August 6, 1920] 



SCIENCE 



119 



are two kinds of discoverers, -whose compara- 

 tive outlines we have not yet well discerned. 

 Of scientific discovery Henri Poincare gives 

 an interesting appreciation; 'he says that dis- 

 covery consists of three stages: the first stage 

 is of laborious work at the problem on all sides ; 

 the next is not one of conscious occupation 

 with the su^bject, but of unconscious cerebra- 

 tion, during which a promising hypothesis may 

 unexpectedly arise in the mind; the third is 

 deliberate verification and completion of form. 

 Thus out of an unlimited nimiber of possible 

 combinations, and by many speculations, the 

 discoverer at length divines the true one. In 

 medicine this has been clearly the course of 

 surgery, the side of medicine which is closer to 

 nature.® The surgery of my young days was 

 only too " observational " ; the friendly fingers 

 of curious colleagues were popped in and out 

 of an operative incision with no apprehensions 

 about " the infinitely little." Now the observer 

 is sadly pushed aside; the ritual of surgery is 

 become like the magic rites of old of which, if 

 a, point were dropped or a word changed, the 

 virtue went out. But the rite could be done 

 over again by the penitent; unluckily in sur- 

 gical rites there is little room for repentances. 

 A new scheme of research into the origin of 

 diseases, lately instituted at St. Andrews, 

 claims our respectful attention. And may I 

 be forgiven if here I pay a tribute to the rare 

 devotion which inspired Sir James Mackenzie 

 to forsake place and honor to follow after 

 knowledge; indifferent whither he were led so 

 long as truth was the leader. Sir James 

 argues that the man in charge of the first devia- 

 tions from health is the general practitioner; 

 and that, if we are to detect diseases in their 

 incipience, he must be the detective. One 

 evening about the year 1879, when staying with 

 Sir George Humphrey, he and I sat into the 

 small hours devising a method by which we 

 hoped to engage the general practitioner in 

 scientific investigation. We secured the co- 

 operation of this association and of many co- 



6 See C. A., 

 Survey. ' ' 



'Hist. Relations of Medicine and 



adjutors;" Dr. Mahomed joined us as secre- 

 tary. We hoped by gathering in large numbers 

 of observations to eliminate error; and several 

 series of questionnaires were distributed. 

 Pour volumes of reports were issued, under 

 such editors as Humphry himself (on Old 

 Age), Butlin (on Cancer), Whipham (on 

 Rheumatic Fever), and Isambard Owen (on 

 Intemperance). But the effort was premature; 

 the data were too rickety, the reports too often 

 irregular, dilatory and imperfect, and the re- 

 porters untrained in observation, punctuality 

 and precision. As things are, few of our col- 

 leagues remember to let us know the issues of 

 cases seen in consultation. We may hope now 

 for better material and more accurate work- 

 ers; not only so, but Sir James Mackenzie is 

 developing another and no doubt better 

 method; he is working with intense culture, 

 on a small holding, and on a more intimate 

 clinical plan. 



In exploring a country the great watersheds 

 and rivers are first laid down ; to map out these 

 and their valleys and tributaries is the first 

 great work. These main features known, bear- 

 ings are obtained whence to discover the con- 

 tours of the hills, and to track up to the hidden 

 sources of the streams. This is Sir James's 

 mission — to track out the nascent rivulets, and 

 with his divining rod to dig for the springs 

 which feed the streams of disease. 



Let us not suppose that this research will be 

 but a matter of cleverness, sagacity, or even of 

 intensive observation; nor fiatter ourselves 

 that because Mackenzie produced his great 

 work on the Pulse while a general practitioner 

 that he achieved this by ordinary clinical ob- 

 servation, however acute The progress of 

 medicine must in large part be endogenous. 

 While our pathologists in balloons were work- 

 ing on 'morbid phenomena without ever see- 

 ing a sick man, Mackenzie was bringing labor- 

 atory equipment, and exquisite laboratory 

 methods, to the bedside. The polygraph, no 

 easy instrument to handle even now, was the 

 grandchild of the kymograph; and by it was 



7 See Sir 6. Humphry 's presidential address at 

 Cambridge, 1880. 



