=Pathogenesis of Guinea-pig Scurvy.=--From a pathogenetic point of view guinea-pig scurvy and human scurvy show remarkable points in common. Any diet that leads to the development of scurvy in man likewise brings it about in the guinea-pig, and contrariwise, any food which cures the disorder has the same beneficent effect on both species. This similarity extends so far that, as will be shown in the chapter on antiscorbutics, the relative potency of the various foods is approximately the same for man and for the guinea-pig. The parallelism generally is striking. The dietary which has been commonly employed in experimental scurvy has been that first suggested by Holst and Froelich, namely, oats, hay and water. Recently, however, this dietary has been enlarged in order to make it more complete, so as to include adequate protein, water-soluble and fat-soluble vitamine, and inorganic salts. To this end the group of workers at the Lister Institute (Chick and co-workers, Harden and Zilva) place their animals on a basal diet of one part of crushed oats and two of wheaten bran, and a daily ration of 50 to 60 c.c. of milk autoclaved for one hour at 120° C. This milk still retains a small amount of antiscorbutic vitamine. Cohen and Mendel have employed, apparently with good result, a "soy bean cracker," containing soy bean flour which has been heated for 30 minutes at 15 pounds' pressure (120° C.), 3 per cent. of sodium chloride, the same percentage of calcium lactate and of dried brewers' yeast, and raw milk sufficient to supply 5 per cent. of butter-fat.