202 THEORETICAL BIOLOGY 



If we call the dominant property " A," the recessive " B," 

 and the corresponding rudiments " a " and " b," the whole 

 process can be reproduced diagrammatically as follows : — 



Pc7renT5 A B 



Camef^e^ (a) (a^ (aUa) fbHb)^)) (b) 



/^Generation: \ ^^^r'^Sc^S'CL /^^ 



Zc/^ofe3 (ab) (ab) (ab) (ab) ... a^^ each comdmtJf^On , 



^c/u/f:5 A A _A_ A 



6ame/e3 . . . . (a)(b) (a)(b) (a)(bWa)(b) 



2''6eneraf,on: \/\/ \/\ 



2.(/gofe5 . . . . (a a) (bb) (ab) (ab> . . .combmec/ accorcZ/np 



/Jc/u/t^ A B A A fofhe/atvo/y?rododj///y 



Comefes .... (7^1) ^ym (a)(b) (lub) 



This diagram gives a firm basis from which we may dispose 

 in a consistent fashion of all questions concerning heredity. 

 It will also meet those complicated relations which come 

 about when two or more pairs of competing properties come 

 into question. 



It is invariably assumed that, in the germ, all the rudi- 

 ments remain completely independent of one another, and that 

 each is inherited by itself as an independent magnitude. And 

 from the outset this disposes of the notion of a hidden frame- 

 work present in the germ and connecting the rudiments 

 together. Occasional exceptions cannot overthrow the prin- 

 ciple that each rudiment of a property is to be regarded as an 

 independent natural factor. 



The nature of these factors also emerges from the Men- 

 delian experiments, which relate not merely to the absolute 

 properties of the individual cells, but also to the relative 

 properties, i.e. to the number and position of the cells and the 

 organs that bear them. It is not only the colour of the peas 

 that is determined by a factor ; so also is their roundness, 

 and this depends on the position of the cells with regard to 

 the centre. 



If we attempt to find a mechanical solution of the trans- 



