vni HEREDITY 147 



We know that the lint hair of the former is shorter and of 

 greater diameter than the lint hair of Egyptian, but there 

 are other differences which the microscope cannot as yet 

 determine, though to the fingers of the expert grader of 

 lint they are far more obvious than is the colour to 

 his eye. 



The F! of ^Egypto-Upland crosses is always a superfine 

 Egyptian. Thus, the mating of a " bread-and-cheese " 

 Egyptian with a short-staple Upland gives a first cross 

 bearing such lint as is required by the fine spinner. In 

 the early stages of these researches we denoted this general 

 peculiarity of these hybrids as " first-cross intensification," 

 in the hope of explanation later. In many characters this 

 explanation has been since obtained, but not in 

 respect of the " style " of the lint. Until we know the 

 component elements of " style " we cannot make much 

 advance. It is safe to expect that such intensified 

 characters will regress to the parental normal in later 

 generations, but further knowledge might enable us to 

 purify the particular combination of allelomorphs which 

 leads to this immediate improvement. In point of fact 

 we have raised families which breed true to an extremely 

 fine and strong Sea Island type of lint, from the cross of 

 King with Charara ; the lint of the latter parent was of 

 the Abbassi type. 



From what has been said above it will be clear that the 

 "style" of a lint sample is the resultant of an unknown 

 number of unknown factors, both zygotic and gametic. 

 When a set of F 2 samples is placed before an expert, this 

 becomes obvious ; the expert finds one lint which 

 resembles Afifi, except that it has the colour of Yannovitch ; 

 he next meets another which has the colour of Afifi, but 

 which he would unhesitatingly affirm to be American 

 Upland if the room were darkened. The task of analysing 

 an F 2 in this way is almost hopeless, however valuable 

 the results may be for other purposes. The author is 



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