92 



SCIENCE. 



[N. S. Vol. VIII. No. 186. 



be explained only in relation to, some spe- 

 cial use which it now has or which a similar 

 structure has had in former times." As 

 well might one say that grass was made for 

 cows to feed on, or that day and night al- 

 ternate that we may have light for work 

 and darkness for sleep. If a special func- 

 tion cannot be assigned to a structure as its 

 raison d'etre it is commonly regarded in one 

 of three ways : (1) the function has not yet 

 been discovered ; (2) the structure is neces- 

 sarily involved in the structure of other 

 parts which have a special fanction ; (3) the 

 structure is ' vestigial ' and its special func- 

 tion has been lost, though the part itself is 

 continued by force of inheritance. There 

 are serious objections to assigning a special 

 function to every part for the fulfilling of 

 which the structure exists : in the first place, 

 the special use is only one of many, and fre- 

 quently not the most important one, which 

 the part performs ; secondly, the special use 

 is merely conjectural, and which of the many 

 uses it has is most important cannot be de- 

 termined. It is impossible for conscious, 

 reflecting beings to give a complete account 

 of the causes of all their actions ; much more 

 must this be true of the uses of parts of 

 organisms viewed objectively. 



Three ' factors of evolution ' are then 

 considered, viz : Lamarckism, Use-inherit- 

 ance, Natural Selection. Lamarck derives 

 the adaptations of organisms from their 

 needs. A certain confusion exists in his 

 theory due to ambiguity in the use of the 

 word ' besoin,' which in some connections 

 means need, in others desire. After quoting 

 several important passages from the Philos- 

 ophie Zoologique, the author says : " Now, all 

 this doubtless appears very ridiculous, and, 

 though it is as good as any theory of trans- 

 formation, so it is. But it reveals one 

 thing, a haunting sense on the part of La- 

 marck that he must bring in the conception 

 of need at every point. These are no facts 

 which he is relating to us ; they are a set of 



the most varied and confused fancies as to 

 how need can bring about the adaptations 

 of organic life. Of the fact that need ef- 

 fects all this he is well' assured, but his 

 knowledge goes no further. And he finds 

 it extraordinarily difficult to imagine how 

 the indispensable principle of his theory 

 does its work. Sometimes that which is 

 needed is represented as actually thought 

 of by the animal, sometimes as merely pres- 

 ent to its ' inner feeling,' and sometimes as 

 belonging to the animal only in one respect 

 • — in that it would be well for the animal to 

 have it, though it has it not. Sometimes 

 the creature needs the particular structure 

 because of other habits or structures which 

 it has already, and which could not exist 

 in fact without that which is represented 

 here as derived from their need of it. In 

 a word, the main principle of a biological 

 system could not well be more formal and 

 all-inclusive, or in its working-out more 

 indefinite." 



As to Use-inheritance the author at once 

 denies the distinction between innate and 

 acquired characters. He takes, as a basis 

 of discussion, the definitions of these terms 

 given by Delage in his work on Heredity, 

 viz : " Innate characters are those which 

 have been contained in the fertilized ovum 

 in some form or other ; whether that form, 

 is known or not matters little. Acquired 

 characters, on the other hand, are those 

 which have been developed only through 

 the action of the surrounding conditions." 

 But the innate characters cannot be present 

 as such in the ovum ; they must be there 

 only as separate and unknowable agents, 

 for if present only in the sense that they are 

 posdhle we cannot distinguish them from 

 acquired characters which are also possible. 

 On the other hand, acquired characters 

 must be represented in some form in the 

 germ. If they are only modifications of 

 innate qualities they are innate qualities 

 which are usually latent. ' ' And not only 



