EXTERNAL TUBERCULOSIS IN THE llOci AND CAT. I03 



the cutaneous ulcer contracts ; in others it gradually increases. 

 Abscesses sometimes develop in the neighbourhood and open externally, 

 producing small wounds, which may unite with the first ; sometimes 

 the skin becomes separated from subjacent structures over a large area, 

 and is rapidly riddled with ulcers. The muscular and connective tissues 

 traversed by the sinuses are inflamed, hardened, and fused together. 

 On dissection granulations and caseous tubercles are found. The 

 retro-pharyngeal and cervical lymphatic glands are always affected ; 

 either they are hypertrophied, inflamed, and on section appear dotted 

 over with yellowish points formed by the granulations, or they appear 

 as little swellings the size of a haricot bean or a hazel nut, with 

 softened purulent centres. I have twice seen the cervical glands 

 connected by knotted lymphatic vessels with the tracheo-bronchial 

 lymphatic glands. 



The mucous membranes in the domain of the affected lymphatics 

 rarely show specific lesions. I have only seen three such. One showed 

 tuberculous ulceration of the left tonsil ; another, a submucous tubercle 

 in the pharvnx ; and the third, ulceration of the mucous membrane of 

 the larynx. 



Despite the very rare occurrence of lesions indicating the point of 

 entrance of bacilli, these tuberculous ulcers of the neck result from 

 auto-inoculation of the pharyngeal, laryngeal, or nasal mucous mem- 

 branes, by purulent products formed in the lung and coughed into the 

 pharynx or posterior nasal cavities. Of the above-mentioned twelve 

 patients showing tuberculous ulcer of the neck ten had very marked 

 disease of the lungs, which were partially destroyed by the formation 

 of cavernous spaces. Pharyngeal catarrh is known to be fairly common 

 in the dog. Under these circumstances auto-inoculation occurs readily. 

 The mucous membrane, whether normal or deprived of its epithelium, 

 when covered with virulent muco-pus is penetrated by the bacilli, 

 which afterwards extend to the neighbouring lymphatic glands. Pres- 

 sure of the collar causes inflammation of the infected glands, favours 

 suppuration of the surrounding tissues, and ulceration of the skin. 

 This is the true pathogeny of tuberculous ulcers in the dog's neck. 



Subcutaneous or <jpen tuberculous lesions are also seen in the cat. 

 In addition to the three cases of this nature mentioned I may cite the 

 two following : 



At the beginning of April, 1895, a seven-year-old female cat was 

 brought to the clinique. It had been ill for some time, and already 

 showed marked wasting. The owner had particularly noted difficulty 

 in breathing, attacks of coughing, and at certain times a little nasal 



