Page:Acute Poliomyelitis.djvu/22

14 in the kidneys. Rarely, subpericardial and subpleural hemorrhages have been observed, which may, in part at least, have arisen from terminal respiratory conditions. More often, a hyperplasia of the lymphoid tissue of, the intestines occurs. Rissler was the first to describe the enlargement of Peyer's patches and of the solitary follicles. It is doubtful, whether this lymphoid reaction is due to a local or to a general action of the virus. Beneke observed moderate enlargement of the tonsils with suppuration.

But the important and essential characteristics of the disease are the changes in the central nervous system.

The cerebrospinal fluid was found always clear and often increased. The only noteworthy change in the pia mater was hyperemia. No cellular exudate was ever noticed, in spite of the fact that microscopic investigation showed implication of the pia mater. Rissler reports two cases of hyperemia of the dura, also, with hemorrhages upon its external surface.

The changes in the spinal cord are usually obvious to the unaided experienced eye. If they are at all marked, the cut surface protrudes, the gray substance is hyperemic, either as a whole, when it appears as a red H, or only in circumscribed areas, especially in the anterior horns. Besides this diffuse coloring, generally, tiny blood specks and streaks also are perceptible; they resemble capillary hemorrhages and have been so reported. But in most of the cases they are actually only vessels distended with blood. As mentioned already, these macroscopical changes are most marked in the anterior horns, especially in the protuberances; but they occur also in the posterior horns and occasionally in the posterior horns alone (Monckeberg). In the white matter usually edema and occasionally vascular distention are seen. The edema may be so great as to appear to the naked eye like a general softening of the cord. (Harbitz and Scheel report areas of softening of the spinal cord.) But on microscopical examination no "softening" in the ordinary acceptance of the term can be detected (Wickman). In certain cases, the cord seems practically normal to the unaided eye, but microscopic examination invariably reveals the presence of morbid changes (Rissler).

In fatal cases edema and hyperemia are found in sections at higher levels of the central nervous system. These changes may be so marked in the brain as to render the dura tense and the con-