130 THOMPSON YATES LABORATORIES REPORT 
Paraplegia fro?n Spinal Tramection in the Ape. 
In the Monkey in some instances three-quarters of an hour or so after transection below 
the region of the brachial enlargement, a itatus supervenes in which with cold hands and ears the 
animal lies down listless, and perhaps unconscious, with respiratory movements of the Cheyne- 
Stokes type. This state may persist twelve hours or so, and end either in gradual recovery or 
death. In most Monkeys this condition does not occur. I have never met it consequent to 
similar operations in the Cat or Dog. It has nothing to do with the surgical progress of the 
wound, which is trifling in extent, and heals readily. It is usual for the rectal temperature to fall 
a degree or more immediately after section of the cord in the thoracic region. 
As regards the nervous reactions elicitable from the isolated length of cord, for about 
twenty minute^ after the performance of the severance, neither by mechanical, thermal, nor 
electrical excitation of the skin innervated from below the point of severance, can any reflex 
movement at all be elicited. The one exception to this is occasionally the so-called crossed 
knee-jerk, which, unlike the direct knee-jerk, is — to judge by the length of its reaction time 
(Burckhardt)* — a true reflex. It may appear strange that a ' crossed reflex ' should be thus 
early among the reflexes to appear. I find on examination that the reflex is not in reality a 
'crossed reflex,' a statement which is amplified below, p. 165. After the brief interval certain 
skin-reflexes begin to appear ; almost always earliest is adduction-flexion of the hallux, elicitable 
by stimuli applied to the 3rd, 4th, or 5th digits (plantar surface or sides), or to the skin of the 
sole, especially of the fibular side. The movement obtained from the hallux is often tremulent. 
Similarly, after section above the brachial enlargement, the earliest skin-reflex to appear is usually 
flexion and adduction of the thumb on stimulation of the palmar surface, or sides of the little 4th 
or 3rd fingers, or of the palm, especially in its ulnar part. A little later, or equally soon in some 
instances, appears feeble movement (generally protrusion) of the anus in response to stimulation in 
the perineal region ; also feeble abduction of the tail in response to stimulation in the perineal 
region, or of the ventral surface of the tail itself ; also, further, movement (usually flexion, 
sometimes extension, sometimes abduction, especially of index) of the digits, in accompaniment to 
that of the hallux (or poUex) on excitation of the plantar (or palmar) surface, generally excluding, 
however, the skin of the hallux (or pollex) itself). 
Usually somewhat later, a slight contraction of the hamstring or gracilis muscles — at first 
often of the inner hamstrings only — becomes elicitable by severe excitation of the sole, and 
generally of no other region than the sole. All this time the limbs hang limp and flaccid, 
without any sign of spasm, except not infrequently fine feeble irregular twitching of the hallux 
(or pollex), sometimes of the other digits as well. The foot is warm. In these experiments, 
when reflexes were to be evoked from the skin, care should be always taken to maintain the 
temperature of the skin. As to the knee-jerk, this phenomenon, not truly reflex, yet intimately 
dependent on the reflex tonus of the crureus and vastus internus, in many instances is elicitable for 
a few seconds immediately following the severance of the cord, but then disappears, to reappear 
* Gottlieb Rurckhardt, ' Uber Sehnenreflexe,' " Festschrift deni Andcnken nn Alb. v. Haller dargebracht." Bern, 
l877> PP- 4-37- 
