17,1 De Leon: Encephalitis Lethargica 129 
slight epithelial desquamation with intratubular and inter- 
tubular hemorrhages, with enlargement of the alveoli, distension 
of the capsular space with serum, injection of the tuft, and 
slight mononuclear infiltration. Pancreas, spleen, and liver 
showed the same high degree of injection with widening of the 
sinusoids of the latter and slight degeneration of the paren- 
chyma. 
It is evident from the protocols of these three cases that the 
predominant picture in the pathology of this disease as rep- 
resented by these cases is, essentially, marked visceral congestion 
and, histologically, minute capillary engorgement and hemor- 
rhages of the brain and cord with distinct perivascular 
infiltration of small lymphocytes and occasionally some large 
mononuclears. In one of these cases there is, histologically, 
bronchopneumonia secondary to bronchitis, probably terminal 
in character, which does not much influence the clinical course 
of the disease, as it was not even noted on physical examination 
and in the clinical diagnosis. These vascular lesions may af- 
fect the whole extent of the nervous system or may localize and 
predominate in any portion of the brain or in the cord; for 
example, in the third case there is involvement both of the 
brain and of the cord simultaneously, with apparently the same 
intensity. The first, while affecting both structures, showed 
more profound changes in the brain. The second case, how- 
ever, did not extend to the cord and, due to the fact that many 
of the brain sections in this case were negative, the lesions 
must have been only localized in a certain region, apparently 
in the region of the basal ganglia. In this connection it may 
be interesting to analyze some of the reports of other workers 
in different portions of the world. 
Wegeforthy and Ayer(1) noted slight evidences in the cord 
of the cases they examined, but laid emphasis upon histological 
findings in sections of the brain; and Breinl,(2) of Australia, 
noting symptoms mostly referable to, and the pathological 
changes being mainly in, the cord, calls this mysterious disease 
“a clinically atypical form of Polyomyelitis.” 
On the other hand, Cleland,(3) also working in Australia, 
in his studies of an epidemic with marked cerebrospinal symp- 
toms found the lesions much like those of cases 1 and 3, in 
which the brain and spinal cord were both heavily involved, 
and designated the disease “Epidemic Acute Encephalomyelitis.” 
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