Science. 1946 May 24;103(2682):646-8. doi: 10.1126/science.103.2682.646.
Severe granulocytopenia and anemia were developed uniformly in rats fed protein-free diets. Casein (18 per cent) prevented these dyscrasias, but crystalline L. casei factor ("folic acid") did not prevent them. In the correction of granulocytopenia in rats fed protein-free diets, L. casei factor alone was only slightly effective, diets of higher casein content (18 or 30 per cent) were ineffective under the experimental conditions described. However, L. casei factor combined with an 18-per cent casein-containing diet or L. casei factor combined with a mixture of purified amino acids were found to be highly effective in correcting the granulocytopenia.
大鼠给予无蛋白饮食后，普遍出现严重的粒细胞减少和贫血。酪蛋白（18%）可预防这些血液学异常，但结晶型 L. casei 因子（“叶酸”）则不能预防。在纠正无蛋白饮食喂养大鼠的粒细胞减少症时，L. casei 因子单独使用效果甚微，在描述的实验条件下，含更高酪蛋白量（18%或 30%）的饮食无效。然而，L. casei 因子与含 18%酪蛋白的饮食联合使用，或 L. casei 因子与纯化氨基酸混合物联合使用，均被发现可高度有效地纠正粒细胞减少症。
