Editing Candling (section)

{{Short description|Method of observing an embryo inside an egg, using a bright light source}}
{{other uses|Candle (disambiguation)}}
{{One source|date=June 2014}}

[[File:CDC microbiologist demonstrating how to candle an embryonated chicken egg.tiff|thumb|Candling an egg]]

'''Candling''' is a method used in [[embryology]] to study the growth and development of an [[embryo]] inside an [[egg (biology)|egg]]. The method uses a bright light source behind the egg to show details through the shell, and is so called because the original sources of light used were [[candle]]s.{{cn|date=May 2014}}

The technique of using light to examine eggs is used in the egg industry to assess the quality of edible eggs.<ref>{{cite web
| url = http://urbanext.illinois.edu/eggs/res26-candling.html | title = Candling eggs | publisher = [[University of Illinois system|University of Illinois Extension]] | quote = Eggs are candled to determine the condition of the air cell, yolk, and white. Candling detects bloody whites, blood spots, or meat spots, and enables observation of germ development. Candling is done in a darkened room with the egg held before a light. The light penetrates the egg and makes it possible to observe the inside of the egg. Incubated eggs are candled to determine whether they are fertile and, if fertile, to check the growth and development of the embryo | date=2019| accessdate = 2012-06-06}}</ref>

<gallery>
File:CDC PHIL 10147 – candling, non-fertile egg.jpg|A non-fertile chicken egg, with only a round yolk sac
File:CDC PHIL 10148 – candling, fertilized egg, non-viable.jpg|A non-viable fertilized chicken egg, with a thin blood ring encircling the yolk
File:CDC PHIL 10149 – fertilized egg, 11 days old.jpg|A fertilized chicken egg, 11 days old, with blood vessels surrounding the yolk
</gallery>