io 4 COMPARATIVE ANATOMY vm 



been produced out of preceding orders of things," l could not 

 pass unnoticed by the biologists. 



First with a faint and uncertain sound, but in later times 

 more boldly and confidently, an hypothesis has been propounded 

 which does profess to account for some, at least, of the facts of 

 animal creation, and to afford a guide to the solution of the 

 problem, if not of the original beginnings, at least of the 

 present diversities, as well as resemblances, among the animal 

 and vegetable life on the globe. 



This theory has for its basis that the secret bond of union 

 is not " conformity to type," is no ideal to which the operations 

 of Creation were limited, but is one of actual consanguinity, 

 or, as otherwise expressed, " genetic affinity." 



The fundamental part of the theory is that, as individuals 

 are known to come into being by a process of generation 

 acting according to fixed and certain laws, the same to-day and 

 yesterday and to-morrow, in like manner have races, varieties, 

 species, and other larger groups of animals* and plants come 

 into being that the species existing at any one period on 

 the earth's surface are, in fact, the direct descendants, modified 

 according to definite laws, of the creatures inhabiting the earth 

 in previous periods. 



The theory of orderly evolution already applied to most 

 of the phenomena of the physical world has thus been also 

 applied to organic nature. 



This hypothesis, originally promulgated in a comparatively 

 crude form by De Maillet, Erasmus Darwin, and Lamarck, 

 and more recently advocated by the author of the Vestiges 

 of Creation, 2 for a long time found little favour with English 

 naturalists of eminence. Indeed, so late as 1856, Baden 

 Powell, in his masterly essay " On the Philosophy of 

 Creation," arguing with great force " that one grand over- 

 ruling principle, the universality of law, order, and continuity, 

 presiding as powerfully over the earlier stages of creation 

 as during its continuance at the present moment, applies 



1 Baden Powell, Unity of Worlds and of Nature, 2nd edition, 1856, p. 448. 



2 A work in many respects far in advance of the age in which it appeared 

 (1844). It was published anonymously, but is now known to have been written 

 by Robert Chambers of Edinburgh. 



