January 10, 1908] 



SCIENCE 



61 



Poiseuille and others, and the studies of 

 the botanists, Pfeffer and de Vries, on the 

 turgor of vegetable cells opened an impor- 

 tant field of physical chemistry. 



Aspects of my subject, full of intei'est, 

 which I can now barely touch upon, are 

 the influence of previous medical or biolog- 

 ical training upon the work of a physicist 

 or chemist, and closely connected with this 

 the extent to which purely physical prob- 

 lems have been approached from the bio- 

 logical side. Call to mind how the central 

 physical and chemical problem of the 

 eighteenth century, the nature of combus- 

 tion, was throughout this period intimately 

 associated with the kindred physiological 

 problem of respiration, and how John 

 Mayow in the seventeenth century, ap- 

 proaching the subject from the biological 

 side, reached a conclusion in accord with 

 that fully demonstrated a century later by 

 Lavoisier, who thereby opened a new era 

 for physiology as well as for chemistry. 

 For the first time clear light was shed upon 

 the function of respiration, the nature of 

 metabolism and the sources of animal heat, 

 and such physical interest was attached to 

 the study of these physiological phenomena 

 that physicists of the rank of Laplace, in 

 association with Lavoisier, Dulong, W. E. 

 Weber, Magnus, A. C. Becquerel, Hirn, 

 Regnault, and of course Helmlioltz, have 

 all made valuable contributions to the 

 elucidation of these subjects. 



The study of electricity, especially after 

 the physiologist, Galvani's epochal discov- 

 ery, more correctly interpreted by Volta, 

 engaged the attention of physicians and 

 physiologists scarcely less than that of 

 physicists. The latter became greatly in- 

 terested in animal electricity, a subject 

 partly cleared up by the physicists, Ritter 

 and Nobili, but mainly by the physiologist, 

 Du Bois Reymond. Ostwald points out, as 

 a matter of interest in the history of the 

 human mind, that the physician Soemmer- 



ing was led to conceive of the transmission 

 of intelligence by electricity from analogy 

 with the conveyance of impulses by the 

 nerves, and thus to invent his pi-actically 

 useless form of the electric telegraph. 

 However fanciful such a relationship may 

 be, it is interesting, as Sir David Brewster 

 discovered, that the first proposal for an 

 electric telegraph worked by statical elec- 

 tricity was made and actually carried into 

 efliect as early as 1753 by the Greenock 

 surgeon, Charles Morrison. It is now well 

 understood that no one has the sole credit 

 of inventing the electric telegraph, the idea 

 of which was implicit in Stephen Gray's 

 observation in 1727 of the transmission of 

 electricity by a wire. 



Of curious interest is the introduction of 

 electricity for the treatment of disease by 

 the physicists, Kratzenstein, NoUet and 

 Jallabert, shortly before the middle of the 

 eighteenth century, who reported cures by 

 its use. 



There is no more striking illustration of 

 the correlation of two apparently distinct 

 lines of approach to the same problem than 

 the attack from the biological and from the 

 purely physical sides upon the thermo- 

 dynamic problem, which is as fundamental 

 for biology as for physics. The conception 

 of the principle of conservation of energy 

 was supplied independently and almost 

 simultaneously on the one hand by stu- 

 dents of the conditions of mechanical work 

 done by the animal machine and on the 

 other hand by investigators of technical 

 machines. Much of the essential prelim- 

 inary study was on the biological side 

 by Boyle, Mayow, Black and Lavoisier. 

 Mainly from the same side the physician 

 and physicist, Thomas Young, first formu- 

 lated the modern scientific conception of 

 energy as the power of a material system 

 to do work. Davy and Rumford contrib- 

 uted, and from the physiological side Mohr, 

 Mayer and Helmholtz, and from the purely 



