shii'es was definitely smaller — 35.6m'. The 

 same difference in size for this breed is reflected, 

 as would be expected, in the nuclear area and in 

 the diameters of the cells and nuclei. If the 

 lymphocytes and their nuclei when flattened had 

 been circular and the nucleus had been in the 

 center, the cytoplasm would have formed a rim 

 around it hardly more than a half micron in 

 width. 



The striking difference in size and nucleocell 

 ratios of lymphocytes and of monocytes is well 

 brought out by comparing the data of table 14 

 with those of table 15. The monocyte area for 

 both lines of Laboratory stock was large, and for 

 both the commercial lines it was small. In other 

 words, in 3 of the 4 groups lymphocyte and mono- 

 cyte areas appeared to be positively correlated, 

 but in the Columbian Plymouth Rocks the as- 

 sociation was negative. The area of the mono- 

 cyte nucleus is approximately half the area of the 

 total cell or, comparing nucleus with cytosome, 

 the ratio is approximately 1: 1.1 in contrast to 

 the lymphocyte, where the ratio is approximately 

 1:0.5. 



Heterophils show a greater variability among 

 birds within a group than among groups (table 

 16) and from tliis there is probably relatively lit- 

 tle significance to the difference in size from 7.9 m 

 diameter for RPL line 6 birds and 9.9m for the 



New Hampshires. The data for the eosinophils 

 emphasize a point that was brought out when the 

 eosinophil of circulating blood was discussed — 

 so often an individual chicken showed almost ex- 

 clusively a large or a small type of cell. This is 

 evident in table 16, where maximum size was 

 6.0m for bird 6 of RPL line 1.5, but the minimum 

 for bird 4 was greater — 6.4^. Almost the same 

 situation existed in birds 4 and 6 of RPL line 6, 

 and in 1 and 4 of the Columbian Plymouth Rock. 

 The average for the basophil diameter of 7.8m 

 for Laboratoi-y birds is less than 8.1 and 9.1m 

 for chickens from commercial sources, but the 

 samples are probably too small to have much 

 significance in view of ranges in diameter as 

 great as 4.9 to 10.9m within a liird and rather 

 wide variability in the averages among groups 

 of birds. 



CELL COUNTS, HEMOGLOBIN LEVELS, 

 AND HEMATOCRITS 



An important function of an atlas on blood is 

 to aid in cell identification so that accurate dif- 

 ferential counts can be made. A review of 

 earlier cell counts in some cases, as well as tabu- 

 lation of new data of their own has been given by 



Table 15. — Area and diameter of monocytes 



Breed 



Single Comb While Leg- 

 horns. 



Average for group . . . 

 Single Comb White Leg- 

 horns. 



Average for group . 

 New Hampshires. . . . 



Average for group . . 

 Columbian Plymouth 

 Rocks. 



Average for group . 



RPL 6. 



RPL 15. 



Commercial 



jommercial 



Bird 2 



Cytosome 



Range 



107. 9-151. 5 



102. 7-151. 5 



97. 6-146. 4 



84. 7-146. 4 



105. 3-226. 



87. 3-138. 7 



66. 8-179. 8 

 77. 0-169. 5 

 53. 1-136. 1 



61. 6-148. 9 

 51.4-133.5 

 71.9-143.8 



Aver- 

 age 



129.0 

 125.4 

 124.2 

 126.2 

 120.7 

 151.9 

 113.2 

 128.6 

 100.3 

 107.7 

 101. 1 

 103.0 

 93.4 

 95.7 

 114. 7 

 101.3 



Diameter fi 



Range 



Aver 

 age 



12.9 

 12.7 

 12.5 

 12.7 

 12.4 

 13.9 

 12.0 

 12.8 

 11.2 

 11.6 

 11.3 

 11.4 

 10.8 

 11.0 

 12.0 

 11.3 



Nucleus 



Area /i ' 



Range 



46. 2-66. 8 

 43. 7-64. 2 

 43. 7-66. 8 



43. 7-64. 2 

 46. 2-84. 7 

 48. 8-71. 9 



38. 5-97. 6 

 41. 1-79. 6 

 36. 0-66. 8 



36. 0-69. 4 

 23. 1-64. 2 

 38. 5-69. 3 



57.9 

 54.2 

 56.7 

 56.3 

 54.3 

 67.4 

 57.0 

 59.6 

 50.5 

 51.8 

 51.4 

 51.2 

 49.2 

 47.4 

 52.9 

 49.8 



Diameter m 



Range 



7. 7- 9. 2 

 7. 4- 9. 

 7. 4- 9. 2 



7. 4- 9. 

 7. 7-10. 4 

 7. 9- 9. 6 



7.0-11.1 

 7. 2-10. 1 

 6. 8- 9. 2 



6. 8- 9. 4 

 5. 4^ 9. 



7. 0- 9. 4 



Aver- 

 age 



8.6 

 8.3 

 8.5 

 8.5 

 8.3 

 9.2 

 8.5 

 8.7 

 8.0 

 8.1 

 8.0 

 8.0 

 7.9 

 7.7 

 8.2 

 7.9 



' RPL = stock from the U. S. Regional Poultry Research Laboratory. 



2 Measiu-ements based on 25 cells per bird. 



214 



