300 WORK ON 'MAN.' [1870. 



but think that the explanation given at p. 541 of the last 

 edition of the ' Origin ' of the long retention of rudimentary 

 organs and of their greater relative size during early life, is 

 satisfactory. Their final and complete abortion seems to me 

 a much greater difficulty. Do look in my ' Variations under 

 Domestication,' vol. ii. p. 397, at what Pangenesis suggests on 

 this head, though I did not dare to put in the ' Origin.' 

 The passage bears also a little on the struggle between the 

 molecules or gemmules.* There is likewise a word or two 

 indirectly bearing on this subject at pp. 394-395. It won't 

 take you five minutes, so do look at these passages. I am 

 very glad that you have been bold enough to give your idea 

 about Natural Selection amongst the molecules, though I can 

 not quite follow you. 



1870 AND BEGINNING OF 1871. 



[My father wrote in his Diary : — " The whole of this year 

 [1870] at work on the * Descent of Man.' . . . Went to Press 

 August 30, 1870." 



The letters are again of miscellaneous interest, dealing, not 

 only with his work, but also serving to indicate the course of 

 his reading.] 



C. Darwin to E. Ray Lankester. 



Down, March 15 [1870]. 

 My dear Sir, — I do not know whether you will consider 

 me a very troublesome man, but I have just finished your 



appeared ; or they are of some use to the animal, in which case they are 

 of no use as arguments against Teleology." — ('Critiques and Addresses,' 

 p. 308.) 



* " It is a probable hypothesis, that what the world is to organisms in 

 general, each organism is to the molecules of which it is composed. Mul- 

 titudes of these having diverse tendencies, are competing with one another 

 for opportunity to exist and multiply ; and the organism, as a whole, is as 

 much the product of the molecules which are victorious as the Fauna, or 

 Flora, of a country is the product of the victorious organic beings in it." — 

 ('Critiques and Addresses,' p. 309.) 



