Intercellular control Subject

Intercellular control of the functions of mammalian cells has been long since evidenced by observations of experimental embryologists and, in recent years, one form of it, contact inhibition, discovered by Abercrombie and Heayesman (1954), has been a most popular subject of study. Contact inhibition is certainly one type of control which is generally not found in bacteria and this difference must be directly correlated with differences between the structures of bacterial and mammalian cell surfaces. Other differences between the structures of bacterial and mammalian cells are the presence in the latter of a nuclear membrane and of an elaborate mitotic apparatus. We shall have little to say about the latter and shall consider mainly the nuclear membrane, to which, we think, are delegated certain functions assumed, in bacteria, by the cell membrane and concerned with die coordinated replication of the chromosomes (Jacob et al., 1963). This idea represents one of a number of inferences from recent observations made in our laboratories on interspecific somatic hybrids between mammalian cells, and it is the primary purpose of this paper to present the evidence on which it is based (Note 2). 

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