246 THE PRESENT IMPORTANCE OF SCIENCE 



will, if traced back, afford illustrations of the value of pure 

 research. For the purpose of illustrating what has happened 

 again and again, several representative cases may now be 

 elaborated. 



DEVELOPMENT OF KNOWLEDGE REGARDING MICROORGANISMS 



By means of this illustration, we propose to show: that 

 facts now recognized as of life-and-death importance for the 

 whole civilized world, had their beginnings in investigations 

 which were of questionable value when judged by the 

 utilitarian standards of the past; and further, that society 

 might profit by this bit of history and assume a more 

 farsighted policy in dealing with scientific investigation in 

 the present. 



That many diseases are caused by minute organisms, 

 living as parasites within the bodies of animals and plants, 

 and so producing the derangements called disease, is a fact 

 made familiar during recent years. It is also well known 

 that progress in the discovery of germs hitherto unrecognized, 

 of antitoxins, of vaccines, and the like is saving the lives of 

 millions. At the present day, diphtheria is no longer the 

 dangerous and often fatal disease it was even twenty years 

 ago. If we take the precautions already well tested, there is 

 no danger that yellow fever will again scourge our gulf 

 cities, or bubonic plague devastate Europe and America as it 

 still devastates the Orient. We have conquered typhoid 

 fever, at least in cases of local epidemics or where large 

 bodies of men are sent into dangerous territory, and no man 

 can foresee where such control of disease will end. 



These are familiar facts. The steps by which the mastery 

 has been attained are less well known. We take this mastery 

 as a matter of course, without understanding the historical 

 development of the knowledge which now means life or 

 death. It is true one may be familiar with the most recent 

 chapters, as heralded in the newspapers and current mag- 



