186 General Notes. [ February, 
to the area outside the fovea centralis. This increase of sensi- 
bility is proportionately greater toward the more refrangible rays. 
This fact affects the tone of colors, and on account of it the lumi- 
nosity of (the more refrangible ?) colors is increased at the expense 
of their saturation. The reader may be reminded, as an interest- 
ing confirmation of this view that, when alternate circles, painted 
blue and red, are looked at in obscurity, the former appear lumi- 
nous and the latter black. Visual purple is bleached by light and 
is regenerated under the influence of the pigmentary layer of the 
retina in the dark. In these facts we have an explanation of the 
varied sensibility toward light of different intensities — Comptes 
Rendus, 1885, p. 821. 
concerning the supply of blood to nerve ganglion cells. In 
his researches on the blood-vessels of the spinal cord, the author 
found that the richness in capillaries was directly proportional to 
the number of nerve-cells. His more special investigations of 
this relation were made on the intervertebral ganglia taken from 
injected animals. The nerve-cells composing these ganglia are 
each inclosed in a connective-tissue capsule, lined by flattened 
cells and having two tubular prolongations from it. The nerve- 
cell itself is inclosed in a special sac of flattened cells and pos- 
sesses two prolongations which reach out into those of the 
surrounding connective-tissue capsule. Between the latter cap- 
sule and the cell is a rather roomy space, and there is also a much 
narrower one between the substance of the cell and its own epi- 
thelial covering. The arterial blood enters by an afferent vessel 
into the pericellular space and leaves it by a much narrower 
efferent vessel. The blood thus surrounds the cell under pressure 
and its liquid portions pass actively by osmosis into the substance 
of the cell itself, in the centre of which they are received by an 
empty space. This empty space is nothing else than what has so 
long been regarded as the nucleus of the cell. This space belongs 
to the venous system with which it is in connection by a minute 
vessel having its own proper wall. A solid body, hitherto called 
the nucleolus, is suspended fixed in the centre of the nuclear 
cavity —Comptes Rendus, 1885, p. 826. 
PasTEUR’s METHOD FOR THE PREVENTION oF HypROPHOBIA.— 
In the Comptes Rendus for October, 1885, is the latest report of 
Pasteur’s experiments upon the prophylaxis of hydrophobia. The 
following is an outline of his procedure: When a small particle 
of the spinal cord of a dog dead from rabies (moelle rabigue) is 
placed under the dura mater of a rabbit the animal always falls 
‘a victim to hydrophobia after a period of incubation which lasts 
some fifteen days. When virus from the first rabbit is transferred 
in the same way to a second and, after the period of incubation is 
