Nicolas Constantine Paulesco achieved the unrecognised distinction of proving that an unknown but constituent factor of the pancreas controls the physiological value of the blood-sugar of a normal animal and that its absence is the cause of diabetes mellitus. His research in this particular field of medicine was carried out on dogs and his proof was the culmination of years of experimental work of precursors, colleagues and himself. This great advance, perhaps equivalent in some respect to the discovery of the therapeutic virtue of penicillin, remains unacknowledged. An exposition of the facts attendant upon this neglect follows. The reader is left to draw his or her own conclusion regarding the award of the Nobel Prize for Medicine in 1923.