It was not until the beginning of the sixteenth century that the St. Vitus' dance was made the subject of medical research, and stripped of its unhallowed character as a work of demons. This was effected by Paracelsus, that mighty, but as yet scarcely comprehended, reformer of medicine, whose aim it was to withdraw diseases from the pale of miraculous interpositions and saintly influences, and explain their causes upon principles deduced from his knowledge of the human frame. "We will not, however, admit that the saints have power to inflict diseases, and that these ought to be named after them, although many there are who in their theology lay great stress on this supposition, ascribing them rather to God than to nature, which is but idle talk. We dislike such nonsensical gossip as is not supported by symptoms, but only by faith, a thing which is not human, whereon the gods themselves set no value." Such were the words which Paracelsus addressed to his contemporaries, who were as yet incapable of appreciating doctrines of this sort; for the belief in enchantment still remained everywhere unshaken, and faith in the world of spirits still held men's minds in so close a bondage that thousands were, according to their own conviction, given up as a prey to the devil; while, at the command of religion as well as of law, countless piles were lighted, by the flames of which human society was to be purified. Paracelsus divides the St. Vitus' dance into three kinds: First, that which arises from imagination (_Vitista_, _chorea imaginativa_, _aestimativa_), by which the original dancing plague is to be understood; secondly, that which arises from sensual desires, depending on the will (_chorea lasciva_); thirdly, that which arises from corporeal causes (_chorea naturalis_, _coacta_), which, according to a strange notion of his own, he explained by maintaining that in certain vessels which are susceptible of an internal pruriency, and thence produce laughter, the blood is set in commotion, in consequence of an alteration in the vital spirits, whereby involuntary fits of intoxicating joy, and a propensity to dance, are occasioned. To this notion he was, no doubt, led from having observed a milder form of St. Vitus' dance, not uncommon in his time, which was accompanied by involuntary laughter, and which bore a resemblance to the hysterical laughter of the moderns, except that it was characterized by more pleasurable sensations, and by an extravagant propensity to dance. There was no howling, screaming, and jumping, as in the severer form; neither was the disposition to dance by any means insuperable. Patients thus affected, although they had not a complete control over their understandings, yet were sufficiently self-possessed, during the attack, to obey the directions which they received. There were even some among them who did not dance at all, but only felt an involuntary impulse to allay the internal sense of disquietude, which is