Studies of Teratological Phenomena. 13 X 



regardless of the very necessary support from evidence based on studies 

 of fossils, and wdthout paying due consideration to the effects of 

 environment. For example, the character fasciation in peas, from the 

 morphologist's viewpoint, is a siugie kind of character, for how are 

 they to know, in the absence of experimental data, that there 

 are, at least, two absolutely distinct forms of this character. Eelatively 

 speaking, perhaps these two forms of the fasciation character are even 

 but remotely related. They differ as to cause and in behavior, but 

 morphologically they are absolutely indistinguishable. If factors have 

 a definite reality in the sense in which we think of the chemical atom, 

 then probably a different combination of factors as well as of environ- 

 mental phenomena are responsible for these two forms, just as the 

 color, quality or character red, may be found in very distinct and 

 relatively remotely related forms of mineral matter. And if the 

 relationships of organisms cannot be judged by characters, how can one 

 formulate a natural system of classification? 



With the elimination of the latency conception from biological 

 discussion, the various perplexing data on fasciation resolve themselves 

 into an orderly and simple scheme. 



From the standpoint of genetics, all fasciations may be divided 

 into two classes ; those inherited and those uninherited, the former due 

 primarily to one or more genetic factors, the latter largely the result 

 of external environmental conditions. The "half" and "eversporting" 

 fasciated races of de Vries probably belong largely to the latter class. 

 No necessity exists for and confusion results from maintaining the con- 

 ception of ''eversporting" fasciated races. Had the studies of de Vries 

 been made at the present time rather than in the pioneer period 

 of genetics, it is safe to say that this conception would never have 

 arisen. 



One may further deduce from this study of fasciation, certain 

 conclusions regarding the phenomenon of dominance. Dominance and 

 recessiveness in the case of the character fasciation is always dependent 

 on the three elements held to be the basis of a character, — the primary 

 factor or factor complex, the complex of all the other genetic factors 

 constituting the total heritage of the organism, and the external environ- 

 ment. Changes in any one of these may give rise to a new character 

 or modify an old one, the distinction between old and new being 

 largely a matter of convenience, for, when a factor still retains its 

 usual or common expression, except for slight modifications which do 



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