TUBERCULOSIS. 447 



we found to be affected in abdominal typ]iu<, arc also the 

 favourite seat of tuberculosis, sc, the lymphatic glands, Fever's 

 patches, and solitary follicles in the neighbourhood of tlie ileo- 

 eoecal valve. The process however is not restricted, as in 

 abdominal typhus, to the lymphatic structures and the parts 

 immediately surrounding them ; it starts from them indeed, but 

 only to extend farther according to a special law of its own. 

 Now it is just these primary' changes in the closed follicles which 

 are not of a tuberculous nature. The grey intumescence which 

 oauses enlargement of the individual follicle to about three times 

 its normal bulk, depends upon the same one-sided kind of pro- 

 liferation of the corpuscular elements in the lymph-paths and 

 the reticular parenchyma of the follicles, with which we arc 

 familiar as the cause of the scrofulous bubo ; the subsequent 

 caseation, it is true, differs in no respect from the degenerative 

 change to which the true tubercles themselves succumb ; so that 

 when once this stage has been reached, it is no longer possible to 

 distinguish between the two processes. It is wortliy of note, 

 moreover, that the disorder of the corresponding mesenteric 

 glands is purely of a ^^ scrofulous" kind, and cannot be con- 

 founded with the very different anatomical aj^pearances presented 

 by genuine tuberculosis of a lymphatic gland. 



The cheesy follicles soften from without inwards, and when 

 the cheesy matter is wholly dissolved, we find a sharply-circum- 

 scribed hemispherical defect, the so-called '' cleansed ulcer," 

 environed by relatively healthy tissue. The close proximity of 

 the neighbouring follicles to one another in a Peyer's patcli, 

 may lead, even at this early stage, to a coalescence of several of 

 these minute ulcers to form those larger defects which, from 

 their being bounded on all sides by segments of a circle, with 

 their convexities outwards, liave been called '' racemose ulcera- 

 tions." 



§ 387. On examining fine vertical sections through the base 

 and edges of one of these ulcers, we notice that it is everywhere 

 surrounded by a tolerably wide zone of corpuscular infiltration 

 of the coimective tissue. But neither in the corpuscular elements 

 themselves, nor in the mode of their arrangement, can we detect 

 anything specific. It would seem, moreover, that the gradual 

 extension of the ulcer is essentially due to the progressive 

 advance of the infiltration into the neighbouring tissues, and tlie 



