396 A SHORT HISTORY OF SCIENCE 



was done, there could be no place for the new cosmogony in the 

 general mind. 



The theory of organic evolution by natural selection as main- 

 tained by Darwin was naturally subjected forthwith to the severest 

 scrutiny, and some of its details have been successfully and 

 destructively criticised. In particular, his explanation of the 

 mechanism of heredity appears to be untenable, as does also his 

 theory that small but incessant variations are gradually accumu- 

 lated into departures from the original, ultimately sufficient to 

 amount to new species. The studies of Mendel and of Weis- 

 mann upon inheritance and of De Vries and others upon varia- 

 tion, have supplemented and to some extent supplanted much of 

 Darwin's work upon those subjects. But apart from these and 

 other readjustments of details, the Darwinian theory stands 

 secure and at present affords the most reasonable explanation 

 hitherto proposed of the origin of man and other animals and of 

 plants; an explanation, moreover, in harmony with the general 

 law of evolution now accepted for the origin of existing forms of 

 language, literature, and art; of chemical compounds; of the 

 earth ; of the solar system ; and of the stars. The law of evolu- 

 tion, long ago foreshadowed by the Greeks, is clearly the law of 

 the lifeless world, and there seems to be no reason why it should 

 not be equally applicable to the world of life, including man. 



INFLUENCE OF AN AGE OF INVENTION AND INDUSTRY. Ac- 

 ceptance of the theory of evolution was quickened by an increase 

 in popular intelligence and a general openmindedness due in part 

 to the broadening of education, in part to the ease of travel, and 

 in part to the appearance, one after another, of revolutionary inven- 

 tions, such as the steam engine and cotton machinery with the 

 factory system at the end of the eighteenth century, and the loco- 

 motive, the steamboat, the telegraph, the sewing machine, the 

 friction match, and many more, in the first half of the nineteenth 

 century. All these marvels had been wrought within the brief 

 space of a single century, while improved printing-presses, cheaper 

 paper, cheaper newspapers, cheaper books, and cheaper illustra- 

 tions, as well as more and better schools and schooling had con- 



