THE HISTORY OF INTERNAL MEDICINE 233 



The utter futility of the speculative method as a means of attaining 

 effective knowledge is completely demonstrated by the stagnation and 

 inefficiency of medicine under its influence for thousands of years. The 

 only sure and effective way of gaining knowledge is the empirical 

 method, by patient observation and investigation, the tardy adoption of 

 which was the sole means by which internal medicine has been revolu- 

 tionized and vivified. The keynote of the true method was struck by 

 John Hunter in his advice to Jenner when the latter was beginning to 

 ponder on the subject of vaccination, " Do not think ; investigate." 

 The whole history of medicine is an imposing demonstration of the 

 futility of theorizing and the utility of scientific investigation. This 

 lesson should come home to every one of us, and indicate the only 

 mental attitude we can safely assume. We should formulate our judg- 

 ments only by the objective and empirical route. We should avoid 

 dogmatism, premature theorizing, and generalization from insufficient 

 data. We should frankly admit our ignorance, and not deceive ourselves 

 or others by unfounded assumptions. We should practise a healthy 

 skepticism, and carefully scrutinize the information offered us. No 

 authority is too eminent, no traditions too ancient, to be exempt from 

 criticism. The vast amounts of chaff in our professional literature need 

 to be carefully sifted for the few kernels of truth ; while to a far greater 

 extent the ready acceptance of the interested representations of com- 

 mercial establishments is a mark of naive simplicity and easy credulity. 

 Always as the test of verity should be demanded the evidence of and 

 agreement with an ample body of objective data. These considerations 

 may seem trite, yet experience constantly demonstrates the necessity for 

 their vigilant observance. 



It is disquieting to reflect on the inefficiency and even harmfulness 

 of much of the medical practise of the past. Yet our predecessors were 

 men of sincerity and high ideals, and had the trust and confidence of 

 the mass of the people. The therapeutic successes of the past must be 

 construed mainly as an exemplification of the potency and action of 

 psychotherapy. 



Although the scientific method imposes rigorous criteria for the 

 acceptance of doctrines, yet truths so established rest on a firm and 

 abiding basis. For this reason we can feel confidence in the validity 

 and permanency of such of our present medical theory and practise as 

 has a thorough scientific basis. We have good reason to feel that at last 

 we have attained some degree of finality in many of our doctrines ; that 

 the medicine of to-day is radically different from the ephemeral systems 

 of the past and wherever thoroughly grounded on a scientific foundation 

 will stand for all time. 



If it be true that medicine has only just emerged from the middle 

 ages, some medieval error must still persist in our doctrines and 



