198 Givynneth Buchanan: 



?wides) smear stained with Giemsa. In the Heron and Spoon- 

 hill there were also doubtful forms, but neither of these slides were 

 very reliable, being fairly pathological. 



Mononuclear Cells. — These varied in percentage count, but never 

 ran higher than 28 per cent, of total leucocytes. They were dis- 

 tinctly divisible into small and large types, the former ranging 

 from 6.8/X-9/M, and the latter from 8.5fi-\4.5fi. The relative dif- 

 ference between the two forms ran as high as 6.5// in one bird 

 (Heron ). 



Polymorphonucleate Cells. — These were difficult to distinguish 

 from the eosinophil, and a percentage count could only he made 

 in the young Mudlark, in which they amounted to 3.5 per cent. 

 of the total leucocytes. In this species also, their diameter was 

 only 6.2/t, while that of the true eosinophils ran as high as 11.6/x. 

 Gruner includes under this head mast cells, eosinophils with rod- 

 like granules, and cells of the same size full of minute oxyphile 

 granules. 



Eosinophil Cells. — In general, the size of these cells averaged less 

 than those of reptiles. They were in most eases divided into those 

 with round granules, and those with the spindle or crystalloid 

 variety (polymorphonucleate leucocytes of Burnett, neutrophile 

 of Gruner), though it was not always possible to distinguish 

 clearly enough between the two forms in order to make a differential 

 count. The crystalloid variety were particularly well marked in 

 the White Pekin Duck and young Mudlark, in each of which they 

 gave a high percentage count, very greatly in excess of the 

 ordinary cells with rounder granules. As a rule the percentage 

 of eosinophil corpuscles was fairly high, running up to 32.4 per 

 cent, of total leucocytes in the Black Mountain Duck. In some- 

 cases, notably the Heron, the granules were very sparse, resembling 

 those of certain reptiles, while in the Black Mountain Duck several 

 large mononuclear cells showed an apparent ebsinophilous granu- 

 lation. In the Ihis there were distinctly three forms, (a) with 

 small granules, (b) with ordinary spindles, (c) with huge spindles 



the last two classes being about equal in number, and varying 

 slightly in size (1 1.6//.- 10. 9//). 



