Gutenberg Articles

Appearance

Excerpt ​

Excerpt from The Voyage of the Beagle, by Charles Darwin

[1] It is remarkable how the same disease is modified in different
climates. At the little island of St. Helena the introduction of
scarlet fever is dreaded as a plague. In some countries, foreigners
and natives are as differently affected by certain contagious disorders
as if they had been different animals; of which fact some instances
have occurred in Chile; and, according to Humboldt, in Mexico (Polit.
Essay, New Spain, vol. iv.).

[2] Narrative of Missionary Enterprise, p. 282.

[3] Captain Beechey (chap. iv., vol. i.) states that the inhabitants of
Pitcairn Island are firmly convinced that after the arrival of every
ship they suffer cutaneous and other disorders. Captain Beechey
attributes this to the change of diet during the time of the visit. Dr.
Macculloch (Western Isles, vol. ii. p. 32) says: "It is asserted, that
on the arrival of a stranger (at St. Kilda) all the inhabitants, in the
common phraseology, catch a cold." Dr. Macculloch considers the whole
case, although often previously affirmed, as ludicrous. He adds,
however, that "the question was put by us to the inhabitants who
unanimously agreed in the story." In Vancouver's Voyage, there is a
somewhat similar statement with respect to Otaheite. Dr. Dieffenbach,
in a note to his translation of the Journal, states that the same fact
is universally believed by the inhabitants of the Chatham Islands, and
in parts of New Zealand. It is impossible that such a belief should
have become universal in the northern hemisphere, at the Antipodes, and
in the Pacific, without some good foundation. Humboldt (Polit. Essay
on King of New Spain, vol. iv.) says, that the great epidemics of
Panama and Callao are "marked" by the arrival of ships from Chile,
because the people from that temperate region, first experience the
fatal effects of the torrid zones. I may add, that I have heard it
stated in Shropshire, that sheep, which have been imported from
vessels, although themselves in a healthy condition, if placed in the
same fold with others, frequently produce sickness in the flock.

Explanation ​

Detailed Explanation of the Excerpt from The Voyage of the Beagle by Charles Darwin ​

Context of the Source ​

The Voyage of the Beagle (1839) is Charles Darwin’s travelogue and scientific account of his five-year expedition (1831–1836) aboard HMS Beagle, which played a crucial role in shaping his theories of evolution and natural selection. While the book is primarily known for its contributions to biology and geology, this particular excerpt (from Chapter 17, "Galapagos Archipelago") reflects Darwin’s broader observations on disease, climate, and human/animal health—topics that interested him as part of his inquiry into adaptation and environmental influence.

This passage discusses how diseases and epidemics appear to spread or manifest differently across regions, often correlating with the arrival of outsiders (ships, strangers, or imported animals). Darwin compiles anecdotes from various sources—missionaries, explorers, and naturalists—to suggest that external introductions (human or animal) can trigger health crises in isolated populations.

Themes in the Excerpt ​

  1. Disease and Environmental Influence Darwin highlights how diseases behave differently in varying climates and populations. Scarlet fever, for instance, is feared as a "plague" in St. Helena but may not be as devastating elsewhere. This reflects his broader interest in how organisms (including humans) adapt—or fail to adapt—to new environments.

  2. Isolation and Vulnerability The passage emphasizes the fragility of isolated communities (e.g., Pitcairn Island, St. Kilda, Otaheite) when exposed to outsiders. The repeated claims that strangers or ships bring illness suggest that these populations lack immunity to "foreign" pathogens—a concept later formalized in epidemiology as the "virgin soil epidemic" (where previously unexposed groups suffer severe outbreaks).

  3. Empirical Observation vs. Superstition Darwin balances anecdotal reports (e.g., Pitcairn Islanders "catching colds" after ship arrivals) with skepticism (Dr. Macculloch calls the idea "ludicrous" but concedes locals unanimously believe it). This tension between folk wisdom and scientific scrutiny is typical of 19th-century naturalism, where observers like Darwin relied on both firsthand accounts and critical analysis.

  4. Human and Animal Parallels The final example—healthy imported sheep causing sickness in local flocks—extends the theme to animals, reinforcing Darwin’s comparative approach. This foreshadows his later work on natural selection, where environmental pressures (like disease) shape survival.

  5. Global Patterns By citing examples from the Pacific (Chatham Islands, New Zealand), the Americas (Panama, Chile), and Europe (Shropshire), Darwin suggests a universal phenomenon: the disruption of isolated ecosystems by external contact. This aligns with his later arguments about the interconnectedness of life.

Literary Devices and Style ​

  1. Anecdotal Evidence Darwin structures the passage as a collage of observations from diverse sources (Beechey, Humboldt, Macculloch, etc.). This technique:

    • Lends credibility by showing the phenomenon is widely reported.
    • Reflects the inductive reasoning of natural science (building theories from specific cases).
    • Creates a narrative of discovery, inviting readers to piece together the pattern.

  2. Juxtaposition of Perspectives

    • Local Beliefs vs. Scientific Skepticism: The Pitcairn Islanders’ conviction is contrasted with Macculloch’s dismissal ("ludicrous"), yet Darwin notes the unanimity of their testimony. This mirrors his own method: weighing evidence before drawing conclusions.
    • Human vs. Animal Cases: The shift from human epidemics to sheep illnesses broadens the scope, implying a unified biological principle.

  3. Repetition for Emphasis The phrase "it is asserted" (Macculloch) and "it is impossible that such a belief should have become universal... without some good foundation" underscores the recurring pattern across cultures. The repetition reinforces the idea that these are not isolated incidents but a global trend.

  4. Scientific Detachment with Subtle Speculation Darwin avoids overt theorizing here, but his selection of examples hints at deeper questions:

    • Why do temperate-zone visitors suffer in tropical climates (Humboldt’s note on Panama)?
    • Is there a biological mechanism (e.g., immunity, adaptation) behind these observations? This foreshadows his later work on adaptation and survival.

  5. Allusion to Authority By citing Humboldt (a renowned naturalist) and Vancouver’s Voyage (a respected exploration account), Darwin anchors his observations in established science, lending weight to his claims.

Significance of the Passage ​

  1. Precursor to Epidemiology and Immunology Darwin’s observations align with modern understanding of disease transmission and herd immunity. Isolated populations (like those on Pitcairn or St. Kilda) lack exposure to pathogens, making them vulnerable—a concept later explored in studies of indigenous populations and zoonotic diseases.

  2. Support for Evolutionary Theory The passage subtly reinforces Darwin’s later arguments about adaptation and environmental pressure. If diseases affect populations differently based on climate or isolation, it suggests that survival depends on gradual exposure and adaptation—a cornerstone of natural selection.

  3. Colonial and Exploration Context The 19th century was an era of global exploration and colonial expansion, which often brought devastating diseases to indigenous peoples (e.g., smallpox in the Americas). Darwin’s notes reflect the unintended consequences of contact, a theme that resonates in postcolonial studies.

  4. Interdisciplinary Approach Darwin blends medicine, anthropology, and natural history, showing how scientific inquiry in the 19th century was holistic. His willingness to consider folk beliefs (even skeptically) demonstrates an open-mindedness that was progressive for his time.

  5. Foreshadowing of On the Origin of Species The focus on variation (diseases modifying in different climates) and interconnectedness (ships spreading illness) mirrors his later arguments about how small changes accumulate to drive evolution.

Line-by-Line Analysis ​

  1. "It is remarkable how the same disease is modified in different climates."

    • Theme: Environmental influence on biology.
    • Device: Understatement ("remarkable" downplays the dramatic implications).
    • Significance: Introduces the idea that disease is not static but adapts, much like species.

  2. "At the little island of St. Helena the introduction of scarlet fever is dreaded as a plague."

    • Context: St. Helena was a remote British colony; its isolation made it vulnerable.
    • Device: Hyperbole ("plague") emphasizes the severity.
    • Link to Evolution: Suggests that isolation = lack of immunity.

  3. "In some countries, foreigners and natives are as differently affected... as if they had been different animals."

    • Theme: Biological variation between populations.
    • Device: Simile ("as if they had been different animals") hints at speciation—a key evolutionary concept.
    • Implication: Humans, like animals, are subject to environmental pressures.

  4. "Captain Beechey attributes this to the change of diet during the time of the visit."

    • Contrast: Beechey offers a proximate cause (diet), while Darwin seems to hint at a deeper pattern (disease transmission).
    • Scientific Method: Shows Darwin evaluating competing explanations.

  5. "Dr. Macculloch considers the whole case... as ludicrous. He adds, however, that 'the question was put by us to the inhabitants who unanimously agreed in the story.'"

    • Theme: Conflict between scientific skepticism and local knowledge.
    • Device: Irony—Macculloch dismisses the idea but concedes the evidence.
    • Significance: Darwin values empirical consensus over individual opinion.

  6. "It is impossible that such a belief should have become universal... without some good foundation."

    • Device: Appeal to probability—if many cultures believe it, there’s likely truth.
    • Link to Science: Reflects Darwin’s inductive reasoning (generalizing from specific cases).

  7. "Humboldt says, that the great epidemics of Panama and Callao are 'marked' by the arrival of ships from Chile..."

    • Context: Humboldt was a pioneer in biogeography; his observation supports the climate-disease link.
    • Implication: Human migration spreads disease—a precursor to pandemic studies.

  8. "I may add, that I have heard it stated in Shropshire, that sheep... frequently produce sickness in the flock."

    • Theme: Parallel between humans and animals.
    • Device: Analogy—reinforces the idea that biological principles are universal.
    • Significance: Shows Darwin’s comparative method, later key to Origin of Species.

Conclusion: Why This Passage Matters ​

This excerpt is a microcosm of Darwin’s scientific approach:

  • Observational: He gathers data from diverse sources.
  • Comparative: He looks for patterns across species and cultures.
  • Speculative but Restrained: He doesn’t jump to conclusions but hints at deeper laws.

While not as famous as his evolutionary theories, this passage reveals how Darwin’s attention to small, seemingly unrelated details (like ship-borne illnesses) contributed to his broader understanding of life’s interconnectedness. It also reflects the 19th-century scientific mindset, where exploration, empiricism, and interdisciplinary thinking laid the groundwork for modern biology and medicine.

In today’s context, the passage resonates with discussions on pandemics, globalization, and ecological disruption—showing that Darwin’s insights remain relevant nearly 200 years later.