566 



CLINICAL VKTERINARY MEDICINE AND SURGERY. 



examinations. In three of these (Cases 25, 26, and 27) we found 

 visceral tuberculosis in the form of little miliary granulations scattered 

 through the liver, spleen, and lungs. In these three cases we also 

 noted tuberculous points in the bones, articulations, and muscles. 



By histological examination of one of these cases we discovered 

 that the tubercles in the liver of the parrot resemble human tubercles, 

 and differ from those of the fowl and pheasant. They consist of 

 central giant-cells, round or fusiform, peripheral cells, and epithelioid 

 intermediate cells (Fig. 80). The giant-cells contained a very large 

 number of nuclei, which are usually distributed throughout the cell, or 

 occupy the centre, but not the periphery, thus differing in appearance 

 from the ordinary giant-cell in human tuberculosis. In these centres, 

 and especially in their giant-cells, bacilli appear very numerous. 



What is the origin of tuberculosis in parrots ? This is the most 



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interesting question both from the theoretical and practical point of 



view, 



One can hardly believe that in the majority of cases parrots have 

 been inoculated by Gallinaceae. Living with man, they never, or 

 scarcely ever, leave the house, and, as a rule, have no opportunity of 

 coming in contact with poultry. It is, therefore, impossible to imagine 

 how they could contract avian tuberculosis. 



These theoretical considerations are supported by the results of an 

 inquiry made by us regarding our twenty-seven cases. In seven in- 

 stances the affected parrots belonged to persons in bad health, who 

 appeared thin and had for a considerable time suffered from chronic 



