184 R-WMOND C. OSBURN Vol. XXII, No. 7 



harmful ones never reach the next generation because they 

 are fatal to the organisms in which they appear. In every 

 species an abundance o^ such inimical variations may be 

 observed to produce the death of the organism, even before 

 hatching or birth. 



The objection has often been raised by the less thoughtful 

 critics of the evolution theory that the principles of selection 

 and adaptation cannot be of much importance after all, since 

 we see many cases where adaptations fail to work and where 

 selection fails to eliminate such variations. A little more 

 insight into the problem would indicate that, after all, any 

 adaptation only needs to work sufficiently to be of benefit 

 to the species as a whole, and not necessarily to all individuals. 

 An adaptation is merely an adjustment to a certain condition 

 of life, and if the condition is changed, naturally the adaptation 

 does not exist; that is to say, the particular reason for the 

 existence of a particular structure, process or instinct, does 

 not obtain and therefore the organism is not adapted any 

 longer. Undoubtedly the reason why it is so difficult to keep 

 many wild animals in confinement, or why they often will 

 not reproduce in captivity, is because we cannot supply the 

 conditions for which they are adapted. A single adaptation 

 is not a master key, it will unlock only one particular gate 

 barring the pathway to existence, and if that gate is replaced 

 by another, that key is useless, but it may not be dangerous 

 to carry it. 



There are, to be sure, many examples of imperfect adapta- 

 tion to be found on every hand and the biologist has not failed 

 to take them into account. The case should perhaps be stated 

 something like this:. vSuccessful organisms, by which we 

 mean all organisms that continue to exist, are fitted to meet in 

 a satisfactory manner, the ordinary conditions of their natural 

 environment. But the environment is always more or less 

 variable and the adjustment can therefore seldom be perfect. 

 The organism which is able to pass the adjustment test with a 

 sufficiently high rating will get along. 



Another misconception along this same line arises from the 

 difficulty which man encounters in attempting to look at the 

 results of evolution from an impartial standpoint. He cannot 

 ordinarily escape from the limits of an anthropocentric evalua- 

 tion of other organisms, and measures all other creatures by 



