66 THE LAMARCKIAN DOCTRINE 



as nourishment and is subsequently exchanged for other matter. 

 It is not a focus of chemical activity. It grows only on the surface. 

 In short, the analogy is strained and false. 



1 02. The Darwinian hypothesis, at any rate as at first enunciated, 

 was not a theory of heredity, but only one of evolution. It did 

 not seek to account for variations, but took them for granted and 

 built on that foundation. Indeed, the only theory of heredity 

 formulated by Darwin, that of Pangenesis, was designed more to 

 satisfy the claims of the Lamarckian conception of evolution than 

 of the one which has received his name. We shall see, how- 

 ever, if we submit the theory of Natural Selection to a rigorous 

 deductive inference of consequences, and appeal to reality for 

 confirmation, that one particular theory of heredity, and that one 

 only, fits it, whereas all the others are incompatible with it. 



103. The theory of Natural Selection is founded mainly on 

 two undisputed inductions and two deductions from them. The 

 inductions are (a) that offspring, while resembling parents on the 

 whole, always vary from them somewhat in every character, 

 being perhaps superior in some characters and inferior in others ; 

 and (b) that in every species the number of individuals that come 

 into being exceeds, sometimes very greatly, the number of those 

 who survive and have offspring. The deductions are (a) that, as 

 a general rule, the individuals selected by nature for survival are, 

 on the whole, better adapted to the environment than those 

 selected for elimination ; and (b) that in this way the ' specific 

 mean,' the racial average, is raised, and consequently evolution 

 results. Unlike the doctrine of the transmission of acquirements, 

 the theory of Natural Selection, as held by its modern followers, 

 really aspires to account for all adaptations. 



104. The main contrast between the Lamarckian and the 

 Darwinian hypotheses arises from the fact that the former 

 attributes progressive evolution to influences that act beneficially 

 on the individual, whereas the latter attributes it to influences 

 that kill or weaken, and so on the average prevent the un- 

 fittest, the most affected, from having offspring, or at any rate 

 their full quota of offspring. Until very recently all students of 

 heredity were zoologists or botanists, or men who drew their facts 

 from materials collected by them. Even now it is difficult to per- 

 suade such workers that useful evidence may be drawn from other 

 sources. When, therefore, they thought of elimination, their minds 

 turned naturally to quick or sudden death, the only forms of 

 elimination familiar to us in wild nature. They conceived the 



