The preparations of nux-vomica are extremely and persistently bitter. Like all bitters, they promote the flow of the stomach and intestinal juices, increase the digestive power, and thus favorably affect the appetite. They also hasten the intestinal movements, and the stools voided are somewhat relaxed.

The alkaloids of nux-vomica are very diffusible substances, and enter the blood very quickly. They lessen somewhat the oxidizing power of the blood, but this effect is quite insufficient to account for the physiological reactions produced in the nervous system. Small medicinal doses of nux-vomica and its alkaloid accomplish no more than other bitters, as respects the circulation. More or less plethora, slightly increased action of the heart, and, as a consequence of this condition of the vascular system, a greater energy in the performance of the various functions, result from their administration.

When a lethal dose of nux-vomica, or of its alkaloid, has been taken, characteristic symptoms follow in a few minutes. The state of the stomach as to food, the presence of tannic acid in the food, and of fat, probably; also the condition of the blood-vessels, influence the rate of absorption, and symptoms may begin in a few minutes or be delayed an hour or even longer. When a full medicinal dose has been taken, some slight shuddering, a sense of constriction of the fauces and jaws, sudden pains like electric shocks passing through the limbs, startings of some of the voluntary muscles, dilated pupils, "a meaningless smile," paleness of the face, followed by flushing and increased warmth of the surface and perspiration, are symptoms which may be produced without further development of a toxic action. If the dose be large enough to cause death, the above-described symptoms are quickly followed by tetanic convulsions, in which nearly all the voluntary muscles are engaged. When the paroxysm occurs, a shudder passes through the whole frame; the head and extremities jerk and twitch, and then suddenly a general tonic convulsion takes place —the limbs are extended, the hands clinched, the toes and feet incur-vated, the head bent backward, the body arched and rigid, the abdominal muscles hard and tense, the respiratory muscles fixed so that the body, curved in the form of a bow, rests on the occiput and heels. The countenance assumes a ghastly grin—the risus sardonicus; the arrest of the respiratory movements suspends oxidation of the blood, and the skin becomes cyanosed; strong erections of the penis occur, and frequently involuntary evacuations of semen, urine, and faeces take place. Rarely does death ensue in the first paroxysm; the spasm relaxes, and nothing remains of the attack but the muscular soreness and fatigue, and the sense of impending dissolution. Absolute quiet retards the paroxysms. At first the senses are preternat-urally acute, and, as the reflex function is abnormally excitable, the slightest peripheral irritation suffices to bring on the spasms. Generally patients experience comfort when the limbs are strongly held, or even rubbed, during the paroxysms; but, in the interval, absolute quiet is most grateful. The mind remains unaffected until the close, or, at least, until carbonic-acid poisoning sets in. The paroxysms rapidly succeed each other, and increase in duration and severity, death occurring usually by fixation of the muscles of respiration, or by exhaustion, and within two hours, as a rule, from the beginning of symptoms.

The remarkable similarity in the symptomatology of traumatic tetanus and strychnine tetanus requires that the points of difference between them be clearly set forth. In strychnine tetanus the jaw-muscles are not first thrown into spasm, and are not always rigid during the paroxysm; in traumatic tetanus, trismus is one of the first symptoms. In strychnine tetanus, after the convulsion, lasting from a half to one or two minutes, there is usually complete relaxation; in traumatic tetanus rigidity of the affected muscles continues. A case of strychnine tetanus goes on rapidly increasing in severity, and lasts from a few minutes to two hours; a case of traumatic tetanus proceeds more slowly, and lasts always a number of hours, and may extend over days and even weeks. And, lastly, in traumatic tetanus, the capital symptom of a wound or injury exists.

No very characteristic post-mortem appearances result from strychnine-poisoning. The muscles, at first relaxed, become rigid, the feet turned in, the fingers clinched, or the body may maintain the position of opisthotonos, in which it was at the moment of death. Congestion of the cerebral and spinal meninges is usually observed, and Schroeder Van der Kolk first ascertained that dilatation of the vessels and sanguineous extravasations are found in the gray matter of the cord (medulla oblongata), and this observation has since been repeatedly confirmed.

The smallest quantity of strychnine which has produced a fatal result in an adult was a half-grain. Rarely can one twelfth of a grain be given without causing muscular twitchings, and one sixteenth of a grain has caused death in a child of between two and three years.

The effects of strychnine are exerted on the spinal cord, on the seat of the motor functions. It does not affect the functions of the motor nerves directly—the irritability of the motor nerves is not destroyed by strychnine, it is exhausted by over-stimulation. The sensory nerves are either unaffected, or their irritability is exhausted. The reflex functions of the spinal cord are exalted. The afferent nerves, while preserving their irritability, communicate impressions to the reflex centers, motor impulses are quickly originated, and the muscles through the motor nerves are fixed in a state of tonic contraction. The over-stimulation of the cord and the motor nerves exhausts the irritability of the latter. The muscles preserve their contractility.

The effects of strychnine are not limited to the nervous system of animal life: the organic nervous system participates in the perturbation. The dilatation of the pupil, the erection of the hair-follicles, the tinnitus, the increased heat in the limbs, and the perspiration which are produced when strychnine is injected subcutaneously, indicate an influence on the sympathetic system similar in kind to that exerted on the voluntary. Experimental investigations have confirmed these clinical observations. A very considerable rise in the arterial pressure, contraction of the vessels in the frog's web, and increased action of the heart, have been experimentally demonstrated to be caused by strychnine (Sigmund Mayer).