GENERAL RECAPITULATIO N 3 PATHOLOGICAL APPLICATIONS. 843 



the Encephalon; and of these reflex movements, there are certain definite groups, 

 which are subservient to the functions of Respiration, Deglutition, Defecation, 

 &c. In so far as these are performed by the Spinal Cord alone, without the 

 participation of the Sensorium, they do not involve any affection of the con- 

 sciousness; and, as the separation of the Spinal Cord from the Sensorium 

 effectually prevents the impression which excites the reflex movement from 

 exciting sensation at the same time, we know that sensation cannot be necessary 

 to the movement ; hence this class of actions is best distinguished as excito- 

 motor, in contradistinction to the sensor -i-motor, in which Sensation necessarily 

 participates. Putting aside, however, those actions which are subservient to 

 the Organic functions, and which are performed in the state of full integrity 

 and activity of the nervous system, we find that the reflex power of the Spinal 

 Cord is only distinctly manifested when that organ is detached from the Ence- 

 phalon ; for in its normal state it serves as little else than the channel through 

 which impressions are transmitted upwards to the Sensorium, and thence to the 

 Cerebrum, and through which motor impulses are propagated downwards from 

 these centres to the muscles. For the actions of the Spinal Cord are placed in 

 subordination to the control of the Cerebrum, in every particular as to which 

 they can be, without detriment to the welfare of the system generally; so that 

 we find excitor impressions, which are quite competent to evoke reflex actions 

 if they are prevented from travelling beyond the Cord, losing their power to do 

 so when they are discharged (so to speak) into the Sensorium ; whilst even the 

 movements of Respiration, Defecation, &c., which do not require the participa- 

 tion of the Cerebrum, in their ordinary performance, can be to a certain extent 

 controlled by the "Will. 



XVI. In the various classes of Convulsive diseases in which the conscious- 

 ness is not affected, we have manifestations of the perverted activity of the 

 Spinal Cord as a whole, or of certain of its segments. Of the distinct forms 

 or combinations of which this class of disorders is composed, Tetanus is one of 

 the most interesting and instructive. This disease essentially consists in an 

 undue excitability of the whole series of Spinal Ganglia ; so that very slight 

 impressions produce violent and extensive reflex actions, the disturbance of nerv- 

 ous polarity induced by the impression, radiating (as it were) through the 

 whole Cord, and affecting nerve-fibres that proceed from each of its different 

 segments ; and when this state is fully established, convulsive actions may pro- 

 ceed from purely centric irritation, no excitor impression being required to ori- 

 ginate them. Such a state may be induced by various causes, among the most 

 prominent of which are, on the one hand, those which affect the nutrition of 

 the Cord, and, on the other, those which call it into disordered action, by alter- 

 ing the relations which the blood bears to it as the exciting fluid of the nervous 

 battery. That which is termed the idiopathic form of the disease seems trace- 

 able to mal-nutrition of the Cord, consequent upon impoverishment or deprava- 

 tion of the blood ; that, on the other hand, which is produced by the intro- 

 duction of Strychnia into the blood, is dependent upon the peculiar potency of 

 this substance in determining a wrong action of the Spinal centres, for which it 

 seems to have an elective affinity, in the same way that alcohol and opium have 

 for the encephalic. With regard to the traumatic form of Tetanus, it is im- 

 possible to say with certainty whether the peculiar condition of the Spinal Cord 

 be determined, as in the preceding case, by the introduction of a poison into 

 the blood, through some morbid action taking place in the wound ; or whether 

 the disturbance of the usual equilibrium be consequent upon the propagation of 

 a morbid influence directly from the injured nerve-trunk to the Spinal centres, 

 without any participation of the Circulating System in this extension of the 

 mischief. Whichever be the true account of it, this much is certain, that when 

 the Tetanic state of the Spinal Cord is once fully established, nothing is gained 



