GENETICS 153 



This seems to indicate that the result of a cross must 

 always depend on qualitative factors, or as I now, in keeping 

 with the further elaboration of my theory, would say it 

 depends on the presence of symbiotics, i.e., symbiotically 

 accumulated ancestral forces. We have seen, in the case of 

 grafting, how the physiological misere of our cultivated plants 

 may be somewhat relieved by the introduction of symbiotics 

 borrowed from a wild stock. This is crossing of one kind. To 

 introduce, instead, diseased strains equivalent to anti-biotics 

 into the already declining constitution of the over-cultivated 

 wheat, however, is crossing of quite another sort, and is bound 

 to produce a lowering of the resultant. Just as we saw that 

 this leads to disaster in nature generally, and just as even 

 cross-fertilisation in spite of its manifest advantages is 

 frequently impracticable in cases of physiological misere, so in 

 this artificial case the introduction of anti-biotics leads to an 

 increased liability to disease generally. The fact of the 

 diseased condition thus becoming " dominant " and the healthy 

 factors being "latent," "recessive," i.e., diminished, in my 

 opinion is of greater significance than the fact that hybridisa- 

 tion with subsequent (more or less) definite ratios of segregation 

 is still possible. It is now a case, as Plato would say, where a 

 thing has become like the evil that is present within it. But 

 the good that the thing contained may, at least, partially be 

 recovered. (It is known that " dominance " is imperfect in 

 the F 1 generation, and that more or less of the recessive 

 "character" is generally outwardly exhibited; which would 

 seem to indicate that all health, although obscured, is not 

 gone.) 



The danger which is the danger of exhaustion and of 

 biological sterility is, in Plato's words, that the presence of 

 evil may be such as to deprive the organism at the same time to 

 an increasing extent of the desire and "friendship " of the good. 



Mature, ever wisely conservative, preserves for a time at, 

 least, the evil for the sake of the little good with which it is 

 still associated, even as the destruction of that ancient citv of 



