338 OSCAR RIDDLE. 



The doctrine of numerous specific enzymes, 1 then, goes the 

 way of the doctrine of specific cliromogens, which is so decisively 

 settled by the work of Bertrand. 2 Remembering that the Men- 

 delian description (by implication) of what is happening on the 

 (color-producing) surface of the body in late stages of develop- 

 ment is thus completely awry, we may not be surprised to find 

 that their assumptions regarding conditions in the germ are in a 

 similarly contradictory tangle. 



Our present knowledge permits neither the realization nor the 

 imagination of a " color factor " in the germ ; not even in a 

 simple form ; much less does it grant us the very composite and 

 elaborate picture presented by Castle. 



The " production of color " is a special manifestation, in rather 

 restricted regions of an organism, of a general po^ver to oxidise 

 organic compounds, possessed, presumably, by all parts of the germ 

 cell from which the organism arose. With the development of 

 the body, the specialization of tissues, there arise very new en- 

 vironments for the oxidative processes, producing localized 

 changes and variations in this power. That this is so is evi- 

 denced by the fact that the living substance of the various body 

 regions oxidizes fats, sugars, and proteids with unequal ease. 

 There can be, moreover, scarcely a doubt that certain of these 

 regions, owing to new structure, new environment, new condi- 

 tions, are able to oxidize different protein substances with variable 

 ease, and to a variable extent, and even in a different way. 



When one has grasped the nature of the process by which 

 melanin color characters are formed, there is as little necessity or 

 truth in assuming that the germ cells contain representatives or 

 determiners to correspond to a particular color, as there is in 

 assuming that the vapors of the Gulf contain determiners for the 

 depth, or distribution, of the mantle of snow which they are to 



1 Mendelians must, however, accept the specificity or non-specificity of enzymes 

 in the production of color (they must have some sort of representative particle in the 

 germ) and either choice leads, when critically examined, to the unqualified refuta- 

 tion of some of their fundamental conceptions and interpretations of heredity. The 

 established fact that each of the melanin colors represents but a point in a line a 

 line which records the continuity of a continuous oxidation process is the fact that 

 strikes hard at the very basis of Mendelian interpretation and description. 



2 Table I. shows, for example, that at least seven of the nine compounds repre- 

 sented are capable of producing the colors yellow and red. 



