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disease, has also the property of restoring health, we must seek 

 after a mode of causation by which this latter effect is accomplished 

 in an indirect way. The question, otherwise stated, is this, how do 

 remedies, whose immediate effect is to disorder the seats of their 

 operation, produce health? 



8. The answer to this question is, that they do it in general by 

 mediate relations, or they do it by a series of causation : ultimately, 

 disease must cease and health be resumed by the efficient causation, 

 so many times described ; but medicines do not commonly operate in 

 this way, they lead up to these results. 



9. Curative medicines may be divided into three classes: 1st, 

 those that cure by a direct relation with the cause of disease; 2nd, 

 those which cure by removing or obviating a perceptible (or sensible) 

 cause of disease by an intermediate relation ; 3rd, those which cure 

 by latent causation. First, to exemplify these. 



1. It is possible that a cause of disease may be removed in a 

 direct way, that is, the artificial means may be related with the 

 perceptible cause of disease, without any intermediate relation: as 

 if a remedy should be found, which being taken into the circulation 

 is chymically related with gall-stone so as to dissolve it, thereby 

 curing jaundice (supposing it to arise from an obstruction of this 

 sort in the biliary duct); or, as if a fluid should mix with indurated 

 faeces, soften them* and so admit a natural evacuation of them ; or, 

 as if a solvent should be discovered for calculus in the kidneys or 

 bladder. The cure of diseases in this way, by medicine, is similar 

 to that of the cure of diseases by the operations of surgery: thus, by 

 lithotomy a stone is removed from the bladder, and the disease 

 which its presence produced ceases; thus amputation is performed 

 above a diseased joint, and the hectic state of the constitution, which 

 was produced or maintained by the local disease, ceases; or, the burst- 

 ing of an aneurism is prevented by intercepting the supply of blood 

 by a ligature, &c. But the instances of the direct relation of an 

 artificial means with the cause of disease, in medicine, are rare. 



2. Recurring to an example, jaundice, we will say, is produced 

 by obstruction of the biliary ducts; under the exhibition of mercury, 

 this obstruction is removed, and the jaundice is cured. We will say, 

 for the sake of a specification, the cause of the disease is a gall- 

 stone. There is no direct relation between the mercury and the 

 gall-stone, by which the latter may be removed ; the gall-stone 

 would not be removed by putting calomel or blue pill into the 

 stomach, or into the gall-duct of a dead man. Mercury, then, re- 

 moves the gall-stone by its relation with some of the properties of 

 life, in some or other of its seats: say that mercury quickens the 

 action of the heart, and increases the impetus of the circulation, and 

 that thus mechanically, by a visa tergo, the obstruction is removed: 

 the relation then of the mercury is with the heart; if any other 

 modus operand! is assigned, then the mercury removes the gall-stone 

 by another intermediate relation. Disorder of the stomach is pro- 

 duced by the presence of bile: this is removed by an emetic, and 



