368 Human Physiology. 



Mineral poisons, to some of which I have referred as- 

 producing the diseases of certain trades, have been used as 

 medicines, when they act primarily as poisons, but secondarily 

 as alteratives or evacuants. Thus, mercury is given as an 

 alterative and cathartic; antimony as an expectorant and 

 emetic. Nearly all the drugs, vegetable or mineral, used as 

 medicines, are of the nature of poisons, and may be, and often 

 are, causes of disease. One irritant poison taken into the 

 stomach produces a spasmodic reversed action by which it is 

 thrown up, with the other matters the organ contains ; another,, 

 of a less suddenly irritative character, is expelled more slowly 

 by the bowels, which are at the same time excited to throw off 

 other matter. In each case good may be done, but in each 

 there may also be more or less injury to the nervous system 

 and the irritated organs. The habitual use of purgative medi, 

 cines is often a serious cause of disease; and nearly all medica- 

 tion must be considered a choice of evils. 



In short, every deprivation of the conditions or violation of 

 the laws of health is a cause of disease. Whatever overtaxes 

 or diminishes the nervous energy, the inner life, or what some 

 have called the vital force, or vital principle, is a cause of dis- 

 ease. Whatever introduces foul, noxious, or poisonous matter 

 into the system, or prevents the waste and morbific matter from 

 being thrown out of it, causes disease. Whatever lessens the 

 normal action of any of the vital organs, is a cause of disease. 

 Whatever diminishes the energy or disturbs the harmonious 

 action of this wonderful machine, or organ of the divine life 

 the body and soul of man is a cause of disease. 



