November 3, 1916] 



SCIENCE 



631 



a perversion of the normal, and nature's 

 attempts to restore it, with what assistance 

 medicine can give. For medicine it is nec- 

 essary to know the normal in its elastic 

 and active organization. He who knows 

 how the body regulates its normal tem- 

 perature will not confuse heat-stroke with 

 fever, or make the mistake of attributing 

 fever to mere increased heat-production in 

 the body. He who knows how the breath- 

 ing is normally regulated will be in a posi- 

 tion to distinguish at once between various 

 causes of abnormal breathing ; and similarly 

 for every abnormal symptom met with in 

 disease. But the mechanistic physiology 

 gives a minimum of information about the 

 regulation of the normal. One looks in 

 vain in physiological text-books for con- 

 nected accounts of the regulation of breath- 

 ing, circulation, kidney activity, general 

 metabolism, nervous activity. The main 

 facts of physiology are partly ignored, and 

 partly strewn about in hopeless disconnec- 

 tion and confusion. A student of medicine 

 may learn some true physiology at the 

 bedside, or he may never learn it at all, 

 and become either a hopeless empiric or 

 what I do not hesitate to call a mechanistic 

 pedant. 



Medicine needs a new physiology which 

 will teach what health really means, and 

 how it is maintained under the ordinarily 

 varying conditions of environment. We 

 also need a pathology which will teach how 

 health tends to reassert itself under totally 

 abnormal conditions, and a pharmacology 

 which will teach us, not merely the "ac- 

 tions" of drugs, but how drugs can be 

 used rationally to aid the body in the main- 

 tenance and reestablishment of health. 

 The new physiology, new pathology, and 

 new pharmacology are growing up around 

 us just now. I can see them more particu- 

 larly in the splendid advances which the 

 medical and other biological sciences are 

 making in America. You have the advan- 



tage of having less of old intellectual ma- 

 chinery to scrap than we have in the old 

 countries; but perhaps we shall not be 

 much behindhand. 



If we look on pathology as simply the 

 description of damage to bodily structure, 

 and the analysis of the causes of this dam- 

 age, then pathology may be very helpful 

 in preventive medicine, but does not help 

 much in therapeutics. When, however, 

 pathology studies the processes of adapta- 

 tion to the unusual, defence of the organ- 

 ism against the unusual, and reproduction 

 of the normal, just as the new physiology 

 studies the maintenance of the normal 

 under ordinary conditions, then thera- 

 peutics and surgery will be aided at every 

 step by pathology, and a rational biological 

 pharmacology will have its chance. 



Sometimes one hears the complaint that 

 the world has grown old: that the great 

 discoveries have all been made; and that 

 nothing is left to us now but to work out 

 matters of sheer detail. Perhaps the great 

 and constantly growing mass of rather un- 

 interesting, but otherwise apparently 

 meritorious scientific literature, increases 

 this impression. At certain moments one 

 may long for the past centuries when there 

 was much less to read, and people seemed 

 to have plenty of time to think, and to have 

 endless material for new discoveries and 

 projects. But in reality I do not think 

 that there was ever more scope for new 

 ideas and discoveries than there is at pres- 

 ent. Among the new ideas are those of the 

 new physiology, the outlines of which I have 

 tried to trace in this lecture. Those who 

 do not feel inclined to accept this new 

 physiology, or who are still sceptical as to 

 its theoretical basis, will, I hope, at least 

 make allowance for any personal failure 

 on my part to present it to them in a more 

 convincing form. J. S. Haldane 



New College, 



University of Oxford 



