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COOK 



formed, or prefixed, inside the reproductive cell. It is highly 

 important, of course, that the nature and extent of all determi- 

 native relations be known, but until the nexus, the modus 

 operandi of the process has been learned, predetermination by 

 material particles has no special standing as a theory, especially 

 where the resulting concept of heredity fails to accord with 

 concrete, facts, such as the need of normal heterism and free 

 interbreeding. 



To those who view the matter from the mathematical side 

 only, it is still impossible to -prove that essential changes occur 

 in mitapsis which make the chromomeres and chromosome 

 aggregates different from what they were before the fusion took 

 "place. Nevertheless, there are three facts of nature, universal 

 and much accentuated among all the higher plants and 

 animals, which these theories of construction of organisms by 

 character-unit mechanisms leave entirely out of account, with- 

 out physiological meaning or explanation, (i) the diversity of 

 the individual members of species, (2) the elaborate adaptations 

 for interbreeding, and (3) the conjugation of the granules in 

 mitapsis. The different assortments of chromosomes or gran- 

 ules might explain the diversity, but they show no use or reason 

 in it. They may cause, too, the adaptive characters of inter- 

 breeding, but still for no purpose. Finally, they perform the 

 elaborate evolutions of mitapsis, but all without result, accord- 

 ing to these hypotheses of purity of germ-cells or of chromosomes. 



For numerical purposes it may be that all these complexities 

 of symbasis are useless and unnecessary. The diversity of 

 genera and species, and of the individuals inside the species, 

 could all be worked out arithmetically if we could be provided 

 beforehand with the determinant mechanisms and a system of 

 permutations for combining them. But from the biological 

 standpoint it seems equally clear that this is not the way the 

 organisms were developed in nature. The character-unit plan 

 might have avoided all these unexplained and apparently un- 

 necessary complications of heterism and symbasis. The diffi- 

 culty is that, like its progenitor, the static theory of evolution 

 by environmental causes, it seems not to be followed in the 

 organic creation. Organisms are not naturally uniform and 



