152 SYMBIOGENESIS 



that of the Mutationist school, and at the same time eject every 

 notion of utility from the conception of the evolutionary 

 process. But we have now sufficiently seen that all genuine up- 

 building processes depend on gradual symbiogenesis, including 

 in Robert Chambers' parlance various forms of "the long- 

 protracted gestation of nature," and though this must become 

 more effective every day, yet it remains inherently true that 

 Natura non facit saltum. Nature is progressing slowly, and 

 this for very good qualitative reasons. There are no jumps, 

 though occasionally through degeneration big falls will occur. 

 In the event of the disruption of the equilibrium through the 

 introduction of a strong genetic dose of anti-biotics (inferior 

 currency) the resultant becomes lowered. 



Nature meets the case as best it can. The cross-fertilisa- 

 tion responsible for the result may have less permanent effects 

 than in-breeding frequently has, and with subsequent 

 in-breeding a separation of strains may take place. In-breeding 

 alone tends to fix the type, though, if long continued, with 

 grave dangers of disease and ultimate extinction. 



The method of segregation is to encapsule, as it were, the 

 inferior strain in a manner similar to that whereby certain 

 animals by means of a secretion seal up intruding pathogenic 

 organisms and then to extrude the "alloy" on the first 

 opportunity. The fact that fertilisation has taken place at all 

 means not much more than that over and above the provision of 

 a just sufficient genetic stimulation, an "infection" has been 

 provided, and that in the new generation an organic " alloy " 

 has been formed. It is also obvious that the eventual riddance 

 of the impure strains so " alloyed " with pure, is a more or 

 less expensive process, during which a considerable amount of 

 vitality may have to be sacrified. 



In my Nutrition and Evolution I have referred to the fact 

 that a cross between an immune and a non-immune strain of 

 wheat from "rust" fungus disease results in hybrids which 

 are all susceptible to "rust," and that immunity in this 

 instance behaves as a recessive to the non-immune condition. 



