688 



SCIENCE 



[N. S. Vol. XXXIV. No. 879 



chemistry, founded by Nernst on Ar- 

 rhenius 's theory of ions. It may well be ex- 

 pected that this new field of investigation 

 will throw much light on problems, when- 

 ever electric currents are generated in the 

 organism. 



It has been but a few years since electro- 

 chemistrj' has found its application in the 

 phj-siology of muscles and nerves. The 

 automatic action of the heart as well as the 

 electrical currents accompanying it will 

 very likely find a physico-chemical ex- 

 planation. These are only a few examples 

 from the field of normal physiology. 



Let us now see what was the influence of 

 physical chemistry on other medical sci- 

 ences. 



Pathological physiology has gained by 

 important discoveries on the chemical 

 causes of disturbances in the circulation 

 and the genesis of oedema. In pharmacol- 

 ogy the great achievements in narcotics 

 and disinfection are due in a large measure 

 to physical chemistry. 



Bacteriology and histology have also 

 profited since by the st^^dy of permeability 

 and the law of dissociation the nature of 

 the process of staining came to be under- 

 stood. We now know why it is that cer- 

 tain kinds of cells absorb some substances 

 while others do not; and we also know 

 why the medium of solution of a stain is of 

 such importance in nuclear and bacterial 

 stains. 



Experimental embryology has gained 

 much by a physico-chemical method of 

 artificial parthenogenesis ; and as for prac- 

 tical medicine, we may say that there is 

 hardly a test-book or a handbook which 

 does not show the influence of the theory 

 of osmotic pressure. This influence may 

 be found even in surgery. Examples of 

 this are the intravenous and hypodermic 

 infusion of the so-called physiological salt 

 solutions and local amesthesia. 



"We have attempted in the above to show, 

 by few examples only, how great an influ- 

 ence the theory of isotonic coefiBcients and 

 the closely related but exact theory of os- 

 motic pressure and that of the electrolytic 

 dissociation exerted on the medical sci- 

 ences. 



Also in an indirect way this theory 

 proved extremely important. The bril- 

 liant results achieved by it in the last few 

 years have been a stimulus for the applica- 

 tion of other branches of physical chemis- 

 try to biological problems. It was, for in- 

 stance, the chemistry of colloids and Van't 

 Hoff's theory of chemical equilibrium and 

 process of reaction that were soon taken 

 up and which, making use of the concept 

 of catalysis introduced by Wilhelm Ost- 

 wald, may aid us in understanding the 

 mechanism of enzyme action. 



To those who desire fuller information 

 on what physical chemistry has given us in 

 a short time, and to become familiar with 

 the names of many of its workers I should 

 recommend consulting some works treat- 

 ing exhaustively on this matter.^^ 



It may well be asked how it came that 

 physical chemistry had such brilliant re- 

 sults in our sciences. It is, I think, easy 

 to fijid the answer to this if we only con- 

 sider the specific methods of this science. 

 These unlike the methods of analytical 

 chemistry do not involve the use of strong 



" Ernst Cohen, ' ' Vortrage f iir Aerzte iiber 

 Physikalische Chemie, " 2. Aufl., 1907, Leipzig, 

 Wilhelm Engelmann; E. Hober, " Physikalische 

 Chemie der Zelle und Gewebe," 2. Aufl., 1906, 

 Leipzig, Wilhelm Engelmann; von Koranyi vmd 

 Eiehter, ' ' Physikalische Chemie und Medizin, ' ' 

 2 Bande, 1907-08, Leipzig, Georg Thieme. Several 

 articles in C. Oppenheimer 's "Handbueh der Bio- 

 chemie des Menschen und der Tierre, ' ' 1907 ff., 

 Jena, Gustav Fischer ; H. J. Hamburger, ' ' Os- 

 motischer Cruck und lonenlehre in den medizin- 

 isehen Wissenschaften. Zugleich ein Handbueh 

 physikalisch-chemischer Methoden," 3 Bande, 

 1902-1904, Wiesbaden, J. F. Bergemann. 



