Natural-Historical Collections. PLO 
sessed of their reason, on the contrary, the ventricles of the brain contain scarcely 
a drachm, and the whole of it does not exceed two ounces. 
M. Magendie thinks that the terms aqueduct, bridge, valvule, employed by the 
ancient anatomists in their descriptions of the organ, show that they were not 
Strangers to the knowledge of the fluid, which fills the cavities of this organ. 
In more modern times, Haller conjectured that it was subjected to a certain de- 
gree of humidity, destined to prevent the union of their parietes, and that its ac- 
cumulation could proceed only from disease; but M. de Semmerring, in a trea- 
tise on the organ of the mind, published in 1796, has already refuted this opinion, 
and shown that the ventricles of the brain are not solutions of continuity, pos- 
sible cavities alone, but true cavities constantly filled with a concrete fluid. It 
is even by the changes in composition which are produced in the fluid by means 
of nervous agency, that he attempts to account for the impressions which the 
mind experiences ; it is in this fluid, if we may be permitted so to speak, that he 
places its seat; but he does not speak of the opening described by M. Magendie, 
and by which the fluid of the ventricles communicates with that which fills the 
the spinal canal. 
M. Flourens, whose important discoveries on the effects of the removal of living 
parts of the encephalon were made known in our last report, has this year applied 
his method to the medulla oblongata and the spinal marrow, and has sought to 
ascertain their limits, and to compare their influence over respiration in the four 
classes of vertebral animals. 
M. Gireux de Buzareingues, corresponding member of the academy, has em- 
ployed a method peculiar to him, to determine the functions of different parts of 
the encephalon ; it is by observing the occasional changes in different sheep, from 
the disease known by the name of fowrnis,* and by remarking after death, the 
place in the brain which was occupied by ‘the parasitical animal or hydatid 
which produces this disease, the Tenia cerebralis of Gmelin, or Cenurus of Ru- 
dolphi. 
Dr Foville, physician to the Alien Hospital at Rouen, has presented to the 
Academy a memoir on the brain, wherein he views in a new manner the relations 
between the different parts of the organ and the spinal marrow, which he regards 
as analogous in composition to the brain itself. We have already made known 
in our analysis for 1823, a memoir of M. Bailly upon the analogy of composition ; 
but M. Foville does not view it in a manner altogether the same ; he considers the 
spinal marrow as formed, in each half of three fasciculi ; one anterior, one posterior, 
and one much larger, forming an imperfect canal, in which there is a band of gray 
substance ; the chords are united by a posterior white commissure. Arrived at the 
base of the cranium, the marrow enlarges and constitutes the anterior pyramids, the 
olivary bodies, the restiform bodies, and the posterior pyramids. The restiform 
bodies, as every one knows, are prolonged into the cerebellum. A little fasciculus, 
which seems to be a continuation of the olivary bodies, terminates, according to 
M. Foville, in the tubercula quadrigemina ; the anterior and posterior pyramids 
form the peduncles of the brain, where they are separated by the locus niger of 
Semmerring ; in the anterior ones only, the fibres decussate. According to the 
author,—and it is here that his ideas begin to take a peculiar direction,—the 
fasciculus formed by the peduncle, in advancing from the corpora striata, divides 
into three superincumbent planes. 
The superior plane disengages itself the first, rises and curves from without 
inwards, to unite with its fellow of the other side, and to form the corpus callo- 
sum, which is thus only a repetition of the commissure which joins the superior 
chords of the marrow, and has not that connection with the hemispheres them- 
selves, which M. Gall attributes to it, when he regards it as their commissure. 
The intermediate plane, the most considerable of the three, passing externally to 
the preceding, and lengthening itself on all sides, within the cortical substance, 
* A kind of paralysis which makes the animal turn round involuntarily.—En. 
VOL. I. 25 
