I04 
PATHOLOGY: S. FLEXNER 
Proc. N. a. S- 
Because of the accompanying paralysis and subsequently because of 
certain peculiar characteristics of the histological changes in the brain, a 
discussion arose whether th^ disease was not merely a peculiar form of 
poliomyelitis or infantile paralysis, which has prevailed epidemically and 
fitfully in Europe and America for a decade or longer. 
It is on this last point that I wish to make a few remarks. At the Rocke- 
feller Institute we have had what may be regarded as a wide experience 
with poliomyelitis during ten or twelve years; and since the winter of 1919 
and up to the present time we have had referred to us material from num- 
bers of cases of the form of encephalitis we are considering. 
On the basis of the studies we have carried out with the latter, it is quite 
safe to say that the diseases — lethargic or epidemic encephalitis and epi- 
demic poliomyelitis — are distinct. A striking difference relates to the 
transmissibility of the one to lower animals (monkeys) and not of the other. 
No special difficulty is encountered in communicating poliomyelitis from 
man to monkey; we have not succeeded in transferring the encephalitis 
to animals. Moreover, the actual histological changes or lesions in the 
two diseases show striking differences, both of distribution in the central 
nervous organs and in minute structure. Lethargic encephalitis is surely 
an infectious disease, but its inciting microbe is still undiscovered. 
The question arises whether encephalitis has been observed before, 
or is to be considered as being a new disease, in the sense that it had never 
before been recognized and described. In this connection it may be said 
that a brief account exists of an outbreak of a so-called "sleeping sickness" 
in the neighborhood of Tubingen in Germany in the year 1712; and what 
appears to be a similar malady more widely distributed in Austria, Italy, 
and Switzerland in 1890. There is a certain amount of mystery attached 
to the latter outbreak, partly because of the odd name "nona" it received, 
which has not been satisfactorily traced etymologically. It has been sug- 
gested that the term is a mere corruption of "coma," and partly because 
the chief accounts of it are given in the lay rather than the medical press 
of the time. 
It is, however, of some significance that the first appearance of the 
present epidemic and the location of the 1890 outbreak coincide terri- 
torially. It is, of course, not absolutely possible to state that the disease 
originated this time in Vienna ; under war conditions its occurrence in out- 
lying rural districts might well have been overlooked. But there is never- 
theless basis for the view that I shall propose tentatively, namely, that an 
endemic focus of a peculiar and specific form of encephalitis exists in South- 
eastern Europe, from which the present wide occurrence of the disease took 
origin. Should this view come to be established, we shall have learned of a 
new and previously unsuspected focus of an endemic-epidemic disease of 
world importance. 
