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LEO LEMEZ
strate the changes—gains and losses in cell number—which a given cell
line had undergone during the period concerned.
This review presents the results of such an investigation on chick
embryo erythrocytes during the entire prenatal period. In Section II the
blood corpuscles of chick embryos during normal development will be
described, from both qualitative and quantitative aspects. Various
experiments and miscellaneous observations concerning chick embryo
blood corpuscles will be mentioned at appropriate places. Section III is
devoted to problems of autodifferentiation of chick embryo blood
corpuscles.
Neither the morphology of blood-forming organs (reviewed recently
by Romanoff, 1960), nor the non-cellular components of the chick
embryo blood (reviewed by Schechtman, 1952, 1955), are dealt with
here ; it is felt that these topics are beyond the scope of this chapter. The
same is also true of those important experiments with an immunological
background, which are concerned, at least partly, with avian embryonic
blood and blood corpuscles (e.g. embryonic parabiosis, graft versus host
reaction, acquired tolerance).
As the chick embryo has become an important scientific and even
industrial experimental subject, it is felt that a summary of our
knowledge of all cell types present in the circulating blood during the
incubation period will be of use.
II. Qualitative and Quantitative Data on Chick Embryo Blood
Corpuscles throughout the Incubation Period
First we shall mention briefly some of the methods used to take blood
samples and to make intravascular injections in chick embryos. An
apparatus (automatic pipette) for blood sampling and for intravascular
injection in the youngest embryos was described by Schechtman and
Hoffman (1953) and by Ancel and Houget (1955). Pure blood samples
may be obtained from the youngest embryos and even from the network
of capillaries in anidian blastoderms (Section III, B) by means of a
pipette, whose bevelled orifice may be as narrow as 20 μ in diameter,
used free-hand under a Greenough binocular microscope (Rychter,
1955). With care the pipette can be removed after sampling without
haemorrhage. On this account it has been used also for intravenous
injections without ligature (Rychter et al., 1955a, b). Larger amounts of
blood, such as are required to obtain sterile embryonic plasma for tissue
culture, can be collected from 10-17-day-old chick embryos by the
methods described by Andai (1932) and Zifferblatt (1932).
Probably the first intravascular injections of various solutions were
made by Guelin-Schedrina (1933), using a micromanipulator, into the
heart of 2-day-old chick embryos or into the vitelline veins in older
LEO LEMEZ
strate the changes—gains and losses in cell number—which a given cell
line had undergone during the period concerned.
This review presents the results of such an investigation on chick
embryo erythrocytes during the entire prenatal period. In Section II the
blood corpuscles of chick embryos during normal development will be
described, from both qualitative and quantitative aspects. Various
experiments and miscellaneous observations concerning chick embryo
blood corpuscles will be mentioned at appropriate places. Section III is
devoted to problems of autodifferentiation of chick embryo blood
corpuscles.
Neither the morphology of blood-forming organs (reviewed recently
by Romanoff, 1960), nor the non-cellular components of the chick
embryo blood (reviewed by Schechtman, 1952, 1955), are dealt with
here ; it is felt that these topics are beyond the scope of this chapter. The
same is also true of those important experiments with an immunological
background, which are concerned, at least partly, with avian embryonic
blood and blood corpuscles (e.g. embryonic parabiosis, graft versus host
reaction, acquired tolerance).
As the chick embryo has become an important scientific and even
industrial experimental subject, it is felt that a summary of our
knowledge of all cell types present in the circulating blood during the
incubation period will be of use.
II. Qualitative and Quantitative Data on Chick Embryo Blood
Corpuscles throughout the Incubation Period
First we shall mention briefly some of the methods used to take blood
samples and to make intravascular injections in chick embryos. An
apparatus (automatic pipette) for blood sampling and for intravascular
injection in the youngest embryos was described by Schechtman and
Hoffman (1953) and by Ancel and Houget (1955). Pure blood samples
may be obtained from the youngest embryos and even from the network
of capillaries in anidian blastoderms (Section III, B) by means of a
pipette, whose bevelled orifice may be as narrow as 20 μ in diameter,
used free-hand under a Greenough binocular microscope (Rychter,
1955). With care the pipette can be removed after sampling without
haemorrhage. On this account it has been used also for intravenous
injections without ligature (Rychter et al., 1955a, b). Larger amounts of
blood, such as are required to obtain sterile embryonic plasma for tissue
culture, can be collected from 10-17-day-old chick embryos by the
methods described by Andai (1932) and Zifferblatt (1932).
Probably the first intravascular injections of various solutions were
made by Guelin-Schedrina (1933), using a micromanipulator, into the
heart of 2-day-old chick embryos or into the vitelline veins in older