Question

what made Pasteur believe that a cow could not have anthrax twice ​

Answer 1

Pasteur's oxygen method dideventually produce a vaccine but only after he had been awarded a patent on the production of an anthrax vaccine. The notion of a weak form of a disease causing immunity to the virulent version was not new; this had been known for a long time for smallpox.

Answer 2

Louis Pasteur, the French chemist who lived in the 19th century, is famous for developing fundamental scientific concepts. He demonstrated the process of fermentation and debunked spontaneous generation, an erroneous belief that bacteria came from inanimate matter such as dust. Pasteur is also recognized for his work on vaccines; he was the first scientist to use live viruses in vaccinations. Pasteur’s work in infectious diseases was momentous for the development of the rabies and anthrax vaccines specifically. Rabies and anthrax are animal-born diseases that cause serious symptoms in humans.