viii TRANSLATOR'S PREFACE 



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 pro- 

 ductions 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. 



