Chloral is an oily, colorless fluid, made by the action of chlorine on alcohol. It is not used in medicine. United with water it forms a hydrate which is the hydrated chloral of the U. S. P.

Chloralum Hydratum. Hydrated Chloral

Colorless, volatile crystals of hot, burning taste and pungent odor; readily soluble in water, ether, or alcohol.

Physiological Actions

Chloral has antiseptic properties and has been so used in a strength of gr. v.- ℥ i. of water. A concentrated solution vesicates and is very painful.

Given internally it acts on the nerve centres as a sedative, its effect on the brain, under suitable conditions, being that of a pure and perfect hypnotic. The sleep it causes resembles natural sleep, coming on quickly and lasting for six or seven hours. The patient may be aroused from it for medicine or nourishment, and falls asleep again, finally awaking refreshed and without headache or the unpleasant after-effects- such as nausea, giddiness, and constipation - which are commonly found after taking opium. Even if given for a long time chloral is not apt to cause constipation or disturbance of the stomach.

In the sleep of chloral the pupil is slightly contracted, the pulse unaltered or a little slower than normal, the respirations regular, full, and quiet. The cases in which its beneficial action is best seen are cases of insomnia from mental labor, anxiety, or fatigue. It is not an anodyne, having no power to overcome pain unless given in dangerous doses. If so given the after-effects are bad.

The action of chloral is not always satisfactory. With some persons headache, excitement, and even delirium are caused by medicinal doses. It is preeminently a great depressant.

Symptoms Of Poisoning

In larger doses the respiratory centre is depressed and the respirations become slow, irregular, and shallow. The activity of the vasomotor centre is lessened, so that the vessels dilate generally, and the heart is depressed and weakened not only through the centre in the medulla but also by a direct influence on its own nerve ganglia.

The pulse becomes weak and slow; in toxic doses it grows rapid and irregular, and in fatal cases feeble and thready, while other symptoms are coma, great muscular relaxation, pupils at first contracted, afterwards dilated; and death results from paralysis of the respirations and heart.

Treatment Of Poisoning

The treatment in chloral poisoning consists in the use of alcoholic stimulants, strong coffee, galvanism, and artificial respiration. The application of external heat is of the utmost importance. Mustard pastes and hot mustard foot-baths may be used, avoiding, however, all measures which might exhaust the patient.

Incidental Effects

There may be noticed after ordinary doses of chloral, dyspnoea; redness and swelling of the conjunctivae; and eruptions of the skin, most frequently a simple erythema which seems to follow preferably the course of the large nerve trunks. Sometimes the eruption takes the form of wheals, and a papular eruption has also been observed. These disorders are often attended by some rise of temperature, and desquamation sometimes results. It is supposed that they, as well as the more alarming ill effects of chloral, are greatly, if not altogether, due to impurities in the drug.

The great danger of chloral is the sudden paralysis of the heart, which may occur even after ordinary medicinal doses, and without warning. This attaches so much uncertainty to its action that it is impossible to express caution too strongly in regard to using it without orders. The patient may be sleeping quietly, but suddenly becomes restless and passes into a state of syncope. The danger cannot be considered past until from 60 to 100 pulse beats can be counted continuously without any irregularity in strength.

The habitual use of chloral may become a disorder almost as grave as the opium habit. Those who have formed this habit are usually excitable in manner; hurried and voluble in speech; nervous and wakeful at night; melancholy and low-spirited during the day, and subject to vertigo and ringing in the ears. The eyes are brilliant and restless; the appetite capricious or lacking altogether; digestion disordered; the heart action weak and irregular; and the secretion of bile deficient.

Average dose, gr. viii-0.5 Gm., diluted only moderately with water or a weak syrup.

Butyl Chloral Hydrate. Croton Chloral. Not Official

A crystalline body formed by the action of chlorine on aldehyde; sparingly soluble in water, readily so in glycerin. It is said to resemble chloral in its action, but to be more depressing and less efficient. A feebler poison, more disagreeable in taste, and having a special anaesthetic effect on the fifth nerve.

Average dose, gr. v.-03 Gm., in syrup or glycerin.

Metachloral. Not Official

A solid substance prepared by acting on chloral hydrate with sulphuric acid, and used as a counter-irritant and local anaesthetic.

Chloral Camphor. Not Official

Equal parts of camphor and chloral, used as an external application for the relief of pain.