Embryology, Epigenetics and Biogenetics

Abstract

IN his stimulating review of Prof. C. H. Waddington's “Principles of Embryology”, Dr. Julian Huxley¹ expresses the hope that Prof. Waddington will write a sequel, and, following his earlier impulse, call it “Principles of Epigenetics”. While the term ‘embryology’ suggests a field far more restricted than that which this department of science is now concerned with, the suggested alternative, ‘epigenetics’, has disadvantages of another kind. It still reverberates with the overtones of a cause célèbre, a controversy in which, as it now appears, neither ‘epigenesis’ nor ‘preformation’ gained a decisive victory. For whereas identifiable organized units, whether organs or tissues, appear successively from an apparently undifferentiated mass, there is now no question but that the material determinants of these new structures are preformed in the chromosomes recognizable before the beginning of embryonic life. That this caution is not a matter of mere historical pedantry is evidenced by the fact that another worker of long experience in this field, M. Jean Rostand, has recently² referred to the “extravagances du préformationnisme” and the “naïvetés de l'pigenèse”.