370
G. V. LOPASHOV AND O. G. STROEVA
when development occurs in light the eye degeneration more or less
ceases, and the eyes approach the normal structure. These investigations must be developed and made considerably more precise in order to
elucidate which developmental phases are affected by light and how the
properties of the cells which undergo changes upon illumination affect
individual morphogenetical mechanisms. Such investigations may provide an approach to the question whether there are phases of light
adaptation in the forms normally developing in light.
The investigation of the metaplastic properties of the pigment
epithelium sets one more problem. Why is the external eye layer, similar
in general outline in all the forms, in some forms capable of transforming
into retina (and lens) throughout life, while in other forms it loses this
ability with the onset of its specific differentiation? The following
questions then arise: (1) are there differences in the number of phases of
changes in the basic mechanisms of cell differentiation in different
forms? (2) Are not these basic mechanisms associated with changes of
the function of nuclei in development (Briggs and King, 1959)? The
development of the eye is likely to represent the most promising model
for the solution of these problems of embryology.
It seems that only certain mechanisms can serve as the basis of
individual development (and the identification of their types makes an
essential task of embryology at its junction with cybernetics). At the
same time, the same mechanism must always ensure adaptivity of the
structure of the organs and their parts in their final state as well as in
the course of their development. The actual mechanisms of development
are likely to be formed just in the unity of these contradictory tendencies.
The development of the eye provides certain material contributing to
the comprehension of the relationship of these tendencies and seems to
be able to serve as a model for their investigation.
References
Adelmann, Η. Β. (1928). Roux Arch. EntwMech. Organ. 113, 704-723.
Adelmann, Η. Β. (1929). J. exp. Zool. 54, 291-317.
Adelmann, Η. Β. (1930). J. exp. Zool. 57, 223-281.
Adelmann, Η. Β. (1934). J. exp. Zool. 67, 217-281.
Adelmann, Η. Β. (1936). Quart. Rev. Biol. 11, 161-182, 284-304.
Adelmann, Η. Β. (1937). J. exp. Zool. 75, 199-227.
Alderman, A. L. (1935). J. exp. Zool. 70, 205-232.
Alderman, A. L. (1938). Anat. Ree. 72, 297-302.
Alexander, L. E. (1937). J. exp. Zool. 75, 41-73.
Amprino, R. (1949). Roux Arch. EntwMech. Organ. 144, 71-80.
Amprino, R., and Pansa, Ε. (1955). Roux Arch. EntwMech. Organ. 148, 179-194.
Baburina, E. A. (1948). CR. Acad. sei. U.R.S.S. 61, 399-402.
Balinsky, Β. I. (1951). Experientia 7,180-181.
G. V. LOPASHOV AND O. G. STROEVA
when development occurs in light the eye degeneration more or less
ceases, and the eyes approach the normal structure. These investigations must be developed and made considerably more precise in order to
elucidate which developmental phases are affected by light and how the
properties of the cells which undergo changes upon illumination affect
individual morphogenetical mechanisms. Such investigations may provide an approach to the question whether there are phases of light
adaptation in the forms normally developing in light.
The investigation of the metaplastic properties of the pigment
epithelium sets one more problem. Why is the external eye layer, similar
in general outline in all the forms, in some forms capable of transforming
into retina (and lens) throughout life, while in other forms it loses this
ability with the onset of its specific differentiation? The following
questions then arise: (1) are there differences in the number of phases of
changes in the basic mechanisms of cell differentiation in different
forms? (2) Are not these basic mechanisms associated with changes of
the function of nuclei in development (Briggs and King, 1959)? The
development of the eye is likely to represent the most promising model
for the solution of these problems of embryology.
It seems that only certain mechanisms can serve as the basis of
individual development (and the identification of their types makes an
essential task of embryology at its junction with cybernetics). At the
same time, the same mechanism must always ensure adaptivity of the
structure of the organs and their parts in their final state as well as in
the course of their development. The actual mechanisms of development
are likely to be formed just in the unity of these contradictory tendencies.
The development of the eye provides certain material contributing to
the comprehension of the relationship of these tendencies and seems to
be able to serve as a model for their investigation.
References
Adelmann, Η. Β. (1928). Roux Arch. EntwMech. Organ. 113, 704-723.
Adelmann, Η. Β. (1929). J. exp. Zool. 54, 291-317.
Adelmann, Η. Β. (1930). J. exp. Zool. 57, 223-281.
Adelmann, Η. Β. (1934). J. exp. Zool. 67, 217-281.
Adelmann, Η. Β. (1936). Quart. Rev. Biol. 11, 161-182, 284-304.
Adelmann, Η. Β. (1937). J. exp. Zool. 75, 199-227.
Alderman, A. L. (1935). J. exp. Zool. 70, 205-232.
Alderman, A. L. (1938). Anat. Ree. 72, 297-302.
Alexander, L. E. (1937). J. exp. Zool. 75, 41-73.
Amprino, R. (1949). Roux Arch. EntwMech. Organ. 144, 71-80.
Amprino, R., and Pansa, Ε. (1955). Roux Arch. EntwMech. Organ. 148, 179-194.
Baburina, E. A. (1948). CR. Acad. sei. U.R.S.S. 61, 399-402.
Balinsky, Β. I. (1951). Experientia 7,180-181.