The comparison of the character, progress, and duration of the diseases in those cases from which these observations were derived (so far as the records extended), with the character, progress, and duration of the cases of malarial fever observed and recorded by ourselves, and the comparison of the results of the chemical examination of the blood in various diseases (allowing due weight to the different methods employed by different observers) with the results of our chemical examination of the blood in malarial fever, have forced upon my mind the conclusion that, so far as these observations extend, the colored blood-corpuscles are more uniformly and rapidly destroyed in severe cases of malarial fever than in any other acute disease.

We would state, distinctly and unequivocally, that this statement applies only to those results of investigation which are now before the profession.

This department of pathological chemistry may, with truth, be said to be in the imperfect and undeveloped state of the embryo. We know little or nothing definitely concerning the changes of the blood in yellow fever, and in the states induced by numerous poisons; and our knowledge, in almost every instance, extends no further than the destruction, or undefined alteration, of one or the other constituent, and does not penetrate beyond the exterior physical and chemical changes, and reveal the relations of the substances destroyed or altered to the poisons, or substances resulting from the action of the poisons.

When not merely the facts of the destruction or alteration of the constituents of the blood in all diseases have been determined, but also the causes of their destruction and alterations, and the methods and results, chemical, physical, physiological, and pathological, have been definitely determined; then, and not till then, will it be possible to draw broad lines of distinction between diseases, based upon the chemical, and physical, and physiological, and pathological alterations of the blood. Nevertheless, the first step in the right direction is to perceive and appreciate the extent and bearing of the established facts, even though they be imperfect, and superficial, and meagre.

In comparing these results, it should be remembered that the individuals whose blood I examined were, as a general rule, stout, athletic seamen and laborers, who had never before been attacked by the malarial fever, and who had been exposed but a short time to the malarial poison.