Further proof of the “bios” character of crystalline bios 223. ∗

Abstract

Conclusions

The isolation of a crystalline substance from an active sub strate always leaves existent the doubt as to whether the activity is due to the crystals themselves or to adhering traces of the potent factor. The complete inactivation of Bios 223 crystals by forming the crystalline benzene sulfonamide and the recovery of activity by hydrolysing this inactive crystalline product seems to remove all reasonable doubt and to demonstrate that the yeast stimulating power of Bios 223 resides in the crystals themselves. The nature of the addition compound also suggested that the NH₂, group is concerned in the exercise of this function.

We also take pleasure in acknowledging the suggestions and advice of Professor John M. Nelson of Columbia University in developing these results.