TWENTIETH CENTURY EMBRYOLOGICAL CONCEPTS
11
certain (Spemann, 1938, p. 142) as to the degree to which he himself,
Spemann, was beholden to Boveri's Vorzugsbereich
for his own conception of a
. . 'center of differentiation as the starting point of this determination. A similar interpretation had been considered by Boveri
(1901), many years earlier, for the development of the sea-urchin
egg and its fragments. The relatively most vegetative point of the
normal germ or a fragment of it might be a privileged region'
('Vorzugsbereich')
from which everything else would be determined. I could myself (Spemann and Hilde Mangold, 1924, p. 636)
point out the likeness of the two conceptions when, many years later,
I again came across this interpretation of Boveri. It may have been
working subconsciously after I had encountered it in the publication
just mentioned, or even in oral communication, or it may have been
part of our common stock of ideas in those invaluable years of daily
intercourse with that great investigator."
It is not only with respect to their twin origins in the parent concept
of polarity and their duplicate postulates of the particular importance
of an especially influential part of the egg or organism that Child's and
Spemann's concepts bore some similarity to each other. They also derived their intellectual descent from the same philosophical confusion
regarding the dichotomy between qualitative and quantitative explanation. Boveri's quantitative conceptions, as noted above, grew out of
qualitative observations. The same was true for Child, a major significance of whose contribution rested on his ability to postulate a
quantitative basis for qualitative differences which had been observed
along an axis. Granted that Child counted his results, the results which
he counted remained qualitatively distinct from one another. While Spemann in contrast eschewed the quantitative as a basis of explanation, his
own most important interpretations were intimately related in their
origins to theories which also, although founded on qualitative observations, were strongly quantitative in their implication, as their later
elaboration was to bear out (J. Loeb, 1905). I refer here to the theories
of tropisms, whose historical relationship to the earliest concepts of induction through Roux and Herbst and Driesch has already been pointed
out (Oppenheimer, 1955a, p. 19).
What Child and Spemann and their various successors have failed to
been investigated, nor have the relationships between the concepts of dominance
in biology and in the political field, except insofar as both may be related to the
struggle for existence implied by 19th century Darwinism.
11
certain (Spemann, 1938, p. 142) as to the degree to which he himself,
Spemann, was beholden to Boveri's Vorzugsbereich
for his own conception of a
. . 'center of differentiation as the starting point of this determination. A similar interpretation had been considered by Boveri
(1901), many years earlier, for the development of the sea-urchin
egg and its fragments. The relatively most vegetative point of the
normal germ or a fragment of it might be a privileged region'
('Vorzugsbereich')
from which everything else would be determined. I could myself (Spemann and Hilde Mangold, 1924, p. 636)
point out the likeness of the two conceptions when, many years later,
I again came across this interpretation of Boveri. It may have been
working subconsciously after I had encountered it in the publication
just mentioned, or even in oral communication, or it may have been
part of our common stock of ideas in those invaluable years of daily
intercourse with that great investigator."
It is not only with respect to their twin origins in the parent concept
of polarity and their duplicate postulates of the particular importance
of an especially influential part of the egg or organism that Child's and
Spemann's concepts bore some similarity to each other. They also derived their intellectual descent from the same philosophical confusion
regarding the dichotomy between qualitative and quantitative explanation. Boveri's quantitative conceptions, as noted above, grew out of
qualitative observations. The same was true for Child, a major significance of whose contribution rested on his ability to postulate a
quantitative basis for qualitative differences which had been observed
along an axis. Granted that Child counted his results, the results which
he counted remained qualitatively distinct from one another. While Spemann in contrast eschewed the quantitative as a basis of explanation, his
own most important interpretations were intimately related in their
origins to theories which also, although founded on qualitative observations, were strongly quantitative in their implication, as their later
elaboration was to bear out (J. Loeb, 1905). I refer here to the theories
of tropisms, whose historical relationship to the earliest concepts of induction through Roux and Herbst and Driesch has already been pointed
out (Oppenheimer, 1955a, p. 19).
What Child and Spemann and their various successors have failed to
been investigated, nor have the relationships between the concepts of dominance
in biology and in the political field, except insofar as both may be related to the
struggle for existence implied by 19th century Darwinism.