Calomel—This is a chemical cathartic. It acts through the blood. When it is absorbed by the blood its chemical ingredients act on certain nerves as irritants. These nerves excite the liver and bowel to action and an evacuation is the result.
Citrate of Magnesia.—This is a saline laxative. It acts by drawing out of the bowel wall enough liquid from the blood to sweep the contents out. It may be likened to the street cleaner who flushes and cleans the street by means of a hose pipe attached to the water hydrant.
Under what condition should a mother use these remedies? Castor oil is ordinarily the best cathartic in childhood; it is not, however, always the best. Most ailments of children are of gastro-intestinal origin—they have either overeaten or they have eaten the wrong kind of food. The stomach and bowel are overloaded: they must be cleaned out. We want a mechanical cathartic, one that will push everything ahead of it, so we use castor oil. When a child needs a cleaning out, use castor oil. By a "cleaning out" we mean, when we know he has eaten too much of a questionable variety of food, as pastries, cakes, fruit, ice cream, etc., as children do at parties; or when he has eaten unripe fruit, as green apples, etc.; or when for some reason he is constipated and complains of not feeling well, use castor oil.
If you decide to use castor oil, use enough. A large dose will act promptly and with less pain and with more certain results than a small dose.
It is always safe and it is always best to decide upon castor oil as the proper remedy, if the child has no fever. If he has a fever he will most likely vomit castor oil when another kind of cathartic would stay on the stomach.
Castor oil works more effectively, more thoroughly, and is less likely to be vomited if given on an empty stomach, so we give it two hours after eating and we give no food for two hours after it is taken.
Castor oil is distinctly of advantage in many chronic diseases of the intestines because of its healing properties. In chronic colitis, for example, when the child is suffering with malnutrition, irregular bowel action with an odor, and mucous or bloody stools, a combination of castor oil and salol, in emulsion, in small doses,—to which a small quantity of opium may be added or withheld according to the frequency of the movements,—with an occasional colon irrigation, is sometimes invaluable.
Mothers must remember that castor oil is not good in the treatment of constipation, because its after effect is to constipate, consequently we would not use it "to keep the bowels open,"—it is only of use to clean the bowel out thoroughly when that is indicated.
How to Give a Dose of Castor Oil—The best way to give a child castor oil is as follows: Place the bottle containing the oil on its side on a piece of ice in the ice box; chill it thoroughly. Take a tablespoon and smear it with butter; pour the ice cold oil into the spoon; it will stick together like a piece of chewing gum and it will slide out of the buttered spoon in one lump. In this way it will not spread over the mouth and teeth and throat, leaving a bad taste, but will go straight and surely into the stomach. The child cannot swallow some and retain enough in the mouth to sputter it all over itself and only get half a dose; it will not nauseate it, because it practically is tasteless if given cold, and the stomach will tolerate the cold oil much better than when given in the ordinary way.
A baby can be given oil in the same way, but in smaller doses. When the teaspoon is put into the mouth of a baby it should be immediately turned on its side so that it will keep the mouth open. If the nose is held closed and the mouth wide open for a few seconds the baby cannot spit the oil out—it must swallow, and if the oil sticks together as cold oil will, it gets the whole dose. It usually takes two persons to give a baby a dose of oil—one to open the mouth and give the medicine, the other to hold the nose and arms.