Characters, Hereditary and Acquired. 65 



that an incipient giraffe should present the peculiar 

 form of the hind-quarters which we now perceive, 

 unless at the same time it presented the correspond- 

 ingly peculiar form of the fore-quarters ; and as each 

 of these great modifications entails innumerable sub- 

 ordinate modifications throughout both halves of the 

 creature concerned, the chances must have been in- 

 finitely great against the required association of so many 

 changes happening to have arisen congenitally in the 

 same individuals by way of merely fortuitous variation. 

 Yet, if we exclude the Lamarckian interpretation, 

 which gives an intelligible cause of co-ordination, 

 we are required to suppose that such a happy con- 

 currence of innumerable independent variations must 

 have occurred by mere accident — and this on innu- 

 merable different occasions in the bodies of as many 

 successive ancestors of the existing species. For at 

 each successive stage of the improvement natural 

 selection (if working alone) must have needed all, or 

 at any rate most, of the co-ordinated parts to occur in 

 the same individual organisms'. 



In alluding to what I have already published upon 

 the difficulty which thus appears to be presented to 

 his theory, Weismann says, "At no distant time I hope 

 to be able to consider this objection, and to show that 

 the apparent support given to the old idea [i. e. of the 

 transmission of functionally-produced modifications] 

 is really insecure, and breaks down as soon as it is 

 critically examined V 



' For another and better illustration more recently published by 

 Mr. Spencer, see The Inadequacy of Natural Selection, p. 23. 



" Essays on Heredity, vol. i. p. 389. 

 [For further treatment of the f nbject under discussion set Weismann, 

 The All-sufficiency of Natural Selection (Contemp. Rev. Sept. and 



II. F 



