28 GENERAL PRINCIPLES OF ZOOLOGY. 



and brooks rushing as torrents towards the sea, are sufficient 

 to furnish a complete explanation. Very gradually in the 

 course of a vast space of time the earth's surface has 

 changed, and passed from one period into the next, and 

 still at the present day the constant process of change is 

 going on. The continuity in the geological history of 

 the earth, here postulated for the first time, has since 

 then become one of the fundamental axioms of Geology ; 

 on the other hand the discontinuity of living creatures, 

 although the geological hypotheses touch lightly upon this, 

 was for a long time regarded as correct. 



Darwin. It is the great merit of Charles Darwin that 

 he took up the theory of descent anew after it had rested 

 a decade, and brought it into general recognition. Thereby 

 was introduced the most important period in the history of 

 Zoology, a period in which the science not only made such 

 an advance as never before, but also began to obtain a 

 permanent influence upon the general views of men. 



Charles Darwin was born at Shrewsbury, Eng., in 

 1809. After a short course of study at the universities of 

 Edinburgh and Cambridge, he joined as naturalist the 

 English warship "Beagle" detailed from 1831-36 for 

 nautical researches on a circumnavigation of the globe. 

 Darwin recognized the peculiar character of island faunas, 

 particularly of the Galapagos Islands, and the remark- 

 able distribution of Edentates in South America; these 

 facts formed for him the germ of his epoch-making theory. 

 Further results of this journey were his beautiful mono- 

 graph on the Cirrepedia, and the classic investigation of 

 coral-reefs. After his return to England Darwin lived, 

 entirely devoted to scientific work, chiefly in the hamlet 

 of Downs, county Kent, up to the time of his death in 

 1882. Above all he was incessantly busy in building up 

 his conception of the origin of species, and in collecting 

 for this an ever richer empiric material. The first written 

 notes, the fundamental ideas of which he communi- 

 cated to friends, particularly the geologist Lyell and the 

 botanist Hooker, were made in 1844, but the author was 



