C H A P T E R
1 5
Embryogenesis in vitro
E T I E N N E W O L F F
Laboratoire cTEmbryologie Experimentale, College de France, Nogent-sur-Marne,
France
I. Culture of Amphibian Embryonic Anlage
532
A. Cultures in vivo and in vitro
532
B. Determination and self-differentiation of developmental regions of the young
gastrula
533
C. Testing the inducing power of tissues and of extracts in in vitro culture
539
D. Specific action of certain artificial inducers
545
E. The chemical nature of specific inducers
548
II. In vitro Culture of Embryos of Birds
553
A. Methods
553
B. Research into experimental morphogenesis
555
C. The nutritive needs and the metabolic activities of blastoderms in culture
565
III. In vitro Culture of Mammalian Ova
575
A. Fertilization and development in vitro
575
B. In vitro culture beginning with fertilized eggs in process of segmentation
576
C. Culture of uterine eggs at the blastocyst stage
577
D. Reimplantation of eggs in the uterus after experiments with them in
in vitro culture
579
IV. Culture in vitro of the Embryos of Fish and Reptiles
582
References
584
It is clearly of interest to try to obtain development in vitro of embryos
or of fragments of embryos when they are placed in nutritive surroundings different from their natural environment.
The culture of whole embryos can apply only to viviparous animals
such as Mammalia or certain reptiles, or to animals with telolecithical
eggs such as fish, reptiles and birds whose blastoderms can be separated
from the yolk. One cannot cultivate eggs or embryos of amphibians
whose yolk is incorporated in the blastomere. But, it has been shown by
much research that, beginning with the blastula stage, certain parts
of amphibian embryos show definite morphogenetic properties, when
isolated from the embryo and placed in appropriate surroundings.
Thus, it is the properties of tissues isolated from embryos of amphibians
that we shall first study. It is difficult to define exactly the limits of this
1 5
Embryogenesis in vitro
E T I E N N E W O L F F
Laboratoire cTEmbryologie Experimentale, College de France, Nogent-sur-Marne,
France
I. Culture of Amphibian Embryonic Anlage
532
A. Cultures in vivo and in vitro
532
B. Determination and self-differentiation of developmental regions of the young
gastrula
533
C. Testing the inducing power of tissues and of extracts in in vitro culture
539
D. Specific action of certain artificial inducers
545
E. The chemical nature of specific inducers
548
II. In vitro Culture of Embryos of Birds
553
A. Methods
553
B. Research into experimental morphogenesis
555
C. The nutritive needs and the metabolic activities of blastoderms in culture
565
III. In vitro Culture of Mammalian Ova
575
A. Fertilization and development in vitro
575
B. In vitro culture beginning with fertilized eggs in process of segmentation
576
C. Culture of uterine eggs at the blastocyst stage
577
D. Reimplantation of eggs in the uterus after experiments with them in
in vitro culture
579
IV. Culture in vitro of the Embryos of Fish and Reptiles
582
References
584
It is clearly of interest to try to obtain development in vitro of embryos
or of fragments of embryos when they are placed in nutritive surroundings different from their natural environment.
The culture of whole embryos can apply only to viviparous animals
such as Mammalia or certain reptiles, or to animals with telolecithical
eggs such as fish, reptiles and birds whose blastoderms can be separated
from the yolk. One cannot cultivate eggs or embryos of amphibians
whose yolk is incorporated in the blastomere. But, it has been shown by
much research that, beginning with the blastula stage, certain parts
of amphibian embryos show definite morphogenetic properties, when
isolated from the embryo and placed in appropriate surroundings.
Thus, it is the properties of tissues isolated from embryos of amphibians
that we shall first study. It is difficult to define exactly the limits of this