CHAPTER 5 



Blood Cells From Bone Marrow of the 

 Hatched Chicken 



Bone marrow of the adult chicken differs in 

 its general appearance from the bone marrow of 

 the embryo or the recently hatched chick by its 

 abundance of mature erythrocytes. Blast and 

 developmental stages are present Init are not so 

 numerous as in the younger ages. These shifts 

 in the incidence of different cell types with age 

 will be described more fully when table 10 is 

 discussed. 



Jordan (1936 and 1937) has described the 

 bone marrow of several species of birds. In 

 the marrow of all young birds he found lymphoid 

 nodules. These he regarded as centers of hema- 

 topoietic activity, especially of erythrocytes. He 

 also observed small vessels plugged with lympho- 

 cytes. Jordan and Robeson (1942) oliserved 

 after splenectomy in pigeons that the lymphoid 

 foci and plugged vessels in the bone marrow were 

 increased. Their interpretations need to be re- 

 viewed rather critically in the light of observa- 

 tions made since then that lymphoid foci are ab- 

 normal in endocrine glands (Payne and Brene- 

 man, 1952), in vessels of nerves and among 

 nerve fd)ers (Oakberg, 1950), and in the pan- 

 creas (Lucas, 1949; Lucas and Oakberg, 1950; 

 Lucas, Craig and Oakberg, 1949; Lucas and 

 Breitmayer, 1949; Lucas, 1950 and 1951; Oak- 

 berg, 1949 and 1951) and in the liver (Dening- 

 ton and Lucas, 1960; Lucas et al., 1954). The 

 spleen like the bone marrow is a hematopoietic 

 organ, and in addition to the white pulp, contains 

 lymphoid foci. Statistically, these are related 

 to the infection by the agent of avian lymphoma- 

 tosis (Lucas et al., 1954). Before similar lym- 

 phoid foci and plugged vessels in the bone 

 marrow can be accepted as normal for birds, it 

 should be demonstrated that these are not equiva- 

 lent to the abnormal lymphoid foci and plugged 

 vessels found in other organs of the body. 



A study by Erdmann (1917) of chicken bone 

 marrow in tissue culture failed to produce a 



variety of differentiated cell types from the small 

 lymphocyte. Cultures in a plasma medium 

 showed, first, a degeneration of mature and late 

 polychromatic erythrocytes and some maturation 

 of granulocytes, but this was followed by de- 

 generation. There was no evidence of cell di- 

 vision in myelocytes or in niicrolymphocytes. 

 Hetherington and Pierce (1931) gave a confirm- 

 atory observation when they noted that in ex- 

 plants of the buffy coat of chicken blood, all of 

 the lymphocytes degenerated after 48 hours. 



Mention has been made of practically all the 

 developmental stages tliat are to be found in the 

 bone marrow of the hatched chicken jjut a special 

 effort has been made to bring them all together 

 in a series of drawings under high magnification 

 (figs. 345-399) in order that studies of bone 

 marrow in the chicken can be made as useful for 

 diagnosis and for following the course of dis- 

 eases as bone marrow studies have been in human 

 medicine. 



ERYTHROCYTES AND 

 THROMBOCYTES 



The erythroblast shown by cell 1 of figure 344 

 is almost an early polychromatic erythrocyte. 

 Younger blast cells may be seen in figures 345- 

 347. The last of the three closely duplicates 

 cell 1 of figure 344. Cell 2 is an early poly- 

 chromatic erythrocyte but shows slightly less con- 

 densation of chromatin than either of the cells 

 represented by figures 347 and 348. In the low- 

 power field (fig. 344) there are no good examples 

 of mid-polychromatic erythrocytes, although cell 

 4 has not passed far beyond this stage. Beside 

 the two cells at 3, there are several additional late 

 polychromatic erythrocytes in the field. Cell 5 

 is one of these in division, which again demon- 



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