420 



STOMACH AND INTESTINE. 



the canal. The follicle itself is thus either 

 evacuated or destroyed: and its situation is 

 then occupied by a small excavated ulcer, va- 

 rying in size from a millet-seed to a pea. 



This primary ulcer now becomes the seat 

 of a process of secondary ulceration, which 

 extends its size in the two directions of width 

 and depth. Its superficial extension causes 

 several of the small primary ulcers to become 

 fused into one ; and sometimes widens the 

 resulting secondary ulcer, so as to form a 

 patch of ulceration that more or less encircles 

 the bowel. Its vertical progress successively 

 engages the submucous and muscular coats, 

 and thus finally reaches the peritoneum. The 

 latter membrane, if not strengthened by the 

 lymph of adhesive inflammation, now sloughs 

 or ruptures ; with the result of a fatal perfo- 

 ration. 



This extension of the ulcerative process, 

 and the means by which it is effected, together 

 constitute the chief characteristics of tuber- 

 cular disease in the intestinal canal : and 

 render the loss of substance it brings about in 

 the walls of this tube, strictly analogous to 

 that by which it excavates the tissues of the 

 lung. The base and margins of the tubercu- 

 lous ulcer have a ragged swollen appearance; 

 are surrounded by a gelatinous infiltration ; 

 and are themselves the seat of an interstitial 

 deposit of cheesy tubercle. The softening of 

 this deposit, and the suppuration of the ori- 

 ginal tissues in which it is entangled, continu- 

 ally increase the size of the ulcer ; and the 

 inflammation thus produced tends as continu- 

 ally to increase the deposit of new tubercle. 

 Hence the tuberculous ulcer assimilates, so to 

 speak, the adjacent tissues to itself: and is 

 never bounded by healthy or heterogeneous 

 tissues ; like those which adjoin the gastric 

 ulcer, or the specific follicular ulcer of the 

 typhoid process. 



As the tubercular ulceration extends, the 

 intervening submucous tissue, even where hi- 

 therto healthy, generally becomes the seat of 

 a similar deposit and destruction. Hence, 

 in well marked instances of acute intestinal 

 tuberculosis, these ulcerations occupy a large 

 proportion of the affected surface of bowel ; 

 leaving only small insulated patches, or 

 fungous projections, of the original mucous 

 membrane. And in extreme cases, they 

 may even remove this tunic from a large con- 

 tinuous segment of the bowel. 



The cicatrization of such ulcers is rarely 

 seen, except in cases where the process has 

 ceased in one part, while it has still been going 

 on in another. In such instances, the removal 

 of the softened mass already present ceases 

 to be followed by any further interstitial 

 deposit of fresh tubercle in the margin of 

 the ulcer ; and a plasma, which exsudes on 

 the bare and ulcerated surface, is ultimately 

 developed into a cicatrix of the ordinary 

 structure and appearance. The subsequent 

 contraction of this cicatrix is of course 

 proportional to the loss of substance which it 

 has had to replace. The zonular direction 



of the previous ulcer often gives it a form 

 more or less approaching that of a cord or 

 imperfect septum ; which lies transversely to 

 the axis of the tube, and materially narrows 

 its calibre. In rare instances, the cicatrix 

 contains fragments of the cretaceous or other 

 varieties of obsolete tubercle. 



Cancer. Cancer affects the intestinal canal 

 under all three of its chief forms ; namely, 

 scirrhous, medullary, and colloid or areolar 

 cancer. And even its villous and epithelial 

 varieties are occasionally present. The latter 

 is, however, very rarely rnet with. 



In most instances the cancerous growth is 

 at first seated chiefly in the submucous are- 

 olar tissue; from which it gradually advances 

 towards the inner and outer surface of the 

 canal, so as ultimately to involve the whole of 

 its coats. But the three forms of cancer fall 

 with various degrees of intensity on different 

 parts of this areolar layer. The scirrhous vari- 

 ety begins in its deepest stratum ; and in those 

 fibrous septa of the subjacent muscular bun- 

 dles which are connected with it. The areolar 

 or colloid variety chiefly affects the middle 

 and looser laminae. While the medullary 

 and the villous variety generally occupy the 

 immediate neighbourhood of the basement 

 membrane of the mucous tunic. Finally, in 

 the epithelial variety, there seems to be 

 a definite metamorphosis of all the histolo- 

 gical elements of the mucous membrane 

 itself. 



Those rare instances in which the cancer 

 seems to begin in the subserous areolar tissue 

 are in reality cases of cancer of the perito- 

 neum ; which membrane they almost always 

 involve in its visceral reflexions (omentum 

 and mesentery), as well as in some parts of 

 its parietal laminae.* 



The cancerous growth is generally primary; 

 but is sometimes secondary to a deposit in 

 some neighbouring organ. In the latter case, 

 the intestinal canal may either be involved 

 by a mere extension of the disease from abso- 

 lute contact ; or it may be affected through the 

 intervention of the lymphatic glands and ves- 

 sels. The first of these contingencies may be 

 illustrated by the way in which the stomach 

 is sometimes involved in a cancerous tumour 

 of the liver : the second, by the far more nu- 

 merous instances, in which the large intestine 

 becomes cancerous, as the result of similar 

 disease occupying the neighbouring lymphatic 

 glands. 



The above varieties of the cancerous 

 growth occur with very unequal frequency. 

 The scirrhous is by far the most common, the 

 medullary less frequent, and the colloid or 

 areolar rarest of all. And while the former is 

 usually primary, the two latter are more fre- 

 quently secondary ; or are often admixed, in 

 varying proportions, with what was originally 

 a scirrhous growth. In the latter instances, 

 the scirrhus is sometimes said to have under- 

 gone a transformation into medullary cancer. 



* Compare Art. PERITONEUM. 



