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THE AMERICAN NATURALIST [Vol. XLV 



the chromosomes are "bearers" of special organizing 

 functions in the mechanism of ontogenesis, a chromatin- 

 particle in the nucleus of a gamete being in some way the 

 representative of an organ or a group of tissues. 



These two ideas: that "elements" in the zygote corre- 

 spond to special organs, and that discrete particles of the 

 chromosomes are "bearers" of special parts of the whole 

 inheritance in question are neither corollaries of, nor 

 premises for, the stirp- or genotype-conception. Those 

 special ideas may have some interest as expressions of 

 the searching mind, but they have no support in experi- 

 ence ; the first of them is evidently erroneous, the second 

 a purely speculative morphological view of heredity with- 

 out any suggestive value. 



The genotype-conception of the present day, initiated 

 by Galton and Weismann, but now revised as an expres- 

 sion of the insight won by pure line breeding and Mendel- 

 ism, is in the least possible degree a speculative concep- 

 tion. Of all the Weismannian armory of notions and 

 categories it may use nothing. It is a well-established 

 fact that language is not only our servant, when we wish 

 to express — or even to conceal — our thoughts, but that it 

 may also be our master, overpowering us by means of the 

 notions attached to the current words. This fact is the 

 reason why it is desirable to create a new terminology in 

 all cases where new or revised conceptions are being 

 developed. Old terms are mostly compromised by their 

 application in antiquated or erroneous theories and 

 systems, from which they carry splinters of inadequate 

 ideas, not always harmless to the developing insight. 



Therefore I have proposed the terms "gene" and 

 "genotype" and some further terms, as "phenotype" 

 and "biotype," to be used in the science of genetics. The 

 "gene" is nothing but a very applicable little word, easily 

 combined with others, and hence it may be useful as an 

 expression for the ' ' unit-factors, " " elements " or " allelo- 

 morphs" in the gametes, demonstrated by modern 

 Mendelian researches. A "genotype" is the sum total of 



