There is, I think, no more wonderful and illuminating spectacle than that of an osmotic growth,--a crude lump of brute inanimate matter germinating before our very eyes, putting forth bud and stem and root and branch and leaf and fruit, with no stimulus from germ or seed, without even {viii} the presence of organic matter. For these mineral growths are not mere crystallizations as many suppose; they increase by intussusception and not by accretion. They exhibit the phenomena of circulation and respiration, and a crude sort of reproduction by budding; they have a period of vigorous youthful growth, of old age, of death and of decay. They imitate the forms, the colour, the texture, and even the microscopical structure of organic growth so closely as to deceive the very elect. When we find, moreover, that the processes of nutrition are carried on in these osmotic productions just as in living beings, that an injury to an osmotic growth is repaired by the coagulation of its internal sap, and that it is able to perform periodic movements just as an animal or a plant, we are at a loss to define any line of separation between these mineral forms and those of organic life. In the present volume the author has collected all the data necessary for a complete survey of the mechanism of life, which consists essentially of those phenomena which are exhibited at the contact of solutions of different degrees of concentration. Whatever may be the verdict as to the author's case for spontaneous generation, all will agree that the book is a most brilliant and stimulating study, founded on the personal investigation of a born experimenter. The present volume is a translation of Dr. Leduc's French edition, but it is more than this, the work has been translated, revised and corrected, and in many places re-written, by the author's own hand. I am responsible only for the English form of the treatise, and can but regret that I have been able to reproduce so imperfectly the charm of the original. W. DEANE BUTCHER. EALING. * * * * * {ix} PREFACE TO THE ENGLISH EDITION C'est par l'initiative du Dr. Deane Butcher que cette ouvrage est presente aux lecteurs anglais, a la race qui a dote l'humanite de tant de decouvertes originales, geniales et d'une portee tres generale. Comme un etre vivant, une idee exige pour naitre et se developper le germe et le milieu de developpement. Il est indeniable que le peuple anglo-americain constitue un milieu particulierement favorable a la naissance et au developpement des idees nouvelles. Pendant notre collaboration le Dr. Deane Butcher a ete un critique judicieux et eclaire, tous les changements dans l'edition anglaise sont dus a ses observations. Il s'est assimile l'ouvrage pour le traduire, et dans beaucoup de parties, il a mis plus de clarte et de concision qu'il n'y en avait dans le texte original. STEPHANE LEDUC. NANTES, 1911. * * * * * {xi}