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R. Ruggles Gates . 
centripetal effect on the nuclei. We also concluded that 
karyogenetic characters were not as a rule recapitulatory, because 
they imply a change in the nuclear unit which is transmitted by 
mitosis to every cell, while organismal characters may become so 
by adding on certain stages to the life-cycle of the organism. The 
existence of these two types of characters accounts for many 
anomalies in the biogenetic law. The existence of two such 
classes of characters makes it possible to understand better many 
features of organic structure and inheritance. 
But it is obvious that the relationship between these two 
types of characters cannot be fully understood in all their aspects 
at the present time, nor can a sharp line always be drawn between 
karyogenetic, cytogenetic and orthogenetic characters—in some 
aspects they shade into each other. As a constructive attempt to 
harmonize two bodies of evidence which are obviously in conflict 
and have long been considered irreconcilable, we make no apology 
for its tentative character and incompleteness. 
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