SPECULATIVE THEORIES ANSWERED. 9 



be said to prove the fallacy of this hypothesis ; for al- 

 though it is utterly impossible to trace the origin of our 

 domestic breeds to one or more original stocks, since even 

 the species cannot now be distinguished from the vari- 

 eties, still the whole tenor of zoological facts is totally 

 against this belief. The plains of the new worlds no 

 less than those of Australia, are as perfectly adapted for 

 the comfortable existence of the horse or the ox, as are 

 the fields and the pastures of Europe, or the grassy 

 deserts of Asia ; yet nature has placed these animals in 

 one hemisphere, and denied them to the other. 



(11.) Some other writers might be mentioned, who, 

 in attempting to explain the causes of animal distribu- 

 tion, have either been but little acquainted with well 

 known zoological facts, or have been led into theories too 

 wild and fanciful to deserve notice. We may, indeed, 

 build a theory upon every ti .ig in nature : but the more 

 we investigate, the stronger will be our conviction in the 

 following deduction : — That the primary causes which 

 have led to different regions of the earth being peopled 

 by different races of animals, and the laws by which 

 their dispersion is regulated, must be for ever hid 

 from human research. This conclusion is strengthened 

 by the inference which will be drawn from the facts we 

 shall subsequently state ; an inference jo well expressed 

 by a very intelligent writer, that we shall give it nearly 

 in his own words. " It appears that the various tribes 

 of organised beings were originally placed by the Creator 

 in certain regions, for which they are by their nature 

 peculiarly adapted. Each species may have had only 

 one beginning in a single stock ; probably a single pair, 

 as Linnaius supposed, was first called into being, and 

 their progeny left to disperse themselves to as great a 

 distance from the original centre of their existence as 

 was compatible with its physical capabilities, and with 

 those unknown laws, by which the Creator has regulated 

 the geographic distribution of his creatures." 



(12.) We have now endeavoured to demo; strate the 

 insufficiency of all theories on the causes of animal dis- 



