384 GENERAL NEUROSES, OF UNKNOWN ANATOMICAL ORIGIN. 



should endeavor to teach the patient, by a systematic and humane 

 system of discipline, to resist the involuntary motions by the force 01 

 his will. 



CHAPTER II. 



LOCKJAW TRISMUS TETANUS. 



ETIOLOGY. Like chorea, lockjaw is a derangement of the motor 

 function. The symptoms of this disease are ascribable to a morbid 

 excitement of the motor nerves, the participation of the sensory nerves 

 in the disease being but slight, and, for the most part, of a secondary 

 character. In this malady, however, we know, with much greater cer- 

 tainty than we do in chorea, that the morbid irritation of the motor 

 nerves proceeds from the spinal marrow. This hypothesis is supported 

 rather than contradicted by the fact that the results of post-mortem 

 examination of the spinal marrow usually are negative in cases of 

 tetanus, and that real tetanic spasms are seldom observed in cases of 

 grave organic disease of the spinal cord. It would be quite impossible 

 for motor impulses to originate from a spinal marrow reduced to a mass 

 of debris, or whose elements were otherwise degenerate or destroyed, 

 wnile experience teaches that the lesions from which abnormally-active 

 impulses proceed are insusceptible of anatomical demonstration. At 

 the outset of the disease, tetanic spasms are generally produced by 

 the action of trifling but still appreciable irritants, which, acting upon 

 the extremities of the peripheral nerves, throw the spinal marrow into 

 a state of excitement, so that, at this period, the spasms, although dis- 

 tinguishable from other reflex symptoms by their greater violence and 

 longer duration, may be called reflex spasms. As the malady advances, 

 however, such causes are not required in order to give rise to the 

 cramps. The spinal marrow then remains permanently in the condi- 

 tion of intense excitement into which it is thrown by the motor nerves. 



With regard to the etiology of the disease, a number of noxious 

 agents may be enumerated, which can be proved capable of inducing 

 the morbid state of the spinal marrow to whicn tetanus is due. First 

 among these are wounds, especially lacerated, punctured, and gunshot 

 wounds, and wounds in which foreign bodies remain lodged. Injuries 

 of this kind are more dangerous upon the extremities than upon othei 

 parts of the body ; but they never give rise to tetanus except under 

 certain conditions, of which, sudden change of temperature (such as 

 hot days followed by cold nights) Ts known to be one, while others are 

 unknown. JZardeleben aptly sums up this condition as follows: that 

 the wound is the predisposing agent, and the chilling the exciting 

 cause. We do nit know, however, what the changes in the nerve- 



