THE BEGINNINGS OF LIFE. 77 



produced under the influence of physical forces alone, 

 just as it is admitted that the first particles of a crystal 

 are formed by c spontaneous ' combination. Just as 

 all subsequent portions of the crystal form in obe- 

 dience to the same molecular properties and physical 

 forces as lead to the collocation of the first particles, 

 so may the first particles of an organism combine 

 by virtue of the same chemical and physical influ- 

 ences as those which subsequently determine its 

 increase 1 . 



The plant takes not-living mineral ingredients from 

 earth and air, and under the influence of solar light 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 c 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. No unknown 

 and independent forces are now supposed to be at 

 work within living tissues, and therefore we must 

 suppose that, under the influence of the physical forces 

 within and those without the organism, lifeless com- 



1 Living matter, like crystalline matter, is only formable by a synthesis 

 of its elements. As Crystals have not the power of self-multiplication, 

 they have only one mode of origin. But because Organisms have repro- 

 ductive powers, the obviousness of these modes of increase has sufficed 

 to cast doubts upon the reality of the independent origin of living units. 

 (See vol. i. p. 473.) 



