472 TETANUS TKISMTJS LOCKED-JAW. 



tion of the polar state commences in the afferent nerves of 

 the seat of the wound : if the tetanus arise from cold, the 

 exalted polarity commences in the nerves of common sen- 

 sation distributed to the exposed parts : from the peri- 

 phery thus irritated the condition is propagated through 

 the nerves to the centres, and the effects on the muscular 

 system show to what portions of the nervous centres the 

 exaltation of the polar force is communicated. This, how- 

 ever, does not afford an adequate explanation of the pro- 

 duction of tetanus ; for peripheral nerves, and even nervous 

 centres, are often subjected to great irritation without 

 giving rise to tetanus ; and it is well known that it is im- 

 possible, even by severe mutilations, to produce tetanus in 

 the lower animals : whereas a slight accidental injury (as 

 when a horse picks up a nail) will often excite the disease 

 in its worst form. It would seem that some peculiar state 

 of the system, probably some peculiar condition of the 

 blood, is a necessary precursor of this malady. Hence, 

 no doubt, its greater frequency in warm and unhealthy 

 climates, in overcrowded and badly ventilated military 

 hospitals, and among ill housed, ill clad, and ill fed infants. 

 That tetanus may be produced through the blood is shown 

 by the results of the administration of strychnine which 

 irritate the tetanic symptoms in a very striking manner, so 

 that you may at will develope the general phenomena of 

 tetanus in an animal by giving him strychnine, or injecting it 

 into his blood, but you cannot cause it by external injuries." 

 The post-mortem appearances of tetanus afford us no in- 

 formation of a positive character. Sometimes a particle 

 of dirt is found near an inflamed nerve ; in other cases the 

 brain and spinal cord are congested, but there is no con- 

 stancy in the lesions met with, and we can furnish no facts 

 of moment regarding them. 



