136 W. JOHANNSEN 



years after the rediscovery of Mendel's laws coincided splendidly with 

 the conception of one independently separable representative in the ga- 

 mete for each : Mendelian unit-character» in the mature organism. The 

 morphological stamp of this initiated »analytical dissection» of the collec- 

 tive character of an organism into alleged unit-characters through hy- 

 bridization and continued breeding, has obtained a pregnant expression 

 in Bateson's term »Allelomorphs» for the units in »Mendelian in- 

 heritance». 



It was undoubtedly a step forward to leave the notion of unit- 

 purts in favour of the notion of un\l-characters . Now this notion too 

 is absolutely untenable. Nowadays each of Bateson's allelomorphs are 

 not regarded as a kind of germ (»Anlage») for a corresponding unit- 

 character. My term gene» was introduced and generally accepted as 

 a short and unprejudiced word for unit-factors in the — as to heredity 

 — essential constitution of gametes and zygotes, but originally I was 

 somewhat possessed with the antiquated morphological spirit in 

 Galton's, Weismann's and Mendel's viewpoints. From a physiological 

 or chemico-biological standpoint we must a priori in characters or 

 developed parts of organisms see Reactions of the (I should say geno- 

 typical) constitution belonging to the zygote in question; and from this 

 point of view there are no unit-characters at all! Undoubtedly all 

 scientific geneticists now are or ought to be in accord as to this matter- 

 But in the language of Genetics we meet with some unhappy old- 

 fashioned expressions, relics of obsolete conceptions — the worst of 

 all these relics is probably the expression Transmission where no trans- 

 mission exists but where continuity is found! »Transmission» is here 

 a kind of Hippocratic-Lamarckian slang-word, very misleading. Here 

 however we shall only try to exterminate in Genetics (perhaps a hard 

 task!) the term unit-character as indicating a notion that is totally in- 

 adequate and hence noxious for Genetics, for words too often govern 

 thoughts! 



Descriptive Natural History operates legitimately with such no- 

 tions, and when we compare the different individuals and generations 

 in our breeding series, w-e of course use methods of zoological, botani- 

 cal or chemical description. Here we are dealing with the realised 

 Phänotypes, i. e. the reactions, direct or indirect (hormones etc.) of the 

 genotypes with the ambient conditions. We may in some way »dissect» 

 the organism descriptively, using all the tricks of terminology as 

 we please. 



But that is not allowed in Genetical explanation. Here, in the pre- 



