It is well known that quinin produces, in the majority of people, additional mild or severe effects. Many complain of a sensation of pressure in the stomach, which may even lead to vomiting. Still, this intolerance of the stomach is rarely so marked as to prevent administration per os (omitting, naturally, those cases in which vomiting is a symptom of the infection).

Very frequently, in fact, almost constantly, it produces a ringing in the ears, associated with a certain amount of deafness, and often vertigo of light degree.

Sometimes a toxic erythema occurs, which may even scale and be mistaken by the inexperienced for scarlet fever. Urticaria and purpura hemorrhagica have been observed. Schulz noted in several healthy persons, after the administration of 0.5 to 1.0 quinin for neuralgia of the fifth nerve, diuresis and polyuria.

Again, there are persons who show a decided idiosyncrasy to even moderate doses of the drug. Schwabach reports the case of a man, thirty seven years old, who, after 1.2 quinin muriate, was attacked by a violent tinnitus aurium, pain in the left ear, stupor, attacks of vertigo, and marked deafness. The hearing remained affected for months.

Trousseau and Pidoux mention a nun who was made insane for a day by 1.2 quinin, and another case that, after one dose of 3.0 quinin sulphate, suffered from ringing in the ears, attacks of vertigo, and uncontrollable vomiting, followed seven hours later by blindness, deafness, delirium, and inability to walk. Recovery was complete.

Floyer observed, in a man of forty, after 0.15 quinin, wide spread urticaria over the body and intense dyspnea, associated with fear of imminent death.

Rizu saw a woman attacked with violent sneezing from 0.10 quinin taken on account of tertian. The face became turgid, the secretion of tears profuse, and an attack of orthopnea followed. The skin, bathed in a profuse sweat, broke out in urticaria. This condition repeated itself every time the woman took quinin.

Symptoms of poisoning after the large doses sometimes administered by physicians are not at all infrequent. Deafness and bilateral blindness are especially sources of worry and torment to the patient. Both conditions are usually transitory, though a contraction of the field of vision may persist.

Geschwind found, in a case of amblyopia following a continuous administration of quinin, a filaceous clouding of the vitreous humor, which might explain the persistence of the derangement of vision.

Under certain circumstances large doses produce extremely threatening symptoms. Roberts observed the following symptoms in a woman after 8.10 quinin sulphate: Unconsciousness, fall of temperature, general lividity, slowed superficial respiration, small, thready pulse (45 to the minute), pupils widely dilated, staring, abolishment of tendon and skin reflexes, coffee ground vomit, in addition to deafness that lasted a week and blindness that continued five months.

Pispiris observed intestinal hemorrhage after quinin in two cases of malarial anemia.

Kuchel, who gives in blackwater fever up to 8.0 pro die, observed once, out of four cases, amaurosis which persisted fourteen days.

Isolated cases of fatal poisoning have also been reported. The following observation of Baills is very interesting:

Two soldiers took by mistake 12.0 quinin sulphate in solution. Soon after they complained of intense ringing in the ears, total deafness, and cramps in the stomach. The skin became extremely pale, the pupils dilated, respiration became superficial, the skin cool, and the pulse slow, small, irregular, and at times impalpable. Auscultation of the heart showed scarcely audible, frequent jerky sounds, and both sounds were frequently run together. One died four hours later in syncope; the other recovered. The autopsy was negative. This case seems to indicate that in large doses quinin acts as a cardiac poison.

In some places metrorrhagia and abortion are attributed to it. Burdel reports five cases of pregnant women who gave birth to stillborn children after large doses of quinin on an empty stomach.

According to the unanimous experience of responsible observers, these effects cannot be laid at the door of quinin. Many obstetricians hold that quinin strengthens uterine contraction during labor, and they, therefore, recommend it in place of ergotin, though they deny that it is able to initiate the contractions and so produce a premature birth. The former belief, which is nothing more than a superstition of some malarial regions, is based on the fact that malaria itself frequently leads to abortion. Fieux reports the case of a woman, in the seventh month of pregnancy, who manifested, during a paroxysm of quotidian fever, a bloody discharge, and complained of pains similar to labor pains. Quinin cured the paroxysm and the premature pain ceased.

The hemoglobinuria following quinin has already been thoroughly discussed in other places. We may add that after large doses of quinin albuminuria is sometimes observed, and an existing cystitis may be made worse.

According to Osier, quinin is by no means contraindicated in malarial hemorrhagic nephritis; on the contrary, it acts quite as successfully and harmlessly as in other cases. Binz recommends the following in case of poisoning:

"Artificial respiration by rhythmic pressure over the region of the heart, in order to irritate this organ at the same time; hot baths (39° C.) with cold douches; internally, hot strong coffee or tea, and probably atropin. In cases calling for large doses of quinin the physician should ask himself whether any contraindication exists in the shape of pulmonary or cardiac weakness."