THE BLOOD OF CHICK EMBRYOS
207
and Dalton (1937a, b) at day 9, Sandreuter (1951) at day 14, Hsu et al.
(1952) at day 18, Lemez (1953) at day 8, Pilipenko (1957) and Barnes
and Jensen (1959) at day 9, Elias and Sandor (1960) at day 11. The
series was completed from the 2nd till the 7th day of incubation by
Rychter (1955), so that complete data for the entire incubation period
are now available (Rychter et al., 1955a).
The haemoglobin concentration curve (Fig. 2B) shows that, from the
initial value of 0-4 g % on the 2nd day, the value increases to a first
maximum (4-8 g%) on the 7th day, and then decreases to 3-3 g % on the
10th day as a result of a fall in the ratio of large relatively mature (rich
in haemoglobin) primitive erythrocytes to definitive erythrocytes (less
mature at this stage), which are also smaller. After this second minimum
the haemoglobin content increases again up to the 1st postembryonic
day (8-4 g%), but again, this value does not exceed the concentration in
the adult bird. Reported values for the hen are 9-7 g% (Bankowski,
1942); 10-4 g% (Lemez, 1953); 9-0 g% (Tanaka and Resenberg, 1954);
8-9 g% (Rychter et al, 1955a); 10-3 g% (Jaffe, 1960). Korzujev and
Galkina (1957) reported that the haemoglobin concentration in the
blood of newborn chicks, ducks, turkeys, and pigeons does not exceed
that of adult birds. The difference between haemoglobin values at
hatching and in the adult is much greater in the nidicolous starling than
in the nidifugous chick, the former also showing a less mature condition
in respect of erythrocyte number, leucocyte differential count, etc.
(Sandreuter, 1951).
If sex and genetic differences exist with regard to erythrocyte number
and haemoglobin content in embryos, such as occur in the adult
(Sandreuter, 1951; Tanaka and Resenberg, 1954; Jaffe, 1960) and in
newly hatched chickens (Juhn and Domm, 1930; Romanoff, 1948), they
have apparently not yet been investigated. Severe anaemia occurs in
lethal mutations of Cornish fowl (Landauer, 1939) and sporadically even
in normal chick embryos (Dareste, 1871). Anaemia occurs in embryos of
eggs from hens fed tankage, an abattoir by-product (McFarlane et al,
1930), in embryos supplied with additional vitamins (Hansborough,
1947a, b) or folic acid antimetabolites (Karnofsky et al, 1949) or in
embryos with transplanted tumours (Taylor et al, 1943; Armstrong and
Ham, 1947).
Because of technical difficulties (use of the microhaematocrit) haematocrit studies in chick embryos have been made alone in only two cases
(Johnston, 1955; Rychter, 1955). They have been made in conjunction
with the determination of circulating blood volume where they are
inevitable (Yosphe-Purer et al, 1953; Rychter et al, 1955a; Barnes and
Jensen, 1959) (Fig. 2A). The haematocrit value is 8-9% on the 2nd day of
incubation. The general course of the curve is similar to that of the haemo-
207
and Dalton (1937a, b) at day 9, Sandreuter (1951) at day 14, Hsu et al.
(1952) at day 18, Lemez (1953) at day 8, Pilipenko (1957) and Barnes
and Jensen (1959) at day 9, Elias and Sandor (1960) at day 11. The
series was completed from the 2nd till the 7th day of incubation by
Rychter (1955), so that complete data for the entire incubation period
are now available (Rychter et al., 1955a).
The haemoglobin concentration curve (Fig. 2B) shows that, from the
initial value of 0-4 g % on the 2nd day, the value increases to a first
maximum (4-8 g%) on the 7th day, and then decreases to 3-3 g % on the
10th day as a result of a fall in the ratio of large relatively mature (rich
in haemoglobin) primitive erythrocytes to definitive erythrocytes (less
mature at this stage), which are also smaller. After this second minimum
the haemoglobin content increases again up to the 1st postembryonic
day (8-4 g%), but again, this value does not exceed the concentration in
the adult bird. Reported values for the hen are 9-7 g% (Bankowski,
1942); 10-4 g% (Lemez, 1953); 9-0 g% (Tanaka and Resenberg, 1954);
8-9 g% (Rychter et al, 1955a); 10-3 g% (Jaffe, 1960). Korzujev and
Galkina (1957) reported that the haemoglobin concentration in the
blood of newborn chicks, ducks, turkeys, and pigeons does not exceed
that of adult birds. The difference between haemoglobin values at
hatching and in the adult is much greater in the nidicolous starling than
in the nidifugous chick, the former also showing a less mature condition
in respect of erythrocyte number, leucocyte differential count, etc.
(Sandreuter, 1951).
If sex and genetic differences exist with regard to erythrocyte number
and haemoglobin content in embryos, such as occur in the adult
(Sandreuter, 1951; Tanaka and Resenberg, 1954; Jaffe, 1960) and in
newly hatched chickens (Juhn and Domm, 1930; Romanoff, 1948), they
have apparently not yet been investigated. Severe anaemia occurs in
lethal mutations of Cornish fowl (Landauer, 1939) and sporadically even
in normal chick embryos (Dareste, 1871). Anaemia occurs in embryos of
eggs from hens fed tankage, an abattoir by-product (McFarlane et al,
1930), in embryos supplied with additional vitamins (Hansborough,
1947a, b) or folic acid antimetabolites (Karnofsky et al, 1949) or in
embryos with transplanted tumours (Taylor et al, 1943; Armstrong and
Ham, 1947).
Because of technical difficulties (use of the microhaematocrit) haematocrit studies in chick embryos have been made alone in only two cases
(Johnston, 1955; Rychter, 1955). They have been made in conjunction
with the determination of circulating blood volume where they are
inevitable (Yosphe-Purer et al, 1953; Rychter et al, 1955a; Barnes and
Jensen, 1959) (Fig. 2A). The haematocrit value is 8-9% on the 2nd day of
incubation. The general course of the curve is similar to that of the haemo-