Now, here there are many things to be regarded; for man is a moral as well as a physical being; and the circumstances by which he is surrounded, even the air he breathes, the moral and physical impressions to which he is subjected, are very often not under his own control, much less that of his medical attendant. On the other hand, the food is, in civilized communities, very much under the influence of his volition; and there are many circumstances which, instead of impeding those adaptations which disorder requires, renders them particularly easy—it frequently happening that those things which are really best, are most easily procured. This is important; because the next proposition is, _that the nervous system is very easily and constantly disturbed by disorder of one or other, or of the whole of the digestive organs_, and that therefore the tranquillizing of disturbance in them is of the highest consequence in the treatment of disease: _few_ propositions in _any_ science are more susceptible of proof than the foregoing. But if this be so, we must now recollect the full force of what we have observed with regard to relation; that is, we must not restrict our notion of it to the general loose assent that there is a relation in all parts of the body, and rest on the simple admission, for example, that animals are formed in adaptation to their habits; but we must sustain the Cuvier-like impression of the fact, the Owen-like application of it to the phenomena; recollect that _preconceived_ ideas of magnitude and minuteness can do nothing but obscure or mislead; and that the relations established in the body are constant and universal, however they may at first—as in the case we have quoted—excite the surprise or the derision of the less informed and less reflecting. We must take their immensely potential power as existing _as certainly in the most trifling headache, as in the most malignant fever_—in the smallest scratch, _as in the most complicated compound fracture_. We have plenty of facts now to _prove_ this; but the first plain, clear enunciation of it all, the successful demonstration of it at the bedside, and the consequent diminution of an enormous amount of human suffering, is the great debt we owe to Abernethy. Mankind in general admitted that Diet was of consequence. Nobody doubted its force as an _accessory_ in treatment. Lactantius said: "Sis prudens ad victum sine quo cetera remedia frustra adhibentur." But no one had recognized the treatment of the Digestive Organs as the essential part of the treatment of _surgical_ diseases, nor founded it on the same comprehensive view of its relations as addressed to organs which executed the nutritive functions of the body on the one hand, and were the _most potential disturbers or tranquillizers of the nervous system on the other_, and thus for ever linked them in their practical relations with the fact, that the essential element of disease, the _fons et origo_, is disturbed nervous power.