DEMOCRATS AND ARISTOCRATS IN SCIENTIFIC RESEARCH 421 



"diseases" of beer and wine, and of the fatal silkworm disease, and 

 thence to the extermination of those plagues, fowl cholera and anthrax, 

 which were wiping out the flocks and herds of France, saving to the 

 country in a matter of months the equivalent of the Franco-Prussian 

 war debt, and thence to preventive vaccination in man, has been the 

 theme of a score of biographies and many an inspiring address. The 

 life of this non-medical man is held up as a shining example by the 

 most intolerant of professions for the guidance of its students and future 

 fellow physicians. 



Commenting on aims in scientific research the famous British 

 chemist, Roscoe, chose a text from Pasteur to bear him out in his con- 

 tention that although it would be foolish and short-sighted to decry the 

 pursuit of any form of scientific study because it was as yet far re- 

 moved from practical application to the wants of man, yet discoveries 

 which tend to diminish the ills that flesh of man or beast is heir to, 

 deservedly create a more general interest than those having no direct 

 bearing on the welfare of the race. In the French hero's simple words, 

 "There is no greater charm than to make new discoveries, but the 

 pleasure of the investigator is more than doubled when he sees they 

 find direct application in practical life." * 



The same year that Pasteur graduated from the Ecole Normale in 

 Paris a young German physician, but a few months older, read, before 

 the physical society of Berlin, one of the two epoch-making scientific 

 contributions of the century, "Ueber die Erhaltung der Kraft" rivaled 

 only by the Origin- of Species in its effect upon thought. The notion 

 of the Conservation of Energy may not have originated in the preco- 

 cious intellect of Helmholtz, for Newton, DesCartes, Leibnitz, Lavoisier, 

 Mayer, Colding and Joule had more than touched it, but it surely 

 crystallized there. It remained for a physician to desert his chosen 

 field for a theoretical one and establish the fact that energy, although 

 it may be transformed in kind, is indestructible, and the total quantity 

 in the universe is constant. The physiologist was also a mathematician 

 of the first order. 



Perhaps the most frequently cited achievement of Helmholtz is his 

 invention of the ophthalmoscope, that familiar combination of mirror 

 and lenses used in examination of the interior of the eye. How did he 

 come to devise it? As a matter of fact it took its origin in a simple 

 desire to exhibit a physiological phenomenon to his students. It had 

 long been known that light could be reflected from the back of an 

 animal's eye, but no one had yet been able to put his own eye in such 

 a position as to have reflected directly back to it light from the 

 illuminated eye in concentrated form. Helmholtz, by the proper dis- 

 position of mirrors, involving a knowledge of optics and the anatomy 

 of the eye, accomplished this for the first time, and, eight days after 



