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418 he Will note, die quite suddenly as if from syncope; but most die in the distressing way described, evidently from paresis and over-distension of the right heart, complicated and aggravated by œdema of the lungs, or by diaphragmatic paralysis, by hydrothorax, or by hydropericardium.

Nomenclature and classification of beriberi.— For purposes of description, the paralytic-atrophic cases are designated " dry beriberi " or beriberia atrophica; the dropsical cases, " wet beriberi " or beriberia hydrops; and those in which there is a combination of both conditions, "mixed beriberi." Sometimes the cases are classified according to the rapidity of development and gravity of symptoms into acute or pernicious, subacute, and chronic. None of these classifications is good, seeing that they all refer to what is clinically the same disease, and that one form may suddenly or more slowly merge into the other.

Etiology.— Sex, age, occupation, etc.— Beriberi attacks both sexes. Not uncommon in the breast-fed infants of beriberic mothers, it is rare in childhood and extreme old age, but occurs at all ages,* its favourite age being from about 15 to 30. It affects rich as well as poor. It is confined to no particular trade or occupation. If anything, it has a predilection for those who lead a sedentary life and are much indoors, as students, prisoners, and the inmates of hospitals and asylums. It is apt to attack pregnant or parturient females. It is quite as common in the strong and full-blooded as in the weak and anæaemic.

Climatic conditions.— In countries in which there are a hot and a cold season the epidemic outbreaks occur during the former, old cases improving and new cases ceasing to crop up during the winter. In countries which are hot all the year round, beriberi may appear at any time; most frequently, however, in such climates it appears during the rains. Thus it resembles malaria in being fostered by damp, by high