One of the characteristic features of pellagra is the periodic recurrences in spring, with almost complete cessation of skin and alimentary tract symptoms in the winter and, again, the tendency in many cases for one group of symptoms to overshadow the symptoms which usually accompany them. These periodic recurrences may well be associated with seasonal variation in diet. =Stages in Pellagra.=—For many reasons it is peculiarly difficult to recognize stages but for convenience many authors describe the disease under a prodromal, 1st, 2d and 3d stage. These stages have reference solely to the degree of severity of the manifestations and a case may never progress beyond the 1st stage, although recurring for a number of years. Again a case may rapidly progress to the 2d stage and even run through the 3d or cachectic stage in a few months. We must not consider these stages as tending to follow in sequence as we do in connection with the stages of syphilis. _The prodromal manifestations_ of neurasthenia, malaise, loss of weight, loss of strength, vertigo and digestive disturbances would be suited to many other diseases, especially tuberculosis, and they are rarely recognized as belonging to pellagra until the appearance of typical skin or other symptoms brings about their association with pellagra. There is little definite information as to the period of incubation although Sandwith places it at from nine to twelve months. In Goldberger’s cases the eruption did not appear until after five months on the experimental diet. In the study of cases of pellagra occurring among Armenian refugees, and in Turkish prisoners of war, oedema was not infrequently noted and its occurrence usually preceded the eruption. =First Stage.=—In the first stage we note the alimentary tract disturbances of sodden fissured conditions at the angles of the mouth, a large indented tongue with central coating and bare glistening sides and tips, often with a shiny mucus coating these red borders and a red buccal mucosa. The fungiform papillae appear as pinhead red elevations. Later on the tongue becomes bare, red and fissured. There is often an increased flow of saliva. Aphthous ulcers are less common than in sprue. The gums are often quite tender and in cases where they are somewhat spongy and swollen, with a tendency to bleed, we note the appropriateness of “Alpine scurvy” as a synonym for pellagra. In cases with very severe stomatitis there may be enlargement of the salivary glands. The pharynx is congested and a similar condition of the oesophagus gives rise to a burning sensation which is often described by the patient as going up the gullet from the stomach.