56 GENERAL BIOLOGY 



the condensation of these amino-acids, other radicles 

 or "albuminous nuclei" are welded on, combined, and 

 recombined with the carbohydrate base, or with each 

 other, each time with the disappearance of the poten- 

 tial energy of chemical affinity, until the huge, com- 

 plex, unwieldy, protein molecule results, and becomes 

 a part of the mixture we call protoplasm. This pro- 

 cess has been shown to take place in the green leaves, 

 although it goes on in the dark. 



To summarize : The plant in its myriads of cell- 

 laboratories is constantly carrying on a variety of 

 chemical syntheses. First, the carbon element of 

 the CO 2 derived from the air, and the H 2 O absorbed 

 from the soil, are combined in the green leaves to 

 form carbohydrates, such as sugars and starch. 

 These molecules may be welded together to form 

 more complex carbohydrates, such as dextrine, 

 cellulose, or wood fiber, or they may be combined 

 and recombined with other elementary compounds 

 containing nitrogen and sulphur until the complex 

 and unstable albuminous or protein molecule results. 

 Each step involves the change of kinetic energy 

 into potential energy, and all this energy is derived 

 in the first instance from sunlight. This building-up 

 process from simple to complex is called Anabolism, 

 and, as a consequence of this process, the plant is 

 endowed with an immense reserve of potential 

 energy. 



Dissimilation. But the plant is all the while 

 living, developing new buds and leaves, maturing 

 its fruit, secreting characteristic products, even 



