We are unwilling to dismiss this paper without directing attention to the illustration it affords of the erroneous views of those who imagine that Abernethy's investigations were confined to the digestive organs, and still less, of course, to one of them (the stomach). It would, on the contrary, be difficult to find any paper on physiology so comprehensive in its views, so simple and clear as to its object, so cautious and logical in its reasonings, so free from any bias, or with so little reference, either directly or indirectly, to what are usually understood by the digestive organs. On the other hand, it is an investigation which (as regards the relation which exists between two organs having a common function) is an exact type of what physiological investigation should be. For we have only to extend the idea of a relation which exists between _two_ organs, to those which exist between _all_ organs; to regard as their _combined_ functions, the sustentation of the life and health of the individual, just as we have been regarding respiration, the common function of the skin and lungs; and we thus arrive at what must be the basis of any sound or comprehensive inquiry into the true relations of the various parts of the economy; by which alone we can interpret the phenomena of health and disease. Moreover—however presumptuous the assertion may appear on the one hand, or however humiliating the view it implies of the present state of medicine as a science on the other—we must regard this investigation, in every philosophical sense of the term, as still among the "means untried" of the illustrious author whose words we have ventured to place at the head of this chapter. [Footnote 19: This statement does not hold in regard to Entozoa (animals living in the bodies of others), or at all events is not proved.] [Footnote 20: The test for carbonic acid.] [Footnote 21: A test for the presence of oxygen.] [Footnote 22: It is in this paper that he uses the significant expression "ventilating the blood," which looks as if the refrigerating effect of respiration—and which we have endeavoured to show is the real, though perhaps not sole, purpose of it—had not wholly escaped his notice.] CHAPTER IX. HIS PAPER ON TIC DOLOREUX. "Quis talia fando Temperet a lachrymis." VIRGIL.