October 7, 1910] 



SCIENCE 



451 



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 phe- 

 nomena. The greatest factor in the diffi- 

 culty of their solution, however, 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 intelli- 

 gently such problems. The biologists, for 

 want of such a wide training, have empha- 

 sized the morphological aspect and the 

 readily observable phenomena of living 

 matter; while the physicist and chemist, 

 knowing little of the morphology of the cell 

 and of its vital manifestations, have been 

 unable to apply satisfactorily the prin- 

 ciples of their sciences to an understanding 

 of its processes. The high degree of 

 specialism which certain departments of 

 biology has in recent years developed has 

 made that difficulty greater than it was. 



It must also be said that in some in- 

 stances in which the physicist and chemist 

 attempted to aid in the solution of biolog- 

 ical problems the result on the whole has 

 not been qi^ite satisfactory. In, for ex- 

 ample, the phenomena of osmosis, the ap- 

 plication of Arrhenius's theory of ioniza- 

 tion 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 theo- 

 ries 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 univer- 

 sal 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 ex- 

 pected. 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 membranes — or, at least, we 

 may assume that it occurs — but in one 

 signal instance at least the very reverse 

 normally obtains. In the kidney, mem- 

 branes formed of cells constituting the lin- 

 ing of the glomeruli and the renal tubules 

 separate the urine, as it is being formed, 

 from the blood plasma and the lymph cir- 

 culating 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 dis- 

 crepancies are explained by the distribu- 

 tion (or partition) coefficient of the solutes 

 responsible for the greater concentration 

 of the product of excretion, these solutes 

 being more soluble in the excreted medium 

 than in the blood plasma and distributing 

 or diffusing themselves accordingly. If 

 such a principle is applicable here as an 

 explanation, it may be quite as much so in 

 other physiological cases in which the re- 

 sults are supposedly due only to the forces 

 postulated in the theories of van 't Hoff and 

 Arrhenius. Whether this be so or not, the 

 central fact remains that the enthusiastic 

 hopes with which the theories were applied 

 b}^ physiologists and biologists in the ex- 

 planation of certain vital phenomena have 

 not been wholly realized. 



The result has been a reaction amongst 

 physiologists and biologists which has not 

 been the least contributory of all the 

 causes that have led to the present revival 

 of vitalism. 



Another difficulty in accounting for the 

 vital phenomena has been due, until re- 

 cently, to a lack of knowledge of the phys- 

 ical and chemical properties of colloids 



