PROTOZOA 315 



substance is formed from lifeless, and changes back 

 into it, we may assume that it had its first origin in 

 inorganic matter. We have the more right to do this 

 since no element has yet been found in living matter 

 that is not found in the inorganic world. There is no 

 essential difference between the albuminoids and other 

 compounds. Finally, we know that all compounds are 

 made up of simple elements. The whole of science 

 is based on this fact. It would be contrary to all 

 experience if compounds suddenly appeared that were 

 not formed from others, but had existed for all 

 eternity without any connection with nature, as it 

 were.^ 



We are thus driven, by a number of considerations, 

 to the conclusion that life was born on our planet. And 

 as there can only have been inorganic matter on our 

 planet from the first, life must have been evolved from 

 it; nothing can be made out of nothing. It is no 

 objection against our theory that we have not 

 yet succeeded in artificially producing living matter or 

 animals. How could we hope to do this when we know 

 neither the structure of living albumen nor the forces 

 that create it. The fact that no living matter has yet 

 been produced artificially only shows that a certain 



1 There is still another important theory of the origin of life, that 

 of Preyer. This takes the idea of life in a wider sense than we 

 usually do. It regards the molten planet as a living organism, 

 and so postulates a continuity of life. In the form to which we 

 now give the name of living matter, Preyer himself admits that 

 it was formed by spontaneous generation. It is a question whether 

 we should be justified in speaking of the movement of inorganic 

 masses as life. It is a question of terms, and we will not enlarge 

 on it. 



