Page:Proceedings of the Royal Society of London Vol 4.djvu/225

Rh two Eyes." By T. Wharton Jones, Esq. Communicated by Richard Owen, Esq., F.R.S.

The author animadverts on the doctrine which Mr. Wheatstone, in his paper on the Physiology of Binocular vision, published in the Philosophical Transactions for 1838, p. 371, has advanced, in oppo- sition to the received theory of single vision being dependent on the images of objects falhng on corresponding points of the two retinae. He maintains that, under these circumstances, the two impressions are not perceived by the mind at the same instant of time, but some- times the one and sometimes the other. If one impression be much stronger than the other, the former predominates over, or even ex> eludes the other ; but still the appearance resulting from the predo- minating image is nevertheless in some manner influenced by that which is not perceived. He supposes that there are compartments of the two retinae, having certain limits, of which any one point or papilla of the one corresponds with any one point of the other, so that impressions on them are not perceived separately ; and consi- ders that this hypothesis, combined with the principle above stated, is required, in order to explain the phenomena in question.

John Parkinson, Esq. and the Rev. Charles Pritchard, M.A, were balloted for, and declared duly elected into the Society.

A paper was read, entitled " Observations on the Blood-corpuscles of certain species of the Genus Cervus." By George Gulliver, Esq., F.R.S., Assistant Surgeon to the Royal Regiment of Horse Guards.

The author has found that the blood of the Muntjac*, the Por- cine f, and the Mexican Deer J, contains, together with corpuscles of the ordinary circular form, a still larger number of particles of less regular shape; some curved and gibbous in the middle, and acutely pointed at the ends, with a concave and convex margin, like a crescent ; others approaching more nearly to segments of a circle ; some shaped like a comma, being obtuse at one end and terminated by a pointed curve at the other ; others having an acute projection of the convex part, so as to constitute a triangular, or even quadrangular outline ; some having the figure of the head of a lance ; while a few- presented a double or sigmoid flexure, as if they had been twisted half round at the middle. Like the ordinary blood-discs, these pe- culiar corpuscles are deprived of their colouring matter by water ; but with only a small quantity of water they quickly swell out, and


 * Cervus Reevesii, f C. Porcims^ I C. Mexicanus.