Varga Benedek szerk.: Orvostörténeti közlemények 149-157. (Budapest, 1996)

KISEBB KÖZLEMÉNYEK / ESSAYS - Jeszenszky Sándor: Gondolatok Alexander Béla (1857—1916) plasztikus röntgenképeiről. A röntgen-sugár felfedezésének 100. évfordulójára

across techniques justified by very similar considerations. The author presents various examples to establish this point. In order to make the pictures easily recognisable computer tomography developed a system based on the very same principles. Since human eye is unable to differentiate between the hundreds of shades of black and white colours, coventionally false, i.e. artificially simplified colours are used to present e.g. the different cells of brain. In astrology the comparison of positive and negative images shot from the same perspective at different times also makes the already known information more visible. In modern radiology subtractive angiography uses also the advantages of positive and negative images. None of these procedures bring any new piece of information together, they simply make things more visible but no one would question their scientific benefits. In this sense up to date natural science introduced very similar principles for all photo techniques, and this was the point that Alexander's invention was about.