Editing Spirometer (section)

===Nineteenth century===
* 1813, Edward Kentish used a simple "Pulmometer" to study the effect of diseases on pulmonary lung volume. He used an inverted graduated bell jar standing in water, with an outlet at the top of the bell jar controlled by a tap. The volume of air was measured in units of [[pints]].
* 1831, [[Charles Thackrah]] described a "Pulmometer" similar to that of Kentish. He portrayed the device as a bell jar with an opening for the air to enter from below. There was no correction for pressure. Therefore, the spirometer not only measured the respiratory volume, but also the strength of the respiratory muscles.<ref name="spiro">''[http://medizin.li/spirometer/spirometer-history.html Spirometer history]'' URL assessed on 21 November 2009</ref>
* 1845, [[Karl von Vierordt]] in his book entitled "Physiologie des Athmens mit besonderer Rücksicht auf die Auscheidung der Kohlensäure" discussed his interest in measuring the volume of expiration accurately. He also completed accurate measures of other volume parameters by using his "Expirator". Some of the parameters he described are used today, including [[Lung volumes|residual volume]] and [[vital capacity]].
* 1846 The water spirometer measuring [[vital capacity]] was developed by a surgeon named [[John Hutchinson (surgeon)|John Hutchinson]]. He invented a calibrated bell inverted in water, which was used to capture the volume of air exhaled by a person. Hutchinson published his paper about his water spirometer and the measurements he had taken from more than 4,000 subjects,<ref name="spiro" /> describing the direct relationship between vital capacity and height and the inverse relationship between vital capacity and age. He also showed that vital capacity does not relate to weight at any given height. Hutchinson is regarded as the inventor of vital capacity because he found that with every inch of height vital capacity increased by eight cubic inches.<ref>{{cite journal |last1=Mcguire |first1=Coreen |title='X-rays don't tell lies': the Medical Research Council and the measurement of respiratory disability, 1936–1945 |journal=The British Journal for the History of Science |date=September 2019 |volume=52 |issue=3 |pages=447–465 |doi=10.1017/S0007087419000232 |pmid=31327321 |pmc=7136074 }}</ref> He also used his machine for the prediction of premature mortality. He coined the term 'vital capacity', which was claimed as a powerful [[prognosis]] for heart disease by the Framingham study. He believed that his machine should be used for actuarial predictions for companies selling life insurance.<ref>{{cite journal |last1=Petty |first1=Thomas L. |title=John Hutchinson's Mysterious Machine Revisited |journal=Chest |date=May 2002 |volume=121 |issue=5 |pages=219S–223S |doi=10.1378/chest.121.5_suppl.219S |pmid=12010855 }}</ref>
*1854 Dr. M. Alton Wintrich developed a spirometer, which was easier to use than Hutchinson's. He did an experiment with 4,000 subjects and concluded that there are three parameters affecting vital capacity: height, weight, and age. His experiment produced results similar to those of Hutchinson's study.
*1859 E. Smith developed a portable spirometer, which he used to measure gas metabolism.
*1866 Henry Hyde Salter (1823-1871) added a [[kymograph]] to the spirometer in order to record time while obtaining air volumes.
*1879 Gad J. published a paper entitled "Pneumatograph" that described a machine that allowed the recording of lung volume changes.