About the end of the 2d day the facial congestion disappears to be succeeded by an earthy tinging and subicteroid tinting of the conjunctivae. The jaundice does not appear until about the fourth day. This may be noted somewhat earlier if one blanches the skin by pressure with a glass slide. Petechial eruptions may be prominent in the later stages. The jaundice is best seen at a distance of 5 to 6 feet. _The Circulatory System._—Of peculiar value in diagnosis is _Faget’s law_—a falling pulse rate with constant temperature or a constant pulse rate with a rising temperature. A markedly slow pulse, between 40 and 50, is often recorded about the time of the period of remission. It is interesting to note that the pulse of yellow fever made a great impression upon Benjamin Rush, who called it the indescribable or sulky pulse. The systolic blood pressure is high at first, but by the 2d day begins to fall, becoming quite low in the asthenic stage (even below 70 mm.) due probably to supra-renal involvement rather than to cardiac weakness. Haemorrhages, especially from gums, nose and intestines, are common. Black vomit is the best known of these haemorrhages. _Blood Examination._—This has generally been considered as varying but slightly from normal findings. Noc states that in the first stages of the disease there is an increase of the polymorphonuclear percentage with a marked diminution or disappearance of eosinophiles while later on, from the 3d to the 6th day, there is an increase in the large mononuclears. _The Alimentary Tract._—The tongue may be coated in the center. Vomiting often appears early and consists of whitish or bile-stained mucus. It must be remembered that if black vomit should appear it almost never comes on before the 4th day. There is usually marked epigastric tenderness. Bleeding from the gums and intestinal canal are not rare. _The Nervous System._—The mind is unusually clear, the patient often mentally alert and suspicious. There is often insomnia. The severe cephalalgia, often frontal or supraorbital, as well as the severe loin pains (_coup de barre_) are striking features. There may be a marked hyperaesthesia. A delirious state may be present. _The Liver and Spleen._—There is no special alteration in the size of either liver or spleen. There may be tenderness about the liver region. The jaundice of the asthenic stage is incident to the pressure of the swollen degenerating liver cells on the bile capillaries while the fatal issue is connected with the loss of the urea formation function. It has been claimed that an acidosis may occur. The spleen is not affected.