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558 spherical indurations, about the size of a pin's head and surrounded by a dark pigmented or congested areola, can be felt in the mucous membrane. On cutting into these, they are found to be minute cystlike dilatations of the follicles filled with a gummy, muco-purulent material. Sections of the diseased bowel (Fig. 83) show under the microscope corresponding changes, such as varying degrees of erosion or ulceration of the surface of the mucous membrane; degeneration of villi, glands, and; follicles; the small mucous cysts referred to; sometimes small abscesses; and, also, infiltration by leucocytes of the basement membrane and submucous layer; and, in the latter, fibro-cirrhotic changes. The mesenteric glands are generally large and pigmented, perhaps fibrotic. The erosion lesions are usually most marked towards the end of the ileum and in the colon; but they may be present in greater or lesser degree universally, or in patches throughout the entire alimentary tract from mouth to anus.

Pathology.— In attempting an explanation of the phenomena of sprue, two features of the disease have to be considered— the catarrhal condition of the alimentary canal, and the absence of the normal colouring matter of the fæces. Possibly one of these is the consequence of the other; possibly the two conditions are concurrent but independent consequences of the same cause. What that cause may be is quite unknown. Whether the first pathological step originates in physiological exhaustion of the digestive functions, brought about by tropical conditions; or whether the disease depends upon a specific organism; or whether there is a combination of these, has still to be settled. In view of the occurrence of morning diarrhœa of dark bilious stools as a frequent first step in the development of sprue, hyperactivity of the liver might be assumed to be a first step in the development of the disease, an activity which in time ends in exhaustion of the chologenic functions of the gland. It might be further suggested that concurrently with this hepatic disturbance there is a similar initial hyperactivity of all the other glands