EXAMINATION OF SOiME SPINAL NERVES 135 
diminished when, instead of skin and nerve-trunk, the spinal roots proximal to their ganglia are 
stimulated. The direction and muscular composition of the primary movements elicitable by 
faradic excitations of the afferent spinal roots themselves are in Cat, Dog, and Monkey, especially 
in the hind-limb region, almost the same for all three types. The spinal machinery for movement 
is therefore actually present in the Monkey as in the other tw^o, and indeed, as was expected, 
appears to be more complex. But it is more difficult to set in motion and to keep going. This 
question requires further appeal to the phenomena of ' shock.' 
As was to be expected, shock is more severe and lasting In the Monkey than in the other 
laboratory types, and its symptoms are more profound and prolonged than in any other animal I 
have observed. The symptoms of shock, in many monkeys, persist for days instead of hours or 
minutes, as in Cat and Dog. It is important to note that in the Monkey, much of what we are, 
from observations upon the lower animal types, inclined to regard as temporary and relegate to 
block or 'shock,' in Goltz's language ^ Hemmungserscheinungen'' — not '• Amfalhersche'inungen'' — 
proves, under prolonged observation, to be, I must think, permanent ; in fact, to be true deficiency 
phenomenon. Every histologist acquainted with the comparative structure of the spinal cord in the 
Ape and in the Dog, must have been impressed with the far greater complexity obvious in the 
former. The above evidence is in accord with that, for it shows that the same trauma inflicted 
upon the cord leads, in the monkey, to much heavier permanent defect than in the dog ; just as, 
in fact, ablations of the cortex cerebri are pregnant with far greater ' Jusfallserscheinungen ' in the 
Monkey (Ferrier, H. Munk, Schafer, Mott) than in the Dog (Goltz). It is reasonable to 
argue still severer results in the case of the human spinal cord ; of which again we know the 
minute structure to be yet more complex still. The permanent dafnagc done is, therefore, as tvell as 
the initial shock, disproportionately greater in Monkey than in Cat and Dog. 
To return briefly for a moment to initial shock due to spinal section in the Monkey. 
There can hardly be witnessed a more striking phenomenon in the physiology of the nervous 
system. From the limp limbs, even if the knee-jerks be elicitable, no responsive movement, 
beyond perhaps a feeble tremulous adduction or bending of the thumb or hallux, can be evoked 
even by insults of a character severe in the extreme. That which the delicate yellow spot is to 
the sensifacient sheet of the retina, may the the thumb and index be said to constitute in the 
great sensifacient field of the limb. Nevertheless, a hot iron laid right across thumb, index, and 
palm, remains an absolutely impotent excitant, or able only to evoke a faint flexion of the thumb ; 
the crushing of a finger has no greater effect. A huge afferent nerve, such as the internal 
saphenous, containing some five thousand sensory nerve-fibres, when laid across the electrodes and 
subjected to currents absolutely unbearable upon the tongue, elicits no further response, and probably 
no movement whatsoever. To the whole popliteal nerve, representing an area of sentient skin 
which includes the entire sole and much of the leg besides, intolerable faradisation can be applied, 
and elicits no more, and often even less, response. A more impassable condition of block, or 
torpor, can hardly be imagined : its depth of negation resembles, to superficial examination, 
profound chloroform poisoning. The circulation is, however, approximately normal in these 
cases ; and the respiration absolutely so. The skin, as above stated, is well warm, even to the 
