297 
1888 - 89 .] Dr R. W. Felkin on Tropical Diseases. 
endemic in some parts of Guyenne and Provence, in Lyonaise and 
Auvergne, in a few valleys of the Yosges, in the marshy districts of 
the Rrenne, and in Sologne and Guer. In Sweden it is probably 
endemic at Jonkoping, Skaraborg, Elfsborg, Wermland, Goteborg, 
and Bohus, and in the island of Gottland. In Russia it casually 
occurs in the Baltic Provinces, hut more especially in Trans-Cau- 
casia. 
Remarks . — That endemic dysentery is due to some microbe, there 
can be little or no doubt ; at least the researches of Prior and 
Cartullis almost definitely prove it. It is, however, difficult to say 
with exactitude what gives rise to the morbific microbe. Although, 
as above stated, endemic dysentery occupies very nearly the same 
geographical distribution as malaria, yet it has some points of 
difference. For instance, its endemic spread can proceed to far 
higher latitudes than does malaria. 
Various facts prove that the disease is influenced by climate, 
for it is endemic at all seasons in hot tropical regions, and it 
is also found that in more temperate latitudes outbursts of the 
disease occur chiefly, one might almost say solely, during the 
late summer and early autumn season. Extreme cold puts an end 
to epidemic dysentery just as it does to yellow fever. All this 
shows that heat is necessary for its production. But, again, we find 
that fluctuations in temperature exert a marked influence in its pro- 
duction and spread. "Where hot days and cold nights obtain in 
tropical regions dysentery is most prevalent. This fact has been 
observed again and again in various wars, as, for instance, in 
Ashantee, Abyssinia, China, and more recently still in the Soudan. 
In Sweden the disease rarely attains any considerable epidemic 
diffusion, unless the summer has been remarkable for great heat ; 
and even the severe epidemics confined to limited portions of the 
country mostly coincide -with extremely hot summer weather. It 
is difficult to decide what influence the moisture in the atmosphere 
has upon the production of dysentery, as authorities differ very 
much on this point, but we cannot help believing that moisture does 
play a part in either the production of the disease or in predispos- 
ing persons to suffer from it, and that marshy districts and the 
neighbourhood of large rivers where morning fogs are of frequent 
occurrence, are certainly injurious, even if the moisture itself does 
