The physiological factor is much less easy to specify than the anatomical, for it is almost certainly an individual pe culiarity. It may be stated broadly, however, that, as regards the ileo-cmcal portion of the intestine, the increased mobility, coupled W ith the unduly rapid growth in the width of the large in testine, is probably associated with in creased and irregular peristaltic move ments of the large intestine. D'Arcy Power (Brit. Med. Jour., Feb. 13, '97).
The main etiological factors of exter nal origin are blows upon the abdomen, violent muscular movements, sudden or repeated jars of the body as in jumping, and. particularly the violent jolting which infants sometimes receive when too violently handled.
In 103 cases of infantile intussuscep tion nearly 50 per cent. occurred during the fourth, fifth, and sixth months, in nearly equal proportions; 75.4 per cent. of the cases occurred in males, and 89 per cent. were of the ileo-caecal variety. Pritchard called attention to the prob able part played by external violence in the causation of this disorder during early life, particularly the careless man ner in which infants are picked up and doubled over the arm of those caring for them, thereby injuring and causing a temporary paralysis of some portion of the intestinal canal. Jacobi has also called attention to this matter, particu larly to the way in which infants are violently jumped up and down to quiet their cry. Frederick Holme Wiggin (AIed. Record, Jan. 13, '96).
Intestinal tumors may act as causative agents by dragging the portion of testine to which they are attached into the adjoining portion.
Example of the causation of intussus ception by polypus within the intestines. Van Bibber (Maryland Aled. Jour., Dec. 31, '87).
In one case the principal cause of ob struction was found, after death, to have been due to a polypoid growth of the small intestine. C. McBurney (N. Y. Afed. Jour., Afar. 28, '91).
Sodium bicarbonate causes contraction of the circular fibres of the intestine. Peristalsis continuing, invagination pro duced, thus showing one class of intus susceptions. R. T. Morris (N. Y. Med. Jour., Feb. 23, '95).
The post-mortem findings depend upon the duration of the intussuscep tion. When death occurs early in the course of the attack but little change is observed. When the case has progressed some time, besides the invaginated por tion of gut there may be localized peri tonitis and, as a result of the circulation of blood by the tension and compression of the mesentery, more or less marked inflammation, extending to necrosis and sloughing of the tissues involved in the invagination. At first but little lymph is thrown out between the layers of gut in contact, and they may be easily dis engaged; but, when the inflammatory: process progresses some time, the sur faces adhere and cannot be separated.
The only chance for the patient then is that the invaginatecl portion slough off, union occurring between the upper edge of the external layer and the free end of the intestine immediately above the invagination. This not infrequently oc curs, the detached portion of gut being voided per anum.
VoLvuLus.—Twists and knots (vol vulus) are more rarely met with than the forms just described: in about 12 per cent. of all cases of intestinal ob struction, according to Fitz's statistics. Volvulus generally occurs in adults be tween the ages of 30 and 50 years, and int IT frtquently in males than females. it is usually associated with abnormal letutli of the intestine involved and a lax niLsoiterv. ln children this elonga tion of the mesentery is always tal (Keen). In adults. on the contrary, it is usually acquired, and arises in chronic constipation, from the weight of lanze masses of ffeces, which pull down and drag, upon the mesentery, thus caus ing, its relaxation and elongation. In a ease reported by I'lllard, for instance, the si7moid flexure was as large as the entire colon: a phenomenon frequently pres ent, doubtless, since one-half the cases of volvulus reported suffered from le sions in this location. Next in frequency is the mount A twist in the long axis of the gut is usually observed, but the intestine may be sharply bent upon self, a loop may become twisted around another portion, or a knot be formed. Several causes of obstruction may be simultaneously present, as in a case wit nessed by Berard, in which a twist, a knot, and a constricting band were re vealed by laparotomy.
Interesting case oi a woman, 59 Vears old, in whom the use of the corset had brought about complete division of the right lobe of the liver, the inferior por tion, nearly six centimetres in length, being united to that organ merely by a band of fibrous tissue, and pushed up ward. The gall-bladder was united to the moving fragment, and fixed to the colon by adhesions of peritoneum. In consequence of these lesions the trans verse colon was drawn up, and the trac tion thus exerted had induced a twisting of the intestines and an obstruction of the intra-intestinal circulation; the ac cumulation of fmces and gas beyond that fold had completed the occlusion. Bonuzzi (Revista Ven. di Sei. Med., Jan., '921.
. Purely mechanical twist ma.y give nse to symptoms without paralysis of twisted portions. Pseudostrangulation may supervene after reposition of gan grenous loop and peritoneal infection follow. Great prostration and high pulse are indications of the latter. Nicolaysen (Norsk Mag. f. Laeg., June, '95).