474 RABIES 



canal, and especially in that of the floor, hemorrhages, some- 

 times symmetrical, are often found. Microscopically, we often 

 find an obliteration or thrombosis of a vessel by a reticulated, 

 hyaline, pigmented material or by leucocytes or hyaline glob- 

 ules, and sometimes a hyaline degeneration or even inflamma- 

 tion of the vascular tunic. The extravasated blood also con- 

 tains much of the hyaline material . The hemorrhages are 

 often limited by the lymphatic sheath of the vessels. At the 

 same time the epithelium of the ventricles and central canal 

 may be partially lost. This last is occasionally filled with 

 blood or plugs, either granular or hyaline in character. 



3. " With the naked eye small centers of degeneration 

 may sometimes be noted in the gray matter, but often they 

 maj^ be sought for in vain. 



4. " The most constant lesions are microscopic in char- 

 ter : they are found more especially in the gray matter sur- 

 rounding the cerebro-spinal canal and in the motor centers of 

 the medulla and spinal cord. These lesions consist at first in 

 hypersemia and accumulations of embryonic cells around the 

 small vessels, perithelial or migratory in origin, often showing 

 indirect division ; finally there are also found lesions of nerve 

 cells. 



5. " The lesions of the nervous elements of the parts in- 

 dicated is quite characteristic ; it consists of signs of prolifera- 

 tion, namely, in the presence of several small cells in place of 

 one large one, or in a uniform degeneration and often in the 

 appearance of vacuoles with a reduction in size or disappear- 

 ance of the nucleus, or again, its chromatic network disap- 

 pears. These cells frequently contain pigment. Round uni- 

 nuclear, more rarely multinuclear, elements of a lymphatic 

 origin often invade the protoplasm even of the cell and fill out 

 the dilated pericellular lymphatic spaces by a multiplication ot 

 small nuclei. 



6. "The lesion of medullary substance is less pro- 

 nounced, it consists chiefly of an edema of the medullary 

 sheath of the nerve fibers. 



