The causes of the ardent continued fever of the tropics, which is usually recognized as a form of simple continued fever, do not differ materially, except in degree, from those of the simpler forms of the disease; but exposure to the direct rays of the sun would seem to be especially prone to give rise to the disease in those who are unaccustomed to the heat of a tropical climate. Robust young Europeans lately arrived in a warm country are, it is said, peculiarly liable to suffer from it.[12] It is most common in those parts of India which do not experience much of the benefit of the monsoon rains, and whose hot season is not tempered by regular breezes from the sea. It is hence more frequently met with {233} in inland districts in which the temperature is high, but in which malaria-generating conditions are absent. [Footnote 12: Morehead, _Clinical Researches on Diseases in India_, London, 1856; also Twining, _Clinical Illustrations of the More Important Diseases of Bengal_, Calcutta, 1835.] SYMPTOMS AND COURSE.--Simple continued fever occurs in this country only as a sporadic disease, and almost invariably ends in recovery; in tropical climates, however, it may prevail epidemically, and sometimes presents symptoms of a very grave character. In its mildest form it not infrequently runs its course in a few hours, and is rarely prolonged much beyond twenty-four, and is hence called ephemera. It then usually begins somewhat abruptly with a chill, but in a few instances this is preceded by feelings of languor and weariness. Febrile reaction is soon established, and is generally well marked; the pulse is quick and full, the temperature rises rapidly, and the face is flushed. The tongue is coated with a whitish fur, the urine is scanty and high-colored, and the bowels are constipated. Other symptoms are excessive thirst, headache, restlessness, and sleeplessness, or, on the other hand, a tendency to somnolence. Vomiting is not common except in those cases which follow upon an error of diet, but there is generally some nausea and anorexia. Muscular pains are also occasionally present, and may give rise to a good deal of distress. The subsidence of these symptoms is often quite as abrupt as their onset, the crisis being frequently marked by a copious perspiration.