696 INFECTIOUS DISEASES. 



to be unyielding and greatly thickened, a point which is the more 

 remarkable as the animals are thinner. 



The wall of the abdomen is stiff, incapable of being depressed as 

 in ordinary subjects, and gives to the fingers the sensation of a thick 

 hard covering, through which the subjacent organs and their contents, 

 that is, the rumen, intestine and alimentary material, can no longer 

 be felt. This rigidity is always most marked in the lower abdominal 

 region. The digestive peristaltic movement can no longer be detected, 

 and on auscultation the normal sounds are manifestly much slower 

 than usual. 



TUBERCULOSIS OF LYMPHATIC GLANDS. 



It might perhaps have seemed more logical to place tuberculosis of 

 the lymphatic glands at the commencement of these clinical divisions 

 of tuberculosis, as when tuberculous lesions, of whatever kind, occur 

 in the lung, pleura, abdomen, etc., the lymphatic glands in the neigh- 

 bourhood are invariably invaded. In such cases, however, the lesions 

 in question are not the dominant features. 



Under this heading must be classed tuberculous lesions which, on 

 the contrary, affect the lymphatic glands in so marked a manner that 

 lesions in other organs may be regarded as secondary. This occurs 

 somewhat frequently, because at the present day there is a tendency 

 to believe that inoculation takes place mainly through the mucous 

 membrane of the pharynx, and thence extends towards the neighbouring 

 lymphatic glands. At any rate, it is unquestionable that tuberculosis 

 of the lymphatic glands may exist quite apart from any other lesion 

 visible to the naked eye. 



Two forms are very common, tuberculosis of the retro-pharyngeal 

 region and of the neck, and tuberculosis of the mediastinal lymphatic 

 glands. 



Tuberculosis of the Retro-pharyngeal Glands. — In addition to 

 the retro-pharyngeal glands the cervical chain of lymphatic glands, 

 the sub-glossal, sub-atloid, pre-parotid, and even the pre-scapular 

 lymphatic glands and those at the entrance to the chest, may also 

 be invaded more or less. 



This form of tuberculosis may remain latent for a long time, atten- 

 tion being attracted to it only when deglutition is impeded and local 

 deformity becomes apparent. 



Swelling of lymphatic glands resulting from tuberculous infection 

 is slow and progressive, differing entirely from that which accom- 

 panies suppurative adenitis. The neighbouring connective tissue is 

 certainly somewhat thickened or infiltrated, but the glands themselves 

 can always be detected. The region of the gullet is enlarged, the 



