128 
THOMPSON YATES LABORATORIES REPORT 
long neural paths either by spinal transection or by certain depths of chemical anaesthetization, the 
various intra-spinal paths and resistances are not merely altered, but altered unequally. It is 
imperative, therefore, here to consider the phenomenon of 'shock' ; I do so the more willingly, 
because this condition lias, as I think, received as yet hardly adequate attention from physiologists. 
' Shock,' like ' collapse,' is a term more used by the clinician than by the physiologist ; the 
scope of both words is usually left ill-defined. In some forms of the clinical condition circulatory 
disturbance and inspissation of the blood play a part in ' shock,' but as understood by the 
physiologist, 'shock' is primarily a nervous condition. ' If in a Frog the spinal marrow be 
divided just below the occiput, there are for a very short time no diastaltic actions in the 
extremities. The diastaltic actions speedily return. This phenomenon is "shock."'* In this, 
as in previous papers, I myself mean by the term the whole of that depression or suppression of nervous 
reaction which ensues forthwith upon a mechanical injury of some part of the nervous system, and is of 
temporary nature. The best explicit account of the condition is contained in the papers of Goltz. 
By him temporary paralysis following injuries of the brain or cord are all classed as Hemmung- 
serscheinungen, and these collectively may be considered to compose the phenomenon of ' shock.' 
GoLTz'st descriptions of spinal shock are masterly, but they refer entirely to the Dog, and to 
transection below the middle of the back. As it is in the Monkey that the phenomenon appears 
at maximum, and especially consequently to high cervical transection, I shall give a description of 
it as so seen. No more remarkable nervous condition can be imagined. 
Whether the position of the severance be near the top or at the bottom of the thoracic 
region makes some, but no very great, difference to the general result, beyond of course increasing 
or reducing the number of spinal segments displaying the phenomenon. The ' shock' appears to 
take effect in a downzvard direction only. Thus section below the brachial enlargement does not 
obviously disturb in any way the reactions of the upper limb and this although we know by 
anatomy (Wallerian method) that the number of upward channels ruptured by such a section is 
enormous, and must think, therefore, that many co-ordinating ties between the upper and lower 
limbs are destroyed. Again, most striking instances of the absence of upward spread of the 
depression due to 'shock' are afforded by transections abutting on the lower edge of the 5th 
cervical segment ; these depress the respiratory activity of the phrenic motor neurons hardly at all 
even momentarily (Cat). The rhythmic action of the motor neurons (for the diaphragm) is not 
obviously interfered with, although on the lower side of the transection depression may be profound. 
Analogously, the sudden cutting off of that stream of subconscious centripetal impulses which 
must be continually pouring to the brain from tail, lower limbs, and trunk, seems to disturb the 
head and brain not at all. The animal immediately after the section will direct its attention to 
catching flies, or looking out of the window, taking no notice of nor apparent interest in its 
paralyzed and insensitive parts. After section of the cord above the ist cervical pair there is no 
obvious disturbance in the head ; as the creatures lie quiet and watchful, the only and dubious sign 
of abnormality is a tendency to drop off rapidly and frequently into sleep. The pupils are equal 
and, of course, small. 
* Marshall Hall, ' Synopsis of the Diastaltic Nervous System,' London, 1850. 
f Pfliiger's ' Archiv.,' vol. 8, 460. ' Die Functionen des Lemlen-markes c!es Hiindes.' 
