Why is a royal said to have blue blood?

i think it is something to do with india in the nineteith century

Why is a royal said to have blue blood?
It goes WAY back before the nineteenth century, and refers to all nobility, not just royalty.





See, the peasants were always outside working, and their skin was always fairly dark, from the sun. But the nobility was fair, and pale, because they didn't have to work as much and they spent more of their time indoors, so their skin was more translucent. Now, if you look at the inside of your arms, where the skin is palest, you can see blue veins. That would have been much more apparent on a nobel's skin, so people thought their blood was bluer than a peasant's.
Reply:A literal translation of the Spanish 'sangre azul', attributed to some of the oldest and proudest families of Castile, who claimed never to have intermarried with Moors, Jews, or other races. The expression probably originated in the blueness of the veins of people of fair complexion as compared with those of dark skin.
Reply:If we prick our finger it bleeds red and thats it. we're all the same blue vains, red blood.
Reply:Maybe all the in-breeding changed the colour!!!
Reply:Years ago, someone told me that... our blood is really colored blue. It becomes red when oxygen gets mixed with it (and it happens either when you get wounded or cut yourself).





The question is: Is it true?





From the wikipedia:





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Hemoglobin





Hemoglobin is the principal determinant of the color of blood in vertebrates. Each molecule has four heme groups, and their interaction with various molecules alters the exact color. In vertebrates and other hemoglobin-using creatures, arterial blood and capillary blood are bright red as oxygen impacts a strong red color to the heme group. Deoxygenated blood is a darker shade of red with a bluish hue; this is present in veins, and can be seen during blood donation and when venous blood samples are taken. Blood in carbon monoxide poisoning is bright red, because carbon monoxide causes the formation of carboxyhemoglobin. In cyanide poisoning, the body cannot utilize oxygen, so the venous blood remains oxygenated, increasing the redness. While hemoglobin containing blood is never blue, there are several conditions and diseases where the color of the heme groups make the skin appear blue. If the heme is oxidized, methemoglobin, which is more brownish and cannot transport oxygen, is formed. In the rare condition sulfhemoglobinemia, arterial hemoglobin is partially oxygenated, and appears dark-red with a bluish hue (cyanosis), but not quite as blueish as venous blood.





Veins in the skin appear blue for a variety of reasons only weakly dependent on the color of the blood. Light scattering in the skin, and the visual processing of color play roles as well.[16]





Skinks in the genus Prasinohaema have green blood due to a buildup of the waste product biliverdin.





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Reply:I've always been told it's to do with the veins on your wrist. Pale skinned people appear to have blue blood in these veins. whereas darker skinned people don't. It was the fashion to be as pale as possible because it denoted that you didn't have to go outside for work etc and that when you when outside you could be covered.
Reply:Blue blood is an English expression recorded since 1834 for noble birth or descent; it is a translation of the Spanish phrase sangre azul, which described the Spanish royal family and other high nobility who claimed to be 'pure', free of Moorish or Jewish blood, being of Visigothic descent. The Spaniards who gave the world the notion that an aristocrat's blood is not red but blue. The Spanish nobility started taking shape around the ninth century in classic military fashion, occupying land as warriors on horseback. They were to continue the process for more than five hundred years, clawing back sections of the peninsula from its Moorish occupiers, and a nobleman demonstrated his pedigree by holding up his sword arm to display the filigree of blue-blooded veins beneath his pale skin—proof that his birth had not been contaminated by the dark-skinned enemy.





There is no connection between the phrase and the actual blood color of nobility; however, in the ancient agricultural societies of Europe the whole upper class had superficial veins that might be more visible and appear bluish by comparison to the rest of the pale-pinkish skin, as the skin itself was not tanned. In contrast with the working class of the time (mainly peasants), nobility and in general upper class people did not have to work outdoors, and mostly lived sheltered from the sun by dwellings and attire. The same contrast could be observed between untanned upper-class Europeans—especially of Northern-European stock, whose skin tends to be less pigmented—and all social strata of Mediterranean populations with higher levels of genetically determined skin pigmentation. An alternative traditional explanation, argyria (a disease causing a blue-grey skin tone after digestion of silver), is considered less valid, as table silverware was not regularly used by much of the nobility.