On this day, 110 years ago, August 20, 1915 (July 10, 1915 in the lunar calendar), Nobel Prize winner in medicine and German bacteriologist Ehrlich passed away. At the end of the 19th century, there was a disease called syphilis that spread around the world. This disease has a history of more than 400 years in Europe. It is extremely contagious and spreads rapidly. It has claimed thousands of lives, but people have no choice but to do anything about it. It was not until April 1910, when German bacteriologist Ehrlich invented "606" that humans were rescued from the threat of this disease. Ehrlich was born on April 14, 1854, in Stern, Silesia, Germany. His father was a Jewish doctor. He has experienced the pain of racial discrimination since he was a child and determined to be a good doctor and provide universal benefits to the world. At that time, germs could not be seen with the naked eye and were raging in Europe and the world. Infectious diseases claimed the lives of tens of millions of people. Ehrlich witnessed this tragic reality and made a grand wish when he first entered the gate of the Military Medical College: "I must invent a magic bullet that will only kill germs in the human body without harming the human body. In 1878, Ehrlich received a medical doctorate from the University of Leipzig. He was recommended to the largest pathology institute in Europe at that time, and became an assistant to Frei Risis, the founder of experimental pathology and professor at the University of Berlin. He started with the stain analysis method and used colorimetry to distinguish between bacteria and normal cell tissues in human and animal bodies. It was called the "Ehrlich reaction." Soon, he founded the "side chain theory", which is the theory of the combination of organisms and surrounding chemicals (food, drugs, etc.), and then scientifically derived the theory of immunochemistry and chemotherapy. After making great contributions to medical theory, Ehrlich devoted all his energy in his later years to the development of chemical drugs in order to realize his ambition when he was young-to use "magic bullets" to shoot germs in the human body. In 1904, he finally found a dye "Atoxsil" that could kill trypanosomes in mice, also known as "trypanosomes red", or para-aminophenylarsine. But although this medicine can kill the bacteria, the treatment results are very miserable. Although the patient does not die, he becomes blind. He decided to change the chemical structure of p-aminophenylarsine, synthesized thousands of arsonene compounds, and then screened them one by one. Among them, the "606" diaminodioxarsonene was achieved in practice. Success, Erlich's ambition came true. Some pharmaceutical manufacturers habitually called diaminodioxarsonbenzene "606", and later became a commonly used drug name. In 1908, Ehrlich received the Nobel Prize in Medicine. In 1915, the pioneer of chemotherapy died on August 20 in Bad Homburg. However, his name and the "606" he invented will always be recorded in history.