Constipation causes self-poisoning chiefly by retaining materials in the digestive tract long enough for absorption to take place, or for poisonous bases to form. It was shown in Part II that putrescin, cadaverin and others required more than one day for their formation, so it is evident that unless there were stagnation of the intestinal current or crypts and diverticula in which food might lodge and putrefy, their formation would be impossible. For when the bowels move freely there is but little opportunity for the production of such poisons, many of whom fortunately cause diarrhea as part of their poisonous action. Constipation favors auto-intoxication not only by the mechanical retention and absorption of end-products, ptomaines and leucomaines, but also by the changes it induces in the digestive tract above. The automatic and co-operative mechanism of the system is altered by the presence of a burden in the colon and rectum, the stomach and higher bowel fail to properly digest and intestinal peristalsis is arrested or delayed.

To be constipated is not necessarily to be visited with fecal poisoning as is seen by the unusual case to be cited. In one person the failure of the bowels to move at the accustomed time invariably means malaise, severe headache, epigastric distress, lassitude, somnolence and nervous irritability; in another no symptoms whatever are experienced until constipation exists for a long time. It is as yet impossible to explain this idiosyncrasy. The writer has carefully examined into the renal condition of many cases of this kind and fails to find any renal cause for the retention of poisonous materials or any reason why one person should be more susceptible to such agencies than another.

Auto-intoxication often takes place with but little disturbance to the rectum, the patient not appreciating the cause until questioned by the attending physician, the symptoms of toxemia being the only ones which cause annoyance. The symptoms most commonly observed are: headache, usually of a dull, heavy character, frontal or temporal in character and increased by physical exertion or mental application, mental apathy, inability to concentrate the attention, failure of memory, general malaise and debility, slight exertion tires, somnolence and drowsiness, but the patient cannot sleep if opportunity offers. From slight ailments like these there are all grades of intoxication symptoms up to convulsions, mania and death. Of this extreme grade of auto-intoxication the following cases of Duprey are illustrative (13):

1. A woman of thirty-five suddenly became unconscious with rapid and shallow breathing, pulse 96, temperature normal. Examination of the urine showed no signs of nephritis. Attention to the bowels was followed by recovery.

2. A young man suddenly became unconscious, but could be roused from his stupor by shaking only to talk incoherently and relapse into the unconscious state. Heart, lungs, and kidneys normal. Recovery after free evacuations of the bowels.

3. A child of three years with a history of constipation suddenly expired while playing. Autopsy showed no condition which could account for death save that of fecal distension of the descending colon.

The following case is of interest as it shows the extreme possibilities of the human organism to eliminate through channels other than the bowels: (13) Mr. K., health good until the age of eleven when he became constipated and would have no movement for three months at a time. At one time he took twenty drops of Croton oil within six hours, but without any result save pain. At the age of twenty-nine, five months and three days passed without a movement, and after a period of regularity his bowels did not move for six months and fourteen days. From June 18, 1900, to June 21, 1901, he had no movement whatever, a period of one year and three days. During these periods of costiveness the patient could eat full meals and do a good day's work, the respiration was always normal, the urine normal when he was free from pain, but high colored when he was in pain, and no convulsions or symptoms of intoxication save that of his sudden death.

The following arguments indicate that auto-intoxication may be the cause as well as the result of constipation:

We know that irritation of the vagus stimulates while that of the splanchnic nerves arrests intestinal movements. It is also true that moderate distension of the intestine with gas or feces increases peristalsis while extreme distension abolishes it, probably from the over-stretching of the muscular fibres. Now we know intestinal fermentation to be the cause of the production of intestinal gas in considerable quantity, as well as of proteid cleavage products, and these states co-operate to irritate the splanchnics, and to distend the bowels, thereby causing intestinal atony, accumulation of digestion residues, constipation, absorption, and the whole clinical sequence already described. It is fortunate that carbonic oxid, hydrogen sulphid, marsh gas, and many of the poisonous diamins are intestinal stimulants, for they tend to offset the retaining forces, and, if present in sufficient potential, they serve to re-establish normal elimination.