IV CAPITAL THE MOTHER OF LAEOUR 155 



does not answer as an article of human diet, and 

 biscuit does. So the usefulness of mutton lies 

 mainly in certain chemical compounds which it 

 contains : the sheep gets them out of grass ; we 

 cannot live on grass, but we can on mutton. 



Now, herbaceous and all other green plants 

 stand alone among terrestrial natural bodies, in so 

 far as, under the influence of light, they possess 

 the power to build up, out of the carbonic acid 

 gas in the atmosphere, water and certain nitro 

 genous and mineral salts, those substances which 

 in the animal organism are utilised as work-stuff. 

 They are the chief and, for practical purposes, the 

 sole producers of that vital capital which we have 

 seen to be the necessary antecedent of every act 

 of labour. Every green plant is a laboratory in 

 which, so long as the sun shines upon it, materials 

 furnished by the mineral world, gases, water, 

 saline compounds, are worked up into those food 

 stuffs without which animal life cannot be carried 

 on. And since, up to the present time, synthetic 

 chemistry has not advanced so far as to achieve 

 this feat, the green plant may be said to be the 

 only living worker whose labour directly results 

 in the production of that vital capital which is 

 the necessary antecedent of human la-bour. 1 Nor 

 is this statement a paradox involving perpetual 



1 It remains to be seen whether the plants which have no 

 chlorophyll, and flourish in darkness, such as the Fungi, can 

 live upon purelv mineral food. 



