378 FALLACIES. 



wonder if a presumption naturally grew up in men's 

 minds, that causes must necessarily resemble their 

 effects, and that like could only be produced by like. 



This principle of fallacy has usually presided over 

 the fantastical attempts to influence the course of 

 nature by conjectural means, the choice of which was 

 not directed by previous observation and experiment. 

 The guess almost always fixed upon some means 

 which possessed features of real or apparent resem- 

 blance to the end in view. If a charm was wanted, 

 as by Ovid's Medea, to prolong life, all long-lived 

 animals, or what were esteemed such, were collected 

 and brewed into a broth: 



. . . . nee defuit illic 

 Squamea Cinyphii tenuis membrana chelydri 

 Vivacisque jeeur cervi : quibus insuper addit 

 Ora caputque novem cornicis saBCula passag. 



A similar notion was embodied in the celebrated 

 medical theory called the " Doctrine of Signatures," 

 " which is no less," says Dr. Paris*, "than a belief 

 that every natural substance which possesses any 

 medicinal virtue indicates by an obvious and well- 

 marked external character the disease for which it is 

 a remedy, or the object for which it should be em- 

 ployed." This outward character was generally some 

 feature of resemblance, real or fantastical, either to the 

 effect it was supposed to produce, or to the pheno- 

 menon over which its power was thought to be 

 exercised. "Thus the lungs of a fox must be a 

 specific for asthma, because that animal is remarkable 

 for its strong powers of respiration. Turmeric has a 

 brilliant yellow colour, which indicates that it has the 

 power of curing the jaundice; for the same reason, 



Pkarmacologia, ut supra, pp. 43 5. 



