Chem. Also kystein, kiestein(e, kiestin(e, kyesteine. [ad. F. kiestéine, the term invented by Nauche (Journ. de Chimie Médicale, 2nd Ser. V. 64, 1839), loosely f. Gr. κύησ-ις conception, app. after protéine and the like. When spelt as in Fr., often pronounced (kīstin, -əin); but more usually written ky- after Gr. κυ-. With more accurate knowledge of the nature of the thing, the name is now little used.] A whitish substance occasionally found as a cloud in or pellicle upon urine; erroneously supposed by Nauche to be diagnostic of pregnancy.
1846. G. E. Day, trans. Simon’s Anim. Chem., II. 329. Nauche regards kystein as an indubitable sign of pregnancy.
1847–9. Todd, Cycl. Anat., IV. 461/1. During pregnancy, a substance, kiestein … is eliminated by the urine.
1888. Syd. Soc. Lex., Kyesteĭn … is now known to be chiefly composed of ammoniaco-magnesian phosphates, with fat-particles, vibrios, and bacteria, and to be found in putrefying urine other than that of a pregnant woman. It is probably produced by the decomposition of the urea in contact with mucus.
