We distinguish between the so-called organic ileus, into the nature of which we have inquired in preceding paragraphs, and dynamic or spontaneous ileus. The latter deserves a careful investigation of its cadaveric relations, the more so as a sound theory of its nature, based upon practical experience, is very much wanted.

Ileus is a rare occurrence, and undoubtedly often dependent upon atony of an intestinal segment, which must be viewed as the proximate cause, in contradistinction to the case just examined, in which the accumulation of foreign matter is the primary affection. It takes its origin in a sedentary mode of life, in depressing physical conditions, repletion, superstimulation by purgatives and injections, rheumatic affection of the intestine, diseases of the spinal cord, and even of the brain. The colon is the part almost invariably affected. Stagnation and accumulation of the faeces in the affected portion of intestine follow, dilatation is induced, and the atony ends in paralysis; when this happens, ileus is at hand. Its actual occurrence, however, as well as the improvement and cure of the affection, depend upon the state of innervation in the upper healthy portions of intestine. If the action of these portions suffices to propel the faeces through the dilated segment, and thus from to time to empty it, the latter may resume its functions, and thus return to a healthy condition. If, however, the upper portion of the intestine does not possess sufficient power, which will be the case if the accumulation be excessive, or the paralyzed segment has sunk to a lower region of the abdomen, the accumulation will proceed, and at last reach up to the healthy intestine. Here the peristaltic action is reversed, the faeces are thrown back into the stomach, and are expelled from there by vomiting.

When the paralysis has reached a ^certain point, inflammation and sloughing set in, and enteritis peritonealis results. As this induces paralysis of the muscular coat and passive dilatation in the upper portion of the intestine, a change occurs in the ileus, inasmuch as the point at which it commences advances with the advance of the inflammation.

All pathologists of distinction deny the possibility of spasmodic contraction or spasmodic stricture in a portion of the intestine, being the cause of obstinate constipation or of ileus. The modus operandi of the various remedial agents employed fully confirms the theory given with regard to this simple form of ileus. The benefit derived from purgatives is to be explained by the force with which the healthy intestine propels the faeces downwards, and the rapidity with which they pass through the distended portion; the advantage of opiates consists in diminishing the activity of the healthy portion, and the consequent accumulation in the dilated part, and in allowing the latter time to recover its activity.

It is highly probable that the use of narcotic enemata of tobacco or belladonna, effects an evacuation of the dilated portion, by inducing a complete relaxation in the inferior portion of intestine, which is thus enabled to admit and convey onwards the accumulated fasces. If the injected fluid can be propelled as far as the diseased part, the discharge of the faeces is aided by the mechanical distension of the intestine, and is undoubtedly further promoted by the change of position which the injection effects in the healthy intestine. It follows that injections of fluids that exert no remedial influence, such as air, may effect an evacuation, and thus establish the first condition of a cure. .