SENNA.
Physiological Action. — Administered alone, magnesium acts very slowly as a purgative, but, contrary to the effects ob tained from sulphate of sodium, the purgative effect seems to increase when the same dose is repeated several days in succession. Again, while the former agent gives rise to no notable phenomena in the intestinal tract, magnesium, cording to Trousseau and Pidoux, may induce an active inflammatory process, thus giving rise to the bloody atonic evacuations and the tenesmus ally noticed. Armand Moreau observed that when a 15- to 20-per-cent. solution of magnesium was inclosed in an intes tinal loop, between two ligatures, very active and localized secretion followed, the result of osmosis. The purgative ac tion is also sustained, however, by the magnesium absorbed in the blood, though the salt thus absorbed is mainly eliminated by the kidneys. It can be found in the urine twenty-four or thirty six hours after the purgative effects are produced.
To increase the rapidity of its action, citric acid is usually added to magne sium. A bicarbonate is thereby obtained which is actively cathartic.
Saline purgatives have the power of ex citing more or less the glands of the in testines and of causing them to pour forth their secretions abundantly. In moderate doses magnesium sulphate ac complishes this without appreciably stimulating the peristaltic action. This being the case, a part of the fluid poured out may be reabsorbed and carry with it into the blood a quantity of the salt. and also cause the contents of the bowel to lose their fluid or semisolid consistency. This seems to explain its action when given hypodermically and also to ex plain constipation after the drug has been given per rectum. In cases treated by the drug 2 or 3 grains of neutral magnesium sulphate injected into the deep muscular layers of the nates in men, or into the calf of the leg in women, were successful in 70 per cent. of the cases; 20 per cent. required more than one injection, and in 10 per cent. the bowels failed to act. In nearly all cases the bowels moved within ten hours after injection. James Wood (Ther. Gaz., Jan. 15, '95).
The preparations of magnesium are not free from toxic properties when taken in large doses.
Case of a woman, aged 30 years, in her usual health, who on retiring at night, took an ounce of Epsom salts. On the following morning she was found, in her room, dead. A careful post-mortem and chemical analysis yielded no evidence of any other cause of death. A. P. Luff (Brit. Med. Jour., Sept. 5, '91).
Case of a woman, about 35 years old, AN ho took at a single dose 4 ounces of Ep som salts, dissolved in hot water. An hour later sbe had burning pains in the stomach and bowels; difficult respira tion, attended by a choking feeling; and a peculiar weakness in the arms and legs.
, There was no vomiting or purging. Presently extreme collapse occurred; the pupils were dilated; there was slight t,\ itching of the facial muscles; paralysis of the limbs N, as observed. The patient quickly became comatose, and death fol lowed in an hour and fifteen minutes after the dose was swallowed. There was no autopsy. Lang (Lancet, Nov. 7, '91).
Case in which patient took 1 ounce of Epsom salts. Only three slight motions resulted, and towards evening he began to feel very ill, and remained so through the night. The following day he was too ill to do anything. IIis illness con tinued, and he vomited frequently during the day. At 6 P.NI. he was found lying on the bed in an attitude of flexion, per fectly indifferent to his surroundings, but answering questions intelligently when smartly roused. The face and hands were deeply cyanosed, the lips, eyelids, aloe nasi, and auricles being of a dark-purple color, while tbe conjunctiv were in tensely congested and the pupils dilated and unequal. The covered parts of the body presented a roseolous rash, and there was a zone of herpes zoster in the left subinammary region extending around to the back. At this time the boy had several attacks of tetanic spasms, affecting the right side of the face and passing down the right arm, together with pronation of the hand. The tongue and teeth were covered with sordes, the stomach was enormously dilated, and urine was dribbling away. The right radial pulse was absent and the left hardly perceptible; the heart-beats were feeble and could not be counted. The extremities were cold; the axillary tem perature was 105 degrees.