Editing Biophoton (section)

===Hypothesized involvement in cellular communication===
In the 1920s, the Russian embryologist [[Alexander Gurwitsch]] reported "ultraweak" photon emissions from living tissues in the UV-range of the spectrum. He named them "mitogenetic rays" because his experiments convinced him that they had a stimulating effect on [[cell division]].<ref name=pmid3294029>{{cite journal | vauthors = Gurwitsch AA | title = A historical review of the problem of mitogenetic radiation | journal = Experientia | volume = 44 | issue = 7 | pages = 545–50 | date = July 1988 | pmid = 3294029 | doi = 10.1007/bf01953301 | s2cid = 10930945 }}</ref>

In the 1970s [[Fritz-Albert Popp]] and his research group at the [[University of Marburg]] ([[Germany]]) showed that the spectral distribution of the emission fell over a wide range of wavelengths, from 200 to 750&nbsp;nm.<ref>{{cite journal | vauthors = Wijk RV, Wijk EP | title = An Introduction to Human Biophoton Emission| journal = Forschende Komplementärmedizin und Klassische Naturheilkunde | volume = 12 | issue = 2 | pages = 77–83 | date = April 2005 | pmid = 15947465 | doi = 10.1159/000083763 | s2cid = 25794113 }}</ref>  Popp's work on the biophoton emission's statistical properties, namely the claims on its coherence, was criticised for lack of scientific rigour.<ref name="coherence"/>

One biophoton mechanism focuses on injured cells that are under higher levels of [[oxidative stress]], which is one source of light, and can be deemed to constitute a "distress signal" or background chemical process, but this mechanism is yet to be demonstrated.{{citation needed|date=February 2020}} The difficulty of teasing out the effects of any supposed biophotons amid the other numerous chemical interactions between cells makes it difficult to devise a testable hypothesis. A 2010 review article discusses various published theories on this kind of signaling.<ref name=pmid20674588>{{cite journal | vauthors = Cifra M, Fields JZ, Farhadi A | title = Electromagnetic cellular interactions | journal = Progress in Biophysics and Molecular Biology | volume = 105 | issue = 3 | pages = 223–46 | date = May 2011 | pmid = 20674588 | doi = 10.1016/j.pbiomolbio.2010.07.003 }}</ref>

The hypothesis of cellular communication by biophotons was highly criticised for failing to explain how could cells detect photonic signals several orders of magnitude weaker than the natural background illumination.<ref name="communication">{{cite journal | vauthors = Kučera O, Cifra M | title = Cell-to-cell signaling through light: just a ghost of chance? | journal = Cell Communication and Signaling | volume = 11 | issue = 87 | pages = 87 | date = November 2013 | pmid = 24219796 | doi = 10.1186/1478-811X-11-87 | pmc = 3832222 | doi-access = free }}</ref>