Leukaemia of the Fowl. 19 



eosinophilic granules predominated, frequently showing mitoses ; others 

 seemed to be composed exclusively of the large mononuclear. Here 

 mitoses were also common. In these foci the convoluted tubules had 

 either been pushed aside or had atrophied. 



Bone-marrow. This was greatly changed. It consisted of a closely 

 packed mass of white marrow cells, with complete atrophy of the fat 

 and great rarity of normocytes. One or two small focal areas of 

 sclerosis were present. The arteries were mostly empty. Some showed 

 a little blood containing a few large mononuclears. Those marrow cells, 

 which were present, both red and white, answered to their descriptions 

 given under normal bone-marrow, with the exception of the large 

 mononuclear myelocyte, which showed considerable variation in its 

 nucleus. This was either single or multiple, round, oval, or horseshoe- 

 shaped. The order of predominance had changed greatly. The large 

 mononuclear myelocyte was present in far greater numbers than any 

 other cell, and showed extensive mitoses. The normoblast and megalo- 

 blast with mitoses followed next in frequency; then the normocyte. 

 Polymorphonuclear myelocytes, those with eosinophilic rods and those 

 with eosinophilic granules, had disappeared entirely. Curious is the 

 fact that the mononuclear myelocyte with eosinophilic granules could 

 not be demonstrated with certainty. As in the normal marrow lymph- 

 ocytes, mast cells and platelets were not seen. 



Thyroids, Parathyroids, Pancreas and Adrenals. These were not 

 studied. 



SUMMAKY. 



In " summarizing the changes in the blood and organs, there was 

 found : 



1. In the Blood. (a) A great increase in the total number of white 

 blood cells. Although a total count was not made, this increase was 

 evident from the appearance of the blood smears, and of the blood- 

 vessels in sections. The actual proportion of white to red cells sub- 

 stantiated this fact. The differential count showed a marked increase 

 of the large mononuclear cell at the expense of the other white blood 

 cells of the normal blood. In addition, a true myelocyte appeared in the 

 circulation. Mitoses of the large mononuclear were common, (b) A 

 corresponding decrease in the total number of red blood cells. These 

 showed a drop in haemoglobin, variation in size and shape, basophilic 

 staining of the cytoplasm, and swelling of their nuclei. Premature 

 red cells, normoblasts and megaloblasts made their appearance. 



