A Possible Factor Influencing the Assimilation of Calcium.*

Hart and associates (1) have shown that milking goats, when fed a green feed, have been able to utilize the calcium to a higher degree than when fed dry feed. They state that “apparently there is something having its source in fresh green materials, which controls or assists calcium assimilation.” Hart and associates (2) have also reported evidence secured with milking cows that it is possible to maintain calcium and phosphorus equilibrium on a ration of grain and dry alfalfa hay-the hay having been cured under caps. These results are contrary to those of Forbes and his coworkers (3) and even to their own later findings (4), when they obtained a negative calcium balance with milking cows on a similar ration. The alfalfa hay in the latter case was cured in windrows for 4 days. They state “these differences in effect of the two alfalfa hays may be attributed to a difference in the degree of destruction during the curing process of the vitamine assisting calcium assimilation.” Working on the hypothesis that most of the calcium, in whatever combination it may be, in the cells of green plants is in a highly dispersed form and hence better assimilated than the calcium in the dry plant, the drying of which no doubt causes a change in the physical properties of the cell and its content, we set about to imitate, in a rough way, the cell content as far as it represents our idea of the highly dispersed form in which the calcium exists in green plants. A starch paste was made up with a known solution of CaClz (4 normal). Then an equal volume