50 PLANT PHYSIOLOGY 



from koporphyrin of colorless organisms such as yeasts. Hemo- 

 globin is derived by eliminating two molecules of formic acid and 

 adding iron to the pyrrol groups, while chlorophyll is derived by 

 eliminating a molecule of carbon dioxide and adding magnesium. 

 Similarly, by removing the magnesium from protochlorophyll, 

 Noack obtained protophseophytin, which has a brilliant red color 

 and is related to the bilipurpurin of animals. Also when magnesium 

 is added to bilipurpurin (also called phylloerythrin), a substance 

 is obtained with almost the same spectrum as chlorophyll. 



.N N 



C- \ / \, 



,Fe' 



chlorophyllin 



In addition to the similarity in chemical analysis between the 

 hemoglobin and chlorophyll, their physiological resemblances are 

 equally striking. Both are pigments; according to Palladin both 

 may be concerned in the transfer of oxygen; Manoilov (1922) 

 has produced evidence that the chemical tests which distinguish 

 male from female blood may also be applied to male and female 

 chlorophyll in dioecious plants; and Raber (1930) called attention 

 to the fact that liver extract, a common treatment for pernicious 

 anaemia, also checked somewhat the etiolation of green plants when 

 placed in the dark. 



These results obtained by biochemistry throw an extremely 

 interesting light on the evolutionary development of plants and 

 animals at the time when these two branches of the organic world 

 were commencing to diverge from each other. Differences between 

 organisms are to be found not only in structure and function, but 

 associated with these differences are differences in metabolism, 

 which in the one group of organisms (plants) have produced inde- 

 pendent individuals able to manufacture their own food, and in 

 the other group (animals) a type of organism which must live 

 dependently upon food built up by the former group. 



