THE AMERICAN NATURALIST [Vol. LIII 



cumulate without the influence of selection at all (ortho- 

 genesis). But can we, without departing from natural- 

 istic grounds, conceive of the production in this way of 

 a structure in anticipation of a need ? May we even con- 

 ceive how appropriate variations could be called forth 

 by an already existing need. 



Of course, much obscurity of thought may be concealed 

 beneath this innocent-looking w^ord ''need." What is a 

 need? It is notorious that what is a luxury to some of 

 us is a necessity to others. Our needs grow with our in- 

 comes. And this line of reasoning is directly applicable 

 to sub-human realms. What an animal has, if this ad- 

 justs it to certain conditions of the environment, may be 

 regarded retrospectively as the fulfilment of a need. 

 Thus eyes fulfil the need of seeing. But can we say that 

 such a need existed before the appearance of visual or- 

 gans? There are beyond doubt still many forms of 

 wave-motion or molecular vibration for which we have 

 no organs of perception. Thus, in a large measure the 

 organism creates its own needs, even in an unclianging 

 environment. The word ''need," like the word "end," 

 is one which has a distinctly Iclcolouical iitii)li(';it i()ii. The 

 more factors of the enviroiiiiiciiinl cumiilfx ;iii orujiiiisni 

 is brought into relation willi, tiir heller is it .'nl.jusicd to 

 its life conditions, and— otlicr tilings cMiual - the higher 

 position it holds in the scale of life. But these adjust-' 

 ments are only thought of as satisfying needs when we 

 come to look l)ack on w^hat has actually happened.^''''' 



There is a more liiiiited sense, however, in which the 

 use (.r tills expression involves us- in no such obscurities. 

 All lliose fnndann'iital reciuirements, such as food, oxy- 

 gen, {)rotectinn from enemies, etc., m;)y l)e termed needs, 

 without there ivHiltinu ;in\ (•nnfn>ion of thought. Now, 

 anythiiiu' which led to the removnl of one or more of 



