The relation of the ‘grass juice factor’ to guinea pig nutrition.
Kohler, G., Elvehjem, C., Hart, E. 1938. J. Nutr. 1938 Vol15. 5:445-459
Guinea pigs were fed on winter milk or milk plus supplement. The winter milk was deficient in one or more essential factors necessary for normal development, and the animals faded away. When dried barley or wheat grass was given as a supplement, growth was normal. The growth stimulating factor of grass is essential for maintenance and growth of guinea pigs. The active principle is soluble in plant juices and activity falls at room temperature.