1. Penicillin is a powerful antibacterial agent, but its rôle is a limited one. Pathogenic bacteria should be divided into two groups, penicillin-sensitive and penicillin-resistant.

2. Penicillin has no serious toxic manifestations in humans.

3. Penicillin alone is effective in acute infections without suppuration or death of tissue.

4. Penicillin and surgery are equally important in acute infections with suppuration and death of tissue.

5. Penicillin is but one of a number of therapeutic agents in the treatment of chronic infection with suppuration and death of tissue. It is effective in permitting adequate surgery earlier and with more safety.

6. The use of penicillin will not obviate the need for good surgery. Sequestra and foreign bodies, in particular, must still be removed from wounds before they will heal.

7. Penicillin is a more effective antibacterial agent than the sulfonamides against penicillin-sensitive organisms. Its action is not affected by the presence of pus, blood, or tissue autolysates.

8. The chief disadvantages of penicillin are the necessity for administering it by frequent intramuscular or intravenous injections, and its instability at room temperature.