354 EXPERIMENTAL STUDY OF INHERITANCE 



while others suppose that latent characters from previous pedigree 

 are hberated by a departure from the usual routine of inbreeding. 



Correns has investigated the interesting case of Mirahilis jalapa. 

 The white variety, alba, crossed with the yellow variety, gilva, 

 yields a hybrid with rose flowers and red streaks. When this 

 is inbred the progeny include forms with white, red, rose, yellow, 

 yellowish flowers, with or without various lands of streaks. 

 It requires some ingenuity to bring this within the Mendelian 

 scheme, but Correns interprets it as due to the activation or 

 liberation of disguised or latent characters. 



Further Elaborations.^As experimentation has increased, 

 the interpretations of the Mendelians have become more subtle. 

 We may be allowed to illustrate this by a quotation from an 

 admirable lecture delivered by Mr. Bateson in 1906 to the 

 Neurological Society of London. 



" A complication we often meet in the application of the rules 

 of heredity lies in the fact that characters belonging to distinct 

 allelomorphic pairs react on each other. A particular appearance, 

 for instance, may depend on the coexistence of both C and R, 

 and either of these factors alone may be unable to manifest any 

 influence on the individual in the absence of the other. In that 

 case there will be nine showing the appearance in question, say 

 a colour, for seven which are without it. Or, again, the factor C 

 may produce an effect alone ; while R, though imperceptible 

 in the absence of C, may modify the effect of C when C and R 

 coexist. There will then be nine of the C + R class ; three of 

 the C class ; and four all alike because C is absent, though their 

 gametic composition is really diverse." 



" For example, grey x albino rabbits gives grey F^, with 

 in F^, three grey : one albino. But F^ may be instead nine grey : 

 three black : four albino. The latter result indicates that the 

 factor which determines the colour to be grey was absent in the 

 albino. The meaning of these occurrences was first pointed out 

 by Cuenot." 



