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La Rivista Italiana della Medicina di Laboratorio 2020 Settembre;16(3):218-24

DOI: 10.23736/S1825-859X.20.00071-7


language: Italian

Urine chemical studies in the first half of nineteenth century: the cianorina

Giuliano DALL’OLIO

Libero Professionista, Montecchio Maggiore, Vicenza, Italia

In the first decades of the nineteenth century, researchers of “animal chemistry” received from doctors requests to carry out chemical research to identify substances that, in specific pathological situations, make urine acquire different colors from the usual shades of yellow. The first chemical analysis on the subject is due to the French pharmacist Jean Sebastien Eugène Julia Fontenelle who in 1823 and 1825 publishes two works on cases of patients suffering from urinary tract diseases with emission of urine with blue color. With the chemical-analytical methods available at the time, he identifies in these urine the presence of urea in small quantities, albumin, gelatin and especially iron hydrocyanate, responsible, in his opinion, for the blue color of the emissions of the patients. Julia Fontenelle’s hypothesis is supported by the research of chemistry professor Giuseppe Mojon who had found iron hydroferrocyanate in the blue urine of a young girl treated with iron protoxide. It would therefore seem essential to take iron preparations for the formation of blue compounds, a hypothesis that falls when one of the patients examined by Julia Fontenelle is discovered to have taken no iron-based remedy. In 1825 too, Henri Braconnot considers the component contained in the blue urine a new substance not yet studied by chemists which he calls cyanourine. At this point, numerous debates among doctors and chemists promote the continuation of investigations. Gian Lorenzo Cantù leans toward the presence of iron ferrocyanide, while others attribute the blue color to the presence of indigo: for this reason, Jons Jakob Berzelius, in 1833, concludes that the blue substances found in urine may be of various nature. In 1846, Giovanni Semmola, given the disagreement of researchers resumes research on the subject. Carefully studying some cases, he extracts from the urine a substance that is different from those until then proposed, which he still wants to call cianorina, and which will be known as “Semmola cianorina.” However, the question remains open.

KEY WORDS: Urina azzurra; Urina blu; Cianorina

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