Page:Acute Poliomyelitis.djvu/37

PATHOLOGICAL ANATOMY 25 C. Medulla Oblongata and Pons. — Changes in the medulla ob- longata have hitherto been found in every fatal case of Heine- Medin's disease in which they have been sought and in which death was not due to an intercurrent malady. The nature of the lesions here, as was first shown by Rissler, is identical with that found in the spinal cord. Wickman, however, has pointed out that the findings in the spinal cord differ regularly from the findings in the bulb ; that in the bulb, the degenerative are less marked than the infiltrative changes; the lesions tend to be disseminated; and no preponderating localization in the motor areas — such as is seen in the spinal cord — occurs. The most intense changes in the bulb appear often apart from the nerve nuclei, in the substantia reticu- laris tegmenti. Exudates are visible in the most diverse areas ; e. g., in the cranial nerve nuclei of the olive; in the nuclei of the columns of Goll and Burdach ; in the nucleus pyramidalis ; in the substantia nigra ; in the central gray matter in the neighborhood of the aqueduct of Sylvius ; in the anterior and posterior corpora quadrigemina ; in the raphe; and elsewhere. Forssner and Sjo- vall, Harbitz and Scheel, Strauss, J. Hoffmann, and others subse- quently corroborated these observations.

In the gray matter, morbid changes are conspicuous in the larger vessels running beneath the floor of the ventricle. The tissue infiltration has an inconstant relation to the nerve nuclei. Sometimes the round cells congregate about the nuclei ; sometimes they are grouped in the vicinity of and only slightly encroach upon the nuclei ; and sometimes they leave the nuclei wholly untouched. Occasionally, a densely infiltrated vessel may be seen wandering through an otherwise intact nucleus ; or almost the whole cross section of a nucleus may be normal and free from infiltrating cells except in one part where an exudate accompanies a vessel.

In general, the alterations of the ganglion cells are slight and are mainly chromatolytic. Where interstitial changes are absent the ganglion cells always appear normal, even when stained by toluidin blue. This may often be observed in the immediate neighborhood of infiltrated vessels, and, also, in places where infiltrations are not intense (Plate II, Fig. 7). Usually the more evident the infiltration the more do the ganglion cells suffer. But it is remarkable how exceptionally well preserved the ganglion cells