Max von Pettenkofer, in October 1892, drank bouillon deliberately infected with a large dose of cholera bacteria. Pettenkofer was attempting to disprove the theory of Robert Koch that the disease was caused by the bacteria "Vibrio cholerae" alone. Pettenkofer also took bicarbonate of soda to counter a claim by Koch that stomach acid killed the bacteria. Pettenkofer escaped with mild symptoms and claimed success, but the modern view is that he did indeed have cholera, luckily just a mild case, and possibly had some immunity from a previous episode.