Maintenance of a Standardised Breed of Young Rats for Work upon Fat-Soluble Vitamins, with Particular Reference to the Endowment of the Offspring

IN an accompanying paper [Chick, 1926] one of the writers discusses some sources of error in the technique usually adopted in the investigations of fat-soluble vitamins by the biological method. The conclusion reached, based on the collective experience of the workers in this Institute over a period of several years, is that one, perhaps the most important, disturbing factor is the variation in the state of nutrition of the young rats employed in the tests; in other words variation in the reserves of these vitamins possessed by the young animals at the beginning of the experimental period.