738 REPORT— 1904. 
common path, but those in separate categories are generally correlated in their 
action on their final common path in such a way as to antagonise one another. 
They are rivals for possession of their final common path, rivals as retinal points 
may be rivals for possession of the visual sensorium. 
The extent to which in the nervous system this competition for posses- 
sion of the common path obtains is very great. The multiplicity of the conflict 
seems extreme. The afferent fibres—that is, private paths—entering the central 
organ are much more numerous than are the final common paths, We owe to 
Fia, 4. 
| 
FO 
a“ 
i} 3 y 
Ba Sanicusadl is 2 to ec aera 
Sp a 
Summation effect between the arcs Sa and 8 of fig.1 B. Fc the flexor muscle of the hip. Sa the 
signal line marking the period of stimulation of the skin belonging to arc Sa (fig. 1 B) of the 
shoulder skin. The strength of stimulus is arranged to be subminimal, so that a reflex response 
in FC is not obtained. sf, the signal line marking the period of stimulation, also subminimal, 
of a point of shoulder skin § centimetres from Sa. Though the two stimuli applied separately 
are each unable to evoke the reflex, when applied contemporaneously they quickly evoke the 
reflex. The two arcs Sa and sg therefore reinforce one another in their action on the final 
common path Fc. Time in fifths of seconds, Read from left to right. 
Donaldson and his pupils enumerations which show that the afferent fibres 
entering the human spinal cord three times outnumber the efferent which 
leave it. Add the cranial nerves and the so-called optic nerves, and we 
may take the. ‘afferent fibres to be five times the greater. The receptor 
system bears therefore to the efferent paths a relation like the wide ingress 
