3 8o SCIENCE PROGRESS 



The experiments of Leduc, some of which have too lightly 

 been considered as mere scientific amusements, are in reality 

 of interest. By a careful study of osmosis and diffusion in 

 relation to life, Leduc has gained some knowledge of the 

 morphogenetic methods which nature appears to use in the pro- 

 duction of living matter. Claiming that all the laws concerning 

 the physical behaviour of gases apply to solutions, he states 

 that osmotic pressure is constantly at work in living beings 

 and that where it ceases to be operative, life becomes extinct. 

 This inquirer has shown that where a membrane of ferro- 

 cyanide is interposed between a substance A in a solution B, 

 there is produced an interchange which results in the swelling 

 of A (enclosed in its membrane) and its expansion into forms 

 resembling both vegetable and animal life, forms in which, as 

 long as they last, a constant process of intussusception is in 

 operation. He has exhibited this osmotic phenomenon in a 

 variety of ways and has also furnished a number of instances 

 of the morphogenetic tendencies of solutions of different degrees 

 of concentration when in contact with each other. Forms of 

 living things can be produced at will, in saline solutions, by 

 the guidance of the operator, a guidance, it must be observed, 

 which, qualitatively at least, is exercised solely in the choice 

 of the substances to be dissolved. These substances are largely 

 compounds the elements of which are found to be concerned 

 in the chemical changes occurring in life. Hence there are 

 carbon (in carbonates), phosphorus (in phosphates) and 

 chlorine (in chlorides), whilst among the metals are iron, 

 manganese, potassium, sodium and calcium in different com- 

 binations. The last two occur abundantly in nature and it is 

 conceivable that they might have been drawn upon originally 

 for the elaboration of life. Again the phenomenon of growth 

 may be considered to be osmotic since it depends upon nutrition 

 and nutrition itself depends upon the distribution of the nutrient 

 substances through permeation. As in the objects produced by 

 Leduc, there comes a time when the nutritional process ceases 

 to promote growth, after which an equilibrium is maintained 

 during a certain period and this is followed by decline and 

 death. This is the history of all life-growth : stability, destruc- 

 tion. No combinations are eternal. Matter whether dead or 

 living is in a constant state of change. These truths are of 

 course not new but as research progresses they acquire clearer 



