MORBID ANATOMY 



473 



is taken of the conflicting results and opinions held by those 

 who have already investigated this field. It also, appears that 

 some portions of the nervous system may exhibit lesions of a 

 pronounced character, other portions very slightly, and still 

 others none at all, thus presenting additional difficulties. 



One of the most common lesions that has been observed is 

 of an inflammatory character, the congested blood vessels fre- 

 quently showing diapedesis and, according to some, a perivas- 

 cular exudation of a granular or a hyaline substance. Hypere- 

 mia and lymph-stasis, although of not so much significance 

 when taken bj' themselves, have been taken into consideration 

 along with other changes. The blood vessels quite as much 

 or even more than the nerve structures have been noted as 

 the focus of some of the most marked changes, among which 

 are the proliferation of the epithelial cells and of the connect- 

 ive tissue elements of the outer coat, with the infiltration of 

 lymphoid cells. Such lesions maj^ be nodular primarily, but 

 later become diffuse. The inflammatory process may progress 

 to such an extent as to obliterate certain vessels. 



Pathological miliary centers have been noted not only in 

 the axial portions of the nervous system, but in the gray 

 matter as well. These centers were formed by lymph cells 

 which accumulate notably around the blood vessels (perivas- 

 cular) and the nerve cells (pericellular) as well. The lesions, 

 when present, are observed most frequently in the motor 

 centers of the oblongata and spinal cord. 



The following observations were made by Babes, in 1887 : 



1. "In animals dead from street rabies there are found 

 usually a hyperoemia and an acute generalized oedema of the 

 cerebral meninges, acute hemorrhages localized around certain 

 vessels, as well as inflammatory lesions. On microscope exam- 

 inations we find an increase of the plasma cells, augmentation 

 of the reticular substance, fibrinous in character, between the 

 several layers of the meninges. 



2. " The epithelium of the cerebro- spinal central canal 

 has proliferated. In the gray matter which surrounds the 



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