MELANIN COLOR FORMATION. 347 



inference, arising from the temporary mixture (heterozygote), or 

 failure to mix (homozygote) in the gamete, of something, no one 

 knew what but which has been generally conceived of as some 

 sort of " particles." (In later additions to, and special applications 

 of the Mendelian conception, certain other biochemical and 

 physiological facts have, of course, been considered.) 



This is precisely why present Mendelian interpretation and de- 

 scription of heredity is a bar to the progress of studies in inherit- 

 ance and 'development ; with an eye seeing only particles, and a 

 speech only symbolizing them, there is no such thing as the study 

 of a process possible. 



The conception that organic color has at its basis not rigid, 

 immortal particles, but yielding, equilibrium-seeking powers, or 

 strengths of processes, makes the infinite variety of colors in 

 organisms intelligible. If, on the other hand, particles, and a 

 mechanism for their continual segregation and propagation pure 

 were in reality at the basis of color inheritance, we should rather 

 expect uniformity, not the actual diversity, to be the dominant fea- 

 ture of organic coloration. Indeed, a modification of the strength 

 of many organic processes (and so of color formation) would be 

 a necessary accompaniment a result, even if not a cause of 

 that " transformation of organs " which has been the very labor 

 of phylogenetic development. The atrophy, superior develop- 

 ment and transformation of organs are certainly efficient factors 

 in such modification, for it is a physiological fact of common ex- 

 perience that many, or most, of the vital processes are not equally 

 strong or pronounced in all of the organs of the same organism ; 

 and that many metabolic processes of the body are dependent 

 upon special organs for their highest expression, for the com- 

 pletest manifestation of their power. 



Let me not be understood to say that our knowledge of the 

 development of melanin color characters is complete. There is 

 much yet to be learned. But the significant thing about it is 

 that we now know so much of the mechanism of the building 

 of these characters in comparison with what we know of a sim- 

 ilar nature in non-color characters. It has been possible, I think, 

 to show by means of what we know of the genesis of these color 

 characters that the Mendelian description of color inheritance 



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