Abstract
1. A basic, water soluble substance, which was prepared from calf thymus and designated as thymus peptide, inhibited the growth of some pathogenic fungi in different degrees, and the growth of Cryptococcus neoformans was inhibited by 50mcg of thymus peptide per ml of medium.
2. The antimycotic activity of this material diminished when the medium was acidic or when the inoculum was large.
3. Cryptococcus neoformans immediately lost its ability to multiply in an aqueous solution of thymus peptide.
4. The significance of the presence of antimycotic substance in normal animal tissues was discussed.
