Mr. T. W. Jones on Single Vision mth two Eyes, 599 
After premising a short account of the labours of preceding wri- 
ters, with reference to a system of notation in the mathematical 
consideration of life contingencies, the author enters at length into 
an exposition of the system of symbols which he has himself de- 
vised, together with the applications which they admit of in a variety 
of cases. 
Jan. 30. — A paper was read, entitled “ Observations on Single 
Vision with two Eyes.” By T. Wharton Jones, Esq. Communi- 
cated 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 falling 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- 
cludes 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. 
Feb. 6. — 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 Guardsf. 
The author has found that the blood of the Muntjac J, the Por- 
cine§, and the Mexican Deerj], 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 
assume an oval or circular figure, forming long bead-like strings by 
* [Noticed in L. and E. Phil. Mag., vol. xiii., p. 46 1.] 
t [Papers by Mr. Gulliver, on the blood-corpuscles of various animals, 
will be found in the present volume, p. 23, 105, and 195. — Edit.] 
I Cervus Reevesii, § C. Porcinus^ || C. Mexicanus, 
