OBSERVATIONS ON THE EPIDEMIOLOGY OF 
DYSENTERY IN JAPAN.! 
By K. Suiaa. 
(From the Imperial Institute for Infectious Diseases, Tokyo, Japan.) 
Before discussing my own work on dysentery I consider it to be advis- 
able to give a brief outline of the course of the epidemics of dysentery in 
Japan, for I believe that in no land other than our own has this disease 
taken such deep root or appeared with such destructive results. Dysen- 
tery for a long time has been prevalent in Japan, its beginning probably 
antedating the present time by hundreds of years, but reliable statistics 
are only available during the last three decades. 
The Japanese Empire extends from 21° 48’ to 50° 56’ north latitude, 
and following the geographical configuration the country is divided into 
seven provinces which, as a rule, are used as the units in statistical work. 
Therefore the southern portion of Japan is tropical or subtropical, whereas 
the northern part belongs to the cold zone. Ameebic dysentery occurs 
in Formosa, but, up to the present time, epidemic or bacillary dysentery 
has not with certainty been proven to exist in that island ; in the island 
group at the extreme north (Chishina) dysentery has not been observed 
at all. The mainland of Japan, on the other hand, is in the temperate 
zone, and it is exactly in this region that epidemic dysentery appears ; 
and therefore, for the purposes of this paper, only the mainland needs to 
be considered. This consists of four islands—Kiushu, Shikoku, Honshu, 
and Hokkaido; Honshu is again divided into the western, central, and 
northern provinces. The following table gives the degrees of latitude 
occupied by the regions in question: 
Kiushu: From about 31° to 33° 58’ north latitude. 
Skikoku: From about 32° 42’ to 34° 34’ north latitude. 
Honshu: Western province from about 33° 30’ to 35° 40’ north latitude. 
Central province from about 34° to 37° north latitude. 
Northern province from about 37° to 41° 38’ north latitude. 
Hokkaido: From about 41° 21’ to 45° 30’ north latitude. 
If we study the course of the epidemics of dysentery in these six 
divisions of Japan we encounter a very interesting picture. In the past 
‘Read before the third annual meeting of the Philippine Islands Medieal Assv- 
ciation at Manila, March 3, 1906. Translated from the German by 2.0. F. 
485 
