TRANSLATOR'S PREFACE 



Rignano is a student of Biology who has also the 

 training of an engineer and physicist. His attack on bio- 

 logical problems is from that side. In this book he offers 

 an explanation on a physical basis of assimilation, cell di- 

 vision, and the biogenetic law of recapitulation in ontog- 

 eny, and he suggests a mechanism whereby the inheritance 

 of acquired characters may be effected. 



Such a study of the most fundamental and difficult of 

 biological problems can not fail to be of the greatest in- 

 terest to all students of science. It points out a way to 

 the understanding of the essential nature of living matter. 

 Therefore the translator has gladly consented to prepare 

 for publication this translation first made for his own sat- 

 isfaction. It has been revised by the author. 



University of Chicago, 1911. 



BASIL HARVEY, 



