Article révisé par les pairs
Résumé : 1. 1. The ultraviolet absorption spectra of synthetic and naturally-occurring pyrimidine nucleosides were measured at various pH values and their "apparent" dissociation constants reported. 2. 2. Spectral variation as a function of pH in the high alkaline range is demonstrated and shown to be due to the dissociation of the sugar moeities. 3. 3. General spectrophotometric patterns are presented which enable the distinction between pyrimidine ribofuranosides and their desoxyribofuranoside analogues. 4. 4. Differences between pyrimidine glycopyranosides and glycofuranosides are presented and some implications for the spectra of hitherto unreported pyrimidine nucleosides are suggested. © 1952.