50 



SUBCELLULAR PARTICLES 



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 o n 



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 •o o 



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 oxui 



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 in 

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 U.Ot> 



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Fig. 5. Suniniary of 

 matrix investigations. 



model s\stems used 



in the sequence of their introduc- 

 tion into experimental work (fig. 

 5), and both the pattern of investi- 

 gations already considered and of 

 those to be treated in following 

 sections may be seen. Although 

 models could conceivably be fabri- 

 cated de novo by a fortunate selec- 

 tion of component parts, it is more 

 probable that a biologically accu- 

 rate and acceptable analog be forth- 

 coming if the materials and phe- 

 nomena under investigation are 

 subjected to a careful, stepwise re- 

 duction in complexity. It is rea- 

 sonable to expect that any biologi- 

 cal problem definable in chemical 

 terms treated in this fashion will 

 in the end be sufficiently grounded 

 in principle so that it will lead to 

 applications far beyond its original 

 scope. Thus the study to follow of 

 the protein matrix as a factor in 

 formation of polyquinones, a 'by- 

 product' of the study of lignin 

 synthesis, has so far required less 

 than one-thirtieth of the time in- 

 volved in arriving at the present 

 picture of lignin synthesis, yet is 

 in some respects fully as well 

 established. 



AN analogy: the protein matrix 



IN POLYQUINONE SYNTHESIS 



Application of the Matrix to 

 Quinone Polymerization. Save for 

 one instance, the term 'melanin' has 

 not been employed in the preced- 

 ing discussion. This omission has 

 been deliberate, in spite of the obvi- 

 ous relationship between quinone 



