Using 4 strains considered to belong to Staphylococcus aureus and albus, selected from various bacteria isolated from the human mouth as test bacteria and one strain each of the standard-strain bacteria kept in our laboratory as the control, the author made comparative studies of the productivity of hemolysins of both growing bacteria and resting cells as well as investigated effects of various conditions on the production of hemolysins. The results are presented in the following. 1. By passage through the animal the productivity of hemolysin increases markedly in the case of standard strain of aureus while with albus the increase is only slight. 2. On the whole the productivity of hemolysin of the bacteria belonging to aureus strain is greater than those belonging to the albus, and No.2 and standard strain of aureus presents the hemolyzat the highest degree. 3. Nitrogen source is required in the production of hemolysins by resting cells, and the most effective one is pepton; while among amino acids, glutamate, aspartate, alanine and glycine are effective, but there is no amino acid known to be indispensable to the hemolysin production.
Though hemolysin production does not occur when carbon source alone is added, when C-source is added in combination with N-source, the hemolysin production is enhanced. However, in the case of sugars, pH is lowered during the oxidation so there is a tendency to inhibit the hemolysin production. 4. Hemolysin production is inhibited by such metal ions as Fe(++), Mg(++), Co(++) and Cu(++), and it is likewise inhibited by monoiodoacetate, aureomycine, and chloromycetine. 5. Hemolysin produced by the resting cells are all unstable against heat with exception of standar strain of albus.