When the nineteenth-century German bacteriologist Robert Koch

Question

When the nineteenth-century German bacteriologist Robert Koch identified a particular bacterium as responsible for cholera, Max von Pettenkoffer, a physician, expressed his skepticism by voluntarily drinking an entire bottle of the allegedly responsible bacteria. Although von Pettenkoffer took his failure to come down with the disease as a refutation of Koch's hypothesis that cholera was caused by bacteria, Koch argued that von Pettenkoffer had been protected by his own stomach acid. The acid secreted by the stomach, Koch explained, kills most ingested bacteria.

Which of the following, if true, provides the most evidence to support Koch's counterargument?

A. Peptic ulcers, often associated with excessive secretions of stomach acid, are common in certain areas characterized by low rates of cholera.

B. As von Pettenkoffer later admitted that he had previously had cholera, it is probable that he had developed antibodies that protected him from a second attack.

C. Cholera is endemic in areas in which poor sanitation results in high concentrations of cholera bacteria in drinking water.

D. Although stomach acid kills most ingested bacteria, large numbers of e. coli bacteria nonetheless manage to make their way to the lower intestine of the digestive tract.

E. Cholera bacteria ingested with bicarbonate of soda, a neutralizer of stomach acid, is more likely to result in cholera than if the bacteria is ingested alone.

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Dereno · Answer

In the nineteenth-century German bacteriologist  Robert Koch identified a particular bacterium  as  responsible for cholera.

Max von Pettenkoffer , a physician,  expressed his skepticism  by voluntarily drinking an entire bottle of the allegedly responsible bacteria.

But, Max was not infected by this disease , hence used this as a refutation of Koch hypothesis that “  the identified bacterium is responsible for causing cholera “.

Robert Koch countered the argument by mentioning the stomach acids of Max has killed the bacteria. The environment inside Max stomach is not conducive for bacterial Growth.

We need to find which options strengthens the counter argument provided by Robert Koch.

A. Peptic ulcers, often associated with excessive secretions of stomach acid, are common in certain areas characterized by low rates of cholera.

We are not interested in Peptic Ulcers. Max did not contract peptic ulcers. Hence out of scope.

B. As von Pettenkoffer later admitted that he had previously had cholera, it is probable that he had developed antibodies that protected him from a second attack.

This is an interesting trap answer. If your carried away with the flow of passage. This can be true that Max has acquired immunity for cholera because of his previous infection. Antibodies have been generated in larger amounts to prevent future infection. DOESNT STRENGHTEN.

C. Cholera is endemic in areas in which poor sanitation results in high concentrations of cholera bacteria in drinking water.

OUT OF SCOPE.

D. Although stomach acid kills most ingested bacteria, large numbers of e. coli bacteria nonetheless manage to make their way to the lower intestine of the digestive tract.

No where it’s mentioned that E. coli is responsible for cholera. Hence out of scope.

E.  Cholera bacteria ingested with bicarbonate of soda, a neutralizer of stomach acid, is more likely to result in cholera than if the bacteria is ingested alone.
 
This strengthens the counter argument of Robert that, the acids present inside the stomach are the main reason for the destruction of cholera causing bacteria in Max. Bicarbonate of soda which neutralises the stomach acid provides a fertile ground for bacterial growth.

Hence,  option E

Abhiswarup · Answer

The passage explains the identification of bacteria which causes Cholera by Robert Koch and same was refuted by Max von Petten koffer by taking a bottle of bacteria and nothing happening to him. The same was explained by Koch that stomach acid is responsible for the digestion of the bacteria.
Analyzing the statements which supports Koch counterargument:
A. Peptic ulcers, often associated with excessive secretions of stomach acid, are common in certain areas characterized by low rates of cholera.
Peptic ulcers are out of scope. However, the option confuses with mentioning of stomach acid and low rates of cholera. Eliminate.

B. As von Pettenkoffer later admitted that he had previously had cholera, it is probable that he had developed antibodies that protected him from a second attack.
Doesn't support the counterargument. Eliminate.
C. Cholera is endemic in areas in which poor sanitation results in high concentrations of cholera bacteria in drinking water.
Factual information. Eliminate.
D. Although stomach acid kills most ingested bacteria, large numbers of e. coli bacteria nonetheless manage to make their way to the lower intestine of the digestive tract.
Stomach acid kills most bacterias but whether it is killing cholera bacteria hasn't been mentioned. Eliminate
E. Cholera bacteria ingested with bicarbonate of soda, a neutralizer of stomach acid, is more likely to result in cholera than if the bacteria is ingested alone.
It explains that stomach acid kills most of the cholera bacteria as neutralizer of acid is taken with bacteria results in cholera. Correct answer is E.

Bunuel · Answer

KAPLAN OFFICIAL EXPLANATION:

E

After reading the stem for question 27, we go to the stimulus with eyes peeled for Koch's counterargument. Koch, we learn, is unconvinced by von Pettenkoffer's dramatic demonstration. When, after drinking a bottle of bacteria, von Pettenkoffer doesn't develop cholera, he claims to have proved that the bacterium doesn't cause cholera. Koch disagrees, saying that von Pettenkoffer's stomach acid killed the bacteria before it could affect him. Be careful; we don't want to strengthen Koch's original argument-that the bacterium causes cholera, but rather his second argument-that von Pettenkoffer's stomach acid killed the bacteria. (E) says that when the cholera bacteria is ingested with bicarbonate of soda, a stomach acid neutralize^ it's more likely that the person will develop the illness. (E), then, shows that acidity has an inhibiting effect on cholera bacteria, exactly as Koch argued.

When the nineteenth-century German bacteriologist Robert Koch

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When the nineteenth-century German bacteriologist Robert Koch

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