PRESIDENTIAL ADDRESS. 74] 



but nothing of these is known to us except that they are quite unlike the pro- 

 cesses the laboratory employs in the artificial synthesis of carbohydrates. Nature 

 works unerringly, unfalteringly, with an amazing economy of material and 

 energy, while ' our laboratory syntheses are but roundabout ways to the waste 

 sink.' 



In consequence, it is customary to regard living matter as unique — eui generis, 

 as it were without an analogue or parallel in the inorganic world— and the 

 secrets involved in its actions and activities as insoluble enigmas. Impelled by 

 this view there are those, also, who postulate as an explanation for all these 

 manifestations the intervention in so-called living matter of a force otherwise 

 and elsewhere unknown, biotic or vital, whose action is directed, according to the 

 character of the structure through which it operates, to the production of the 

 phenomena in question. Living protoplasm is, in this view, but a mask and a 

 medium for action of the unknown force. 



This is an old doctrine, but it has again made headway in recent years owing 

 to the reaction from the enthusiasm which came from the belief that the applica- 

 tion of the known laws of physics and chemistry in the study of living matter 

 would explain all its mysteries. A quarter of a century ago hopes were high 

 that the solution of these problems would soon be found in a more profound 

 comprehension of the laws of the physical world. Since then there has been an 

 extraordinary increase in our knowledge of the structure and of the products of 

 the activity of living matter without a corresponding increase in knowledge of 

 the processes involved. The obscurity still involving the latter appears all the 

 greater because of the high lights thrown on the former. Despair, in conse- 

 quence, has taken the place of hope with some, and the action of a mysterious 

 force is invoked to explain a mystery. 



It may be admitted that our methods of investigation are very inadequate, 

 and that our knowledge of the laws of matter, seemingly comprehensive, is not 

 at present profound enough to enable us to solve all the problems involved in the 

 vital phenomena. The greatest factor in the difficulty of their solution, how- 

 ever, has been the fact that there has been a great lack of investigators specially 

 trained not only in biology, but also in physics and chemistry, for the very 

 purpose of attacking intelligently such problems. The biologists, for want of 

 such a wide training, have emphasised the morphological aspect and the readily 

 observable phenomena of living matter ; while the physicist and chemist, know- 

 ing little of the morphology of the cell and of its vital manifestations, have 

 been unable to apply satisfactorily the principles of their sciences to an under- 

 standing of its processes. The high degree of specialism which certain depart- 

 ments of biology have in recent years developed has made that difficulty greater 

 than it was. 



It must also be said that in some instances in which the physicist and 

 chemist attempted to aid in the solution of biological problems the result on 

 the whole has not been quite satisfactory. In, for example, the phenomena of 

 osmosis the application of Arrhenius' theory of ionisation and van't Hoff's gas 

 theory of solutions promised at first to explain all the processes and the results 

 of diffusion through animal membranes. These theories were supported by such 

 an array of facts from the side of physics and physical chemistry that there 

 appeared to be no question whatever regarding their universal validity, and their 

 application in the study of biological phenomena was urged with acclaim by 

 physical chemists and eagerly welcomed by physiologists. The result in all 

 cases was not what was expected. Diffusion of solutes, according to the theories, 

 should, if the membrane is permeable to them, always be from the fluid where 

 their concentration is high to that in which it is low. This appears to happen in a 

 number of instances in the case of living membrane — or, at least, we may assume 

 that it occurs — but in one signal instance at least the very reverse normally 

 obtains. In the kidney, membranes formed of cells constituting the lining of the 

 glomeruli and the renal tubules separate the urine, as it is being formed, from 

 the blood plasma and the lymph circulating through the kidney. Though the 

 excreted fluid is derived from the plasma and lymph, it is usually of much 

 greater osmotic concentration than the latter. 



It may be urged that this and other discrepancies are explained by the 

 distribution (or partition) coefficient of the solutes responsible for the greater 



