Observations on the effect of an animal protein factor concentrate on persons with the macrocytic anemia of pernicious anemia, of nutritional macrocytic anemia and of sprue, and on persons with nutritional glossitis.

soya bean meal was not adequate as the only source of protein in poultry feeds.! The hatchability of eggs produced by hens fed these diets was low; whereas this defect could be remedied by feeding meat scraps. Later it was found that a supplement of dried cow manure was effective in increasing the egg production and the hatchability of the eggs from hens fed on such a restricted diet.2 Whitson, Hammond, Titus, and Bird3 concluded that the substance was not a protein or any known vitamin. Bird, Rubin, Whitson, and Haynes4 aided in the search for the hatchability factor by investigating a large number of widely used foodstuffs; and Mishler, Carrick, and Hauge5 found that the addition of fish solubles supplied a missing factor or factors not present in a vegetable protein ration supplemented with vitamins. Rubin, Bird, and Rothchild6 demonstrated the presence of a chick growth factor in hen feces. As these studies progressed on the new factor or factors necessary for the hatchability, growth, and viability in chicks, Ross, Phillips, and Bohstedt,7 Cunha,8 Spitzer and Phillips,9 and Cary, Hartman, Dryden, and Likely’0 independently showed that proper growth, reproduction, and lactation did not occur in rats fed a diet of highly purified casein as the source of their protein and that they required an unidentified factor. More recently, Zucker, Zucker, Babcock, and Hollister” fed rats a purified diet containing protein and all of the known essential vitamins. The female rats maintained on this diet reproduced normally and had normal lactation, but the young born of such females frequently died soon after weaning. Crude casein, fish solubles, or liver extract corrected the deficiency, and the new factor was tentatively named “zoopherin.” The authors pointed out that it is not the same as the fat-soluble “animal protein factor” of Heuser, Norris, Lucas, and Combs’2 and of Johnson, Carrick, and Roberts.’3