AND ITS RELATION TO ANIMAL LIFE 2J 



animals or in the products of their decom- 

 position, are divided directly or indirectly 

 from the organs of the plants which contain 

 chlorophyll." 



Encyclopaedia Britannica, vol. xix. p. 52 

 says 



" The general conditions upon which 

 chlorophyll is formed are light, heat and sup- 

 ply of iron." 



Plants which have grown in absence of a 

 supply of iron are said to be chlorotic. 



In Encyclopaedia Britannica, vol. xix. p. 53, 

 Hansen says : " The only normal ash con- 

 stituent in chlorophyll is iron." 



Iron is known to be essential only to those 

 plants which contain chlorophyll. If pale 

 leaves be painted over with a dilute solution of 

 iron they will soon become green. Iron, there- 

 fore, plays an important part in connexion 

 with the green colouring matter chlorophyll. 



From the above quotations it is clear that 



