at present in amplifying this detail. The manner 

 in which such a series becomes established requires some further 

 explanation. Let A'-a, B'-b, and C'-c 6 represent heterodetic 

 muscular arcs (that is perceptual arcs) which have become ha- 

 bitual. If on certain occasions we have reactions through these 

 in succession, we may have the afferent current from a' collected 

 by central neurons and combined with the current from B' into 

 the discharge to b; similarly, the current from &' collected and 

 combined with the discharge to c, and so on. As a result of this 

 process, especially if the serial stimulation of A', B r , and C' is 

 repeated a number of tunes, we have the homeodetic arcs a'-6, 

 &'-c, and so on, established as paths of habitual reactions. In 

 other words: the sets of muscular contractions habitually asso- 

 ciated with A', B', C' and so on, have become associated into a 

 series. 



Going back now one step farther; the reaction, although repre- 

 sented above as occurring in a simple arc from A' to a, is really 

 a complicated reaction built up in' a manner similar to that in 

 which the homeodetic reflex a'-b is established. That which 

 was originally a simple discharge from A' 7 has, in the course of 

 many repetitions, been combined with discharges in many other 

 arcs Af'-ra, JV'-n, O'-o, etc., and thus not only may homeodetic 

 arcs between a and ra', n', o', etc., have been established, but also 

 central connections between A'-a, M'^m, N'-n t O'-o, etc., have 

 been formed. As a consequence of this central fusion a condition 

 has been established such that a current from A' alone will be 

 distributed, not to a alone, but also to m, n, o, etc. That is to 

 say, stimulation of A 1 alone will produce somewhat, though not 

 exactly, the same results which would earlier have been produced 

 by the stimulation of A', M', N', 0', etc. 



At this point our analysis compels us to plunge into the episto- 

 mological whirlpool, but by holding fast to our reaction hypothe- 

 sis we can come safely through. The heterodetic reaction A'-a, 

 in its simplest or original form, conditions the consciousness of 

 A y the sense quality corresponding to the stimulation A'. In the 



6 See figure 1. 



7 See figure 2. 



