INFLUENZA, one of the class of diseases to which the term zymotie (q.v.) is now applied, has been long recognized by medical writers, although its name, borrowed from the Italian, is comparatively modern in this country. Cullen called it eatarrhus e contagio, hut although, in most cases, it closely resembles ordinary catarrh it presents certain points of difference from that disease. In addition to the ordinary symptoms of catarrh, there is a sudden, early, and very striking debility and depression of spirits. This early debility is one of the most marked and characteristic signs of influenza. The mucous membranes (especially the pulmonary membrane) are much affected. The tongue is white and creamy, the sense of taste is lost, there is no appetite, the pulse is soft and weak, the skin, although at first hot and dry, soon becomes moist, and the patient complains of pains and soreness in various parts of the body. .
In simple, uncomplicated cases, convalescence supervenes in the course of a week or sooner, but influenza is very frequently conjoined with bronchitis or pneumonia, in which case it is much more persistent and dangerous.
Influenza affords an excellent example of an epidemic disease, a whole community being often attacked in the course of a few hours. From this it may be inferred that the occurrence of this disease is connected with some particular condition of the atmos phere, but what that condition is, is not known. Not unfrequently, influenza follows close upon a sudden thaw; sometimes it is preceded by thick, ill-smelling fogs. One
hypothesis refers the complaint to some change in the electrical state of the air; and one of the latest and most probable conjectures regarding its exciting cause is that of Sehi)n hein, who refers it to the presence of an excess of ozone (q.v.) in the atmosphere. Like cholera, influenza generally follows a westerly direction, or one from the s.c. towards the n.w., and its course seems to be altogether independent of currents of air, as it fre quently travels against the prevailing wind.
The most important point in the treatment of influenza is not to bleed the patient, or in any way to depress his vital powers. He should be kept in bed; his bowels should be gently opened; his skin slightly acted upon, if dry; and, if the cough be troublesome, a mustard-poultice should be applied to the chest, and an expectorant mixture prescribed. In persons of weak or broken-down constitutions, ammonia, beef-tea, and wine and water must be given from the outset. The debility that often remains for a consider able period after the establishment of convalescence, is best met by the preparations of iron and quinine.
Few diseases increase the death-rate to such an extent as influenza, more, however, in consequence of the great number of persons who arc attacked in a severe epidemic, than in consequence of its danger in individual cases.