Mettam — Malignant Tumours in Birds. 73 



in formalin, and eventually sections were made in the usual way, stained, 

 and examined. Blood-films were at once obtained, and, after rapid drying 

 in the air, were fixed by pure methyl alcohol, and stained by the Giemsa and 

 Eomanowski methods. 



It may be mentioned that there were no parasites found in the trachea or 

 any portion of the respiratory track, and that the hindrance to respiration 

 was due entirely to the tumour replacing the lung. Sections were also made 

 of the liver and spleen ; but there were no secondary tumours observed in 

 these organs, nor could any be found on naked-eye examination in any other 

 part of the body. 



Microscopical examination of the Lung. — The tumour proved to be an 

 epithelioma— a true cancer. The epithelial cells, small, crowded together 

 with large vesicular nuclei, poor in chromatin, showed in many places cell- 

 inclusions of the usual types. Mitoses were common, and in some instances 

 quite atypical. Large portions of the tumour had undergone coagulative 

 necrosis from some cause, but not from aneemia, because vessels containing 

 apparently unaltered blood were readily discovered in the necrotic areas. 

 Moreover, the line of demarcation between the unaltered and necrotic lung- 

 tissue was a sharp line. Numerous leucocytes had begun to invade the 

 necrotic tissue, and the characteristic eosinophiles of the bird, with their rod- 

 like granules, could be easily detected. In places, bud-like out-growths from 

 the tumour in full cellular activity had sprouted into the lumina of bronchial 

 tubes still patent, filling them with an epithelial growth more or less 

 completely. There were no signs of keratinisation of cells; no parasites, 

 such as inhabit the bronchial tubes, were noticed ; nor could any bacteria be 

 revealed on staining sections by the usual methods. 



The Blood. — Examination of the blood-films made and stained as above 

 described revealed a very interesting condition. The red-blood corpuscles of 

 the thrush, as in other birds, are nucleated and oval in form. The long 

 diameter is approximately 14/x, the widest transverse diameter being 6//. 

 The normal nucleus is also oval in outline, about 7/x by 2-6/t. Stained by 

 the Giemsa method, the normal corpuscles react as follows : the protoplasm 

 of the red corpuscles takes on a faint yellowish-pink tint; the nucleus is 

 reddish-purple, with several darkly stained bodies imbedded therein. These 

 bodies are probably lumps of chromatin attached to the linin threads of 

 the nuclear network. In some corpuscles there are two nuclei smaller 

 than the usual single one ; and it is probable that the two result from amitotic 

 division of a mother nucleus. Occasionally a corpuscle without a nucleus 

 may be met with ; but in every other particular it agrees with the nucleated 

 corpuscle. 



