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THE AMERICAN NATURALIST 



[Vol. XLVII 



between a and B, or even between a and b. Think of it ! 

 How can something be coupled with nothing? How can 

 nothing be inseparably bound up with nothing? It seems 

 to me the consequent effect on inheritance is absolutely 

 "nothing" ! 



Not only do the small letters thus lead to confusion of 

 thought, they also tend to make formulae needlessly cum- 

 bersome, for they call for the use of two symbols for 

 every character difference dealt with. These two sym- 

 bols also are so much alike that both printer and reader 

 are in momentary danger of confusing them, with the 

 consequence that what is is not, and what is not is! 



The small letters are not indispensable to accurate and 

 exhaustive analysis of Mendelian phenomena, or to lucid 

 exposition of them. See, for example, the fundamental 

 researches of Cuenot into the color inheritance of mice, 

 and his classic " notes" describing them. Like Cuenot, I 

 have not found the use of the small letters necessary ; but 

 among nearly all other Mendelians the double termin- 

 ology has become so nearly universal that a different 

 usage seems almost to demand an apology. Indeed Lang 3 

 has suggested that such offenders against uniformity as 

 Cuenot and I should be haled before an International 

 Congress and be directed to conform; since which time 

 I had almost abandoned hope of ever seeing improve- 

 ment in the current confusing system, but Morgan 's pro- 

 test and proposal gives me new courage. 



What we need first of all to symplify our present usage 

 is to abandon the dual terminology. Where we are deal- 

 ing with a single set of variations, let a single set of sym- 

 bols suffice. Let us give up either the small letters or the 

 large ones, it matters not which. If we retain A, then we 

 have no need of a, for it is not, as Morgan at one time 

 seems to assert and at another to deny, the " residuum' ' 

 when A is lost; it means on the presence and absence 

 hypothesis nothing but this, that A is not present. The 

 rest of the organism is the " residuum. ' ' Morgan poinl 



*Zeitsch. f. ind. Abstammungs- und Vererbungslehre, 4, p. 40, 1910. 



