Editing Joseph Lister (section)

====1858 An Inquiry Regarding the Parts of the Nervous System Which Regulate the Contractions of the Arteries====
During 1856, Lister has been thinking about the nervous control of blood vessels and had been studying the work of various French researchers who were examining the [[denervation]] of the [[sympathetic nerves]].{{sfn|Best|1970|p=12}} Lister thought that how blood vessels behaved when irritated was important to understand the inflammatory process.{{sfn|Fisher|1977|p=87}}

The experiments on [[vasomotor]] [[Vasomotor center|control]] began in the autumn of 1856 and continued until the autumn of the next year.{{sfn|Best|1970|p=16}} In total, Lister conducted 13 experiments, some of which were repeated to verify the results of other experiments in the series.{{sfn|Best|1970|pp=17-21}} He used a microscope fitted with an [[ocular micrometer]], a recent invention, to measure the diameter of blood vessels in a common frogs web. In a before and after experiment, he [[ablated]] parts of the central nervous system{{sfn|Lister|1858b|pp=610–611}} and also before and after, split the [[sciatic nerve]].{{sfn|Howard|2013|p=194}} Lister concluded that blood vessel tone{{efn|Known as vascular tone, that is defined as the degree of constriction experienced by a blood vessel relative to its maximally dilated state{{sfn|Chatziprodromou|Tricoli|Poulikakos|Ventikos|2007}}}} was controlled from the [[medulla oblongata]] and the [[spinal cord]].{{sfn|Lister|1858b|p=625}} This refuted Wharton's conclusions, in his paper ''Observations on the State of the Blood and the Blood-Vessels in Inflammation.''{{sfn|Jones|1853|pp=391–402}} who was not able to confirm that the control of blood vessels of the hind legs was dependent upon spinal centres.{{sfn|Best|1970|p=5}}

In October 1857, the referee for ''[[Philosophical Transactions]]'' John Goodsir wrote to Sharpey who warned Lister that the experimental conclusions were similar to findings by the German [[physiologist]] [[Eduard Friedrich Wilhelm Pflüger]].{{sfn|Best|1970|p=15}}  This was to enable Lister to print an acknowledgement.{{sfn|Best|1970|p=15}} Pflüger found that vasomotor control was through nerve fibres connected to the [[spinal canal]] which were similar to Lister research showing vaso-motor fibres came from the spinal canal through the sciatic plexus.{{sfn|Best|1970|p=16}} Although their approaches were similar, Lister used denervation and discovered that even after parts of the spinal cord were removed, the [[arteriole]]s eventually recovered their contractility.{{sfn|Best|1970|p=16}}

These experiments{{sfn|Lister|1858b}} settled a contemporary dispute between physiologists concerning the origin of the influence exercised over [[blood vessel]] diameter (calibre) by the [[sympathetic nervous system]].{{sfn|Howard|2013|p=195}} The dispute began when [[Albrecht von Haller]] formulated a new theory known as ''Sensibility and Irritability'' in his 1752 thesis ''De partibus corporis humani sensibilibus et irritabilibus''. The dispute had been debated since the middle of the 18th century. Haller put forward the view that contractability was a power inherent in the tissues which possessed it, and was a fundamental fact of physiology.{{sfn|Best|1970|p=23}} It concerned the property of ''irratability'', the supposed automatic response of muscular tissue, especially visceral tissue, to external stimulus, that caused them to contract when stimulated.{{sfn|Best|1970|p=23}} Even as late as 1853, highly respected textbooks, for example [[William Benjamin Carpenter]] ''Principles of Human Physiology'' stated the doctrine of 'irritability' was a fact beyond dispute,{{sfn|Carpenter|1853|p=309}} and this was still considered contentious when [[John Hughes Bennett]] created the ''Physiology'' article for the 8th edition of [[Encyclopædia Britannica]] in 1859.{{sfn|Best|1970|p=23}}