Differentiation of oxytalan fibres from elastic fibres with reagents for detection of magnesium.

Elastic fibres in various human and animal tissues revealed positive results with reagents for the detection of magnesium. By contrast, no Mg could be detected in oxytalan fibres or in zonular fibres of the ciliary body, which are composed of microfibrils not containing elastin. Mg is therefore concluded to be associated with the elastin core of elastic fibres. Its antagonism to calcium is speculated to play a protective role in maintaining the extensibility of elastin.