for basic dyes and die resulting color produced 

 in the stained object is different from the color 

 of tlie dye in solution. Even with a group of 

 slides that receive the same treatment, there is 

 considerable variability between birds in the re- 

 sistance of the granules to water. This may in 

 part reflect differences in age of the cells but it has 

 not been proved that the granules developing in 

 basophil myelocytes are more resistant to water 

 dian they are in older cells. 



The nucleus of basophils is usually masked by 

 granules, but occasionally it may be visible as a 

 structureless, pale blue staining body lying in the 

 center of the cell. The penetration of Wright's 

 stain, found to be poor in the heterophil nucleus 

 is practically nil in basophils. Sometimes it ap- 

 pears as if chromatin clumps of the nucleus were 

 being stained (figs. 190, 191, and 192), but this 

 is due to the basophilic bodies of the cytoplasm 

 that are trapped above or below the nucleus when 

 the cells are flattened in drying. For some 

 reason the pressing of the nuclear membrane 

 against the cell membrane protects tlie granules 

 to some extent from the action of water. Failure 

 of the nucleus to stain is not evidence of de- 

 generation — when fixed with Petrunkevitch No. 

 2, they stain as strongly as any normal nucleus 

 (fig. 221). 



Variations in shape of nuclei and number of 

 lobes are seen in figures 222 and 223. Usually 

 tlie nucleus is centrally placed and lias a round 

 shape. Constricted nuclei may be seen, but only 

 rarely. A nucleus in the condition shown in 

 figure 222 is counted as one lobe; only when the 

 isdnnus between is reduced to one or more deli- 

 cate sti'ands is the nucleus regarded as bilobed 

 (fig. 223). A trilobed nucleus has never been 

 observed in a basophil, and from the Arneth 

 counts on these cells (table 6), the bilobed con- 

 dition occurs only about once in one hundred 

 cells. 



After one has seen a representative collection 

 of basophils, this cell type becomes the most 

 easily recognized leukocyte of the blood. Yet 

 errors have been made in the literature; Emmel 

 (1936) labeled as "normal premyelocyte" (his 

 fig. 6E) a cell that is a typical basophil of cir- 

 culating blood, as nearly as can be determined 

 from his black-and-white drawing. This would 

 help to explain why he found only two basophils 

 in diflierential counts made on 50 chickens. In 

 normal chickens tested at this Laboratory, these 



cells run about 2 percent of the differential count, 

 and in pheasants it may be 10 percent (table 20) . 



Developmental stages found in circulating 

 blood (fig. 193) 



This is the only immature basophil that has 

 been seen in the circulating blood. It closely 

 resemldes in cellular and nuclear detail the 

 heterophil granuloblast (fig. 168) ; but resem- 

 l^lance is lacking in one respect — the cytoplasm 

 contains numerous magenta granules. These 

 ])odies are equivalent to the granules and rings 

 found in heterophils at this same stage of de- 

 velopment, and often the two cells are hard to 

 separate. Usually the magenta rings of the 

 heterophil are larger than those of the basophil, 

 and in the latter there is less vacuolization of the 

 cytoplasm and the nucleus tends to remain in the 

 center of the cell more frequently than in the 

 heterophil. These points are made evident by 

 a comparison of immature granulocytes from 

 bone marrow shown in figures 370-372, 382, 

 and 383. The magenta body in the basophil 

 promyelocyte is not the definitive basophilic 

 granule and is not affected by aqueous solutions. 



Technic artifacts (figs. 194-196) 



Since aqueous staining methods dissolve the 

 Ijasophilic granules, every cell illustrated as 

 typical of the normal is, in reality, an example of 

 a technic artifact, and the same can be said for 

 the failure of the nucleus to take the stain. In 

 addition to these artifacts, squashed cells may be 

 found. Figures 194^196 show three degrees of 

 severity. In figure 194 the cell is only slightly 

 squashed; the granules are separated and they 

 are larger than normal, and the nucleus of the 

 cell shows earlv autolysis. In figure 195 the cell 

 membrane wall is definitely broken and some of 

 the granules are scattered. In this particular 

 cell there is considerable variation in the way the 

 granules take the stain. This, however, may 

 have existed in the cell before it was broken. The 

 granules from the cell shown in figure 196 have 

 been widely scattered and for some reason retain 

 a strong affinity for stain. Obviously, all the 

 factors responsible for dissolution of granules 

 are not yet fully known. The clefts in die auto- 

 lysing nucleus are probably the spaces between 

 the blocks of chromatin. 



92 



