526 INDUCTION. 



any of the three methods, but which is all the more 

 suited to illustrate the difficulties inherent in them. 

 Let the subject of inquiry be, the conditions of health 

 and disease in the human body ; or (for greater sim- 

 plicity,) the conditions of recovery from a given dis- 

 ease ; and in order to narrow the question still more, 

 let it be limited, in the first instance, to this one 

 inquiry : Is, or is not some particular medicament 

 (mercury, for instance,) a remedy for that disease. 



Now, the deductive method would set cut from 

 known properties of mercury, and known laws of the 

 human body, and by reasoning from these, would 

 attempt to discover whether mercury will act upon 

 the body when in the morbid condition supposed, in 

 such a manner as to restore health. The experi- 

 mental method would simply administer mercury in 

 as many cases as possible, noting the age, sex, tempe- 

 rament, and other peculiarities of bodily constitution, 

 the particular form or variety of the disease, the par- 

 ticular stage of its progress, &c., remarking in which 

 of these cases it produced a salutary effect, and with 

 what circumstances it was on those occasions com- 

 bined. The method of simple observation would com- 

 pare instances of recovery, to find whether they agreed 

 in having been preceded by the administration of mer- 

 cury ; or would compare instances of recovery with 

 instances of failure, to find cases which, agreeing in 

 all other respects, differed only in the fact that mer- 

 cury had been administered, or that it had not. 



7. That the last of these three modes of inves- 

 tigation is applicable to the case, no one has ever seri- 

 ously contended. No conclusions of value, on a sub- 

 ject of such intricacy, ever were obtained in that way. 

 The utmost that could result would be a vague general 



