transudation of its serum. They are often produced by the same exciting causes, and occur in very similar states of the system. Flux is very common amongst the natives of tropical countries, and often traceable to the debility resulting from long- continued attacks of intermittent fever. Doubtless, in these cases, it may be ascribed to an atonic condition of the vessels, and a thin or altered state of the blood.
Dropsy also is not uncommon in similar conditions, but is more frequently due to mechanical obstructions to the passage of the blood through the veins, as in valvular disease of the heart, cirrhosis of the liver, &c.
The details in connection with flux and dropsy will form a part of Special Pathology.
CHAPTER IV.
DERANGEMENTS IN THE CIRCULATION OF THE BLOOD (continued).
The derangements of the circulation w r hich have been hitherto considered, admitted of a clear and precise definition. But we have now to notice a condition, our acquaintance with which is imperfect, and which cannot therefore be satisfactorily denned. The definition given below is, perhaps, the least open to objection; but it must be clearly understood, that this may turn out to be incomplete or even incorrect.
INFLAMMATION; increased quantity of blood; movement in part accelerated in part retarded. There is no subject in the whole range of Pathology that has such important relations as inflammation. Few diseases of a serious nature are unconnected with it, either at their onset or in their progress, and still fewer terminate fatally in which the fatal result is not mainly due to it. Great, however, as is its influence for evil, inflammation has also its influence for good. It is the medium through which many injuries are repaired ; by it alone collections of pus in internal parts, or the contents of the hollow viscera, are prevented from being discharged into
