Vomiting.— No one can say when or how soon fatal implication of the pneumogastric and other cardiac nerves may take place, but vomiting is always an ugly and threatening symptom in beriberi; it probably indicates that the former important nerve is being attacked. The Japanese regard the occurrence of vomiting as of fatal import. Marked dilatation of the stomach has a similar significance.
Prognosis is improved if the patient is placed on a non-beriberic diet and is removed (that is before the heart muscle, or the cardiac or respiratory nerves, are gravely degenerated) from the place in which the disease was contracted, to a healthy, non-beriberic, high-lying locality.
Mortality.— The mortality in beriberi varies in different epidemics and in different localities. On the whole, it is greater in low than in high latitudes, in the dropsical than in the atrophic forms, in the acute than in the chronic. In some epidemics it is as high as 30 per cent, of those attacked; in others as low as 5 per cent. , or even lower.
Diagnosis.— Usually the diagnosis of beriberi is not difficult. Multiple peripheral neuritis occurring as an epidemic, or in a place or ship in which the disease has occurred on some previous occasion, may as a rule be set down as beriberi. Sporadic cases may be difficult to diagnose, more especially if there is a history of alcoholism, of malaria, or of drugging with arsenic. The presence, actual or past, of œdema especially of œdema over the shins and palpitations and other evidences of cardiac implication, are significant of beriberi. It must be borne in mind that slighter degrees of beriberic poisoning, evidenced only by slight anæsthesia of the pretibial skin area, by slight œdema of the same region, by slight hyperæsthesia of the calf muscles, and, perhaps, by impairment or absence of knee-jerk, may be the only symptoms present. True rheumatism is rare in the tropics. Among natives, especially if their language is not understood, complaints of what may seem to be rheumatic pains in the legs should always be carefully investigated, the knee-jerks tested,
