ON THE MYSTERY OF LIFE. 661 



seen in the phenomena of life the operation of some strange and unknown vital force, 

 some ' entelechy,' some expanding vital impulse ; or at least some new and undis- 

 covered form of ' biotic ' or ' nervous ' energy. It is difficult to resist the comparison 

 of the developing embryo with the building of a house to the plans of an invisible 

 architect. Growth and development seem to proceed on a definite plan and 

 apparently purposeful adaptation confronts us at many stages of life. How can the 

 differential equations of physics or the laws of physical" chemistry attempt to explain 

 or describe such strange and apparently marvellous phenomena ? The answer to 

 this question was given more than fifty years ago by the great French physiologist, 

 Claude Bernard. We must patiently proceed, he said, by the method of general 

 physiology. This is the fundamental biological science towards which all others 

 converge. Its method consists in determining the elementary condition of the phenomena 

 of life. We must decompose or analyse the great mass phenomena of life into their 

 elementary unit or constituent phenomena. That was the great answer given by 

 Claude Bernard. It is worthy of a Newton or an Einstein. It sounded the clarion 

 note of a new era of biological science. To-day general physiology in its application 

 of physics, chemistry and physical chemistry to the operations of the living cell is 

 the fundamental science of life. Patiently pursued and step by step it is unravelling 

 the mystery. The late Prof. Bayliss was one of the greatest of the pioneer successors 

 of Claude Bernard in England. Another of the greatest ones was Jacques Loeb in 

 America, whose death we all so deeply deplore. Although it is always invidious to 

 mention the names of living men, it is good to think that in England to-day we possess 

 three of the greatest living exponents of general physiology, namely, Barcroft, Hill 

 and Hopkins, whilst in America the great work of Jacques Loeb is carried on by 

 distinguished men of the high calibre of Lawrence Henderson, Osterhout and van 

 Slyke. In Germany we have such great names as Meyerhof, Warburg, Bechhold 

 aiid Hober, to mention only a few. What are these men attempting ? Just what 

 Claude Bernard set out in his programme, namely, by a patient, exact and quantitative 

 application of the facts and laws of physics and chemistry to the elementary phenomena 

 of life, gradually to arrive at a synthesis and understanding of the whole. That was 

 precisely how Newton was able to determine the motions of celestial objects, namely, 

 by going back to the elementary or fundamental law of gravitation. Through fine 

 analysis to synthesis is indeed the only true scientific method. I do not mean that 

 general physiology in the pursuit of its studies will not discover many things as yet 

 unknown to us. The future findings of this science might be as strange to the investi- 

 gators of to-day as the relativity theory of Einstein and Minkowsky was to the 

 physicists of a ifew years ago. What I do mean is that the future discoveries and 

 explanations of general physiology will be continuous and homologous with the 

 science of to-day. Should, indeed, a new form of energy, ' a vitalistic nervous energy,' 

 be discovered, as predicted by the eminent Italian philosopher, Eugenio Rignano, it 

 will be no twilight will-o'-the-wisp, no elusive entelechy or shadowy vital impulse, 

 but an addition to our knowledge of a character permitting of exact measurement 

 and of exact expression by means of mathematical equations. 



To give you the barest outline of the progress made by General Physiology since 

 the death of" Claude Bernard fifty years ago (his statue, together with that of Marcellin 

 Berthelot, stands in front of the College de France) would require at least a hundred 

 lectures and the encyclopaedic knowledge of a Bayliss. Permit me, however, to 

 mention one or two examples, and those with all brevity. The chemistry and energy 

 changes of muscle have been discovered recently by Meyerhof in Germany and by 

 A. \. Hill and Hopkins in England. When the muscle tissue contracts and does 

 work it derives the necessary free energy, not from oxidation, which is not quick 

 enoueh, but from the rapid exothermic conversion of the carbohydrate glycogen mto 

 lactic acid. When the fatigued muscle recovers it recharges its store of free energy ; 

 that is to say, by oxidising or burning some of the carbohydrate, it reconverts the 

 lactic acid into glycogen. Thus in the recovery stage we have the coupled reactions 

 of exothermic oxidation and endothermic conversion of lactic acid into glycogen. 

 Everything proceeds according to the laws of physics and chemistry. The story of 

 the mode of action and recovery of the muscle cells forms one of the most fascmating 

 chapters of general physiology. Here we see one of the elementary phenomena of 

 life already to a great extent analysed and elucidated. How this would have rejoiced 

 the heart of Claude Bernard ! That is one of the examples which I wished to mention. 

 Another is what I may call the blood equilibrium. The red blood cells are enclosed 

 in a membrane which does not allow the haemoglobin to escape, and only permits 



