TWENTIETH CENTURY EMBRYOLOGICAL CONCEPTS
15
tended during the first third of the century to the proportions of rather
grandiose conceptual schemes. Such concentration of attention on a few
major formulations may seem to savor of inconsistency in the light
of the emphasis placed in the introductory remarks on diversification of
activity as a particular attribute of the embryology of the beginning
part of the century.
At least certain of the laws of probability are as applicable to the
study of the development of developmental ideas as to any other natural
phenomena. The more words written, the more words read, and the
greater the probability of their striking fire to stimulate further work;
and it is hardly to be denied that a goodly number of words have been
indited in relation to organizers and gradients and fields. The laws of
probability are however notoriously refractory of application to a single
case, and there are a number of individual circumstances where investigation cloaked by fewer generalizing words may be equally interesting in its conception and pregnant in its influence. Especially is
this true of the studies by Harrison, which, although they contributed
heavily to the development of the concepts both of organizers and fields,
originated quite independently of these and have been no less significant in their weight of influence, though never unified into a single
didactic theory. If it was Roux who insisted that understanding of the
Causalnexus of events in morphogenesis must rest on a knowledge of the
behavior of cells in terms of their relationships, positive or negative, with
their neighbors, it was Harrison who made this goal possible and actual
of attainment by hastening the introduction into the embryological
laboratories of the techniques whereby cells could be isolated and recombined.
Granted that he may not have been the first to isolate and grow cells
separated after the blastomere stage from the whole organism (see L.
Loeb, 1912), he first had the intuition to devise and utilize the technique of tissue culture to perform a crucial experiment for the solution
of an embryological problem (Harrison, 1907). One might be tempted
to assert that his originality of insight, as evidenced by his application
of this new technique towards the solution of an old morphogenetic
problem, was almost unique, were it not for the fact that he himself
had previously (Harrison, 1898, 1904) matched this accomplishment by
recognizing in the fusion of embryonic parts by the method of Born
(1897) the way to recombine cells which subsequently became the
means by which their interrelationships were put to the crucial test. The
first published descriptions of Harrison's grafting experiments antedated
those of Spemann (1901, 1906a, b) and were independent of them.
15
tended during the first third of the century to the proportions of rather
grandiose conceptual schemes. Such concentration of attention on a few
major formulations may seem to savor of inconsistency in the light
of the emphasis placed in the introductory remarks on diversification of
activity as a particular attribute of the embryology of the beginning
part of the century.
At least certain of the laws of probability are as applicable to the
study of the development of developmental ideas as to any other natural
phenomena. The more words written, the more words read, and the
greater the probability of their striking fire to stimulate further work;
and it is hardly to be denied that a goodly number of words have been
indited in relation to organizers and gradients and fields. The laws of
probability are however notoriously refractory of application to a single
case, and there are a number of individual circumstances where investigation cloaked by fewer generalizing words may be equally interesting in its conception and pregnant in its influence. Especially is
this true of the studies by Harrison, which, although they contributed
heavily to the development of the concepts both of organizers and fields,
originated quite independently of these and have been no less significant in their weight of influence, though never unified into a single
didactic theory. If it was Roux who insisted that understanding of the
Causalnexus of events in morphogenesis must rest on a knowledge of the
behavior of cells in terms of their relationships, positive or negative, with
their neighbors, it was Harrison who made this goal possible and actual
of attainment by hastening the introduction into the embryological
laboratories of the techniques whereby cells could be isolated and recombined.
Granted that he may not have been the first to isolate and grow cells
separated after the blastomere stage from the whole organism (see L.
Loeb, 1912), he first had the intuition to devise and utilize the technique of tissue culture to perform a crucial experiment for the solution
of an embryological problem (Harrison, 1907). One might be tempted
to assert that his originality of insight, as evidenced by his application
of this new technique towards the solution of an old morphogenetic
problem, was almost unique, were it not for the fact that he himself
had previously (Harrison, 1898, 1904) matched this accomplishment by
recognizing in the fusion of embryonic parts by the method of Born
(1897) the way to recombine cells which subsequently became the
means by which their interrelationships were put to the crucial test. The
first published descriptions of Harrison's grafting experiments antedated
those of Spemann (1901, 1906a, b) and were independent of them.