354
G. V. LOPASHOV AND O. G.
STROBVA
bians (Lopashov, 1960) also provide evidence for this. Finally, It.
Kawakami (1959), wrapped pieces of differentiated retina of adult
newts and of late chick embryos in gastrula ectoderm and showed that,
unlike eye rudiments, they evoke trunk-tail structures or neural
vesicles, but no lenses. The problem of the period of time during which
ectoderm and other tissues form the lens and the problem of the inductive ability of the retina at larval stages has to be reinvestigated with
special attention given to the differences in various groups of Vertebrates and with the use of modern methods for careful separation of
individual tissues (Rinaldini, 1959).
With the aim of elucidating the course of the processes leading to the
formation of specific proteins and other substances characteristic of
definite organs, the lens included (Pirie and van Heyningen, 1956),
immunological methods of detecting their appearance in the course of
development have been applied (reviews: Woerdeman, 1953b, 1955;
Konyukhov, 1958; Ebert, 1959). The development and application of
sufficiently sensitive methods begins with the work of ten Cate and van
Doorenmaalen (1950) who suggested the method of reaction in capillaries; other investigators have used the method of reaction in agar
(Langman, 1959b) or a combination of both methods (Konyukhov and
Lishtvan, 1959), or have used labelled and stained antibodies for the
detection of antigen distribution in the eye (Clayton, 1954; Clayton and
Feldman, 1955; van Doorenmaalen, 1958), and for that of antibody
action on the developing lens anläge (Langman et al., 1957; Langman,
1959a). The main experiments were carried out on the chick embryo
and compared with a detailed analysis of structural changes of the lens
during its origin and development (McKeehan, 1951; Langman, 1956,
1959b). The adhesion of lens-forming chick ectoderm with the eye rudiment (onset of the induction) takes place at the stage of 9-12 somites,
the first cytological ehanges in ectoderm cells begin at the stage of
13-16 somites, onset of cell elongation at 16-19 somites, onset of
placode formation at 20-23 somites while the first antigens are found
at the stage of placode formation, 19-25 somites (ten Cate and van
Doorenmaalen, 1950; Flickinger et al., 1955; Konyukhov and Lishtvan,
1959; Langman, 1959b). At the same time, a diffuse reaction is noticed
even at the stage of 16-18 somites (Konyukhov and Lishtvan, 1959).
The two latter works showed a regular increase of the number of bands
in agar corresponding to individual antigens, up to the 7 antigens found
in the lens in adult fowls. Similar data were obtained with the use of
labelled and stained antibody; Clayton found that antibodies to the
lens showed reaction with other parts of the eye as well (as in the work
of Langman et ah, 1957, with the use of the precipitation method),
unlike van Doorenmaalen (1958) who obtained selective staining of the
G. V. LOPASHOV AND O. G.
STROBVA
bians (Lopashov, 1960) also provide evidence for this. Finally, It.
Kawakami (1959), wrapped pieces of differentiated retina of adult
newts and of late chick embryos in gastrula ectoderm and showed that,
unlike eye rudiments, they evoke trunk-tail structures or neural
vesicles, but no lenses. The problem of the period of time during which
ectoderm and other tissues form the lens and the problem of the inductive ability of the retina at larval stages has to be reinvestigated with
special attention given to the differences in various groups of Vertebrates and with the use of modern methods for careful separation of
individual tissues (Rinaldini, 1959).
With the aim of elucidating the course of the processes leading to the
formation of specific proteins and other substances characteristic of
definite organs, the lens included (Pirie and van Heyningen, 1956),
immunological methods of detecting their appearance in the course of
development have been applied (reviews: Woerdeman, 1953b, 1955;
Konyukhov, 1958; Ebert, 1959). The development and application of
sufficiently sensitive methods begins with the work of ten Cate and van
Doorenmaalen (1950) who suggested the method of reaction in capillaries; other investigators have used the method of reaction in agar
(Langman, 1959b) or a combination of both methods (Konyukhov and
Lishtvan, 1959), or have used labelled and stained antibodies for the
detection of antigen distribution in the eye (Clayton, 1954; Clayton and
Feldman, 1955; van Doorenmaalen, 1958), and for that of antibody
action on the developing lens anläge (Langman et al., 1957; Langman,
1959a). The main experiments were carried out on the chick embryo
and compared with a detailed analysis of structural changes of the lens
during its origin and development (McKeehan, 1951; Langman, 1956,
1959b). The adhesion of lens-forming chick ectoderm with the eye rudiment (onset of the induction) takes place at the stage of 9-12 somites,
the first cytological ehanges in ectoderm cells begin at the stage of
13-16 somites, onset of cell elongation at 16-19 somites, onset of
placode formation at 20-23 somites while the first antigens are found
at the stage of placode formation, 19-25 somites (ten Cate and van
Doorenmaalen, 1950; Flickinger et al., 1955; Konyukhov and Lishtvan,
1959; Langman, 1959b). At the same time, a diffuse reaction is noticed
even at the stage of 16-18 somites (Konyukhov and Lishtvan, 1959).
The two latter works showed a regular increase of the number of bands
in agar corresponding to individual antigens, up to the 7 antigens found
in the lens in adult fowls. Similar data were obtained with the use of
labelled and stained antibody; Clayton found that antibodies to the
lens showed reaction with other parts of the eye as well (as in the work
of Langman et ah, 1957, with the use of the precipitation method),
unlike van Doorenmaalen (1958) who obtained selective staining of the