20 VITAL AND PHYSICAL FORCES 



The plant, as we have seen, takes not-living mineral ingredients 

 from earth and air, and under the influence of solar Ught and 

 heat, these simple materials assume, within its tissues, those higher 

 modes of combination which are necessary in order that they may 

 be converted into 'living' matter. The forces at work in and 

 upon the plant are supposed to be nothing more than ordinary 

 physical forces. Here, however, it is true, matter passes from 

 the lifeless to the living state of combination under the influence 

 of pre-existing protoplasm. But as no unknown and independent 

 forces are now believed to be at work within living tissues we 

 must suppose that, under the influence of the physical forces 

 within and those without the organism, Ufeless compounds fall 

 more or less immediately into such and such living combinations. 

 The influence of the pre-existing protoplasm would seem to 

 expend itself chiefly in the building up of the living matter after 

 its own likeness. Here, at all events, facts lend no support to the 

 common notion that there is some extraordinary difficulty to be 

 overcome in order that matter may fall into living modes of 

 combination. The further common supposition as to the necessity 

 for long intervals of time, during which numerous intermediate 

 stages in molecular complexity may be passed through before 

 the combinations resulting in what we know as living matter can 

 arise, seems directly opposed to the facts made known concerning 

 the nutrition of plants and the free growth of Bacteria and 

 Torulas in comparatively simple solutions of not-living matter. 



