TUI\rORS 163 



The cyst wall was made up of white, fibrous connective tissue The 

 wall was thin. The cyst contained a colorless li(inid which escaped 

 from the punctured cyst wall. The cyst was attached by means 

 of a pedicle to the roof of the lumbo-pelvic cavity about midway 

 of the kidneys. The cyst apparently had its origin from the su- 

 perior ligament of the oviduct. The oviduct contained in its pos- 

 terior portion a fully developed egg with shell. 



CONTAGIOUS EPITHELIOMA 



Cause.— Thin is a specific infectious disease. It is trans- 

 mitted from one bird to another in the infected tiock. It is 

 quite widely distributed, being reported in Europe and (^ther 



Fig. 63. Photograph of the Heads of Two Chicks Affected With Contagious 



Epithelioma. 



countries and has been observed in many sections of tlie 

 United States. 



Symptoms. — The disease appears first as a catarrhal in- 

 flammation of the mucous membranes of the head folUnved 

 by the development of epitheliomatous enlargements which 

 may involve any part of the head, especially the unfeathcred 

 portions. These epithelial growths at first appear small, have 

 a smooth surface and a hyperemic zone; later they may de- 

 velop to the size of a hazelnut or larger. Necrosis may take 

 place in various portions of the new growth ; the sloughing 

 may leave ulcerative surfaces Avhicli may cicatrize. Tlie 

 lesion may o])struct the sight and even ohlitei-ate tlie eye. 

 The nasal lesions may interfere with respiration and cause 

 the bird to hold its mouth partly open. 



A microscopic examination shows the structure to be that 

 of an epithelioma. The cells are arranged in more or less 

 irregular rows supported by a network of connective tissue 



