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The rate of release of central acetylcholine (ACh) was determined in unanaesthetized cats by perfusing the sensorimotor cortex or the lateral ventricles with a neostigmine-containing solution by means of push-pull cannulae.

Ovariectomized female rats were injected with estrogen and progesterone and actinomycin D was implanted into different brain areas. Implants of actinomycin D inhibited estrogen-induced lordosis behavior when applied to the preoptic region within 12 hr of estrogen treatment regardless of whether the interval between implantation and testing was 29, 38, or 68 hr. Implants 21 hr after estrogen treatment were ineffective. Attempts to localize the site of action showed that implants into the preoptic region were effective even when the implant cannulae did not pierce the ventricles, that implants into the caudate nucleus were ineffective even if the cannulae pierced the lateral ventricles, and that implants into the third ventricle were highly effective in inhibiting lordosis behavior.

Two children presented with hydrocephalus associated with neurological signs. Plain radiographs of the skull were normal. In both cases carotid angiography demonstrated an obstructive hydrocephalus associated with elevation of the internal cerebral vein, suggesting a suprasellar mass. Air studies demonstrated an air-filled mass extending upwards into the 3rd ventricle from the suprasellar region. In one case the mass was seen occupying a significant part of the lateral ventricles. At operation suprasellar arachnoid pouches were demonstrated and successfully treated.

Intravenous administration of 5 mg/kg of morphine sulfate to unanesthetized rabbits was without effect on the output of acetylcholine (ACh) into the effluent collected by push–pull perfusion from the cerebral lateral ventricles or the sensorimotor cortex. Alterations in the rate of ACh release (enhancement of cortical release and depression of ventricular release) were noted with a variable delay following the injection of 10 mg/kg of morphine. These effects of morphine on cortical and ventricular ACh release were observed while behavioral sedation, analgesia, and respiratory depression were manifest in the animals. These results suggest a lack of correlation between behavior and ACh release from these areas of the brain in response to administration of morphine to the rabbit.

Four patients are reported who in the first decade of life developed intractable seizures, progressive dementia and a neurological deficit in the form of hemiplegia or quadriplegia. Pneumoencephalograms showed focal dilatation of lateral ventricles in 3 and generalised dilatation in 1 case. Electroencephalograms showed evidence of focal spike activity in 3 patients. These were operated upon for the relief of intractable seizures and in 1 patient only brain biopsy was done. The first patient with a total duration of illness of 5 years had complete relief from seizures and the EEG became free of spikes following a right temporal lobectomy. In the other 2, where right frontal lobectomy and cortical excision of right parietal lobe were done respectively, only moderate improvement in seizure control occurred and this too was not sustained in the second case. Histopathological study of resected brain tissue revealed areas of necrosis in the cortex associated with gliosis and areas of perivascular lymphocytic infiltration in the cortex and white matter. In 1 case in addition focal areas of inflammatory cellular infiltration of the meninges, composed mainly of lymphocytes and plasma cells, was seen. These changes suggested some form of chronic encephalitis. A viral aetiology could not be proved but was though to be most likely.

The brain lesions produced in mice by the administration of Clostridium welchii Type D toxin were examined by light and electron-microscopy. The earliest morphological changes were periaxonal and intramyelinic oedema in the white matter of the cerebellar corpus medullare and swelling of axon terminals and dendrites in grey matter adjacent to the lateral ventricles. Mitochondrial swelling was also a feature in areas of early malacia. These lesions progressed to severe malacia with extracellular oedema in white matter, occlusion of many capillaries by platelet-plugs, and petechial haemorrhages. It is suggested that the primary lesion responsible for these changes may be within the vascular endothelium of the brain.

Saline, dopamine, or norepinephrine was infused into the lateral ventricles of unrestrained rats via chronically implanted cannulae. Immediately after infusion, the amount of shock-induced fighting between pairs of rats was determined. Low doses of dopamine increased the number of attacks while norepinephrine infusions markedly reduced fighting. Two weeks after intraventricular injection of 6-hydroxydopamine, when shockinduced fighting is increased, the infusion of norepinephrine, but not dopamine, reduced the amount of attack behavior. The possibility is discussed that this type of aggressive behavior is modulated in part by a balance between dopaminergic and noradrenergic systems.

ThE considerable difficulties in diagnosis of tumors of the corpus callosum, often met with, made a detailed roentgenological study seem desirable. In this paper we present ~1 cases from the Neurosurgical Clinic of the University of Cologne in the years 1951 to 1957, and refer to another ~0 cases, described in an earlier paper, 15 from the Neurosurgical Clinic of the University of Berlin* in the years between 1937 and 1944. In respect to the roentgenological diagnosis of these tumors most authors seem to agree that deformation of the ventricular system seen in pneumoencephalographic studies is characteristic. Following is a summary of the descriptions given by Lysholm, 25 Dyke and Davidoff, 9 Davidoff and Epstein, ~ Kautzky and Ziilch, is Gebhardt, 15 and Lindgren: 22 Tumors of the corpus callosum are characterized by a separation of the lateral ventricles, usually causing a broadening of the septum pellucidum in its uppermost part, this deformation being best observed in the sagittal (anteroposterior) view. Usually the separation of the ventricular system is accompanied by a more or less pronounced lowering and bowl-like impression in the roof of both ventricles. On the lateral view one meets with a similar aspect, there usually being an impression in the roof of the anterior horn of both sides, usually with an irregular contour, and sometimes a deformation of the roof of the third ventricle. According to the size of the tumor and the possible obstruction of one or both interventricular foramina, there may exist a concomitant dilatation of the lateral ventricles. Tumors involving the corpus callosum do not always have a perfectly symmetrical growth and consequently the roentgenological aspect may vary. If the tumor has grown mainly to one side there will still be a deformation of the ventricles, but one of them will be more deformed than the other. This applies to expanding lesions of the rostrum and middle third of the corpus callosum. The separation of ventricles is very difficult to appreciate closer to the splenium of the corpus callosum, as similar pictures may be obtained when there is an insufficient quantity of air in the ventricles3 9,3~ As the ventricular cavities tend to separate from the midline in their posterior aspect, a chance of appreciating the deformity in * At that time Prof. W. Ttinnis was Director.

1. Adult rabbits received intravenous injections of N-Methyl-N-nitrosourea (10 mg/kg) every two weeks. Of 25 animals 14 (48%) developed malignant tumors of the central nervous system. The average total dose was 150 mg/kg and the mean survival time was 349 days from the beginning of the experiment. 2. All tumors of the central nervous system originated in the cerebral hemispheres with a preferential location in the periventricular zones of the lateral ventricles. 3. Histopathologically, most tumors were classified as oligodendrogliomas or mixed gliomas with varying degrees of cellular dedifferentiation, and as ependymomas.

Intermittent abnormal growth rate of the head was observed in an infant. Air studies revealed the presence of a cisterna veli interpositi with a typical connection into the cisterna venae magnae Galeni. Two months later another air study (pneumoencephalogram) revealed the lateral ventricles to be slightly larger and an increased distance between the roof of the third ventricle and the floor of the lateral ventricles with an abnormally wide distance between the lateral ventricles. No air filled the area of the previously shown cisterna veli interpositi. A transformation of the cisterna veli interpositi into a cyst was postulated and verified at surgery. The intermittency of symptoms was explained by a ball-valve type of connection between the cisterna veli interpositi and the cisterna venae magnae Galeni. The possible reason for the final obliteration of the outlet of the cisterna was discussed and also its therapy.

A review of a series of 1,550 pneumoencephalograms showed that the ventricles failed to fill in 48 patients (3.1%), in whom a tumour or obstructive lesion was present in 18 (37.5%). Possible causes for the non-filling of the ventricular system are discussed. Emphasis is placed upon filling of the pericallosal cisterns, as their position accurately indicates the size of the lateral ventricles.

HE injection of phenosulfonpthalein (PSP) into the lateral ventricles is followed, usually within minutes, by the appearance of the dye in the cerebrospinal fluid (CSF) of the basilar cisterns and subarachnoid space. Failure of the dye to appear, or any substantial delay in its rate of appearance, may be regarded as strong evidence of an obstruction of the ventricular system. On this basis, the dye has been widely used in the clinical diagnosis of hydrocephalus and has served to distinguish the obstructive and communicating types reliably.I, 7 In the current experiment, the circulation of PSP in the ventricles and subarachnoid space of normal and hydrocephalic animals was investigated. A number of observations concerning the normal migration of the dye as well as its altered circulation in obstructive and communicating hydrocephalus have not been previously reported. The significance of these findings is discussed.

During the past two decades intracranial surgery for intractable mental disease has evolved in the direction of greater precision in and the making of smaller lesions. The most experience has been with bilateral stereotactically produced lesions of a few milliliters' volume in the white matter related to the limbic system. These have been placed just above the anterior half of the corpus callosum in the fibers deep to the gyrus cinguli or in the fibers below the anterior horns of the lateral ventricles or in both areas. Such operations have nearly eliminated the sequelae of the earlier much more extensive lobotomies. Critical and thorough evaluations in Great Britain of relatively small numbers of patients operated on compared with retrospectively matched controls not operated on have revealed superior results in the leucotomized groups. The mental disorders most clearly responding to this surgery appear to be those characterized by stereotypy of an excessive and futile emotional response — i.e.,...

Portions of the wall of the lateral ventricles of the cat were obtained directly and after initial chrome-osmium perfusion. After further fixation they were embedded in Epon-812, sectioned on a Porter-Blum microtome and examined in the electron microscope. Observations on the ultrastructure of ependyma and subependymal glia of the feline lateral ventricle are described. The ependyma contains a pale cytoplasm with many vesicles, a network of fibrils, endoplasmic reticulum, Golgi apparatus and numerous dense mitochondria. Cilia are present along the luminal surface which have a well defined basal body from which cross-striated rootlets diverge to make close contact with other ciliary rootlets and enter into complex relationships with a specialized cell juncture composed of mitochondria in linear arrangement along an intercellular membrane studded with zonula adherens. These rootlets thus form accommodating links between cilia and a morphologic relation to the plamsa membrane between ependymal cells. Theories of metachronal motion in ciliated mammalian epithelia may incorporate such structures in the future. Three varieties of subependymal glia are described. Oligodendrocytes are the least common but are observed in close relation to myelinated axons. Fibrous astrocytes send short processes beneath the ependyma, but ependymal astrocytes send thick processes deep into the underlying white matter. No ependymal cells are observed to send processes into the white matter, and it is suggested that in the adult cat this is the property of the ependymal astrocyte.

Summary A symmetrical degeneration of the basal ganglia, medulla oblongata and spinal cord, seemingly older rostrally and more fresh caudally, was found in a 10 year old boy who died suddenly after a progressive disease of 8 years duration. The symptoms consisted in spasticity, rigidity, dysarthria, and abnormal movement patterns resembling torsion spasm. His intelligence was normal. Encephalogrammes showed progressive dilatation of the lateral ventricles, corresponding to the atrophy of the basal ganglia. The relationship of these clinical and pathoanatomical findings to established clinicopathological syndromes is discussed. Un garcon de 10 ans deceda brusquement apres une affection progressive qui dura 8 ans. L'autopsie montra une dogenerescence symetrique des noyaux de la base, du bulbe et de la moelle rachidienne, qui paraissait plus ancienne du cote cranial, et plus recente dans la partie caudale. Le tableau symptomatique etait celui d'une association de spasticite, de rigidite, de dysarthrie et de mouvements anormaux analogues a des spasmes de torsion. L'intelligence etait parfaitement conservee. L'encephalographie montrait une dilatation progressive des ventricules lateraux par atrophie des noyaux de la base. La relation entre l'aspect clinique et les lesions anatomopathologiques est ensuite passee en revue.

A survey of postmortem material related to cerebral injury at birth disclosed 13 cases of periventricular leukomalacia. Six patients survived for three months or longer; one reached adulthood. Our observations suggest that the lesions are infarcts located in the periventricular arterial end zones, between the ventriculopetal and ventriculofugal branches of deep penetrating arteries. They apparently are due to episodes of impaired circulatory perfusion during the first weeks of life. In children who survive the neonatal period, these infarcts appear as cavitations or as bands of gliosis in the periventricular regions, with extreme thinning of the white matter and secondary enlargement of the lateral ventricles. Whereas the clinical manifestations in the neonatal period are not distinctive, severe mental retardation and extensive neurological deficits appear in children who survive after the first few months of life.

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Experiments in rabbits were conducted to study early neuropathological changes caused by the direct action of manganese on brain tissue. Manganese chloride (0.5 mg in 0.1 ml normal saline) was injected on alternate days into one of the lateral ventricles of the brain for 15 days. The injection of manganese chloride produced excitability in the form of convulsions. Electrocorticography at various intervals showed an arousal pattern at a frequency of 20–22 Hz, but after 9 days the amplitude was lessened in manganese-injected as compared to normal and saline-injected animals. Neuropathological changes of the early stages of manganese toxicity were in the form of scattered neuronal degeneration in cerebral and cerebellar cortex, small haemorrhagic areas in the pons and medulla oblongata. It has been possible to produce an experimental model in rabbits of early clinical manganese toxicity related to neuropathological changes, which shows alterations in electrocorticograms.

Summary Five cases of meningiomas of the lateral ventricles are reported in this paper. And a brief survey of the frequency of such meningiomas as compared with all intraventricular tumors is given (11.67–57.32%). As regards the lateralization, the meningiomas in question occur, at least, twice as frequently on the left side as on the right side; the confidence interval of the ratio between the right-sided and the left-sided being 8.37–47.55%. Symptoms of such tumors are not uniform and even the ventriculography may fail to yield any information about the tumor. But when a tumor of the lateral ventricle is suspected, particularly on the left side, a meningioma should be considered as a diagnosis of likelihood. Histopat-hologically, the tumor may take any type common to intracranial meningiomas of other localizations.

EVERAL theories have been launched to explain the often dramatic improvement that follows the shunting procedure in patients with hydrocephalus. In cases with intracranial hypertension an increase in blood flow seems a likely consequence of the reestablishment of normal pressure conditions. In low pressure hydrocephalus ~,1' the favorable results seem more difficult to explain. One theory, first set forth by Yakovlev, ~ states that the neurological disturbances, particularly those affecting the gait, are due to stretching of the long paracentral fibers located close to the walls of the lateral ventricles, and that release of this stretching could explain the postoperative improvements. Periventricular demyelination was found by Penfield and others, ~- and a vascular cause of the changes was considered most plausible. A decrease in cerebral blood flow has been found in occult hydrocephalus, in the high-pressure as well as in the low-pressure type, ~-~ and improvement of flow following the shunting procedure has been described in a few cases with an ectatic basilar artery. :,~ It therefore seems justified to present data allowing more definite and generalized conclusions to be reached about the pre- and postoperative cerebral circulation in hydrocephalic patients.

The Autor has studied in man the structure of the periventricular glial membranes (corneal laminae) of lateral ventricles of normal and hydrocephalic brains. In normal, these membranes are constituted of three layers: ependyma, sub-ependymal fibrillar layer and vascular layer, whose thickness varies according to the region. In advanced hydrocephalus, the corneal laminae become notably thicker building up a plurilaminar structure, while many gliocytes undergo a clear hypertrophy accompanied with an increase of the intracellular proteic substance. These findings confirm the mechanic significance of the glial structures and the possibilities of structural adaptation of fibrous gliocytes to modified mechanical conditions. The structural peculiarities of corneal cytomorphosis of fibrous gliocytes allow to establish an interesting comparison with the behavior of the epidermal cells.

A case of Dandy-Walker cyst is described in which radionuclides but not air penetrated the cyst and lateral ventricles from a lumbar injection. This case demonstrates the difficulty in differentiating posterior fossa cysts by roentgen techniques. Further studies are needed to determine the role of cisternography in evaluating these cysts.

Hydrocephalus, according to Matson, is a pathological condition with many variations. The amount of cerebrospinal fluid, however, is always increased and the cerebrospinal fluid pathways are always dilated. Hydrocephalus may occur at any period of life and may be due to a number of causes: congenital, neoplastic, infectious, traumatic, operative(1). Most cerebrospinal fluid is secreted in the ventricular system by the choroid plexus, a growth of blood vessels covered by a thin coat of epithelial cells(2). There are four cerebral ventricles. The two lateral ventricles, one located in each of the cerebral

Experiments in dogs and observations on human subjects during pneumoencephalography have shown that with the head in the brow-up position, ascending fluid levels in the lateral ventricles are due to active formation of cerebrospinal fluid. This accumulation of cerebrospinal fluid displaces air down the aqueduct and fourth ventricle, which may remain opacified for several hours.Using roentgenographic measurements of the rate of ascent of lateral ventricular fluid levels and a cross-sectional area of the posterior two-thirds of the lateral ventricular bodies, the rate of cerebrospinal fluid formation in the lateral ventricles was calculated in 16 patients. The average cerebrospinal fluid formation for the lateral ventricles was about one-quarter of the accepted total cerebrospinal fluid formation (bulk flow). Possible reasons for this low figure are discussed.

Massive, spontaneous hemorrhage into primary intracranial neoplasms is uncommon. ~-~ The majority of the examples reported have been in either pituitary adenomas TM or glioblastomas. ~-6' s.9.~3 We have recently encountered an example of massive, fatal hemorrhage into a medullo- blastoma. This case, together with a review of the literature, constitutes this report. Case Report intervals revealed distinct demarcation between gray and white matter. The cortex and central white matter were intact, but slightly expanded (edema). Moderate amounts of fresh blood were in the lateral and third ventricles. The various nuclear components of the basal ganglia were sharply demarcated from each other, and appeared well preserved. The septum pellucidum and corpus callosum were intact. The glomi of the choroid plexi ia the lateral ventricles were coated with fresh hemorrhage, but otherwise normal. There was, in spite of tile cerebral edema, slight and symmetrical dilatation of the lateral and third ventricles. The pineal gland was of normal size and contained no significant mineraliza- tion. No areas of hemorrhage, calcification, necrosis, or neoplasia were present within the parenchyma of the the cerebral hemispheres. The blood in the lateral and third ventricles did not seem to come from the cerebral hemispheres. Serial sections of the brain stem and cerebellum at 3-ram intervals revealed a massive hemorrhage within the fourth ventricle, which apparently arose in the

1. Noradrenaline given directly into the lateral cerebral ventricles induced hypothermia in mice. This hypothermia was antagonized and eventually reversed to a hyperthermia by imipramine-like antidepressant drugs.2. The mechanism of action involved in this effect of antidepressant drugs has been studied using nortriptyline as a typical representative of antidepressant drugs.3. Nortriptyline pretreatment did not modify either the uptake, subcellular distribution, or the metabolism of (3)H-noradrenaline injected into the lateral cerebral ventricles.4. Nortriptyline had the same order of activity in reversing the hypothermia produced by the intraventricular injection of noradrenaline irrespective of whether it was given directly into the lateral cerebral ventricles or subcutaneously.5. Noradrenaline given subcutaneously caused hyperthermia in mice which antagonized and reversed the hypothermia induced by noradrenaline given directly into the lateral ventricles.6. The antagonism by both noradrenaline given subcutaneously and nortriptyline was reduced to the same degree by alpha- and beta-adrenoceptive receptor blocking agents.7. Nortriptyline, at dose levels required to antagonize and reverse the hypothermia induced by intraventricular injections of noradrenaline, potentiated the hyperthermia caused by noradrenaline given subcutaneously in conscious mice and the pressor responses to noradrenaline given either intravenously or into the lateral ventricles in anaesthetized mice.8. It is suggested that imipramine-like antidepressant drugs antagonize the hypothermia produced by intraventricular injections of noradrenaline by potentiating the hyperthermic effects of that part of the centrally administered noradrenaline that passes to the periphery rather than a direct central antagonism of the effects of noradrenaline.

VENTRICULOGRAMS are radiographs of the ventricular system after the cerebrospinal fluid has been completely or partially replaced by air. In order to understand the abnormalities in the ventricular system it is necessary to have a minute knowledge of anatomy and physiology. To review these briefly, let us recall that the intracranial ventricular system is composed of two lateral ventricles, a third ventricle, and a fourth ventricle. One lateral ventricle lies in each hemisphere of the brain and is composed of anterior, posterior, and temporal horns. The anterior horns are somewhat larger and more rounded, while the posterior horns come more to a point and are separated much farther apart than the anterior horns. The temporal horns are the smaller and extend downward and forward. These horns form more or less a wishbone-shape, as is seen in the lateral view. The capacity of the normal ventricle is about 60 c.c. From near the center of the anterior horn on the medial side is the foramen of Monro, which conn...

One intraventricular injection of 5,6-dihydroxytryptamine (5,6-DHT) caused the disappearance of fluorescent histochemically detectable 5-hydroxytryptamine (5-HT)-containing terminals and a loss in 5-HT uptake sites. There was an almost complete disappearance of 5-HT-containing nerve terminals in periventricularly located diencephalic areas and in the spinal cord 10–15 days after 75 μg of 5,6-DHT. The noradrenaline and dopamine innervation patterns in the hypothalamus, septum, basal ganglia, and spinal cord appeared normal, except in a narrow zone of the caudate nuclei facing the lateral ventricles, where there was a marked reduction in dopamine fluorescence. These changes were accompanied by 50–87% reductions in the uptake of [ 3 H]5-HT by thin slices of cortex, hypothalamus and spinal cord in vitro . In contrast, the uptake of L -[ 3 H]noradrenaline was close to normal in hypothalamus and spinal cord slices, and about 35% reduced in the cortex slices. These results are consistent with the idea that intraventricularly administered 5,6-DHT causes extensive axonal degeneration of central serotonin neurones, and that noradrenaline and dopamine neurones are largely unaffected after one injection of 75 μg.

Fetal tissues in a state of incomplete embryologic development and adult organs which are in a state of functional hyperplasia frequently offer difficulties in the correct interpretation of the histologic alterations, particularly when associated with true pathologic processes. This is the case when the cerebrum of the premature or newborn term infant is subjected to gross and microscopical examination. Most are prone to examine such a subject for evidence of gross maldevelopment or gross intracranial hemorrhage, and specimens taken for microscopic study are apt to be selected in a haphazard manner. Frequently, therefore, when sections which include the lateral ventricles are studied, one becomes interested in round cell infiltrations, often in perivascular position, berieath the ependyma. When this is associated with perivascular hemorrhages and degenerative changes of variable degree, many pathologists are convinced that the criteria of inflammation have been established, and a diagnosis of encephalitis is made. Such a conclusion seems to be confirmed when the clinical or necropsy data indicates congenital syphilis or postnatal infection. It seems entirely logical to correlate the subependymal cellular features with the established infection. However, such a conclusion has a major factor of error if one does not appreciate the extent, the location and degree of developmental activity in the case under consideration. The American medical literature is remarkably lacking in references to the subject of encephalitis congenita. Most of the

The fine structure of periventricular pleomorphic gliomas has been studied. The tumours were induced with a single i.v. dose of 30 mg/kg of N-ethyl-N-nitrosourea administered to pregnant BD-IX rats on the 15th day of gestation. The neoplastic transformation observed in the litters was followed from early neoplastic cell proliferations to tumours of macroscopic size. Foci of proliferating undifferentiated glial cells (the subependymal plate cells) were seen subjacent to the ependymal lining of the lateral ventricles. The same cell type was also present in larger tumours. The gliomas contained a mixture of oligodendrocytes, astrocytes and ependymal cells together with anaplastic glial cells. It is suggested that periventricular pleomorphic gliomas might arise from the primitive cells of the subependymal plate.

Casts of cat cerebro-ventricular system have been studied. A rapid-hardening polyester resin was injected under controlled pressure conditions into the two lateral ventricles of anaesthetized cats. Linear as well as volumetric measurements of the ventricular casts were obtained. The ventricular system consists of two lateral ventricles, the third ventricle, the aqueduct of Sylvius and the fourth ventricle. From there two lateral recesses join the subarachnoid space. In 2 out of 18 animals a prolongation which appeared to be a homologue of the human posterior horn of the lateral ventricle was found. The mould of the third ventricle consists of two arches surrounding an ovoidal space which corresponds to the massa intermedia. The cast of the fourth ventricle consists of a rectangular fovea with two triangular prolongations. Larger individual variations were found in volumetric measurements than in linear ones. A constant asymmetry of lateral ventricles in the same animal was found. There was no correlation between the size of the ventricular cast and that of the cerebral hemispheres and skull.

In cases of hydrocephalus, echoes from the region of the cerebral median segittal plane may show a fluttering variation both in amplitude and range. Evidence is presented that, in the case studied, these movements arose from the falx cerebri and that they were caused by ballistocardiac forces presumably setting the CSF in the enlarged lateral ventricles into resonance within the enlarged cranium. Similar movements would be expected in the lateral ventricular walls as well as the septum pellucidum when the latter is imperforate. It is suggested that the lowering of the resonant frequency of the ventricular CSF in cases of hydrocephalus with both large ventricles and large heads allows ballistic and acceleratory forces applied to the hydrocephalic head to cause large pressure changes between the two lateral ventricles with consequent lateral movement of the midline structures separating them and possible rupture of the septum pellucidum, as is commonly found in hydrocephalus.

THE roentgenographic follow-up in the study of encephalography with the use of ethylene gas (1,2) has been of great interest. In certain patients the ethylene has disappeared at an unusually slow rate when compared with that at which the gas disappears in the great majority of cases. This report deals with the estimation of the rate of disappearance of the gas, the interpretation of this phenomenon, and its correlation with the clinical data, especially in those patients in whom the gas disappeared with unusual slowness. Method.—Single horizontal transverse projections with the occiput down, tube to the side, have proved to be the most valuable views in estimating the rate of disappearance of the gas from the ventricles and subarachnoid spaces following encephalography. This projection is most likely to show any gas that remains. It permits a demonstration of both lateral ventricles and the third ventricle in their long axes and, in addition, demonstrates to the best advantage subarachnoid gas in the basa...

I have lately been engaged on a research into the normal and morbid histology of the choroid plexuses of the lateral ventricles.

1. The diagnosis of simple aqueductal obstruction in adults can usually be suspected from cerebral angiography, provided both supra- and infra-tentorial vessels are well opacified. The morphologic changes seen in aqueductal stenosis are the result of marked pressure hydrocephalus involving the lateral ventricles, the third ventricle and upper portion of the aqueduct above the obstruction with resultant downward axial herniation and compression of the upper brain stem. Narrowing of the anterior basal cisterns and dilatation of the posterior basal cisterns at the tentorial notch are usually marked.2. The angiographic features faithfully reflect the morphologic changes and are described in detail.3. A characteristic deformity of the superior vermis demonstrated by changes in the course of the precentral cerebellar vein and of branches of the superior cerebellar artery is described and illustrated.4. Although the angiographic features of simple aqueductal obstruction in adults are characteristic, contrast stu...

Cannulas were implanted in the lateral ventricles, cisterna magna and subarachnoid spaces of goats. Perfusion with synthetic cerebrospinal fluid (CSF) permitted study of exchange rates of test materials between CSF perfusion fluid and blood. Diodrast or phenolsulfonphthalein in low concentrations is removed from ventriculocisternal perfusate by a process of active transport resembling secretion by the proximal tubules of the kidney. The transfer maximum is 2–3 µg/min. and is reached at an inflow concentration of about 20 µg/ml. Active transport occurs from a volume of about 2 ml (total CSF volume is c 20 ml) located in the region of the 4th ventricle and cisterna magna. The choroid plexus of the 4th ventricle could be the site of active transport. After inhibition of active Diodrast transport, a passive component of transfer is revealed. Comparative studies with creatinine, fructose and inulin show that passive transfer takes place by diffusion as well as by absorption in bulk. Rates of passive transfer of these substances (per unit concentration difference) are comparable in magnitude with diffusion rates from the capillaries in 1 gm of skeletal muscle.