Question 34·Easy·Central Ideas and Details
While physician John Snow is often credited with demonstrating that contaminated water caused London’s 1854 cholera outbreak, the passage highlights the essential role of Reverend Henry Whitehead. At first, Whitehead dismissed Snow’s waterborne theory, believing instead that cholera spread through “miasma,” or foul air. Determined to test Snow’s claims, Whitehead interviewed nearly every resident of the affected Soho neighborhood and made a detailed map linking each cholera case to its water source. His investigation traced the outbreak to a baby’s soiled diapers that had polluted the Broad Street pump. Whitehead’s evidence persuaded local officials to remove the pump handle, an action that quickly curbed the epidemic and helped secure wider acceptance of Snow’s theory.
According to the passage, how did Whitehead help validate Snow’s theory about cholera?
For "According to the passage" questions, first underline the key task words in the question (here, "how did Whitehead help validate Snow’s theory"). Then, go straight to the sentences in the passage that describe that person’s actions or role and restate them in your own words. Finally, eliminate any choices that (1) talk about a different time (before or after the described action), (2) add extreme or new details not in the passage, or (3) directly contradict what the passage says, and choose the option that best paraphrases the key lines you identified.
Hints
Restate the task
Focus on what the question is really asking: it is not asking what Whitehead believed at first or what officials did, but specifically how he helped support Snow’s theory.
Find the relevant sentences
Reread the part of the passage starting with "Determined to test Snow’s claims" and ending with "helped secure wider acceptance of Snow’s theory." What actions are described there?
Connect actions to the theory
Ask yourself: Which described actions would provide evidence about whether cholera came from contaminated water, rather than just from air or from other causes?
Eliminate off-topic choices
Cross out any answer choices that focus on Whitehead’s initial beliefs, on things other people did, or on actions that the passage never mentions.
Step-by-step Explanation
Clarify what the question is asking
The question asks: "According to the passage, how did Whitehead help validate Snow’s theory about cholera?"
So you must identify what Whitehead actually did that helped show Snow’s idea (that cholera came from contaminated water) was correct.
Locate the key part of the passage
Look at the middle part of the passage, starting with "Determined to test Snow’s claims" and continuing through "helped secure wider acceptance of Snow’s theory."
This section explains both Whitehead’s actions and how those actions affected acceptance of Snow’s theory.
Understand Whitehead’s actions and their purpose
In that section, the passage says that Whitehead:
- "interviewed nearly every resident of the affected Soho neighborhood"
- "made a detailed map linking each cholera case to its water source"
- "traced the outbreak to a baby’s soiled diapers that had polluted the Broad Street pump"
- His "evidence persuaded local officials to remove the pump handle" and this "helped secure wider acceptance of Snow’s theory."
So his main contribution was collecting and organizing evidence that tied cholera cases to a specific contaminated water source (the Broad Street pump), which supported Snow’s waterborne theory.
Match the passage to the correct answer choice
Now compare each answer choice to what the passage says Whitehead did to support Snow:
- One choice talks about collecting interviews and mapping data that linked cholera cases to the Broad Street water pump. This directly matches the passage’s description of him interviewing residents and making a detailed map of cases and water sources that traced the outbreak to the Broad Street pump.
Because this choice accurately reflects the evidence-based work described in the passage, the correct answer is:
He gathered interviews and mapping data that linked cholera cases to the Broad Street water pump.