It is rather a rude and unscientific theory. There is a trifling mistake in calling such _compounds_ as earth, air, water and fire _elements_. Still, as a theory, it is quite as rational as most of the theories spun from the more refined brains of some of Thompson’s enemies, the ‘regulars,’ as they are styled by his erudite followers; and I may say too that it is quite as good a guide in actual practice. But this point I shall speak of in another place. Thompson makes great account of ‘obstructed perspiration’ in his theory. ‘All diseases,’ he says, ‘arise directly’ from it. It is difficult to conceive what he does in his theory with the cold _sweat_ of death; with the _sweating_ sickness, as it was called, once so extensively prevalent and so fatal; with the colliquative _sweat_, always so bad a symptom in disease, though there may be heat enough with it to satisfy the most _ardent_ Thompsonian; or with the _sweat_ of rheumatism, so unapt to bring relief to the disease. In all these cases, there is certainly _un_obstructed perspiration, and yet it does not remedy the disease, as it should do, according to the Thompsonian theory. While he considers fire or heat as life, he thinks that the ‘obstructed perspiration’ always ‘originates from _cold_,’ which he seems to personify as a sort of master spirit, producing all disease—it is the ‘legion,’ which his medicines, and his alone, are fitted to overcome and dispossess. With him, heat and cold are the two combatants that fight in the battle of disease. And while the doctors, he says, ‘assist the cold to kill the patient,’ under his practice, ‘the heat gains the victory, the cold is disinherited, and health is restored.’ The fact, that the ‘obstructed perspiration’ is often made free by cooling medicines, or by the direct application of cold to the skin, and thus, disease is relieved, (a fact which is as well known to common observers, as it is to ‘doctors,’ and which is directly in the face of his theory,) I suppose he flatly denies, as he asserts in regard to fever, that ‘if you contend against the heat, the longer will be the run of the fever, and when extinguished, death follows.’