Many of the peculiarities of sex and place distribution could be explained by the stable fly, _Stomoxys calcitrans_, a fly which bites viciously in the district in which they worked. This fly bites only by day and is intimately associated with human dwellings so that the greater incidence of the disease in the women, who stay at home, as against an incidence five times less in the men who work in the mill during the day might be explained by _Stomoxys_ bites. At the same time their failure to transmit pellagra to monkeys by injections of defibrinated pellagra blood would militate against any infectious agent existing in the blood. It may be stated that Harris has claimed to have produced a disease resembling pellagra in two monkeys by injecting filtrates from emulsions of brain, skin and intestinal tract of cases dying of pellagra. Lavinder and Francis injected 79 monkeys and 3 baboons with varying material from pellagra autopsies. Some of the animals were injected with emulsions or Berkefeld filtrates of such emulsions made from brain and cord. Other monkeys were inoculated with material from skin similarly prepared, others with stomach and mouth mucosal emulsions, and still others with intestine and faeces emulsions. Blood, urine and cerebro-spinal fluid were also injected. Feeding experiments were also carried out. With one exception, and that one only suggestive of pellagra, the experiments were negative. Sixteen volunteers, working under Goldberger, tried to infect themselves with blood, nasopharyngeal secretions, epidermal scales, feces and urine from pellagrins. Various atria of infection were tried according to material; blood by intramuscular injection, excreta by mouth. After a period of six months all the subjects of the experiments remained well. _This evidence is certainly against the infectious nature of the disease._ _Greater Prevalence in Women_.—Now that we attach no weight to insect transmission of pellagra we have only the debilitating effects of menstruation, pregnancy and lactation to explain the marked susceptibility shown by women of from seventeen to forty years of age. Before and beyond these ages the incidence in males and females is about the same. Before Goldberger began his experiments he was struck by the relation poverty had to pellagra epidemiology, and as diet is the chief element differentiating poverty and affluence, he chose this line of research with the results recorded under etiology. His explanation of the greater incidence in adult females, especially wives and mothers, was their act of denying themselves the more desirable parts of the food. Sandwith has noted the great frequency of pellagra in hookworm patients, thus of 300 such cases in Egypt, 46% had pellagra.