PACCHIONTANBODIES, or GLANDULA: PACCHIONI, numerous small, whitish gran ular looking bodies, collected together in clusters of varying size, found upon the human meninges, or cerebral membranes, principally in the following localities: 1. Upon the aute7 surface of the dura mater, in the superiorlongitudinal sinus, being received into little depret sions, called Pacchionian depressions on the inner surface of the skull. 2. Upon the Mimi surface of the dura mater. 3. In the superior longitudinal sinus (a large venous canal, oi vein, attached to the inner surface of the skull, running from before backward). 4. Upon the pia meter, near the margin of the hemispheres. The Pacchionlan bodies are not gland ular in structure, but are composed of a fibro. cellular matrix originally developed from the pia mater. Their growth and consequent pressure produces absorption of the dura mate! through which they pass to the inner surface of the skull as well as into the superior longitudinal sinus. These bodies do not occur in infancy, and very seldom before the third year; usually after the seventh, increasing after this as age advances. Sometimes they arc wanting. What purpose they may serve is not known.
PACE (Lat. passes), in its modern acceptation, is tile distance, when the legs are extended in walking, between the heel of one foot and that of the other. Among dis
ciplined men the pace becomes of constant length, and as such is of the utmost value in determining military movements, the relative distances of corps and men being ,fixed by the number of paces marched, and so on. The pace in the British army is 2 ft. for ordinary marching, and 3 ft. for "double quick" or running time.—With the Romans, the pace had a different signification, and it is important to bear the distinction in mind, when reading of distances in Latin works; the single extension of the legs was not with them a pace (passes), but a step (yradus); their pace (passes) being the interval between the mark of a heel and the next mark of the same heel, or a double step. This pace was equivalent to 4.84 English ft. The pace was the Roman unit in itinerary measure; the mile being 1000 paces, or 5.000 Roman ft. equal to .917 of an English mile. See MILE. measurements were effected by actually counting the paces, or by the time occupied is not clear; but either method would, with disciplined troops give a safe result.
In the middle ages, writers confuse accounts of distances by allusion to a geometrical pace, a measure which varied with different authors.