ON THE FORMATION OF ANTHOCYANIN. 



By M. WHELDALE, 



Fellow of Neivnham College, Cambridge. 



Nature of Problem and Preliminary Statement of 

 Conclusions. 



The problem to which I have attempted to give a solution in the 

 following pages may be briefly stated as follows : — what are the 

 chemical processes which underlie the formation of anthocyanin ? 



In my attempt to arrive at some solution I have used as data the 

 results of observations upon the general distribution of pigment, its 

 formation in relation to other metabolic processes and to the chemical 

 constituents of the tissue : also the conditions, both natural and 

 artificial, which lead to its appearance, and lastly, the detection of 

 enzymes which may be involved in its production. 



As an outcome of this general investigation, I venture to bring 

 forward an hypothesis which may afford in many respects an explana- 

 tion, in terms of chemical reactions, of the mechanism underlying the 

 phenomenon of soluble pigment formation. At the same time I may 

 say that I look upon my suggestions as tentative and as having value 

 possibly only in so far as they combine together into a general scheme 

 a number of more or less isolated facts. I fully realise that the under- 

 lying causes of such a phenomenon are of a complex nature and may in 

 reality demand a very different explanation from that which I am able 

 to offer. 



The ultimate object of the enquiry is the identification of the 

 Mendelian factors for colour. There is little doubt that the formation 

 of anthocyanin does involve a series of progressive reactions each of 

 which is contioUed by a certain enzyme. In variation, whatever that 

 may be, the loss of these enzymes gives rise to different colour varie- 

 ties. Hence the greater the complexity of the pigment-forming process 



