166 FEVERS tween lat. 20 S. and 40 N. The disease pre- vails more in the eastern than in the western hemisphere, and in certain parts of Europe and America more than in Africa. In the western world it occurs especially in the commercial towns on the Atlantic coast south of Charles- ton, on the gulf of Mexico, and in the West India islands. In some seasons it prevails either as an endemic or an epidemic, and is largely destructive of human life. The mor- tality varies much in different seasons, the variation ranging from 10 to 75 per cent. The question as to its contagiousness has been here- tofore much mooted, but at the present time comparatively few physicians regard it as com- municable. The special cause, however, may be transported by means of infected vessels and merchandise, and in this way the disease is liable to be imported. Hence the disinfection of vessels coming from ports where the disease prevails, together with certain quarantine re- strictions, are important. The nature of the special cause of this, as of others of the essential fevers, is unknown, but the germ theory is perhaps the most consistent with known facts relating to the history of epidemics. Facts show that the prevalence of the disease in situ- ations where it is indigenous, and also where it has been imported, is much promoted by auxiliary causes, such as overcrowding, defec- tive drainage or sewerage, filth', and other cir- cumstances affecting unfavorably public health. The special cause is destroyed by a temperature of 32 F. Irrespective of the killing effect of frost, epidemics appear to have a self-limited duration, averaging .a little under 60 days. Acclimation protects against the disease, the natives of yellow fever localities, and those who have been long resident therein, being rarely attacked, although they have never ex- perienced it; and this is one of the diseases which, as a rule, are experienced but once in a lifetime, being in this respect in striking con- trast to intermittent and remittent fever. In places where the disease is indigenous, it is common for it to occur sporadically during the hot seasons ; that is, cases occur, but not in a sufficient number to constitute an endemic ; and when persons receive into the system the spe- cial cause in a place where the disease prevails, and going to another place experience in the latter the disease, as a rule it is not dissemi- nated. These facts show that the special cause is not generated within the bodies of those af- fected. Yellow fever generally is abrupt in its attack; that is, it is preceded by few or no premonitions as a rule. It commences with a chill, which is often not of marked intensity. The fever varies in its intensity in different cases, as denoted by the temperature, the pulse, and other symptoms. Pain in the loins and limbs is usually a prominent symptom. The fever continues for a period ranging in different cases from a few hours to three days, when it either subsides notably or entirely ceases. In mild cases convalescence now ensues ; and in a certain proportion of cases the disease is mild, and not always easily discriminated from an ephemeral fever or a febricula. In grave cases the symptoms which especially denote gravity occur after this paroxysm of fever. Among these symptoms is yellowness of the skin, or jaundice, whence the name yellow fever. This, however, does not occur in all cases, being absent in very mild attacks. It denotes a certain measure of gravity, but is by no means a fatal omen. A much graver symp- tom is the vomiting of blood, or, as it is called, the black vomit. Oases very rarely end favor- ably when this symptom occurs. Hemorrhage in other situations, namely, the bowels, blad- der, nose, eyes, and wounds which may exist on the skin, is an event denoting danger in proportion to the loss of blood. Suppression of urine occurs in some cases ; and convulsions with coma, which sometimes occur, are prob- ably caused by the retention in the blood of the excrementitious principles of the urine. The mode of death is generally by exhaustion. The muscular strength in some instances is preserved in a remarkable degree, patients not taking to the bed and sometimes continuing their avocations until shortly before daath. These have been called "walking cases." The dura- tion of the disease in fatal cases ranges from three to nine days, the average being less than a week. The treatment does not embrace any specially curative remedies. Quinia and mercury have been considered as exerting a controlling in- fluence over the disease, but at the present time no one attributes such a power to these remedies. Complete rest is highly important. Opiates and other anodyne remedies are in- dicated if there be great restlessness. All per- turbatory and debilitating medication is inju- rious. Diaphoretic remedies are considered useful. Alcoholic stimulants are to be given, if tolerated, in .proportion as the symptoms denote exhaustion. There is reason to believe that lives are sometimes saved by the free use of wine or spirits. Remedies to palliate vomiting, and to avert hemorrhage if this occurs, enter into the treatment. II. CONTINUED FEVERS. 3. Typhus Fever. Of the fevers distinguished as continued, typhus and typhoid were former- ly considered identical ; but the researches of Louis and later observers have established their non-identity. They are distinct species of fe- ver, and not merely different varieties of one disease. The name typhus (Gr. ri^of, stupor) has reference to the stupor which is a marked feature in the majority of the cases of the fe- ver so called. It was applied to the disease in 1759 by Sauvages. In this country the disease has been known as ship fever from the fact that it is imported in emigrant vessels. It prevails especially in Ireland. It has also been called jail fever, camp fever, petechial fever, &c. ^ It is a contagious disease, being com- municated by an impalpable emanation from the bodies of those affected with it ; that is, by an infectious miasm, the nature of which is
