60 GERMINATION 



with them all in this chapter. First as to chlorophyll ; 

 which in my view is to the plant what haemoglobin is to 

 the animal. ^ 



In Physiological Chemistry, Matthews says : The 

 chemical composition of chlorophyll is not yet known. 

 . . . When decomposed it yields, like haemoglobin, the 

 colouring matter of the blood, pyrrol derivatives. It is 

 evidently related more or less closely to the hematin of 

 the haemoglobin, hemopyrrol being identical with phyto- 

 pyrrol. Unlike haemoglobin it contains no iron, but the 

 plant must have iron for its synthesis. Its close relationship 

 to haemoglobin is further established by the discovery of 

 the plant chromoproteins, phycoerythrin and phycocyan, 

 which are crystalline conjugated proteins like haemoglobin, 

 but they are found in plants and are closely related to their 

 chlorophyll. ... It has recently been suggested that 

 the iron which is always 'present in the chloroplasts of plant 

 cells plays a very important part in the synthesis of the 

 formaldehyde as well as of the chlorophyll. There can be 

 no doubt that many colourless plant tissues, if exposed to 

 light and if they contain iron, are able to synthesize chloro- 

 phyll." The italics are mine. 



Halliburton gives the chemical formula of hemopyrrol 

 (dimethylethyl-pyrrol) as follows : 



CHg C — • C — ^Hf 



hJ^H 



What I am aiming at, however, is to find firm ground 

 upon which to build up the hypothesis that chlorophyll in 

 combination with oxygen is capable of generating force 

 to give out energy to the plant in the possible absence of 

 supply or in the event of insuflScient supply from the earth 

 and it is for that reason I have italicised the words " iron 

 which is always present in the chloroplasts of plant cells.'* 

 Nor am I altogether convinced that chlorophyll cannot be 

 formed except in the presence of light, or rather, is it quite 



