With respect to any influences immediately directed to the nervous system, these we apprehend to be few and simple; some kinds of medicine, are, no doubt, in particular cases useful, none are susceptible of _general_ application. None of them are _certain_; and sedatives of all kinds, which appear to have the most direct influence on the nervous system, either require to be employed with the utmost caution, or are in the highest degree objectionable. But there are other _direct_ influences, certainly; and very important they are. Quiet, avoidance of disturbing external impressions, whether of light, sound, temperature, &c. whether in fact of mind or body; but, in the majority of mankind, how few of them we can, in a strictly philosophical sense, command. We are therefore driven to other sources of disturbance; and in the digestive organs we find those on which we can exert great influence, and in which tranquillity, however procured or under whatever circumstances, is _certain_, _pro tanto_, to relieve the whole system. This Abernethy attempted, and with a success which was remarkable in no cases more than those which had resisted all more ordinary modes of proceeding; by general measures, by simplicity of diet, by occasional solicitation of this or that organ, by air and exercise, and measures which were directed to the general health. No doubt in some cases he failed, and so we shall in many; but let us look boldly at the cause, and see whether we do not fail a great deal more from our own ignorance than from any natural impossibility. To examine the question, we must for the moment forget our admiration of Abernethy; be no longer dazzled by his genius, but look only to our duty; endeavour to discover his defects, or rather those of the state of the question when he left us, and see what further investigation has afforded in aid of supplying them. In the first place, we must examine a little further that proposition which we have seen both in Hunter and Abernethy under different forms. Hunter says the disturbance of the organ sympathizing is sometimes more prominent than that of the organ with which it sympathizes. Abernethy says that the organ primarily affected is sometimes very little apparently disturbed, or not even perceptibly so.