1872.] 'DESCENT OF MAN.' 3 4I 



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. Dartuin 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 ex- 

 tremely 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 pres- 

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

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

 acter, 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 

 Linnseus, who was so good a judge of affinity. The man 

 who in England knows most about the structure of the 

 Simiae, namely, Mr. Mivart, and who is bitterly opposed to 

 my doctrines about the derivation of the mental powers, 

 yet has publicly admitted that I have not put man too 

 close to the higher Simian, as far as bodily structure is con- 

 cerned. I do not think the absence of reversions of struct- 



