relations, all the diseases found in the district, and as they affect, generally, all classes, or particular classes of the inhabitants; to trace their locality,—general and local causes,—relative degree of prevalence, as well in regard to the same diseases in other districts, as to other diseases in the same district,—particular forms, and, if modified, the causes of this modification,—modes of treatment, with particular reference to local modes, and the result; &c. &c.
In noticing the various diseases, it would, I conceived, be found most useful to arrange them in groups, having more relation to their etiological than to their pathological characters, with a view to attaining, what I stated, in the beginning of this paper, to be the great object of Medical Topography, viz. "the tracing the causes of diseases, with a view to their prevention." With this view, diseases might be very variously arranged. I had thought of some such order as the following:—
1. Epidemic diseases, divisible into two principal groups, viz. such as seem to depend on a specific contagion; and such as seem to originate in more general causes, whether of known or unknown nature.
2. Climatorial diseases, or such as seem to depend for their origin, degree of prevalence, or modification| of character, on the external influences more or less directly flowing from the peculiar nature of the climate, atmosphere, weather, &c.
3. Endemic diseases, also divisible into two principal groups, viz. such as seem to originate in natural or external causes, known or unknown, and
