xm EXTENSIONS OF DARWINISM 255 



marvellous substance, protoplasm, and they were rendered 

 possible when that substance was endowed with the mysterious 

 organising power we term life. First the cell was produced ; 

 and, from the continued subdivision of the cell at each sub- 

 division taking a slightly different form and function, numerous 

 one-celled animals were formed ; and a little later the union 

 of many cells of diverse forms and functions led to the endless 

 multicellular creatures, constituting the entire world of life. 



Thus every substance and every organ came into existence 

 when required by the organism under the law of perpetual 

 variation and survival of the fittest, only limited by the 

 potentialities of living protoplasm. And if the higher sense- 

 organs were so produced, how much easier was the production 

 of such superficial appendages as horns and tusks, scales and 

 feathers, as they were required. Horns, for instance, are 

 either dermal or osseous outgrowths or a combination of 

 both. In the very earliest known vertebrates, the fishes of 

 the Silurian formation, we find the skin more or less covered 

 with tubercles, or plates, or spines. Here we have the 

 rudiments of all those dermal or osseous outgrowths which 

 continue in endless modifications through the countless ages 

 that have elapsed down to our own times. They appear and 

 disappear, as they are useful or useless, on various parts of 

 the body, as that body changes in form and in structure, and 

 modifications of its external covering are needed. Hence 

 the infinite variety in nature a variety which, were it not so 

 familiar, would be beyond the wildest flights of imagination 

 to suggest as possible developments from an apparently 

 simple protoplasmic cell. The idea, therefore, that there 

 were, or could be, at any successive periods, anything of the 

 nature of the abrupt beginning of completely new organs 

 which had nothing analogous in preceding generations is quite 

 unsupported by what is known of the progressive develop- 

 ment of all structures through slight modification of those 

 which preceded them. The objection as to the beginnings 

 of new organs is a purely imaginary one, which entirely falls 

 to pieces in view of the whole known process of development 

 from the simplest cell (though in reality no cell is simple) to 

 ever higher and more complex aggregations of cells, till we 

 come to Mammalia and to man. 



