12 THE CANADIAN NATURALIST. [Vol. vi. 



tt'i's of Genesis cannot reasonably be interpreted in their literal 

 sense ; so that for a distinct statement of this view we must look 

 to the great English poet, who, however, was not a scientific man.'-"^ 

 The idea that orscanisms were created as es-^s, which have a sim- 

 pier structure, is less difficult to comprehend than the foregoing, 

 but it is not easy to see how this could occur with the higher 

 animals whose young are born alive, and not in the form of eggs. 

 A rather vague enunciation of this idea is contained in a little 

 work by Swedenborg,-]- which is probably to be regarded as purely 

 j)hilosophical and not as one of his theological works. 



The second and more numerous family of theories is called 

 " Derivative," because they all involve the supposition that in 

 some way the lower and earlier forms have served as the means 

 of producing higher and later ones. But it will be seen that 

 they differ essentially as to the manner of this derivation. La- 

 marck was impressed with the amount of variation in size and 

 form which the parts of an animal may undergo in consequence 

 of their use or disuse, and so indirectly from any desire or " appe- 

 tency " which the animal experienced, e.g., a fish might thus 

 become a quadruped if forced to live upon the land, and an ape 

 might become a man. The amount of change in any one genera- 

 tion might be very slight, but the next generation would inherit, 

 increase, and perpetuate the transformation. 



In the endeavour to eive a concise statement of Darwin's own 

 theory, we sufi"er from an " embarras de richesses ;" for not only 

 is his own work one long presentation of it in many different 

 aspects, but each later writer upon the subject has given his par- 

 ticular version, and from a different stand-point. Summary ex- 

 pressions of the theory are given by our author on pages 40, 70, 

 178, 412, 437 ; but a more diagrammatic enunciation is that of 

 Wall-ace, who not only presented publicly an independent theory 

 of natural selection at the same time with Darwin (1858), but 

 has since paid a warm tribute to the latter' s work, while expres- 

 sing a doubt respecting the sufficiency of that theory for the pro- 

 duction of man. With a few unimportant changes, his presenta- 

 tion is as follows : % 



* " Paradise Lost," Book VI. 

 f '< Worship and Love of God," Section 3. 



X " Contributions to the Theory of Natural Selection." London 

 and New York : 1870. Pp. 302. 



