EXAMINATION OF SOME SPINAL NERVES 129 
If after transection above the ist cervical level in the Cat, sufficient time be allowed for the 
first effects of shock to pass away, the condition of the reflexes in the limbs, both fore and hind, be 
examined, and if then the cord be a second time transected, and this time at the 6th thoracic 
level, the second section produces a shock effect, but only on tlie aboral side of it. In tlie lower 
limb the skin reflexes, which may have been numerous and of sustained discharge, become few 
and brief, e.g., at the ankle, instead of an alternating discliarge of dorsal and plantar flexors, the 
idio-lateral reflex may be reduced to a simple dorsal flexion. In tlie fore-limbs, on the contrary, 
exaltation has occurred : the skin reflexes are more numerous and more sustained. The crossed 
reflex (in my experience rarely obtained) from one fore-limb to the other, may become elicitable, 
although not so previously. Similarly in front of the top section signs of exaltation are present. 
The surface seems hyperaesthetic ; a single touch with a piece of paper on the snout elicits 
vigorous licking of the spot touched ; the mere approach of a hot-water can (used to keep the 
animal warm) evokes screwing up of the eyes and of tiie mouth ; salivation is profuse, as a rule ; 
a touch on the vibrissae evokes exaggerated facial movement ; I have seen photophobia. 
The downward, posterior, aboral direction in which shock takes effect is, although the 
opposite of the direction of the vast majority of the fibres of the great afferent column of the cord, 
the same as that of easiest spread, both of the short and long paths that are intraspinal in the sense 
of confined in their course to the limits of the cord itself The ground for this, which is contrary 
to the ' law ' of PFLticER, will be given on a later page. It will be seen that Pfi.uger's ' laws ' 
must be modified in various particulars (see below pp. 170-175). 
After transection at the top of the cord there appears to be more shock in the fore than in 
the hind limbs. Long path reflexes are less able to evoke movement from the fore-limbs than 
from the hind, e.g., stimulation of pinna of ear more easily evokes movement of foot than of hand. 
Also the reflex movements obtained from each limb by excitations incident on itself are 
movements less forcible than those elicitable from the hind-limb. Occasionally, stimuli applied to 
the fore-limb evoke no movement in itself, though a brisk movement in the fellow hind-limb. 
The reflexes obtained under these conditions from the fore-limb, especially of flexion of elbow, 
tend to be tonic rather than clonic, whereas clonic contractions are the rule in the hind-limb, but 
this may depend on something other than depression. The depression of reflex activity after high 
cervical transverse section might be supposed to be due to the fall in general arterial blood-pressure 
which must ensue. That this cannot be the chief part of the explanation of this shock is clear 
from the above considerations : (i) that the head does not participate in the 'shock,' although 
participating in the lowered blood-pressure ; and (2) that when the transection is in lower dorsal 
region, the 'shock' distal to the sections is about as severe as after cervical transection. Besides, 
OwsjANNiKOW* pointed out that section of the splanchnics and its accompanying fall of blood 
does not cause shock, and that excitation of the peripheral ends of the cut splanchnics and the 
production of a good arterial pressure does not set it aside. 
* Ludwig's ' Arbeiten,' 1874, p. 314. 
R 
