(personal communication) have obsei-ved that 

 in some cells the rods are grouped in a fanlike 

 cluster. This arrangement has never been ob- 

 served in mature cells in any of our smears; in- 

 stead the rods are always scattered like a pile of 

 short straws with pointed ends. Ryerson ( 1943) , 

 in his study of heteropliils in tuilles, shows a 

 radial arrangement of the rods in the myelocytes 

 but not in the mature cells. There may be con- 

 siderable variability among cells in the length of 

 these rods. Some are long and narrow (fig. 

 154) and others short and relatively broad (fig. 

 2, 1). In some cases these differences can be 

 characteristic of a species (figs. 400, 401, 403, 

 and 406.) 



In many heterophils some rods may contain 

 central granules. Hamre is of the opinion diat 

 each rod contains a central granule that is re- 

 vealed when Wright-Giemsa is used (p. 230). 



The research necessary to prove or disprove the 

 point has never been undertaken Init the results 

 obtained with Wright's stain gave no indication 

 that every rod has a central granule and the same 

 opinion is supported by evidence from a study 

 of developmental stages in bone marrow and 

 spleen stained with May-Griinwald Giemsa. 

 Even in squashed cells where the individual rods 

 are thrown apart from each other, central gran- 

 ules may be absent in one case (fig. 175) and 

 present in another (fig. 176). Additional evi- 

 dence on this point comes from the fact that in 

 cells where the rods have disappeared there may 

 remain numerous central granules (fig. 161) or 

 they may be absent (fig. 165). 



Sometimes instead of a granule there may be 

 a vacuole or at least a nonstaining clear space in 

 the center of each rod (figs. 166 and 167). In 

 the second figure most of the rod substance has 



Figures 154-176. — Heterophils from circulating blood — mature, immature, and smudged cells. Some 

 evidence of technic artifact is apparent in practically all normal mature heterophils. (The terms 

 "central bodies" and "central granules" as applied to heterophils are synonymous.) 2,470X. 



Figures 154-167: Normal mature heterophils selected to 

 shoiD variahility in structure and size of cells and in 

 staining defects. 



154 Well-preserved rods, without central granules. 

 Nuclear lobes are poorly stained. 



155 Rods with a few central bodies. Variable staining 

 of the nuclear lobes. 



156 Approximately one central granule per rod. Nuclear 

 lobes are fully stained. 



157 Partial dissolution of rods; central bodies are large 

 and do not disappear. Variable staining of the 

 nuclear lobes. 



158 Nearly complete dissolution of rods; the rod sub- 

 stance gives to the cytoplasm an overall pink color 

 with Wright's stain. Central bodies are small. 



159 Nearly complete dissolution of rods, which gives an 

 intense color to the entire cytosome. The outer 

 portions of the nuclear lobes are well stained; inner 

 parts are poorly stained. 



160 Small heterophil showing only central bodies of 

 varying size. 



161 Heterophil with only central bodies visible. The 

 large central bodies of this and the preceding cells 

 cause these cells to resemble the eosinophils, but they 

 can be separated by the difference in color of the 

 cytoplasmic ground substance. Compare with fig- 

 ures 177-180. 



162 Completely dissolved rods with only relatively few 

 small central bodies. Nuclear lobes are weakly 

 stained. 



163 Central bodies few, with a range in size varying 

 from small to large. 



164 Heterophil with but few central bodies and no rods. 



165 Heterophil without rods or central bodies. 



166 Heterophil in which the central bodies appear as 

 vacuoles within the rods. 



167 Heterophil in which the rods have contracted around 

 the vacuolar-type central bodies. 



Figures 168-173: Developmental stages of heterophils found 

 in circulating blood. 



168 Heterophil granuloblast. No nucleolus visible. 

 Found on same slide with heterophil mj'elocytes, 

 figures 169-172. 



169 Heterophil promyelocyte. Nucleus in lower two- 

 thirds of cell appears to merge with the cytosome. 

 Magenta granules and rings identify this as a 

 heterophil. 



170 Heterophil promyelocyte. Approximately the same 

 stage of development as preceding cell, but smaller. 



171 Heterophil promyelocyte. 



172 Heterophil promyelocyte. Greater vacuolization 

 of cytoplasm than in preceding cells. Nucleus is not 

 yet clearly separated from cytosome. 



173 Heterophil mesomyelocyte. Early stage in the 

 differentiation of the specific heterophil rods. 



Figures 174-176: Technic artifacts. 



174 Mature heterophil. M. G. G. ; the central bodies 

 were retained as they are following Wright's stain 

 but the rod substance was almost completely 

 dissolved. Nucleus poorly stained. 



175 Smudged heterophil with two nuclear lobes. Rods 

 retained their form. 



176 Smudged heterophil with rods dissolved. The large 

 spheres are the central granules and the small ones 

 are serum granules 



74 



