308 GENERAL PHYSIOLOGY 



has simply been transferred from one world to another. In the 

 present condition of our knowledge it is scarcely possible to obtain 

 a direct contradiction of this doctrine and conclusive proof of its- 

 impossibility. This will be true so long as experience does not 

 suffice to enable us to recognise as wholly impossible the transfer 

 of protoplasmic germs capable of life from one world to another. 

 But ; although direct contradiction of the doctrine is at present 

 impossible, the thought that living substance has existed from 

 eternity and has never originated from inorganic substance appears 

 in the highest degree improbable. 



As a comparison of organisms and inorganic bodies has shown, 1 

 organisms originate only from those chemical elements that 

 occur in inorganic matter also, and differ from the latter only in 

 the chemical compounds of which they are composed. The essen- 

 tial compounds of living substance, proteids, do not stand, therefore,. 

 in fundamental contrast to inorganic compounds, and differ from 

 the latter no more than these differ from one another. Hence any 

 general consideration that is formulated regarding the derivation 

 of living substance, especially of proteid, must be equally applic- 

 able in its fundamental points to inorganic compounds, such as 

 minerals, feldspar, quartz, etc. But it is shown more clearly in 

 non-living than in living substance to what untenable consequences 

 the idea that lies at the foundation of the doctrine of cosmozoa 

 leads ; for, if it be assumed that the complex compounds of living 

 substance, especially proteids, have never originated, but have 

 existed from eternity somewhere in space and have come thence to 

 the earth, with the same logic and the same degree of probability it 

 must be assumed that inorganic compounds also, quartz and feldspar, 

 have always been present as such somewhere in space, and have come 

 to the earth through space from another world. And if this line of 

 thought be carried out to all chemical compounds composing the 

 earth, and it is as probable of them as of the compounds of living 

 substance it would lead to the absurd conclusion that all of the 

 earth's compounds have wandered already complete as such from 

 outside into our planetary system. Scarcely any man of science 

 would be willing to accept this conclusion ; every geologist is 

 acquainted with examples of minerals that demonstrably have 

 originated as such chemically upon the earth, and every chemist 

 manufactures daily in his laboratory chemical compounds out of 

 simpler substances. No thinking chemist, indeed, now doubts that 

 even the so-called chemical elements did not exist originally as 

 such, but that those elements possessing high atomic weight have 

 been derived by condensation from those having less atomic weight. 

 If the final conclusion be deduced from the cosmozoan ideas, all 

 evolution, not only of living substance but of the whole earth, must 

 be denied ; for, if all compounds have existed as such from eternity 



1 Cf. p. USetfolg. 



