378 Canadian Record of Science 



lations of previous students of Natural History, so far 

 as they had any bearing on his quest. What is spoken 

 of as the ladder of life had been frequently commented 

 on, — the gradations of structure from simple forms, at 

 the bottom, to complex ones at the top, as seen in living 

 things, and of their relations to one another, — Algae, 

 nearly allied to Lichens, Lichens to Fungi, Fungi to 

 Hepaticae, Hepaticae to Mosses, Mosses to Ferns, and 

 then the series of Phasnogams, leading up to the Compo- 

 sitae. 



Similarly animal life begins with the Amoeba and 

 ascends to man. 



It has been observed before his day that large groups 

 of species of widely different habits present the same 

 fundamental plan of structure, — all the vertebrates, for 

 instance, — and that parts of the same animal or plant, 

 the functions of which are very different, likewise ex- 

 hibit modifications of a common plan. 



The existence of structures in a rudimentary and 

 apparently useless condition, in one species of a group, 

 which are fully developed and have definite functions in 

 other species of the same group, — the flaps of seals and 

 whales, — had been dwelt on. The modifications pro- 

 duced on living organisms when placed in new condi- 

 tions, and the effects resulting from Geographic Distri- 

 bution, were facts well known. And specially the revel- 

 ations of palaeontology, showing a succession of life, 

 simpler in the older rocks, and more complicated as we 

 examine the more recent formations, were highly sug- 

 gestive. Familiar with all these facts, the enquiring 

 mind of Darwin felt that the universe held in its bosom 

 profound secrets which had not yet been brought to 

 light, and he determined to fathom them so far as it was 

 within the power of man to do so. 



All his subsequent publications took their colour 

 from his views as to the origin of species, and their gen- 

 eral aim was to show the singular endowments possessed 

 by plants and animals, in some regards equal to the 



