III. Worms and certain acrid matters in the alimentary canal. Morgagni relates an instance of the former, and I shall hereafter mention instances of the latter in new-born infants.
IV. Certain poisonous vegetables. There are several cases upon record of its being induced by the hemlock dropwort, and the datura stramonium, or Jamestown weed of our country.
V. It is sometimes a symptom of the bilious remitting and intermitting fever. It is said to occur more frequently in those states of fever in the island of Malta, than in any other part of the world.
VI. It is likewise a symptom of that malignant state of fever which is brought on by the bite of a rabid animal, also of hysteria and gout.
VII. The grating noise produced by cutting with a knife upon a pewter plate excited it in a servant, while he was waiting upon his master's table in London. It proved fatal in three days.
VIII. The sight of food, after long fasting.
X. Certain emotions and passions of the mind. Terror brought it on a brewer in this city. He had been previously debilitated by great labour, in warm weather. I have heard of its having been induced in a man by agitation of mind, occasioned by seeing a girl tread upon a nail. Fear excited it in a soldier who kneeled down to be shot. Upon being pardoned he was unable to rise, from a sudden attack of tetanus. Grief produced it in a case mentioned by Dr. Willan.
All these remote and exciting causes act with more or less certainty and force, in proportion to the greater or less degrees of fatigue which have preceded them.
It has been customary with authors to call all those cases of tetanus, which are not brought on by wounds, symptomatic. They are no more so than those which are said to be idiopathic. They all depend alike upon irritating impressions, made upon one part of the body, producing morbid excitement, or disease in another. It is immaterial, whether the impression be made upon the intestines by a worm, upon the ear by an ungrateful noise, upon the mind by a strong emotion, or upon the sole of the foot by a nail; it is alike communicated to the muscles, which, from their previous debility and irritability, are thrown into commotions by it. In yielding to the impression of irritants, they follow in their contractions the order of their predisposing debility. The muscles which move the lower jaw are affected more early, and more obstinately than any of the other external muscles of the body, only because they are more constantly in a relaxed, or idle state.
