A Study of the Heat Stability of the Vitamin B Factors Required by the Chick*

Vitamin Bz has been considered the more heat-stable constituent of the vitamin B complex since the early work of Goldberger, Wheeler, Lillie, and Rogers (1) in 1926. In the preceding paper (2) results were presented to show that vitamin Bz was destroyed in a ration of natural foodstuffs when heated dry at 100’ for 144 hours. These results show that under certain conditions vitamin Bz can be inactivated at a temperature lower than that required for the destruction of vitamin B1. It is evident, therefore, that further studies on the heat stability of the vitamin B fractions are necessary. The present investigation deals mainly with results obtained when the diets described in the preceding paper and yeast were used for studying the stability of vitamins B, and Bz. However, the use of these rations also afforded us some opportunity to study the possible existence of the heat-labile vitamin B3 which was first described by Williams and Waterman (3) as an additional vitamin B factor required by the pigeon and later regarded to be necessary for the chick by Eddy, Gurin, and Keresztesy (4). Since the original ration used in these studies undoubtedly contained all additional heat-stable factors required by the chick, it was impossible to study such factors as vitamin Bg described by Carter, Kinnersley, and Peters (5). However, we have studied the importance of additional factors for the chick when synthetic diets are used but this work will be reported in a later paper.