douglas bag
Very Low Frequency (C2/Professional)Technical/Scientific
Definition
Meaning
A flexible, airtight container, traditionally made of rubberised fabric, used for collecting and measuring the volume of expired air during respiratory studies.
A piece of early physiological and sports-science laboratory equipment used for measuring oxygen consumption, carbon dioxide production, and thereby calculating metabolic rate.
Linguistics
Semantic Notes
Term refers to a specific, named apparatus, not a generic bag. It is historically significant but largely superseded by electronic gas analysers. The name is typically capitalised in scientific literature. It is a compound noun treated as singular.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage; the term is identical in technical contexts in both varieties.
Connotations
Connotes historical or foundational laboratory methods in exercise physiology and respiratory medicine.
Frequency
Extremely rare in both varieties, confined to specialised historical or methodological discussions in physiology.
Vocabulary
Collocations
Grammar
Valency Patterns
SUBJECT + [verb of use/collection] + (air/gas) + in/into + a Douglas bagThe Douglas bag + [verb of being used/connected] + to/for + PURPOSEVocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “Not applicable.”
Usage
Context Usage
Business
Not used.
Academic
Used in historical reviews of physiology, papers on the history of sports science, or methodological comparisons.
Everyday
Virtually never used.
Technical
The primary context; used in exercise physiology, respiratory therapy, and human performance laboratories when discussing legacy techniques.
Examples
By Part of Speech
verb
British English
- Not applicable.
American English
- Not applicable.
adverb
British English
- Not applicable.
American English
- Not applicable.
adjective
British English
- Not applicable.
American English
- Not applicable.
Examples
By CEFR Level
- Not applicable for this level.
- Not applicable for this level.
- Scientists sometimes used a Douglas bag to measure the air a person breathed out.
- The classic Douglas bag method involved collecting expired air over a set period to determine basal metabolic rate, though modern systems are now fully automated.
Learning
Memory Aids
Mnemonic
Imagine DOUG-LASS carrying a BAG of air to measure how hard he's breathing during his famous run.
Conceptual Metaphor
THE BODY IS A MACHINE (whose fuel efficiency is measured by analysing its exhaust).
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Avoid direct translation as "сумка Дугласа" without immediate technical explanation, as it will sound nonsensical. Use descriptive translation like "мешок Дугласа для сбора выдыхаемого воздуха" initially.
Common Mistakes
- Using lowercase ('douglas bag') in formal technical writing.
- Treating it as a plural countable noun (e.g., 'three Douglas bags' is fine, but 'Douglas bags' as a generic term is less common than 'the Douglas bag').
- Confusing it with a simple breathing bag used in anaesthesia.
Practice
Quiz
In which field would you most likely encounter the term 'Douglas bag'?
FAQ
Frequently Asked Questions
It was named after the British physiologist Claude Gordon Douglas (1882–1963), who contributed significantly to respiratory physiology.
Rarely. It has been largely replaced by faster, more accurate electronic metabolic carts and breath-by-breath analysis systems in modern laboratories.
Its primary purpose was the quantitative collection of all air exhaled by a subject over a period of time, allowing for measurement of its volume and analysis of its gas composition (O2 and CO2).
No, it is a highly technical term with no established metaphorical or everyday usage. Its use outside scientific discourse would be obscure and confusing.