162 < DESCENT OF MAN ' — EXPRESSION. [1872. 



I hope and trust that you will throw light on these points. 



P.S. — I will add another remark which I remember 

 occurred to me when I first read M. Wagner. When a 

 species first arrives on a small island, it will probably increase 

 rapidly, and unless all the individuals change instantaneously 

 (which is improbable in the highest degree), the slowly, more 

 or less, modifying offspring must intercross one with another, 

 and with their unmodified parents, and any offspring not as 

 yet modified. The case will then be like that of domesticated 

 animals which have slowly become modified, either by the 

 action of the external conditions or by the process which I 

 have called the unconscious selection by man — i.e., in contrast 

 with methodical selection. 



[The letters continue the history of the year 1872, which 

 has been interrupted by a digression on Isolation.] 



C. Darwin to the Marquis de Saporta. 



Down, April 8, 1872. 



DEAR SIR, — I thank you very sincerely and feel much 

 honoured by the trouble which you have taken in giving 

 me your reflections on the origin of Man. It gratifies me 

 extremely that some parts of my work have interested you, 

 and that we agree on the main conclusion of the derivation of 

 man from some lower form. 



I will reflect on what you have said, but I cannot at present 

 give up my belief in the close relationship of Man to the 

 higher Simise. I do not put much trust in any single cha- 

 racter, even that of dentition ; but I put the greatest faith in 

 resemblances in many parts of the whole organisation, for I 

 cannot believe that such resemblances can be due to any 

 cause except close blood relationship. That man is closely 

 allied to the higher Simise is shown by the classification of 



