'That a perception initiated from corresponding retinal points is commonly referred without ambiguity to a single locus in visual space has often been regarded (Newton [note: 'Opticks, Quer. 112.'] Wollaston [note: Philosoph. Trans. London, 1824.'], Rohault [note: 'Physique, I. 31.'], Joh. Müller [note: 'Elements of Physiol. Vol. II. p. 1199, Baly's edit. 1843.'] as evidence of community of the nerve apparatus belonging to the paired retinal points. Rohault and Miiller supposed the points to be served by twin fibres "from one and the same ganglion-cell in the cerebral substance."' (53)