All students of the classical languages are aware that, in referring to intervals of time, the Greeks and Romans often employed a method of reckoning which was inclusive and consequently different from our own. The Greeks, for example, refer to the period between two celebrations of the Olympic games (e.g. 776–772 B.C.) as a though we should call it a four-year interval. One instance of this kind of usage in Latin is the stereotyped formula employed in expressing a date: ante diem quintum Id. Mai. is 11 May, though we should say that there was an interval of four days only between 11 and 15 May. Another instance is the use of tertiana and quartana as applied to fevers which recur on alternate days and on every third day respectively. The ramifications of this mode of expression are extensive, but I am only concerned here with one, namely the use of quisque with ordinals.