THE GENERAL CONDITIONS OF LIFE 309 



and have never originated from simple substances, evolution has not 

 taken place. This is the inexorable consequence of a full acceptance 

 of the cosmozoan doctrine. We repeat that one has no right to 

 assume for feldspar a principle of derivation different from that 

 assumed for albumin. Both are compounds of chemical elements. 



One fundamental fact in plant physiology practically contra- 

 dicts the assumption that life has never originated from inorganic 

 substances ; namely, at the present time living substance is con- 

 tinually being formed in the plant-cell from simple inorganic 

 compounds, carbonic acid, water, sulphates, nitrates, etc. Between 

 the small seed put into the earth in the spring and the huge plant 

 that grows from it during the summer, an enormous quantity of 

 living substance has been formed out of the purely inorganic sub- 

 stances of the environment, and when winter comes, almost the 

 whole quantity of this living substance returns again to simpler 

 inorganic compounds. It is here seen how inseparably related are 

 inorganic and organic nature, how living substance is originating 

 continually from lifeless substance, and is continually being decom- 

 posed again into lifeless substance. Nageli ('84), one of the most 

 talented botanists, says rightly : " One fact that in organisms inor- 

 ganic substance becomes organic substance, and that the organic re- 

 turns completely to the inorganic is sufficient to enable us to deduce 

 by means of the law of causation the spontaneous origin of organic 

 nature from inorganic." " If in the physical world all things stand 

 in causal connection with one another, if all phenomena proceed 

 along natural paths, then organisms, which build themselves up 

 from and finally disintegrate into the substances of which inorganic 

 nature consists, must have originated primitively from inorganic 

 compounds. To deny spontaneous generation is to proclaim a 

 miracle." 



In a sense entirely different from that of the doctrine of cos- 

 mozoa, which has met with little acceptance, Preyer, in his 

 theory, interprets life as without beginning and eternal. He 

 says : The living substance now inhabiting the earth's surface 

 is derived by continuous descent from the substances that once 

 in a melted condition constituted the earth's mass. Not to 

 term the latter substances living would be arbitrary, since no 

 .sharp limit can be established. Since, however, these substances 

 are derived from the sun's mass, and the latter forms simply 

 a portion of the matter of the universe, which is in eternal 

 motion, so life, which itself is only a complex process of motion, 

 is as old as matter. 



It is evident that the essential difference between Preyer's 

 theory and the doctrine of spontaneous generation consists in a 

 different understanding of the conception of life. Following the 

 usage of language, the doctrine of spontaneous generation terms 

 living only living substance as it is now recognised, in contra- 



