132 MENDELISM chap, xi 



portant influence which that little creature is now 

 exerting on the science of genetics must be reserved 

 for another chapter. Meanwhile it is clear that the 

 phenomenon is of very great importance. Apart 

 from the light it may be expected to shed upon the 

 architecture of the cell and upon the mechanics of 

 cell division, it is likely to help us in understanding 

 many a puzzling group of facts. Those who attempt 

 to interpret what is known of inheritance in man in 

 terms of the facts of Mendelian heredity must often 

 have encountered the difficulty of the remarkable 

 resemblance so often found between parent and 

 offspring. Civilised man is such a mongrel ; teem- 

 ing with heritable characters, yet so hopelessly 

 heterozygotic, that he might well be the despair of 

 any bold enough, even in thought, to isolate pure 

 strains of human beings. Nevertheless, how often 

 do we find that one child is extraordinarily like the 

 father, while another closely resembles the mother. 

 Were all of the separately heritable characters trans- 

 mitted entirely independently of one another, these 

 cases of close resemblance should be rare. The fact 

 that they are so numerous suggests that in man 

 factors are transmitted as it were in bunches, and it 

 is not improbable that the study of cases in which 

 coupling and repulsion occur, will eventually render 

 more clear what is evidently an important feature in 

 the heredity of our own species. 



