1 10 WALTER KIDD, M.D., F.Z.S., ON 



2nd. That to Avhich it is adapted. 3rd. The purpose for 

 wliich it is adapted. 4th. The agent who adapts it. The 

 fourth of these ideas must be surrendered in the present day 

 on account of the resolute way in wjiich the word is used 

 without any reference to a person or agent, and because^ 

 scientists have adopted this term and must have their tools- 

 or conceptual formulae with which to do their work. We 

 must take adaptation as a term employed by the leaders of 

 biology as one condemned to not more than three, and 

 probably only two, of the four meanings which truly belong- 

 to it. We must also bear in mind that for their own 

 convenience biologists have enlarged the abstract idea of 

 adaptation further, and speak of '' an adaptation " or 

 " adaptations," as concrete nouns substantive, as formerly 

 the Avord " means " was used. 



It mast be remembered that the term adaptation is further 

 complicated because a thing may be (1) adapted as a whole- 

 to its surroundings, (2) a part may be adapted to the- 

 efficiency of the whole — the adaptation may be extrinsic or 

 intrinsic. 



The most usual, if not exclusive, application of the word' 

 in science is to the phenomena of organic existence; it is 

 therefore the special tool of the biologist, and it is in his; 

 department of science that misapplications must be most 

 carefully watclied, more particularly because in the province 

 of life such are the most important, as tending to belittle the 

 teleological meaning of that part of the cosmos with, which 

 we are chiefly acquainted. One of the simplest instances of 

 adaptation, and one which is confessedly a matter of pure 

 chancG;, as we call it, and due only to the action of purposeless, 

 mechanical causes, is the fail of an avalanche down a 

 moun(:ain side, the result of which is that various fragments 

 of rock or ice roll on until they find their resting place and 

 each is at rest in its suited position. These fragments may 

 be said, to he adapted each to its position for no pm-pose 

 whatever. The fragments of various shapes and sizes settle 

 down into such situations as suit their size, Aveight and 

 character, from the mass of rock weighing several tons to 

 each grain of sand, each disintegrated and set going by 

 certain physical laws. This entirely mechanical case of" 

 adaptation connotes two of the four ideas only — the thing 

 adapted and that to vv^hich it is adapted ; purpose must be 

 exchuhid. But it is just this form of mechanical adaptation, 

 under certain chemical and physical laws which some extreme 



