Hyperemesis Gravidarum, the Pernicious Vomiting of Pregnancy, is commonly classified among the toxemias; but as the etiology is not known definitely, this classification is one of convenience more than exactness. Nausea and vomiting occur so frequently in the early months of gestation that they are deemed almost physiological, but when these symptoms become very grave and persistent they are undoubtedly pathologic, and are said to be pernicious, as they may lead to abortion, or to the death of the woman. In 1813, Simmond first successfully employed artificial abortion to save the woman in this condition, and thus added a possible moral quality to the disease. Therapeutic abortion was used in 1608, and Soranus of Ephesus, in the second century, mentions it. The pernicious nausea commonly begins in the second month of pregnancy, less frequently in the fourth month, but it may be delayed until the sixth month; if it occurs after the sixth month it is, almost as a rule, an evidence of nephritis. It may last from about a month and a half to three months, but in toxemic cases it may result in death in two weeks. Sometimes remissions occur. In 1852, Paul Dubois described the disease, and his division into three stages is still used in articles on pernicious vomiting, although these stages are not clearly marked clinically. In the early months of gestation the stomach may become unable to retain food, and there is notable loss of appetite; the condition is then grave. There may be retching at the sight of food, at any change of position, or at the entrance of a person into the room. The emesis may recur so often at night as to cause exhaustion from insomnia. Hiccough, thirst, pain in the stomach, and soreness of the thoracic muscles are frequent and troublesome symptoms. In some cases there is salivation. The vomitus is food, mucus, and some bile at first; later mucus and bile; finally it contains blood. The blood may come from the mouth, pharynx, or stomach, and it is serious if it is gastric. The urine is scanty, and shows nephritic irritation. At times it contains blood, bile, acetone, diacetic acid, indican, and rarely sugar. In the second stage of the disease all symptoms are aggravated, and the stomach will not retain anything. There is extreme thirst; the patient faints often, and loses weight rapidly. In chronic cases there is much emaciation. The mouth is like that in a case of typhoid. Sometimes there is a low fever; again, the temperature is subnormal, with a rise before death. The pulse is rapid and weak, and the post-mortem heart shows fatty degeneration as in a fatal sepsis. In the third stage the mind is affected, there is delirium, stupor, and coma; the vomiting ceases, the pulse grows more rapid and feebler, and the weakness becomes more and more overwhelming until the patient dies. This third stage is commonly short. In these conditions it is too late to empty the uterus, and any attempt to do so then only hastens death.