intestinal mucous membranes previous to absorption; others, again, affect the bowels after they have entered the circulation-strychnine, for example, physostigmine, pilocarpine, etc., acting in this

manner.

Certain other drugs, such as podophyllin, colocynth, etc., if injected into the circulation are excreted by the mucous membrane of the intestines, and by their irritation produce catharsis.

The condition of the intestinal canal has much to do with the activity of certain drugs. Thus certain medicines produce catharsis regardless of the reaction of intestinal fluids; others are inert without the presence of bile or other alkaline fluids or salts; and still a third class occasion catharsis only when after ingestion they come in contact with an acid. Of the last mentioned, magnesium carbonate is an excellent example, the drug being inert unless it be acted upon by an acid in the stomach or bowels.

It is a remarkable fact that, as is shown in the tables, different cathartics act more energetically upon different portions of the intestines. The action of calomel, for instance, is almost entirely confined to the duodenum, while aloes acts only upon the descending colon and the rectum.

In selecting a cathartic, therefore, a knowledge of the part of the intestinal canal to be acted upon and the locality in which the drug operates is necessary in order to secure the most satisfactory results.

Many cathartics contain principles which render them tonic to the stomach; others greatly stimulate the secretion of bile (hepatic stimulants); while the cholagogues merely hasten the expulsion of bile from the intestinal canal, preventing its absorption.

Certain drugs, being excreted in the milk, which it renders purgative, are well adapted for administration to the nursing mother in order to produce catharsis in the infant. Castor oil, greatly augmenting the secretion of milk, is an excellent medium as a laxative in such cases.

Aloes increases the menstrual flow; other drugs promote the secretion of urine, etc.

Therapeutics.-Cathartics are employed

1. To remove feces and produce a simple evacuation of the bowels. The Laxatives are best adapted for this purpose.

2. For the relief of chronic constipation. For this purpose great judgment is requisite in the selection of a drug or combination of agents, it being important to determine whether there is diminished peristalsis or secretion; whether there exists an atonic condition of

the intestinal muscles; or whether the disorder is located in the small intestine, the colon, or the rectum.

3. To remove from the bowels noxious substances or pathogenic matter. For this purpose the mercurial preparations, calomel or gray powder, are best, since they are not only active cathartics, but bactericides as well.

4. To stimulate the torpid liver. For this purpose the hepatic stimulants would naturally be employed.

5. To lessen the activity of the liver, as in bilious conditions. In such cases the cholagogue cathartics should be used.

6. To deplete the gastro-duodenal mucous membrane, where the congested and swollen mucous membrane obstructs the outflow of bile, resulting in jaundice. In this condition the salines, especially the sodium salts, are the most efficient cathartics.

7. To promote absorption and remove dropsical effusions in certain diseases of the heart, liver, and kidneys. Here active catharsis is necessary, the hydragogue cathartics being indicated.

8. To remove urea, etc., from the blood. Occasionally in certain renal diseases the functional activity of the kidneys is so defective that waste matter, urea, etc., rapidly accumulates in the system, occasioning uremic convulsions, coma, or other serious symptoms. In such cases it may be necessary to give a drastic purgative, such as croton oil, which acts rapidly, causing profuse watery stools.

9. To lower the blood-pressure where high arterial tension aggravates a malady, as at the onset of many acute diseases, and in cerebral hemorrhage, meningitis, etc. In these conditions it is necessary to employ such drugs as, by dilating the intestinal bloodvessels, drain the blood away from other organs and cause abundant watery discharges from the bowels. Hydragogue or drastic purgatives answer the required purpose.

10. For the relief of hemorrhoids, in which cases the mild laxatives, such as sulphur, senna, etc., are serviceable.

II. To aid the restoration of the catamenia. For this purpose aloes is usually employed, particularly if it be necessary to determine more blood to the pelvic organs. If depletion be required, the selection should be made from the hydragogue cathartics.

12. To purge the nursing infant through the mother's milk. For this purpose such drugs as rhubarb, senna, and castor oil may be administered to the mother.

13. To lower the temperature in fever, in which cases the saline cathartics may be advantageously employed.

Contraindications.-Active catharsis by the more powerful hydragogue or drastic purgatives would be contraindicated in appendicitis, peritonitis, typhlitis, intussusception, pregnancy, and typhoid fever, or where there is inflammation of the mucous membrane of the gastro-intestinal tract.

Administration.-Probably no group of medicines demands greater judgment in administration than Cathartics.

Ordinarily, the efficiency of these agents is increased and their operation rendered less irritant by associating drugs acting upon different portions of the alimentary canal. Their action, too, is more prompt and certain when the remedies are given upon an empty stomach and the efficiency of their operation is enhanced by exercise and diminished by sleep.

The action of cathartics is promoted by the addition of small doses of emetics, mydriatics, quinine, and bitters, quinine especially strengthening the action of magnesium sulphate. Mild diluent beverages also promote the activity of cathartics. Cold applied to the abdomen, enemata, massage of the abdominal walls, and electricity, all act as adjuvant measures in the employment of purgative medicines.

As has been previously suggested, a knowledge of the portion of the intestinal canal upon which the various cathartics act is of primary importance. Thus, if it be necessary to influence only. the duodenum, calomel or podophyllin should be used; if the small intestine, senna or jalap; if the descending colon or rectum, aloes, the drugs acting upon these organs alone.

Moreover, due consideration should be given to the proper time for the administration of the different cathartics, the resinoid purgatives acting best when taken at night or before dinner, and the salines when taken in the morning before breakfast.

The mode of administration is also of great importance, in order to obtain from these agents the fullest benefit. The salines, for instance, act best when given in solution in either very cold or very hot water, their activity being enhanced by association with bitters, iron, or sulphuric acid. On the other hand, the resinoid. drugs should be administered in the form of pills, and if, for any reason, it is desirable that the drug should enter the intestine without coming in contact with the mucous membrane of the stomach, the drug may be given in the form of pills coated with keratin, which is unaffected by the gastric juice, but readily dissolved in the alkaline intestinal juices.

In the following detailed description cathartic drugs are grouped according to their modus operandi, the mildest drugs or laxatives being first considered.

LAXATIVES.

Certain substances never produce active purgation, but simply unload the bowels by slightly increasing both peristalsis and secretion, expelling the feces in a softened though solid and formed condition, without irritation and without perceptibly affecting the general system.

These agents are especially useful where we wish to evacuate the bowels with the least possible local derangement, as in simple constipation from dyspepsia, in children, pregnant women, convalescents from acute disease, or patients affected with hemorrhoids, hernia, affections of the rectum or womb, typhoid fever, early simple diarrhea, or in inflammation or surgical operations about the abdomen and pelvis.

Besides the laxative drugs mentioned below there are many articles of diet which by purely mechanical action produce catharsis, such as oatmeal, brown bread, whole flour, molasses, prunes, figs, etc.

Căssia Fistula-Căssiæ Fistula-Cassia Fistula.

U.S. P.

(PURGING CASSIA.)

Origin. The fruit of Cassia Fistula L., a tree 30 to 50 feet (9-15 M.) high, indigenous in the East Indies.

Description and Properties.-Cylindrical, 1 to 2 feet (45-60 Cm.) long, nearly 1 inch (25 Mm.) in diameter, blackish-brown, somewhat veined, the sutures smooth, forming two longitudinal bands; indehiscent, internally divided transversely into numerous cells, each containing a reddish-brown, glossy, flattish-ovate seed imbedded in a blackish-brown sweet pulp; odor resembling that of prunes.

Dose.-1-2 drachms (4.0-8.0 Gm.).

Official Preparation.

Confectio Sennæ-Confectiōnis Sennæ-Confection of Senna.-Described under Senna, p. 681.

Physiological Action and Therapeutics.-Cassia is a mild and pleasant laxative. It is seldom given alone, however, but forms an ingredient in the confection of senna.

Oleum Ricīni-Olei Ricini-Castor Oil. U. S. P. Origin. A fixed oil expressed from the seed of Ricinus communis L., a plant indigenous in Southern Asia and cultivated in temperate countries for ornament and other purposes, remaining a large annual.

Description and Properties.-A pale-yellowish or almost colorless, transparent, viscid liquid, having a faint, mild odor and a bland, afterward slightly acrid and generally offensive taste. Soluble in an equal volume of alcohol and in all proportions in absolute alcohol. Castor oil should be kept in well-stoppered bottles. Dose. 1-2 fluidounces (8.0-60. Cc.)

Physiological Action.-Externally and Locally.—Castor oillike other bland fixed oils, such as almond oil, olive oil, etc.-is sedative and protective when applied to the skin or mucous membranes.

Internally. The only important action is upon the intestinal tract, on which the oil acts as a mild irritant, causing purgation. Chemically castor oil is a combination of glycerin, fatty acids, and ricinoleic acid. This combination passes the stomach unchanged, but in the presence of the bile and pancreatic juice it is broken up into glycerin and ricinoleic acid; the ricinoleic acid combines with sodium and forms sodium ricinoleate, which has marked irritating properties. The ricinoleate of sodium is absorbed and excreted in various ways, appearing in the mother's milk and imparting to it purgative properties.

Castor oil requires from four to six hours to operate, its action being usually attended with little pain. Indeed, the author is inclined to attribute anodyne properties to the drug, since it has frequently occurred to him in practice that a dose of castor oil given to a child suffering with colicky pains, while producing no movement of the bowels, served to allay the distress and cause the patient to sink into a quiet sleep.

The poisonous principle, ricine, found in castor beans is an albuminous substance belonging to the globulin group, and is generally termed a toxglobulin. Ricine is one of the most powerful poisons known, but being insoluble in oil and soluble in water it is not present in expressed castor oil. The symptoms of poisoning from castor beans are violent abdominal pain, vomiting, purging, and collapse. Post-mortem examinations have revealed evidences of severe inflammation in the stomach and intestines.