269 



INTESTINES. 



INULA. 



270 



small molecules or drops of the same kind as those which were at 

 first developed secondarily in the cells. On the other hand, at a 

 subsequent period, we not uncommonly meet in the interior of the 

 villi with large round drops, which appear especially inclined to 

 form considerable accumulations at their apex. In man the process 

 is probably the same as in animals. These observations demonstrate 

 that fatty matters are absorbed as such, and are not saponified ; on the 

 other hand, it cannot at present be certainly stated how it is possible 

 that they penetrate the membrane of the epithelial cells, the 

 parenchyma of the villi, and the walls of the lacteals. 



The whole process may be compared to the imbibition of an emul- 

 sive fluid, such as milk, by a porous body ; and the fatty molecules 

 of the chyme are probably absorbed simply in consequence of their 

 being carried along with its fluid part. While digestion is going, on, 

 we frequently find the whole parenchyma of the villi densely tilled 

 with small nuclei, here and there surrounded by cell-membranes 

 elements which are never entirely absent in a villus, but are at other 

 times far fewer, and particularly are not to be distinguished in its 

 interior. 



The small intestines contain two kinds of true glands ; 1, tubular 

 glands, which are disposed over the whole mucous membrane ; 2, 

 racemose glands, in the submucous tissue of the duodenum. 



The Hacemose Glands, or as they are commonly named, after their 

 discoverer, Brunner's Glands, form, at the commencement of the duo- 

 denum, upon the outer side of the mucous membrane, a continuous 

 layer, which is best developed and thickest close to tbe pylorus, where 

 it constitutes a considerable glandular ring, and extends about as 

 far as the aperture of the biliary ducts. If the two layers of the 

 muscular tissue be dissected off a stretched or distended duodenum, 

 the glands may readily be recognised as yellowish flattened bodies of 

 fa'" IJ"' (on the average \"' J'"), with their angles rounded off, which 

 inclosed within a little connective tissue, lie close to the mucous mem- 

 brane, and send short excretory ducts into it. In their minute 

 structure, Brunner's glands, the terminal vesicles of which measure 

 0-03'" 0'06'", even 0'08"', agree perfectly with the racemose glands of 

 the mouth and oesophagus. Their secretion is an alkaline mucus, in 

 which no formed elements are contained, having no digestive action 

 upon coagulated protein compounds, and probably merely subservient 

 to mechanical ends. 



The Tubular, or Lieberkuhnian Glands (crypUe mucosae), are dis- 

 tributed over the whole small intestines including the duodedum as 

 innumerable straight narrow caeca, which occupy the entire thickness 

 of the mucous membrane, and are frequently slightly enlarged at their 

 extremities, though hardly ever dichotomously divided. The best 

 idea of their number is obtained by viewing the mucous membrane 

 either from above or in vertical section, under a low power. In the 

 latter case we see the cccca standing close together, almost like 

 palisades ; in the former we observe that the glands do not occupy 

 the whole surface, but only the interspace between the villi ; here 

 however they exist in such numbers as to leave no intervals of any 

 width, the mucous surface between the villi appearing pierced like a 

 sieve. Even on Peyer's patches, and over the solitary follicles, these 

 glands are to be met with ; but in man they leave those portions ol 

 the mucous membrane which lie immediately over the centre of the 

 follicles free, and therefore are arranged like wings around the 

 follicles. 



The length of the Lieberkuhnian glands equals the thickness of the 

 mucous membrane and varies from \'" }"'; their breadth is 0'028"' 

 :"', that of thx-ir aperture, 02'" 0'03'". They are composed oi 

 a delicate homogeneous membrana propria, and of a cylindrical 

 rpithelium, which even during cbylification never, like that of the 

 intestine, contains fat ; their cavity is filled during life by a clear fluid 

 secretion, the so-called intestinal juice, which however becomes 

 rapidly changed after death, or on the addition of water, so that the 

 glands appear to be filled with cells, or with a granular mass. 



The most important of the Closed Follicles are Peyer's patches 

 (glanduUu agmiuatie). They are rounded flattened organs, invariably 

 situated along that surface of the intestine which is opposite the 

 mesentery ; they are most distinct upon the inner surface, where they 

 appear as rather depressed smooth spots, without any very sharp 

 detinitioii, but they are also recognisable from the exterior by the 

 slight elevation to which they give rise ; by transmitted light they 

 look like mere opaque portions of the membrane. These patches are 

 usually the most abundant in the ileum, but they are not uncommonly 

 to be met with in the lower part of the jejunum ; occasionally they 

 exist in the upper portion close to the duodenum, and even in the 

 inferior horizontal portion of the duodenum itself. Ordinarily there 

 are 20 to 30 of them ; but when they are found higher up there may 

 be as many as 50 to CO ; but they are always most closely set in the 

 lowest portion of the ileum. The dimensions of the separate patches 

 are in general the larger the closer they are to the caecum ; their 

 length is usually 6"' 1J", but may diminish to 3'", and increase to 

 3"' 5'", or even 1'; their breadth varies from 3"' to 5'", or 9'" 

 Where the patches lie the valvulae conuiventes are usually interrupted 

 in the jejunum however these folds are also to be met with upon th< 

 Peyer's patches and in the ileum ; rows of closely-set villi often take 

 their place. More minutely examined, every Peyer's patch is seen to 

 be an aggregation of closed follicle* of $"' i'" 1"' iu diameter, either 



rounded or slightly conical towards the intestinal cavity, which lie 

 lartly in the mucous membrane itself, partly in the submucous 

 issue; and are on the one side not more than 0'02'" 0'03"' distant 

 Vom the mucous surface, while on the other they are in immediate 

 contact with the muscular tunic, which is here somewhat more closely 

 united with the mucous membrane. 



Viewed from the interior of the intestine their most striking feature 

 n man is the presence of many small rounded depressions "' '" 1'" 

 apart, which corresponds with the separate follicles, and whose floor 

 s indeed rendered slightly convex by the latter, but which present 

 no villi whatever. The remainder of the patch is occupied by com- 

 mon villi, or by reticulated folds, and by the apertures of the 

 L.ieberkuhnian glands; the latter are disposed around the slight 

 elevations produced by the follicles in circlets of 6 to 10 and more 

 apertures, the coronoe tubulorum of authors. 



The Solitary Follicles (glandules solitaria;) resemble the separate 

 elements of Peyer's patches so closely in size, contents, and general 

 structure, that thero is no reason for considering them as distinct, 

 particularly as the number of follicles is subject to all possible , 

 varieties, and since, in animals at least, we find Peyer's patches with 

 2 3 5 follicles. In man, as all writers justly agree, their number is 

 exceedingly inconstant ; sometimes not one can be found, whilst in 

 other cases the whole intestines, as far as the margins of the ileoccecal 

 valve, is thickly beset with them ; or, lastly, they may occur in the 

 ileum and jejunum, but in no very great number. Their entire 

 absence must probably be considered abnormal, since they are con- 

 stant in newly-born children, being more abundant in the jejunum 

 than in the ileum. The miliary vesicles however, which are often met 

 with in immense quantities in the small intestines and stomach in 

 catarrhal affections of the alimentary tract, may very probably be 

 entirely or partially pathological, since the occurrence of such follicles 

 has been demonstrated in other organs also (iu the liver, according 

 to Vorhow). The solitary follicles have the same structure as the 

 elements of the patches, only they occur also in the inesenteric border, 

 and support villi upon their intestinal surface, which is usually 

 somewhat convex. 



Professor Kulliker expresses himself as decidedly opposed to the 

 notion that the follicles of Peyer's patches have any apertures. Of 

 their functions he says : " They and the follicles of the intestine in 

 general appear to me to be closed glandular organs, analogous to the 

 splenic follicles, the tonsils, and the lymphatic glands, which contain 

 peculiar elements and a vascular network. In these a constant 

 development of cells takes place, and at the same time substances are 

 elaborated from the plasma, supplied by the bloodvessels, and perhaps 

 also from matters not of a fatty nature, absorbed from the intestine, 

 a part of which in all probability is at once taken up by the internal 

 bloodvessels, whila the larger proportion is excreted, and absorbed by 

 the lymphatics." 



The structure of the mucous membrane of the large intestines 

 agrees so closely with that of the small intestines, that it need not be 

 described separately. With the exception of the rectum it has no 

 proper folds, for the transversely fibrous muscular layer also enters 

 into the plicae sigmoidese. The villi are absent from the edge of the 

 ileocoocal valve. The glandular organs are Lieberkiihn's glands ar.J 

 solitary follicles. The latter are arranged close together iu the pro- 

 cessus vermicularis, aud are very frequent in the rectum and coocum, 

 and are also usually more abundant in the colon than iu the small 

 intestines. [DIGESTION ; FOOD ; STOMACH ; BILE ; LIVER.] 



INTESTINES, SMALL. [INTESTINES.] 



INTBICA'RIA, a small Polypifer from the Oolitic rocks of France, 

 allied to Cellaria. 



INULA, a genus of Plants belonging to the natural order Composite 

 and the sub-order Asteracete. It has a many-flowered heterogamous 

 head. Florets of the ray female in one row, sometimes by abortion 

 sterile, usually ligulate, sometimes somewhat tubular and trifid ; 

 those of the disc hemaphrodite, tubular, 5-toothed ; involucre 

 imbricated iu several rows ; receptacle flat or somewhat convex, naked ; 

 anthers with 2 seta; at the base; achenium without a beak, 

 tapering, or in /. llelmiutn 4-cornered ; pappus uniform in ons row, 

 composed of capillary roughish seta;. 



/. IfeUniwn, Elecampane, is found in pastures in various parts of 

 Europe. It is a native of Great Britain. It has a thick branching 

 root, which is aromatic, bitter, and mucilaginous. The stem is 3 feet 

 high, leafy, round, furrowed, solid, branched, and most downy in the 

 upper part. The leaves are large, ovate, serrated, and veiny ; downy 

 aud hoary at the back, radical, 1-stalked ; the rest sessile, clasping 

 the stem. Flower-heads solitary at the downy summits of the 

 branches, 2 inches broad, of a bright yellow colour ; the scales of 

 the involucre broad, recurved, leafy, finely downy on both sides; rays 

 very numerous, long, and narrow, each terminating in three unequal 

 teeth ; achenia quadrangular, smooth ; pappus roughish ; receptacle 

 reticulated, not quite smooth or naked. Various preparations of the 

 boiled root have been recommended mixed with sugar to promote 

 expectoration and to strengthen the stomach. Some think a spirituous 

 extract contains most of its aromatic and tonic properties. The 

 plaut is generally contained in rustic gardens on account of its many 

 reputed virtues. JnuUn, the peculiar property contained in the root, 

 is a white powder, like starch, is insoluble in cold, and soluble iu hot 



