stained slide. Two slides are necessary for 

 bird's blood — one processed to show the struc- 

 ture of the cytosome and its inclusions, and the 

 other to show the nucleus. This may be the rea- 

 son why so few counts thus far have been pub- 

 lished for birds on the number of lobes in 

 heterophils. 



Avian blood has not as yet received the same 

 critical study as human and mammalian bloods 

 nor have avian diseases been approached with the 

 idea of closely correlating the physiology of the 

 diseased condition with the hematologic re- 

 sponse, although from the reviews given by Ol- 

 son (19.37 and 1952) it is indicated that many 

 workers have made important contributions to 

 blood diseases of birds. 



Differential counts serve a useful purpose but 

 actually hold only a small place in the total of 

 blood reactions. The Arneth or Cook-Ponder 

 counts can contribute additional information. 

 Figures 203-214 sliow the range of variation in 

 number of nuclear lobes in heterophils. It is 

 obvious that a single nucleus will be separated 

 into two lobes by a gradual process. Thus all 

 stages will be found, and it becomes necessary 

 to decide arbitrarily when one nuclear mass has 

 been sufficiently separated from another to be 

 called a second lobe. Figures 204 and 205 

 would each be considered to have a single nu- 

 cleus. In mammalian work cells of this type are 

 often called juveniles, nonsegmenters, and band 

 cells. 



There may be some question as to the proper 

 designation for figui'e 206 but since there is a 

 deep constriction, rather than a broad band, it 

 has been called two-lobed. In chicken blood, a 

 small particle of nuclear material may be re- 

 tained more frequently along the length of the 

 desmos as the lobes pull apart than in manmial- 

 ian blood. An example of tliis is seen in figure 

 207; it meets the requirements of a distinct lobe 

 in that it is separated from adjacent lobes by a 

 complete constriction but, to be arbitraiy, and to 

 give some meaning to the Arneth count, it seems 

 inadvisable to count these small nuclear masses 

 as lobes. On this basis the figure referred to has 

 2 instead of 3 lobes. Three lobes are shown in 

 figure 203. 



Three lobes are shown in figure 208, and if 

 the small spatulate portion still attached to the 

 upper lobe were completely separated by a con- 

 striction, it would be counted as a fourth lol)e. 



The spatulate portion is somewhat larger than 

 the small mass discussed for figure 207. 



Four lobes would be counted in figures 210— 

 212. The fourth lobe in figure 210 is the long 

 narrow structure that is separated from the lower 

 lobe by a complete constriction; no connecting 

 thread has yet been fonned. The constriction 

 near the tip of the left lobe is not sufficient to 

 warrant counting this body as 2 lobes. Figures 

 211 and 212 have 4 lobes each, and figures 213 

 and 214 have 5 each. Sometimes the lobes 

 break apart and no trace of a connecting line be- 

 tween is visible (fig. 213, upper lobe). 



Judgment in counting lobes of eosinophils and 

 of basophils is based on the same criteria already 

 described for heterophils. The eosinophil, fig- 

 ure 216, is counted as one lobe. In this particu- 

 lar cell, there actually may be two lobes, one 

 overlying the other, but it is less confusing and 

 probably sufficiently accurate to include this in 

 the single-lobe class. Figure 215 is an example 

 of a nucleus belonging to class II. Figures 217- 

 219 are examples of nuclei belonging to class III. 

 In figure 217, the middle lobe, although small, is 

 sufficiently large and definite to be counted as one 

 lobe. Figure 220 is an example of a nucleus be- 

 longing to class IV. No examples of class V 

 were found among the eosinophils. 



Basophils usually have but a single nuclear 

 lobe (figs. 221 and 222). Rarely the nucleus 

 may be divided into two lobes (fig. 223). 



The Arneth index gives a useful statistic that 

 measures the rate at which old cells are being re- 

 placed. There are 5 classes. Class I includes 

 all cells in which the nucleus is composed of one 

 lobe. The remaining classes — II, III, IV, and 

 V — include cells that have the corresponding 

 number of nuclear lobes; class V includes, also, 

 those of over 5 lobes. Cells with more than 5 

 lobes are rare; none were found in a sample of 

 1,500 cells counted. The results of one Arneth 

 count on 1,500 heterophils, 142 eosinophils, and 

 295 Ijasophils are given in table 6. Ameth used 

 nuclear lobe counts on eosinophils and basophils 

 but they have never been found as useful as the 

 counts made on the heterophils. In the litera- 

 ture it is stated that heterophils have more lobes 

 than eosinophils. This observation is supported 

 by the data in table 6 where the index for the 

 former is 2.44 and for the latter 1.97. How- 

 ever, the presence of more lobes is definitely not 

 a characteristic by which the two cell types can 



84 



