German scientist Hansdrish strong approach Roux’s Mosaic theory. He conducted experiment on sea-urchin eggs exactly in a similar way like Roux. He separated the blastomere at two called stage of sea-urchin and allow to grow them separately instead of destroying one of them. In contract Roux’s finding Disch each of the separate 2 blastomere grow to develope into complete embryo of comparatively similar size but not half of the embryo. Blastomere isolated at four cell stage showed the same results. i.e blastomere isolated at 4stage also develop in to whole embryo.
Such experience, he concluded that the blastomere together form one whole embryo and separately each blastomere also develop into the whole embryo but are of reduce size observing these cellular results he proclaimed that early cleavage of the egg are equational which divides the egg material equally so that all the early blastomere have equal potencies for development. The fate is determined by their position. Hence he regarded a cleaving egg as a Harmonious as equipotential system. Hence in which every part has potentiality of properties of the whole development as observe by drisch in sea urchin eggs was to be called regulative development and the eggs capable of performing such devloping are called regulative eggs. The same results obtained by Endrus and Spemsn on the eggs of newts.