100 GENERAL ORNITHOLOGY part ii 



disposition of its knowledge, and so discover the reciprocal relations 

 and interdependencies of the things it knows. Classification pre- 

 supposes that there do exist such relations, according to which we 

 may arrange objects in the manner which facilitates their compre- 

 hension, by bringing together what is like, and separating what is 

 unlike ; and that such relations are the results of fixed, inevitable 

 law. It is, therefore. 



Taxonomy (Gr. ra^ts, taxis, arrangement, and vo/ios, nomas, law), 

 or the rational, lawful disposition of observed facts. Just as taxi- 

 dermy is the art of fixing a bird's skin in a natural manner, so 

 taxonomy is the science of arranging birds in the most natural 

 manner ; in the way that brings out most clearly their natural 

 affinities, and so shows them in their proper relations to one another. 

 This is the greatest possible help to the memory in its attempt to 

 retain its hold upon great numbers of facts. But taxonomy, which 

 involves consideration of the greatest problems of ornithology, as of 

 every other branch of biology {biology being the science of life and 

 living things in general), is beset with the gravest difficulties, 

 springing from our defective knowledge. We could only perfect 

 our taxonomy by having before us a specimen of every kind of bird 

 that exists, or ever existed ; and by thoroughly understanding how 

 each is related to and differs from every other one. This is obvi- 

 ously impossible ; in point of fact, we do not know all the birds 

 now living, and only a small number of extinct birds have come to 

 light ; so that many of the most important links in the chain of 

 evidence are missing, and many more cannot be satisfactorily jouied 

 together. With these springs of ignorance and sources of error 

 must be reckoned also the risk of going wrong through the natural 

 fallibility of the mind. The result is, that the "natural classifica- 

 tion," like the elixir of life or the philosopher's stone, is a goal still 

 distant ; and as a matter of fact, the present state of the ornitho- 

 logical system is far from being satisfactory. It is obvious that 

 birds, or any other objects, may be classified in numberless ways, 

 — in as many ways as are aflforded by all their qualities and rela- 

 tions, — to suit particular purposes, or to satisfy particular bents of 

 mind. Hence have arisen, in the history of the science, very many 

 different schedules of classification ; in fact, nearly every leader of 

 ornithology has in his time proposed his own system, and enjoyed 

 a more or less respectable and influential following. Systems have 

 been based upon this or that set of characters, and erected from 

 this or that preconception in the mind of the systematist. Down 

 to quite recent days, the modifications of the external parts of birds, 

 particularly of the bill, feet, wings, and tail, were almost exclusively 

 employed for purposes of classification ; and the mental point of 

 view was, that each species of bird was a separate creation, and as 



