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this are flat, join one another by broad edges, and closely 
resemble those lately described by Ranvier as existing in the 
tendons (‘ Quarterly Journal of Microscopical Science,’ Oct., 
1870). A more intimate connection is thus shown to exist 
between the structure of the cornea and that of ordinary 
connective tissue. 
Under the flat epithelial cells lies a gluey albuminous 
substance which also extends into the interspaces between 
the felted fibres of which the mass of the cornea is composed. 
It is the aggregation of this substance in irregular masses 
round the nucleus of the superincumbent cell under the 
influence of reagents, to which the positive and negative 
images are due. Schweigger-Seidel has further discovered 
a remarkable geometrical structure in Descemet’s membrane, 
or the posterior elastic layer of the cornea, which is brought 
into view by the use of a solution of common salt as a 
reagent. 
Connective Tissue of the Brain.—Signor Golgi (in ‘Rendi- 
conti del R. Instituto Lombardo di Scienze e Lettere,’ ser. ii, 
vol. iii, fas. vii, p. 3) has been making some interesting 
investigations on the structure of the brain after maceration 
for twenty-four or forty-eight hours in osmic acid. Thin 
sections thus treated exhibit numerous stellate cells, the pro- 
toplasm of which gives off a variety of branches, some of 
which anastomose with those of other cells, whilst others are 
lost in the grey and finely-granular neuroglia; and others 
again, and these are the most numerous, pass to the walls of 
the capillary blood-vessels and larger lymphatics. He 
makes the observation that in such sections the brain sub- 
stance is seen to be in immediate contact with the vascular 
walls, no intervening space being visible, as in preparations 
that have been treated with bichromate of potash. This has 
an important bearing on the histology of the brain, since 
Eberth, His, and others have regarded these spaces as the 
lymphatics of the brain. The anastomosing connective tissue 
cells above described are most abundant near the surface of 
the brain, and they gradually diminish in the deeper parts, 
so that in the region of the ganglion-cells, and still more of 
the white substance, they are very sparingly present. 
Development.— Parthenogenesis in the Pupa state of Insects. 
—In vol. xv, No. 8, of the ‘ Memoirs of the Academy of St. 
Petersburg,’ M. O. von Grimm describes a curious instance 
of Parthenogenesis in a species of the dipterous genus Chiro- 
nomus. Like the well-known case of Miastor, discovered by 
Professor Wagner, this is an example of reproduction by 
an insect in one of its preparatory, and therefore sexless 
