A Typical Case of Tubercular Meningitis. 185 



and without the blood-vessels proper, the latter are encroached 

 upon by the cell accumulation, and their caliber is more or less 

 diminished. Moreover, the tubercular masses are generally 

 deposited in bead-like nodules, or spindle shaped growths; 

 hence, the blood-vessels are alternately contracted and dilated, 

 the contraction always occurring opposite the points of tuber- 

 cular deposit. Moreover, during the progress of the disease, 

 the external coat of the implicated vessels undergoes inflam- 

 matory hypertrophy and subsequent contraction, and this pro- 

 cess also aids in the production of the changes in the blood-ves- 

 sels. It is very common to find the tubercular nodules at points 

 where afferent vessels subdivide; in such cases, the distal 

 branches usually present a withered or shriveled appearance, 

 and sometimes they are quite obliterated (Fig. i). 



{b) Transudation of serum. This is probably mainly due 

 to a mechanical cause, namely, the retardation of the blood- 

 stream, in consequence of tubercular deposit around the blood- 

 vessels. Everybody knows that an obstructed circulation is more 

 than likely to produce transudation. In the case upon which 

 this article is based, the lateral ventricles were distended with 

 fluid, and some fluid was found beneath the arachnoid. But it 

 is certain that some portion of the escaped fluid was inflamma- 

 tory exudation, since flakes of lymph were floating therein, and 

 the microscope demonstrated that the fluid contained multi- 

 tudes of leucocytes. Whether these leucocytes migrated from 

 the blood-vessels proper, or from the lymph-channels, is an 

 open question; and it is a question which concerns the source 

 of wandering leucocytes, in other locations than the one now 

 under consideration. 



(r) Softening of the brain substance. This is the conse- 

 quence of mal-nutrition, and is the inevitable result of the di- 

 minished caliber of the afferent blood-vessels above noted. It 

 is simply a process of local starvation, and proceeds rapidly or 

 slowly as the vascular changes proceed rapidly or slowly. It 

 is not peculiar to tubercular meningitis, but takes places when- 

 ever the nutrition of the brain is interrupted. 



Woman's Hospital Medical College, 

 Chicago, 111. 



