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the preservation of the character of the species, the law of 

 variation in the determination of individual characters." 



" According to the Darwinian theory," says Balfour, in his 

 admirable Comparative Embryology, " there are two guiding 

 and, in a sense, antagonistic principles which have 

 rendered possible the present order of the organic world. 

 These are known as the laws of heredity and variation. The 

 first of these laws asserts that the characters of an organism, 

 at all stages of its existence, are reproduced in its descendants 

 at corresponding stages. The second of these laws asserts 

 that offspring never exactly resemble their parents. By the 

 common action of these two principles, continuation from a 

 parent type becomes a possibility, since every acquired 

 variation has a tendency to be inherited." The so-called 

 theory of evolution is the sublimest philosophical conception 

 of the present century, and has received its grandest 

 expression in the elaborate works of Mr. Darwin, in which 

 he has brought it to bear upon the highest problems which 

 can engage the attention of mankind. Succeeding the 

 metaphysical system of Hegel, it has itself been further 

 extended by the more recent efforts of Mr. Herbert Spencer, 

 Professors Huxley, Tyndall, and others ; but with the name 

 of Darwin will ever be associated the completion of the 

 doctrine of the great organic revolution which may be said 

 to have been originated by the illustrious Lamarck. As 

 heredity is inseparable from evolution, I may here briefly 

 glance at the salient points of the theory, as propounded by 

 Darwin himself. 



The theory of evolution as affecting biology asserts that 

 " all the species of living beings, both animal and vegetable, 

 have not been originally created as we see them, but are 

 derived from ancestors of lower and simpler organisation 



