(80) The door to bacterial chemotherapy was opened. All over the world, pharmacists launched an offensive along the road pointed out by Ehrlich. It was not until 1935, 24 years after the invention of 606, that the young German doctor Gerhard Domagk made a new breakthrough.

(81) Domagk was a diligent scholar. He and his assistants, like many other pharmacists around the world, worked day and night on a drug to fight against bacteria.

(82) Domagk, who was like a magician, selected a red dye and changed the chemical structure of it in various ways. After constant efforts, scientists learned that prontosil red pigment can kill streptococcus.

(83) With further improvement, the red pigment liquid was refined into white powder and the efficiency was increased dozens of times. This powder is called “sulfa” according to its chemical structure. “sulfa” has been tested on animals many times, and it has worked.

(84) Streptococcus is the cause of many human infectious diseases. Is sulfa effective for human? Domagk was not sure yet. However, the first human subject of sulfa was her little daughter, Elisa.

(85) Elisa's finger was cut and streptococcus entered her blood through the wound. She was in critical condition. Domagk applied sulfa decisively. When the hard night was over, Elisa opened her eyes, which sparkled with vitality.

(86) Day after day, little Elisa was healed. How happy Domagk was. Not only could he put his daughter around his neck and hear her fondly call “Daddy, Daddy” as he did in the past, but he really proved the power of sulfa.

(87) Sulfa was in widespread use and scientists went on to develop hundreds of new sulfas to treat patients. But sulfas were powerless against nasty bugs. A more effective new drug was needed.

(88) In 1943 when the World War II was raging, thousands of anti-fascist soldiers were injured, some were cured by sulfa, some were not, and many died. Scientists have racked their brains to develop new drugs.

(89) In Burlehan city, America, there was a large base hospital in the years of the war, thousands of wounded soldiers were brought in from the front for treatment.