214
LEO LEMEÈ
possible : the tissue expiant ; differentiation of tissue lymphocytes ; and
chick embryo extract, if used.
C. Leucocytes
The white blood cells are the final regular cellular component to
appear in the chick embryo blood during ontogenesis. Different leucocyte
lines appear at various stages of development. We shall, therefore, begin
by introducing the differential count of the adult hen.
First a remark on nomenclature. The granulocytes with eosin-stainable
spindle-shaped granules and a segmented nucleus are referred to
throughout this review as neutrophils (these are the polymorphonuclears,
pseudoeosinophils, heterophilic granulocytes of other authors). This
name was chosen because of the close functional and quantitative
resemblance to the neutrophils in mammals (Sandreuter, 1951).
Granulocytes with eosin-stainable round granules and a segmented
nucleus are designated as eosinophils (=true eosinophils of other
authors). Basophils possess in most instances one unsegmented nucleus
and dark round granules scattered over the nucleus as well.
Only two authors have made simultaneous leucocyte differential
counts in chick embryos and in adult hens, so that the identity of white
blood cells in both cases might be securely established (Sandreuter,
1951 ; Lemez, 1955). Other authors, who have made differential leucocyte
counts in adult hens, are quoted in these papers.
The adult hen differential count is as follows (first value according to
Sandreuter, 1951, second according to Lemez, 1955): neutrophils
(14-2%; 27-5%), eosinophils (2-8; 3-7), basophils (2-5; 2-9), lymphocytes
(74-7; 60-4), monocytes (7-5; 5-5), plasma cells (1-7; 0-5). All these
leucocyte lines, with the exception of the last, appear successively in
this sequence in chick embryo circulating blood under normal conditions
of development. The discrepancies in the neutrophil and lymphocyte
counts between these two series can readily be explained by the fact
that Sandreuter (1951) obviously collected blood samples in the early
morning, while ours were taken shortly before noon. According to
Sandreuter (1951) the percentages of neutrophils and lymphocytes in
hens' blood in the morning were 12% and 75%, respectively, while in
the afternoon they were 39% and 53%, respectively. On the other hand,
Glick (1960) reported that in young chicks a greater proportion of
neutrophils was present at 8 a.m. than in the afternoon or evening.
i. Differential Count of Chick Embryo
Leucocytes
The various types of leucocyte appear in circulating embryonic blood
in the following sequence: neutrophils at about the 4th to 5th day
(Engel, 1895; Dantschakoff, 1908a; Sabin, 1921; Sugiyama, 1926;
LEO LEMEÈ
possible : the tissue expiant ; differentiation of tissue lymphocytes ; and
chick embryo extract, if used.
C. Leucocytes
The white blood cells are the final regular cellular component to
appear in the chick embryo blood during ontogenesis. Different leucocyte
lines appear at various stages of development. We shall, therefore, begin
by introducing the differential count of the adult hen.
First a remark on nomenclature. The granulocytes with eosin-stainable
spindle-shaped granules and a segmented nucleus are referred to
throughout this review as neutrophils (these are the polymorphonuclears,
pseudoeosinophils, heterophilic granulocytes of other authors). This
name was chosen because of the close functional and quantitative
resemblance to the neutrophils in mammals (Sandreuter, 1951).
Granulocytes with eosin-stainable round granules and a segmented
nucleus are designated as eosinophils (=true eosinophils of other
authors). Basophils possess in most instances one unsegmented nucleus
and dark round granules scattered over the nucleus as well.
Only two authors have made simultaneous leucocyte differential
counts in chick embryos and in adult hens, so that the identity of white
blood cells in both cases might be securely established (Sandreuter,
1951 ; Lemez, 1955). Other authors, who have made differential leucocyte
counts in adult hens, are quoted in these papers.
The adult hen differential count is as follows (first value according to
Sandreuter, 1951, second according to Lemez, 1955): neutrophils
(14-2%; 27-5%), eosinophils (2-8; 3-7), basophils (2-5; 2-9), lymphocytes
(74-7; 60-4), monocytes (7-5; 5-5), plasma cells (1-7; 0-5). All these
leucocyte lines, with the exception of the last, appear successively in
this sequence in chick embryo circulating blood under normal conditions
of development. The discrepancies in the neutrophil and lymphocyte
counts between these two series can readily be explained by the fact
that Sandreuter (1951) obviously collected blood samples in the early
morning, while ours were taken shortly before noon. According to
Sandreuter (1951) the percentages of neutrophils and lymphocytes in
hens' blood in the morning were 12% and 75%, respectively, while in
the afternoon they were 39% and 53%, respectively. On the other hand,
Glick (1960) reported that in young chicks a greater proportion of
neutrophils was present at 8 a.m. than in the afternoon or evening.
i. Differential Count of Chick Embryo
Leucocytes
The various types of leucocyte appear in circulating embryonic blood
in the following sequence: neutrophils at about the 4th to 5th day
(Engel, 1895; Dantschakoff, 1908a; Sabin, 1921; Sugiyama, 1926;