This short treatise deals with practical clinical aids useful for prognosis in the acute febrile illnesses. Typhoid, the pneumonias, diphtheria, scarlet fever, endocarditis, pericarditis and meningitis are the diseases discussed. The book has little that is new. Such signs as pulse rate and character, the appearance of the tongue, presence or absence of abdominal distention, and the quantity of urine are the features stressed in discussion of pneumonia and typhoid. Many of the prognostic signs mentioned are of little value now, owing to new modes of therapy which have altered the course of these diseases, as serum therapy in pneumonia or sulfanilamide in meningitis.