416 INTRODUCTORY LECTURES. 



sity, while the most part of practitioners at least profess empiri- 

 cism. The last have occasion so often to declare against theory, 

 that they either influence the opinion of students on this sub- 

 ject, or at least render them undetermined. I consider this as 

 of the worst consequence, that is, for students to be prejudiced 

 against a measure they are obliged to pursue, and it must lead 

 to a pernicious inattention and negligence ; for it must very 

 often happen, that in neglecting what they think is theory, they 

 must miss or neglect the most important facts. It is necessary, 

 therefore, that you should be determined on this subject ; but a 

 full discussion of it would require more time than we can bestow 

 upon it. I must suppose that you have in some degree con- 

 sidered it at first entering upon the Institutions of Medicine. If 

 any of you have not had that opportunity or some other such 

 of considering it, I would still earnestly recommend it to your 

 particular attention. The subject has hitherto been treated as 

 a controversy between parties, who always embrace or reject 

 without distinction ; but it will appear that there are advan- 

 tages in either plan, and that therefore we should endeavour to 

 employ the useful parts, while we carefully avoid and reject the 

 faults, of both. It is not necessary to determine absolutely 

 either for experience or against reasoning, but it is extremely 

 necessary to know that both have their imperfections, that 

 both are exposed to fallacies, and that, in the present state of 

 science, either of them is by itself insufficient. Every body ad- 

 mits the use of experience, and the necessity of consulting it, 

 but few are aware of its being exposed to much fallacy, and that 

 we have more false facts obtruded upon us, and subsisting in 

 our books, than false reasonings ; so that the stock of true facts 

 is very small, and far short of the demands which the practice 

 of physic has for them. On the other hand, no body pleads for 

 the use of theory alone, and every body knows, that it is falla- 

 cious, and has often corrupted our art ; but few perceive that at 

 the same time it is unavoidable, necessary, and to a certain ex- 

 tent useful. Almost every body can perceive the errors of 

 theory in general, but very few are aware, that, while they de- 

 clare against it in general, they themselves employ it on parti- 

 cular occasions too freely, and with more mischief, because of 

 their general prejudices. For perceiving and understanding all 



