414 



STOMACH AND INTESTINE. 



indicated by the preceding description. The 

 floor of the ulcer is formed by the muscular 

 coat of the bowel, covered by a very thin 

 stratum of areolar tissue. Its margin, some- 

 what irregular in outline, is a reddish or bluish- 

 gray edge of mucous membrane : which was 

 formerly raised and almost detached from the 

 subjacent tissue by the distended and pro- 

 jecting follicles in its neighbourhood ; but has 

 now fallen down upon it, so as to form a per- 

 fectly flat, loose, and relaxed border, around 

 the shallow ulcerated fossa of the patch. 



In its further progress, the ulceration may 

 extend in two directions. In the horizontal 

 plane, it generally follows the shape, and 

 rarely much exceeds the size, of the original 

 patch. In the vertical plane, it may gradually 

 destroy the muscular and peritoneal coats, 

 and thus give rise to perforation. Such a 

 deepening of the ulcer is accompanied by 

 a narrowing of its width, so that the aperture 

 in the serous membrane is generally of very 

 small size. 



The cicatrization of the ulcer, which follows 

 the cessation of the local and general malady, 

 takes place by the development of a firm, but 

 very delicate layer of fibrous tissue, on the floor 

 of the ulcer. This merges, by a gradual increase 

 of its thickness, into the thickened margin be- 

 fore alluded to, where the original mucous 

 membrane becomes intimately blended with the 

 new fibrous cicatrix. The latter exhibits under 

 the microscope the ordinary characters of 

 this variety of fibrous tissue, and is generally 

 covered by one or two layers of irregular 

 flattened cells. The junction of the old and 

 new structures is often marked by wrinkles 

 and puckers, which appear to radiate from 

 the new tissue of the cicatrix ; and thus, as 

 it were, measure and express its contraction. 

 In very rare instances, this contraction gives 

 rise to an obstruction of the canal. That 

 it does not oftener do so seems due, not only 

 to the limited extent of the ulcer around the 

 bowel an extent which scarcely ever exceeds 

 id or ^th of its circumference but also to 

 the little injury generally inflicted on the tex- 

 tures subjacent to the ulcer, and to the amount 

 and situation of the new tissue of the cicatrix. 

 So little of this is deposited, and so exclu- 

 sively is it limited to the surface of the 

 ulcer, that the process of repair might almost 

 be regarded as resulting in a mere conden- 

 sation of those superficial layers of the 

 original areolar tissue which are left intact by 

 the ulcer. 



The above series of morbid changes in the 

 solitary and agminate follicles, is accompanied 

 by a somewhat similar alteration in the lym- 

 phatic or mesenteric glands connected with the 

 affected segments of intestine. This process 

 closely resembles the preceding, except in 

 the fact that it scarcely ever ends in the ulce- 

 ration of the structures it engages. A stage of 

 hyperaemia is soon followed by one of enlarge- 

 ment; the latter being due to the deposit of a 

 substance, which gives to the glands affected, 

 much the same grayish or reddish colour, and 

 soft firm consistence, as that seen in the folli- 



cles. This deposit next undergoes a limited 

 degree of softening : which is sometimes ac- 

 companied by haemorrhage, rarely by sup- 

 puration, ulceration, or peritonitis ; and is 

 followed by its gradual absorption. The 

 latter process slowly restores the glands to 

 their normal size and colour. 



Among the various inflammations of the 

 different segments of the alimentary canal, 

 there are only two to which we need accord 

 any notice, apart from the general description 

 as given above. These are, the gastritis pro- 

 duced by the ingestion of irritant (or rather 

 caustic) mineral poisons ; and the dysenteric 

 inflammation which affects the large intestine. 



In the acute gastritis caused by caustic 

 substances, the stomach presents appearances 

 of two kinds : one, which forms a series of 

 effects produced by the mere chemical action 

 of the poison on the tissue, and which might 

 therefore be to some extent imitated by in- 

 troducing it into the stomach of a newly killed 

 animal; and another, which represents the 

 subsequent vital reaction of the tissue against 

 the poison, constituting the phenomena of in- 

 flammation, properly so called. 



The first of these will of course vary, not 

 only with the nature of the poison, but also 

 with a variety of other circumstances ; es- 

 pecially with its quantity, concentration, and 

 solubility, as well as with the amount and 

 duration of its contact with the stomach. 

 Thus according to the nature of the poison, 

 the organ may either undergo softening and 

 solution, or hardening and coagulation ; may 

 either be blanched, or carbonized; coloured, 

 or deprived of its colour; swollen by an im- 

 bibition of fluid, or contracted by the loss of 

 its own water of composition. 



The second or inflammatory class of ap- 

 pearances will necessarily depend upon the ex- 

 tent in which the first preceded them ; since 

 it is chiefly in the tissue beneath the de- 

 stroyed part, that the reactive inflammation is 

 set up. Thus if the epithelium be the only 

 structure which has been acted upon by the 

 poison, it is soon replaced by the development 

 of a new layer in the exsudation poured out ; 

 a process which implies but a moderate hy- 

 pera3mia, and leaves no traces in the struc- 

 ture of the part. While, if the direct action 

 of the poison involve all the coats of the organ, 

 it may give rise to a more or less extensive 

 (and generally fatal) perforation. 



The intermediate degrees of this action are , 

 followed by a set of appearances which, with 

 great differences in particular poisons and in- 

 dividual cases, may be summed up as follows. 

 The vascular changes consist chiefly in the 

 production of an intense congestion or hyper- 

 aemia. The blood-vessels thus injected com- 

 municate to the mucous membrane a colour 

 which takes every conceivable shade, from in- 

 tense red to almost black. In the latter case, 

 the microscope will often show that the blood 

 is coagulated within the vessels, and here and 

 there forms patches of haemorrhage externally 

 to them. The exsudation which accom- 

 panies this congestion, renders the mucous 



