The mucous membrane of the duodenum and small intestine ap pears thickened in places, with injected portions alternating rather regularly with pale areas. The follicular apparatus appears involved to a varying extent, from slight swelling to marked infiltration of the solitary and grouped follicles. These at times show only projecting grayish yellow patches, or lenticular nodules, and at other times they show a grayish slate coloring or marked hyperternia, and are surrounded by a circle of vessels. These may present more or less deep ulcerations, which finally become confluent, and lead to the formation of an irregu lar ulcer, with a purulent or membranous base. I have had reproduced some microscopic preparations and photographs from the Gratz Children's Clinic showing these types.* In the Peyer's patches this inflammatory process is limited to infiltration, or occasionally hamorrhage, while necrosis with the resulting ulceration and confluence of these ulcers is found only in the solitary follicles of the large intestine. Where most niarked the process passes over without any sharp dividing line into the anatomical picture of infantile dysentery, which is caused by bacteria, and the boundary lines of which are. also shifting, as the most recent reports of Jehle demonstrate.
There are cases in which the pathologic changes in the large intes tine are to a certain extent characteristic, in that they occur with little or no involvement of the other divisions of the intestine. Consequently the establishing of the anatomical conception of colitis (enteritis follicularis) is to a certain extent justified.
The serosa is usually not involved, except that with intense in flammation of the solitary follicles with ulceration, the process can extend to the peritoneal covering. Also the mesentery shows at most only slight swelling and induration of its lymph-nodes, while its peritoneum remains unchanged.
The other organs are affected in a varying degree. The liver pre sents almost constantly a general enlargement. One finds at times a more marked extension of the process of fatty degeneration and infil tration already described in the cases of acute course., or else the tissue shows only here and there lighter spots, being otherwise of normal or darker color and harder consistency.
The same is true of the kidneys, which consequently give a clear impression of induration, and of the spleen, which usually shows chronic enlargement and induration.
When the .symptom-complex is clinically that of atrophy, which can form the starting point of various types of acute and chronic dis eases of nutrition, the cadaver presents the picture of marked emacia tion. The skull appears small, its bones overlapping, the face senile and shrunken, the lower jaw sunken, the neck thin and wrinkled. The.
skin of the extremities is loosely hanging. shrivelled. and entirely without fat, and is often the seat of various suppurative and ulcerative processes, while the skin of the abdomen in contrast to the general emaciation is tight like a drum. Small nodules shine through the greatly thinned skin of the anterior abdomen, which appear to be connected with thin bands of fibrous tissue. Opening; the skull causes a very slight effusion of thin pale blood. The meninges and the veins of the con
vexity appear thinner than nortnal, and almost empty of blood, and the brain substance itself appears dry and extremely pale. Infrequently, and as a rule only in infants whieh have died with the symptom-complex of atrophy in the first three months of life, are found suppurating processes in the meninges, cerebral substance, and the accessory cavities of the skull. This process when present in the brain substance, consists of multiple pus cavities irregularly scattered through the tissue, or else of diffuse htemorrhagic and purulent softening of the tissue.
The lungs are usually the seat of inflammation which presents itself at times as chronic purulent bronchitis, at times as lobular pneu monic areas, often becoming purulent or gangrenous, at times as a lobar infiltration, and which in the pleura presents itself as serofibrinous or purulent inflammation.
The intestines and stomach show notable distention, and a thin ning of the walls to such an extent that their contents are often visible. On the surface arc seen only a few scarcely filled vessels. The mucous membrane appears in places as thin as paper, in other places of normal thickness, but is always markedly pale and looks washed out.
The large abdominal glands show shrinking and increase in con sistency as a part of the general wasting, and only exceptionally show suppurating areas. On the other hand such areas are very commonly present in the subdermal cellular connective tissue, and appear in the form of abscesses which are localized sometimes in the superficial and sometimes in the deeper layers, and which contain thin greenish yellow pus. Also one finds not infrequently, especially in very young infants, ulcerations of varying extent, usually resulting from inflamed parts of the skin. They may occur in many places, as the back of the pelvis and heel, and may go as far as to lay bare the bone.
The histologic changes in the different types of acute and chronic diseases of nutrition may be treated as a whole, since they usually represent only different grades of intensity of the sante process, which localizes itself with special clearness at times in one kind of tissue, at other times in another. A change of opinion has taken place in the course of time which has replaced the original undervaluation of the importance of the histologic changes. Improved technique, and the observing of certain precautions has taught us certain sources of error, and made us more careful in judging and interpreting many findings. Among these precautions I must mention as of first impor tance, the examination of material either absolutely fresh, or obtained soon after death, and the taking into consideration of the stage of digestion at the time of death, and of the amount of contraction of the bowel. If we allow for all this, and proceed with the greatest pre cautions against drawing false conclusions, we must still admit that the microscopic changes form an integral element of the pathologic process, and help in the explanation of the individual phases of its clinical eourse. This I hope to be able to prove, by means of numerous histologic pic tures, for the niost part especially prepared for the purpose of this article.