312 Proceedings of Royal Society of Edinburgh. [sess. 
The statistics showing the frequency of the disease are chiefly based 
upon the records which refer to Europeans in the tropics, but it also 
affects the natives of tropical places. 
There is no doubt that congestion of the liver in the tropics is 
brought about by heat and malaria, and that it most frequently 
occurs in the cold or rainy season. It is to a great extent 
caused by the great diurnal fluctuations of temperature, the days 
being very hot and the nights cold, but this is not the only cause. 
Malaria may, and probably does, predispose to tropical abscess of 
the liver, on account of the congestion of the liver caused by it, and 
yet the areas of distribution of the two diseases do not coincide. 
Alcohol is another cause of the disease in question ; this is shown 
by the fact that it occurs chiefly in Europeans, and in Europeans of 
the male sex; also that natives who ape European customs of drink- 
ing suffer severely, and that Mohammedans are very rarely affected. 
It was at one time very generally thought that dysentery was the 
great cause of tropical abscess, but this is not the case. The two 
diseases do occur together sometimes, and abscess of the liver may 
cause dysentery, but many things go to prove that dysentery is not 
the cause of abscess of the liver. In very many instances_pos£-mor£em 
examinations have revealed no intestinal lesion at all in the case of 
deaths from abscess of the liver. Dysentery occurs in temperate 
climates, but is not there followed by abscess of the liver, as 
would be the case were it the cause of that disease. Again, in the 
tropics women suffer very rarely from abscess of the liver, but are 
as liable to dysentery as men are. Dysentery is very common 
in Egypt, whereas abscess of the liver is of very rare occurrence 
there. Lastly, children are very frequently the victims of dysentery, 
but not of abscess of the liver. 
To what, then, is abscess of the liver due 1 To the action of 
excessive heat (and possibly too to the amount of moisture in the 
air), to chills caused by great diurnal fluctuations of temperature, 
and to the consumption of a too stimulating diet with regard to 
both food and drink. 
A few general remarks must bring this paper to a close. I have 
endeavoured as briefly as possible to call attention to the various 
physical phenomena which may influence the production or spread 
