Manson (13) deduced from all the evidence which he had accumulated, the theory that the disease was due to a toxin elaborated by a germ growing outside the body. He suggested that improper handling of rice led to its infection and the development of the toxin. He was opposed to the theory that meat in the diet was a protection against the disease, and cited the experience of the Singapore jail, where in 1898-99, there was an ordinary and a penal diet. The former was a liberal one of wheat flour and fresh meat. The penal diet contained no meat. The greater number of cases of beri-beri occurred among those inmates of the prison having meat in their diet. McLeod (cited by Manson) mentions a case where beri-beri attacked the officers on shipboard, but not the common sailors. The former had such luxuries as haddies, clams, oysters, lobster and salmon. It was argued that lack of protein could not be the cause of the outbreak.

Manson also cited the observation of Hirota, who witnessed 52 instances of the development of the disease in nursing infants whose mothers were suffering from beri-beri. When these infants were weaned and fed condensed or fresh milk they recovered promptly, whereas five not so treated died. It was argued by Manson that a child acquiring a germ disease from the mother will not recover so rapidly, but that one intoxicated by taking poisonous milk would be expected to do so. This was interpreted by Manson as supporting his theory of intoxication.

225. Arsenic Suggested As The Agent Producing Beri-Beri

Mention should also be made of the view of Sir Ronald Ross, who believed that beri-beri was due to arsenical poisoning (14). Symptoms of peripheral neuritis have been observed in persons who drank beer containing arsenic.

The view that beri-beri was due to lack of sufficient phosphorus in the diet was supported by Edie and Simpson (15). Polished rice and cereal foods prepared from the endosperm of the grains contain very little phosphorus, and suggested the phosphorus starvation theory. In the light of later experimental studies, these seemingly irreconcilable observations have been made clear.