156 
THOMPSON YATES LABORATORIES REPORT 
For the sequence of movements in a spinal reflex the term which Hughlings Jackson's 
writings on epilepsy introduced and have rendered classical will here be used — the march. As 
instances of the march' in spinal reflex movements may be given the following: — 
Excitation of afferent root of Vlllth post-thoracic (Monkey) gave flexion of hallux, with some 
adduction of it, followed by plantar flexion of ankle, followed by movement of tail. 
Pinching the back of the thigh towards its medial side high up elicited (Monkey) flexion and 
adduction of hallux, followed by flexion of knee, followed by movement of tail, accompanied by protrusion 
of anus. 
Touching the skin at the side of the vaginal orifice (Monkey) evoked depression of tail, accompanied 
by protrusion of anus, followed by flexion of knee, with some abduction of thigh, followed by flexion of 
hallux. 
A long-continued pinch of the pad will in the Cat sometimes induce a short series of alternating 
flexions and extensions of both hind-limbs, or simply a series of alternating flexions of the two ankles. 
In the Rabbit, similarly, a series of flexions of the ankles are sometimes elicitable, but — in accordance 
with the hopping progression of the animal — are not alternately, but bilaterally, symmetrical. These 
reflexes can sometimes be evoked by merely holding the animal up so that the paralytic hind-limbs 
hang. 
Touching the pad of the fore-paw evokes (Cat) flexion of all digits, then extension of wrist and 
pronation of forearm, then flexion of elbow, and retraction of shoulder. 
Pinching the outer edge of the sole (Macacus) evoked adduction and flexion of the hallux, 
accompanied by extension of the other digits at metatarso-phalangeal joints, followed by eversion of foot, 
with dorso-flexion at ankle, followed by flexion at knee and hip, accompanied by adduction towards 
opposite thigh, and, finally, slight depression of tail and adduction of opposite thigh itself 
Pinching the inner edge of the sole {Macacus) evoked adduction flexion of hallux, accompanied by 
extension of the other digits at metatarso-phalangeal joints, followed by inversion of foot, followed by 
flexion of knee, in which the inner hamstrings were chiefly concerned. 
Pressure close in front of heel ( Macacus) gave flexion of hallux and other digits, followed by plantar 
flexion of ankle, followed by flexion at knee. In one Monkey, stroking or blowing upon the hair of one 
flank evoked flexion of hip, followed by flexion of knee, followed by flexion of ankle and digits. 
From a spot in the perineum the following sequence was obtainable ; protrusion of anus, followed 
at once by elevation of tail, succeeded by lateral wagging of tail, continued for about 30 seconds ; evacua- 
tion of fasces sometimes followed (Macacus). 
In the Monkey, after spinal transection, it is quite rare for a moderate stimulus to provoke 
discharge of successive opposite movements at one and the same joint, e.g.., those of lateral wagging 
of tail or alternating flexions and extensions of limb joints. This is consonant with the rule that 
the groups of motor neurons most readily combined iif action by spinal reflexes are those which 
are synergetic, not antergetic. In Cats and Dogs, in whom the depression of spinal reflex action 
is not so severe as in Macacus., the spinal reflexes in their march do combine and discharge, 
especially in the hind-limbs — where depression is less than in fore-limbs — antergetic groups of 
neurons in the course of their march, but not (my own experience is never) contemporaneously, 
though often successively. Hence the alternating discharges., which, though very rare in Macacus^ 
are common and characteristic of the reflexes of the hind-limbs and tail of Cat and Dog, and of 
the Guinea-pig and Rabbit. In these alternating discharges only one group of an antagonistic 
couple is discharged at a time. These alternating discharges are especially prone to appear when 
the stimulation is prolonged. An excellent illustration of this is given by Cat or Dog when one of 
the hind-paws is pressed between finger and thumb, and continued to be held even after the flexion 
of ankle, knee, and hip which results ; alternating extensions and flexions of the limb then occur. 
