Analyze each of the following reports, explaining the ways in which the method of difference has been applied in the investigations recounted. Discuss the strengths and weaknesses of the method of difference as it is used in each case.

Does Louisiana hot sauce, the principal ingredient of the spicy New Orleans cocktail sauce commonly served with raw shellfi sh, kill certain bacteria found in raw oysters and clams? The answer appears to be yes. Bacteria of an infectious and sometimes fatal kind—Vibrio vulnifi cus—are found in 5 to 10 percent of raw shellfish on the market. Dr. Charles V. Sanders and his research team, from Louisiana State University Medical Center in New Orleans, added Louisiana hot sauce to cultures of Vibrio growing in test tubes; the sauce, even when greatly diluted, killed V. vulnifi cus in five minutes or less. “I couldn’t believe what happened,” Dr. Sanders said. He admits that he still eats raw oysters, “but only with plenty of hot sauce.” 

—Reported to the Interscience Conference on
Antimicrobial Agents, New Orleans, October 1993