57° 



CLINICAL, VETERINARY MEDICINE AND SURGERY. 



on the crown of the head with canine tuberculosis. At the commence- 

 ment of June the skin over this part became thickened and covered 

 with crusts. The lesions continued to grow and vegetations developed, 

 one of which was specially notable on account of its size and horny 

 covering (Fig. 83). 



The parrot died on the 13th September, 1895, having survived ino- 

 culation 179 days. On post-mortem examination no visceral growth was 

 discovered, but the tuberculous lesion developed at the point of inocu- 

 lation was seen to have invaded and perforated the subjacent bones of 



Fig. 83. 



the cranium. On microscopical examination tubercle bacilli were 

 identified in the new growth. 



Mammalian tuberculosis inoculated into parrots had therefore pro- 

 duced lesions similar to those of spontaneous tuberculosis. The birds 

 lost condition, and died emaciated in from four to thirteen months. 

 On post-mortem examination the viscera appeared healthy, and con- 

 tained no bacilli ; the organisms had remained confined to the point of 

 inoculation. Sections showed large numbers in the local lesions. A 

 single inoculation, however, does not always produce tuberculous 

 lesions. In some cases the virus must be introduced several times, a 

 fact which explains how certain parrots only become contaminated 

 after months, or even years, passed in the neighbourhood of tuber- 

 culous persons. 



