10 PUBLICATION OF THE 'ORIGIN OF SPECIES.' [1859. 



of a cow — Ovigerous fre?ia, in certain cirripedes, are nascent 

 branchiae — in [illegible] the swim bladder is almost rudi- 

 mentary for this purpose, and is nascent as a lung. The 

 small wing of penguin, used only as a fin, might be nascent 

 as a wing ; not that I think so ; for the whole structure of 

 the bird is adapted for flight, and a penguin so closely re- 

 sembles other birds, that we may infer that its wings have prob- 

 ably been modified, and reduced by natural selection, in ac- 

 cordance with its sub-aquatic habits. Analogy thus often 

 serves as a guide in distinguishing whether an organ is rudi- 

 mentary or nascent. I believe the Os coccyx gives attachment 

 to certain muscles, but I can not doubt that it is a rudiment- 

 ary tail. The bastard wing of birds is a rudimentary digit ; and 

 I believe that if fossil birds are found very low down in the 

 series, they will be seen to have a double or bifurcated wing. 

 Here is a bold prophecy ! 



To admit prophetic germs, is tantamount to rejecting the 

 theory of Natural Selection. 



I am very glad you think it worth while to run through 

 my book again, as much, or more, for the subject's sake as 

 for my own sake. But I look at your keeping the subject 

 for some little time before your mind — raising your own diffi- 

 culties and solving them — as far more important than reading 

 my book. If you think enough, I expect you will be per- 

 verted, and if you ever are, I shall know that the theory of 

 Natural Selection is, in the main, safe ; that it includes, as 

 now put forth, many errors, is almost certain, though I can- 

 not see them. Do not, of course, think of answering this ; 

 but if you have other occasion to write again, just say whether 

 I have, in ever so slight a degree, shaken any of your objec- 

 tions. Farewell. With my cordial thanks for your long let- 

 ters and valuable remarks, 



Believe me, yours most truly, 



C. Darwin. 



P. S. — You often allude to Lamarck's work ; I do not know 

 what you think about it, but it appeared to me extremely 

 poor ; I got not a fact or idea from it. 



