An Introduction to a Biology 



view, namely, that a disturbance occurs proportional to 

 the length of time of isolation of the two strains, then sooner 

 or later purple will appear. Darbishire predicts that this 

 is what will happen. 



Ill 



LETTER FROM A. D. DARBISHIRE TO M. BERGSON, of Decem- 

 ber 6th, 1912, accompanying a copy of his book " Breed- 

 ing and the Mendelian Discovery." l 



LETTER FROM M. BERGSON TO MR. DARBISHIRE. 



Villa Montmorency, 



18 Avenue des Tilleuls, 



Auteuil, Paris, 



12. Dec. 1912. 



CHER MONSIEUR, Je tiens a vous remercier pour 1'envoi 

 de votre ouvrage " Breeding and the Mendelian Discovery " 

 et pour 1'aimable lettre qui 1'accompagnait. Quoique surcharge 

 de travail, d' occupations, et de preoccupations en ce moment, 

 je n'ai pu resister a la tentation de lire tout de suite le livre 

 jusqu'au bout, tant les premiers chapitres m'avaient seduit 

 par la precision et 1'elegance de Fexposition. Vous avez 

 bien raison de presenter cet ouvrage dans votre preface 

 comme nous donnant une vision immediate des faits, sans 

 hypotheses interposees ; mais cette vision, en raison meme 

 de sa nettete et de son caractere concret, suggere au lecteur 

 des hypotheses et des idees explicatives. Sur ces hypo- 

 theses vous avez eu la discretion de ne pas appuyer dans 

 1' ouvrage lui-meme ; mais vous les formulez dans la lettre 

 si interessante que vous avez bien voulu m'ecrire. L'idee 



1 This letter, to which I have found many references in correspondence 

 and notes, has not yet been traced. M. Bergson, who has the letter in 

 his possession, promised to let me have it as soon as it could be found, 

 but it has not reached me in time for publication in the present volume. 

 I am greatly indebted to M. Bergson for his kindness in allowing me to 

 print his reply of December 12th, 1912, which gives an indication of the 

 contents of Mr. Darbishire's letter. ED. 



I0 3 



