204
LEO LEME2
numerical data were given. Lemez (1953) classified the reticulocytes
according to the amount of the granulo-filamentous substance and
designated three groups. The reticulocyte differential count was undertaken between the 7th and 18th days of incubation in both the primitive
and definitive (E II t as well as Ε II 2 ) elements. While the primitive
erythrocytes showed gradual maturation, losing the last traces of
granulo-filamentous substance between the 13th and 17th days of
incubation, the definitive erythrocytes with round nuclei (E II 1 ) were,
up to the 12th day, more mature on the whole than those with oval and
oblong nuclei (E II 2 ) thus demonstrating that Ε II X cannot be the
younger forms or precursors of Ε II 2 . On the 18th day 31-5% of Ε IIj
were without granulations as compared with only 2-5% for Ε II 2 . From
time to time after the 12th day, however, there was an increase in
young forms of ΕII X as compared with Ε II 2 erythrocytes, which implies
further production of this cell type. In contrast to the primitive
erythrocytes, which may be considered as a maturing generation (all
cells are of approximately the same age), Ε II X erythrocytes form an
undoubted population (cells of all age groups are present, from those
just formed up to the oldest which are about to die). Perhaps the presence
of the younger forms of Ε II x in later stages of embryonic development
led most of the above mentioned authors to consider them as young
forms of Ε II 2 . By the establishment of two types of definitive erythrocytes, a new morphologically labelled embryonic cell line was obtained.
The origin of these two cell types must now be considered. During the
early developmental stages, the erythrocytes differentiate and mature
from strongly basophilic stem cells, thus ripening in a heteroplastic way
(Dantschakoff, 1908a). But about the 11th day the production of
definitive erythrocytes tends to become balanced, the erythrocytes
maturing from a more advanced maturation compartment; and
definitive erythrocytes with oval and, later, with oblong nuclei start to
prevail in the circulation. This is called the homoplastic path of
maturation. Heteroplastic maturation may still be occurring at some
points and this would explain the presence of young Ε II X cells during
this period (after the 11th day—Lemez, 1958) when they are rapidly
declining in both total and relative number.
The embryonic blood picture is characterized by anisocytosis and
poikilocytosis due to the presence of blood cells of various series and
types as well as of various maturation compartments. In addition blood
smears contain abnormal red blood cells, for example giant polyploid
cells with one large or several normal nuclei, erythroplastids and
microcytes (nuclear remnants of erythrocytes), cells with pycnotic
nuclei, and amitotic cells. They were described by most of the above
mentioned authors. In recent years some new types of these abnormal
LEO LEME2
numerical data were given. Lemez (1953) classified the reticulocytes
according to the amount of the granulo-filamentous substance and
designated three groups. The reticulocyte differential count was undertaken between the 7th and 18th days of incubation in both the primitive
and definitive (E II t as well as Ε II 2 ) elements. While the primitive
erythrocytes showed gradual maturation, losing the last traces of
granulo-filamentous substance between the 13th and 17th days of
incubation, the definitive erythrocytes with round nuclei (E II 1 ) were,
up to the 12th day, more mature on the whole than those with oval and
oblong nuclei (E II 2 ) thus demonstrating that Ε II X cannot be the
younger forms or precursors of Ε II 2 . On the 18th day 31-5% of Ε IIj
were without granulations as compared with only 2-5% for Ε II 2 . From
time to time after the 12th day, however, there was an increase in
young forms of ΕII X as compared with Ε II 2 erythrocytes, which implies
further production of this cell type. In contrast to the primitive
erythrocytes, which may be considered as a maturing generation (all
cells are of approximately the same age), Ε II X erythrocytes form an
undoubted population (cells of all age groups are present, from those
just formed up to the oldest which are about to die). Perhaps the presence
of the younger forms of Ε II x in later stages of embryonic development
led most of the above mentioned authors to consider them as young
forms of Ε II 2 . By the establishment of two types of definitive erythrocytes, a new morphologically labelled embryonic cell line was obtained.
The origin of these two cell types must now be considered. During the
early developmental stages, the erythrocytes differentiate and mature
from strongly basophilic stem cells, thus ripening in a heteroplastic way
(Dantschakoff, 1908a). But about the 11th day the production of
definitive erythrocytes tends to become balanced, the erythrocytes
maturing from a more advanced maturation compartment; and
definitive erythrocytes with oval and, later, with oblong nuclei start to
prevail in the circulation. This is called the homoplastic path of
maturation. Heteroplastic maturation may still be occurring at some
points and this would explain the presence of young Ε II X cells during
this period (after the 11th day—Lemez, 1958) when they are rapidly
declining in both total and relative number.
The embryonic blood picture is characterized by anisocytosis and
poikilocytosis due to the presence of blood cells of various series and
types as well as of various maturation compartments. In addition blood
smears contain abnormal red blood cells, for example giant polyploid
cells with one large or several normal nuclei, erythroplastids and
microcytes (nuclear remnants of erythrocytes), cells with pycnotic
nuclei, and amitotic cells. They were described by most of the above
mentioned authors. In recent years some new types of these abnormal