118 



PLANTS, THE FOOD OF ANIMALS 



tion is masked by the more active processes going on under 

 the action of chlorophyll, so that in sunlight the oxygen needed 

 is provided by the residue of oxygen after starch is formed 

 the remainder being given off, while the waste matter CO 2 is 

 reduced and manufactured into starch. The essentials of 

 respiration, therefore, go on all the time but C02 is actually 

 given off by the plant only in the absence of sunlight. The 

 oxygen given off cannot be considered a waste matter or prod- 



SALTS (Ca, Ha, P, F e ,Tn<j, 5,nH 3 ,etc.j COj 

 NITRATES , NITRITE5 



fl^O SALTS 



NM CO^ NITRATES 



Pn05PMATE5 

 OTHER 5ALT5 



EARTH -"WATER 



FIG. 48. Diagram illustrating the cycle of living matter and energy in animals, 

 plants, yeast and bacteria. 



uct since it has not been a part of the plant organism but is 

 only a by-product of chlorophyll activity. Nitrogenous waste 

 may be disposed of when present in small quantities, by 

 being stored in the leaves and finally cast off by the annual 

 shedding of leaves and their contents. 



Cycle of Matter and Energy. The autotrophic nutrition of the 

 fern and plants generally, is the starting point for the wonderful 

 cycle of matter and energy in nature whereby living things are 

 all interrelated and balanced. Plants manufacture proteids 



