{{Short description|English doctor (1789-1840)}} {{Use British English|date=October 2019}} {{Use dmy dates|date=October 2019}} {{Infobox person | name = Tweedy John Todd | image = Portrait_of_Tweedy_John_Todd_by_John_Partridge.jpg | image_size = | citizenship = British | caption = Portrait of Tweedy John Todd by John Partridge | birth_date = 1789 | birth_place = Berwick-Upon-Tweed | death_date = 4 August 1840 | death_place = Hurst, West Sussex | occupation = Naturalist<br>Doctor<br>Navy Surgeon | spouse = | parents = | children = }}
'''Tweedy John Todd''' (1789–1840) (also known as Tweedie John Todd, or John Tweedy Todd) was an English doctor, Royal Navy surgeon and naturalist who conducted early experimental work on healing and regeneration in animals.<ref name=":0">{{Cite journal|date=1940-08-03|title=Dr. Tweedie John Todd|journal=Nature|language=En|volume=146|issue=3692|pages=162|doi=10.1038/146162a0|bibcode=1940Natur.146Q.162. |doi-access=free}}</ref>
==Biography== ===Early life=== Tweedy John Todd was born in 1789 in Berwick-Upon-Tweed where his father was a borough treasurer.<ref name=":0" /> Todd studied medicine at the University of Edinburgh, but did not complete his degree, joining the Royal Navy instead in 1809.<ref name=":4">{{Cite journal|date=1840|title=Obituary: Dr. Todd|journal=British and Foreign Medical Review|volume=10|pages=599–600|url=https://archive.org/details/britishandforei00sgoog/page/n621}}</ref>
===Navy career=== Todd began his career as a Royal Navy surgeon working in the Royal Naval Hospital at Plymouth. He later sailed to the East Indies and the Cape of Good Hope and was appointed surgeon on the flagship of Sir Robert Stopford aged only 23.<ref name=":4" /> While at the Cape of Good Hope aboard {{HMS|Lion|1777|6}}, he performed experiments on the ''Torpedo'' electric ray, which were published in the ''Philosophical Transactions'' ''of the Royal Society.''<ref>{{Cite journal|last=Todd|first=John T.|date=1816-01-01|title=VI. Some observations and experiments made on the torpedo of the Cape of Good Hope in the year 1812|journal=Philosophical Transactions of the Royal Society of London|language=en|volume=106|pages=120–126|doi=10.1098/rstl.1816.0007|issn=0261-0523|doi-access=}}</ref>
Todd retired from the navy in 1816, and lived in Italy for 6 or 7 years.<ref name=":1">{{Cite book|title=A History of regeneration research : milestones in the evolution of a science|date=1991|publisher=Cambridge University Press|others=Dinsmore, Charles E., American Society of Zoologists.|isbn=9780521392716|edition= 1st|location=Cambridge [England]|oclc=22890868}}</ref> Following this he returned to his studies and completed two medical degrees, first at the University of Montpellier, then at the University of Aberdeen<ref name=":4" /> before ultimately settling in Brighton in 1829, where he developed a medical practice.<ref name=":0" />
===Scientific work=== While studying and then working as a physician in Brighton, Todd continued to publish papers on natural history, including work on fireflies in ''The Luminous Power of Some of the Lampyrides'' in 1827.<ref>{{Cite journal|last=Todd|first=Tweedy John|date=1827-01-01|title=Ueber die Natur des Leuchtvermögens einiger Lampyrus-Arten|journal=Archiv der Pharmazie|language=en|volume=21|issue=2|pages=169–173|doi=10.1002/ardp.18270210211|s2cid=91276339|issn=1521-4184|url=https://zenodo.org/record/1902195}}</ref> In 1831 wrote ''The Book of Analysis. A New Method of Experience'',<ref>{{Cite book|url=https://archive.org/details/bookofanalysis00todd|title=The Book of Analysis|last=Todd|first=Tweedy John|date=1831|publisher=J. Murray|language=en}}</ref> in order to encourage physicians and scientists to apply the Baconian method of inductive reasoning to medicine and the other natural sciences.<ref name=":0" />
Todd began experiments on healing using newts at the British Naval base in Naples, and continued when he moved to Brighton.<ref name=":1" /> He conducted a series of experiments on the newts and other animals such as worms to study the processes of healing and regeneration of wounds and amputated body parts. These were the first experiments that proved that nerves have a role in healing, and that amphibian limbs cannot regenerate if the nerves are cut.<ref>{{Cite journal|last1=Kumar|first1=Anoop|last2=Godwin|first2=James W.|last3=Gates|first3=Phillip B.|last4=Garza-Garcia|first4=A. Acely|last5=Brockes|first5=Jeremy P.|date=2007-11-02|title=Molecular Basis for the Nerve Dependence of Limb Regeneration in an Adult Vertebrate|journal=Science|language=en|volume=318|issue=5851|pages=772–777|doi=10.1126/science.1147710|issn=0036-8075|pmid=17975060|pmc=2696928|bibcode=2007Sci...318..772K }}</ref><ref name=":1" /> He observed the healing process microscopically and collaborated with histologist Charles Ager to produce over 3,000 microscope slides to illustrate his findings. These slides are amongst the earliest surviving examples of the use of Canada balsam as a mountant.<ref name=":2">{{Cite journal|last=Bracegirdle|first=Brian|date=1988|title=John Thomas Quekett and his work on the healing of wounds|journal=Quekett Journal of Microscopy|volume=36}}</ref>
Todd's research was not well known in the second half of the 19th century,<ref name=":1" /> but was the basis of many studies in the early 20th century,<ref name=":3">{{Cite book|title=Principles of regenerative biology|last=M.|first=Carlson, Bruce|date=2007|publisher=Elsevier/Academic|isbn=9780080477961|location=Amsterdam|oclc=162573165}}</ref> and more recently the importance of Todd's work has been acknowledged by medical historians.<ref name=":1" /><ref name=":3" />
Todd died from tuberculosis on 4 August 1840, in Hurst, Sussex. He was aged 50 or 51.<ref name=":4" /> After his death his large collection of microscope slides came to the attention of Richard Owen, who was then the conservator of the Hunterian Museum at the Royal College of Surgeons in London, but would later become the first director of the Natural History Museum. Owen was impressed by the quality of the slides and in 1841 he purchased 1,500 of them for £150 ({{Inflation|UK|150|1841|fmt=eq|cursign=£}}) to use in the teaching of surgeons.<ref name=":2" /> The slides are considered to be important in the history of medicine, histology and microscopy and they remain in the College's collection today.<ref name=":2" />
==Published works== * Some Observations and Experiments Made on the ''Torpedo'' of the Cape of Good Hope in the Year 1812. John T. Todd ''Phil. Trans. R. Soc. Lond.'' 1816 '''106''', 120-126, published 1 January 1816 * The Regeneration of Parts in the Aquatic Salamander ''Quarterly Journal of Science, Literature and Arts'' 1823 * The Luminous Power of Some of the Lampyrides 1827 * ''The Book of Analysis: Or, a New Method of Experience, Whereby the Induction of the Novum Organon [Of F. Bacon] Is Made Easy of Application'', 1831, Published by John Murray, London
==References== {{Reflist}}
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{{DEFAULTSORT:Todd, Tweedy John}} Category:1789 births Category:1840 deaths Category:Royal Navy officers Category:English surgeons Category:19th-century British biologists Category:Alumni of the University of Edinburgh Category:Alumni of the University of Aberdeen Category:19th-century English naturalists