WHAT ARE SPECIES 



species of the genus Yiola. But, as these also each produce 

 their like and do not intermingle, it was believed that every 

 one of them had always been as distinct from all the others as 

 it is now, that all the individuals of each kind had descended 

 from one ancestor, but that the " origin " of these hundred 

 slightly differing ancestors was unknown. In the words of 

 Sir John Herschel, quoted by Mr. Darwin, the origin of 

 such species was "the mystery of mysteries." 



The Early Transmutationists. 



A few great naturalists, struck by the very slight difference 

 between many of these species, and the numerous links that 

 exist between the most different forms of animals and plants, 

 and also observing that a great many species do vary con- 

 siderably in their forms, colours, and habits, conceived the idea 

 that they might be all produced one from the other. The 

 most eminent of these writers was a great French naturalist, 

 Lamarck, who published an elaborate work, the Philosophic 

 Zoologique, in which he endeavoured to prove that all ani- 

 mals whatever are descended from other species of animals. 

 He attributed the change of species chiefly to the effect of 

 changes in the conditions of life — such as climate, food, etc. — 

 and especially to the desires and efforts of the animals them- 

 selves to improve their condition, leading to a modification of 

 form or size in certain parts, owing to the well-known physio- 

 logical law that all organs are strengthened by constant use, 

 while they are weakened or even completely lost by disuse. 

 The arguments of Lamarck did not, however, satisfy naturalists, 

 and though a few adopted the view that closely allied species 

 had descended from each other, the general belief of the 

 educated public was, that each species was a " special creation" 

 quite independent of all others ; while the great body of 

 naturalists equally held, that the change from one species 

 to another by any known law or cause was impossible, 

 and that the " origin of species " was an unsolved and 

 probably insoluble problem. The only other important work 

 dealing with the question was the celebrated Vestiges of 

 Creation, published anonymously, but now acknowledged to 

 have been written by the late Robert Chambers. In this 

 work the action of general laws was traced throughout the 



