and induce a belief that these pieces of wood and iron were endowed with some peculiar virtues." The result of Dr. Haygarth's experiments was the overthrow of Perkins, and the enlightenment of the public as to the real worth of the celebrated metallic tractors. In achieving this the worthy physician added some interesting facts to the science of psychology. But of course his influence upon the ignorant and foolish persons he illuminated was only transient. Ere a few short years or even months were over, they had embraced another delusion--not less ridiculous, but more pernicious. CHAPTER XV. IMAGINATION AND NERVOUS EXCITEMENT. MESMER. At a very early date the effects of magnetic influences, and the ordinary phenomena of nervous excitement, were the source of much confusion and perplexity to medical speculators, who, with an unsound logic that is perhaps more frequent than any other form of bad reasoning, accounted for what they could not understand by pointing to what they were only imperfectly acquainted with. The power of the loadstone was a mystery; the nervous phenomena produced by a strong will over a weak one were a mystery:--clearly the mysterious phenomena were to be attributed to the mysterious power. In its outset animal magnetism committed no other error than this. Its wilder extravagances were all subsequent to this assumption, that two sets of phenomena, which it has never yet been proved are nearly allied, were connected, the one with the other, in the relation of cause and effect, or as being the offspring of one immediate and common cause. To support this theory, Mesmerism called into its service the old astrological views regarding planetary influence. But it held also that the subtle fluid, so transmitted to the animal life of our planet, was capable of being passed on in greater or less volumes of quantity and intensity. Nervous energy was only that subtle fluid which was continually passing and repassing in impalpable currents between the earth and the celestial bodies; and when, by reason of the nervous energy within him, any one exercised control over another, he was deemed only to have infused him with some of his own stock of spiritual aura. Here was a new statement of the old dream which had charmed the poets and philosophers of buried centuries; and as it was a view which did not admit of positive disproof, it was believed by its excited advocates to be proved. One of the first British writers on animal magnetism was William Maxwell, a Scotch physician, who enunciated his opinions with a boldness and perspicacity which do him much credit. The first four of his twelve conclusions are a very good specimen of his work:-- "_Conclusio 1._--Anima non solum in corpore proprio visibili, sed etiam extra corpus est, nec corpore organico circumscribitur. "_Conclusio 2._--Anima extra corpus proprium, communiter sic dictum, operatur.