In none of these early experiments was the importance of the germ or embryo of the seeds recognized as of special importance. The cortical layer was regarded as the part producing the favorable results. McCollum and Davis (9) in their study of the wheat kernel were the first to call attention to the fact that the germ is exceedingly rich in the substance which is curative for polyneuritis. They suggested that it is the loss of the germ of the rice kernel rather than the cortical layer which robs the seed of its protective power against beri-beri.

These experiments of Eijkman, Grijns, Hoist and Schaumann established the fact that the feeding of milled products of the cereals caused the degeneration of the peripheral nerves characteristic of beri-beri. They did not make clear the cause of this degeneration. It has been mentioned that Eijkman believed that there was a detoxicating effect of the "silverskin" for the injurious effects of the endosperm of the rice or other cereal. Schaumann (10) examined the hypothesis that food-stuffs causing beri-beri contain a toxic substance or substances which produce the disease. He was unable to detect any poison which might have been produced as a metabolic product by a microbe. He tested polished rice for acetone, aceto-acetic acid, oxalic acid and oxybutyric acid with negative results. He found the urine of patients did not contain a toxin, and offered the explanation that beri-beri was due to starvation for certain organic phosphorus compounds which were removed during the milling process.

223. Other Views Relating To The Cause Of Beri-Beri

In 1899 Laurent (11) attributed beri-beri to lack of sufficient fat in the diet. He believed this type of specific starvation caused a lowering of the vitality and made the subjects susceptible to an infection which was the specific cause of the disease. He attributed the beneficial effects of the addition of meat to the diet of the Japanese sailors, to the increase in the fat content in the food.

Montgomery Smith (12) supported the infection hypothesis. He cited the ship Lodestar as having a bad reputation for beriberi outbreaks. A Japanese revenue cruiser had new cases of beri-beri during successive years while the southwest monsoon blew.