Brenner, Sydney2017-04-042017-04-041947http://hdl.handle.net/10539/22296Thesis presented in fulfilment of the requirements far the degree of Master of Science in the University of the Witwatersrand.Every organism, whether it he plant or animal, worm or man, propagates Itself with a definable degree of constancy* Such constancy cannot be entirely related to the ever-changing external environment; it becomes,of necessity, mainly an inherent function of the organism itself* Somewhere in the organism, there exists a system which determines, controls, or regulates the visible expressions of organlsmal constancy.enCell DifferentiationMorphogenesisChromosomesThesis