144 THE ENZYME TREATMENT OF CANCER
Like
my fellow-workers, I had been taught to regard the development of any of the
higher animals as “direct”; that is to say, from the fertilized egg a new
sexual organism, a worm or a fish, a bird or a man, arose directly. From the
tissues or soma of this sexual organism new reproductive products, eggs or
sperms, sprang. In this way the simple cycle of “egg-sexual organism,
egg-sexual organism” repeated itself ad infinitum. Under this, still
generally accepted, conception of development, the germ-cells were somatic in
origin, and the gradual building up (epigenesis) of a new sexual organism happened
directly, when such an egg had been fertilized. Such, briefly, was the simple
embryological creed which my teachers, Mimes Marshall, Huxley, and Carl Semper,
taught. During some eight or ten of the early years of my original work this
was my embryological faith, if an investigator may have any scientific creed.
Epigenesis,
direct development, and a somatic origin of germ-cells, have now long been
associated with another embryological dogma, the recapitulation theory, according
to which any higher animal “climbs its own genealogical tree in the course of
its development.” To what lengths and depths of scientific error this latter
doctrine can lead, see the fifth revised edition of Haeckel’s “Evolution of
Man.”
My
embryological faith was perfectly orthodox when, on June 14, 1888, I left the
shores of Black Lake, New York, with an extensive assortment of preserved
material of fish development. One of the earliest finds made after the return
to the Anatomical Institute of the University of Freiburg in Breisgau was of
the existence of two distinct and separate nervous systems in the life history
of the bill-fish, Lepidosteus osseus. About a year later the like find
of a twofold nervous apparatus was