IgO Tke Philippine Journal of Science 1920 
He is of the opinion that the virus of that particular epidemic 
which was successfully transmitted, and which reproduced 
lesions in monkeys, horses, and calf, may be a “mutant” of the 
virus that causes polyomyelitis and encephalitis lethargica. 
Bassoe,(4) of Chicago, described a series in which the engorge- 
ment and perivascular infiltration were more localized and 
pronounced at the midbrain. Flexner(5) also found consider- 
able involvement of the cord and brain. 
It is scarcely necessary to remark that the microscopical 
findings of these and other workers are similar to our observa- 
tions. 
I am sorry that I cannot orientate from what definite portions 
of the brain each section was cut, but we always take sections 
of the different portions, including that of the basal ganglia 
and the peduncle. 
It would seem then that, depending upon the portion of the 
brain or cord involved, the symptoms will vary and that the 
diagnosis will be a difficult matter clinically unless the disease 
appears in epidemic forms as it has lately done in other countries. 
Just to illustrate this diagnostic difficulty for the clinician 
and even for the pathologist at the autopsy table, I will cite 
that during the short period following the discovery of its 
presence here we examined in all eight cases with which the 
connection of the diagnosis of encephalitis lethargica has been 
made, either clinically, at the time of autopsy, or later on 
histological examination. 
The three cases here reported are included in these eight and, 
as you have heard, two of these three bore the clinical diagnosis 
of tuberculous meningitis, and one of the cerebral type of ma- 
laria. The first of the cases was diagnosed influenza at the 
table and subsequently found to be encephalitis on histological 
examination. The other two were diagnosed encephalitis with 
question mark, anatomically, but corroborated later micro- 
scopically. Three cases bore as one of the principal clinical 
diagnoses encephalitis lethargica, two of which turned out to 
be typhoid, and one tuberculous meningitis. Two of these were 
also provisionally diagnosed encephalitis anatomically, for pos- 
sible association with other conditions found, but resulted 
negative microscopically. 
Two others were diagnosed at the table probable encephalitis 
along with the other conditions present, on account of capillary 
congestion in the brain, but resulted negative histologically. 
