778 



SCIENCE. 



[N. S. Vol. XX. No. 519. 



duces a chemical or an osmotic change, or 

 whether it brings about a change of phase 

 or some other effect. It goes without say- 

 ing that a theory of sexual fertilization is 

 impossible until the independent variable 

 in the process of sexual fertilization is 

 known. 



But the investigations of the biologist 

 differ from those of the chemist and 

 physicist in that the biologist deals with 

 the analysis of the mechanism of a special 

 class of machines. Living organisms are 

 chemical machines, made of essentially 

 colloidal material which possess the pecul- 

 iarity of developing, preserving and re- 

 producing themselves automatically. The 

 machines ^vhicli have thus far been pro- 

 duced artificially lack the peculiarity of 

 developing, growing, preserving and repro- 

 ducing themselves, though no one can say 

 with certainty that such machines might 

 not one day be constructed artificially. 



The specific and main work of the biol- 

 ogist will, therefore, be directed toward 

 the analysis of the automatic mechanisms 

 of development of self-preservation and 

 reproduction. 



II. 



THE DYNAMICS OF THE CHEMICAL PROCESSES 

 IN LIVING ORGANISMS. 



The progress made by chemistry, espe- 

 cially physical chemistry, has definitely 

 put an end to the idea that the chemistry 

 of living matter is different from the chem- 

 istry of inanimate matter. The presence 

 of catalyzers in all living tissues makes it 

 intelligible that in spite of the compara- 

 tively low temperature at which life phe- 

 nomena occur the reaction velocities for the 

 essential processes in living organisms are 

 comparatively high. It has been shown, 

 moreover, that the action of the catalyzers 

 found in living organisms can be imitated 

 by certain metals or other inorganic cata- 

 lyzers. We may, therefore, say that it is 

 now proved beyond all doubt that the vari- 



ables in the chemical processes in living 

 organisms are identical with those with 

 which the chemist has to deal in the labo- 

 ratory. As a consequence of this result 

 chemical biology has during the last years 

 entered into the series of those sciences 

 which are capable of predicting their re- 

 sults quantitatively. The application of 

 the theory of chemical equilibrium to life 

 phenomena has led biological chemists to 

 look for reversible chemical processes in 

 living organisms and the result is the dis- 

 covery of the reversible enzyme actions, 

 which we owe to A. C. Hill. I think it 

 marks the beginning of a new epoch of 

 the physiology of metabolism that we now 

 know that the same enzymes not only ac- 

 celerate the hydrolysis, but also in some 

 cases, if not generally, the synthesis of the 

 products of cleavage. It is not impossible 

 that the results thus obtained in the field 

 of biology will ultimately in return benefit 

 chemistry, inasmuch as they may enable 

 chemistry to accomplish syntheses with the 

 help of enzymes found in living organisms 

 which could otherwise not be so easily ob- 

 tained. 



A very beautiful example of the con- 

 quest of biological chemistry through chem- 

 ical dynamics is offered by the work of 

 Arrhenius and Madsen. These authors 

 have successfully applied the laws of chem- 

 ical equilibrium to toxins and anti-toxins 

 so that it is possible to calculate the degree 

 of saturation between toxins and anti- 

 toxins for any concentration with the same 

 ease and certainty as for any other chem- 

 ical reaction. 



We know as yet but little concerning 

 the method by which enzymes produce 

 their accelerating effects. It seems that 

 the facts recently gathered speak in favor 

 of the idea of intermediary reactions. 

 According to this idea the catalyzers par- 

 ticipate in the reaction, but form com- 

 binations that are again rapidly decom- 



