= C. B. McKerrow
{c}
\b[<C. B. McKerrow>] coauthored the 1959 primary report with <Basil Martin Wright> on maximum forced expiratory flow and a portable instrument for measuring it. The primary record retains the initials C. B.; no fuller name is established here. The scientific contribution links a compact flow measurement to quantitative assessment of ventilatory performance.<Maximum Forced Expiratory Flow Rate as a Measure of Ventilatory Capacity by Basil Martin Wright and C. B. McKerrow>[Primary byline; BMJ 2(5159), pp. 1041–1046; indexed subtitle on the portable instrument]{ref}
<Peak expiratory flow> is the maximum of the expiratory volume-flow curve, whereas expired volume is its time integral:
$$
Q_{\rm peak}=\max_t Q(t),\qquad V_{\rm expired}=\int Q(t)\,dt.
$$
A maximum and an integral preserve different information. Their distinction motivates a flowmeter even when a volume measurement is also available.
For two original triangular flow pulses, let one have height 8 L/s and base duration 0.25 s, and the other height 4 L/s and duration 0.50 s. Both enclose 1 L, but their peak flows are 480 and 240 L/min. Equal expired volumes therefore do not imply equal peak flow. These stipulated traces are not human reference values or results assigned to McKerrow's experiment.
The surviving Wright instrument is documented by a primary museum collection record, including its portable construction and a dial graduated in litres per minute.<Wright Peak Flowmeter at the Wood Library-Museum of Anesthesiology>[Object description and catalogue, accession 1998-02-25-1]{ref} Such an instrument supplies a specific observable. It does not, from one peak alone, reconstruct the entire expiratory curve or distinguish every possible cause of an altered measurement.
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