Studies in intracranial physiology & surgery : the third circulation, the hypophysis, the gliomas / by Harvey Cushing.
- Harvey Williams Cushing
- Date:
- 1926
Licence: In copyright
Credit: Studies in intracranial physiology & surgery : the third circulation, the hypophysis, the gliomas / by Harvey Cushing. Source: Wellcome Collection.
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![To what primary diseases are they subject ? How early in embry¬ onal life do they secrete ? Why does the fluid which they elaborate differ so greatly from that secreted by most other glands ? Why are the cells so impermeable to the passage from the blood stream of drugs and of substances such as the bile pigments, which in conditions of jaundice quickly stain all other body tissues and fluids ? Granting that the fluid thus secreted by the choroid plexuses leaves the ventricles and spreads over the brain and down the cord in the subarachnoid spaces, does it receive accessions from else¬ where, from the ependyma or from pituitary or pineal glands ? Are there lymph channels in the brain, and if not, how does the central nervous system dispose of its products of tissue waste ? If there are [anything comparable to] cerebral lymphatics do they discharge into the subarachnoid spaces and is the subarachnoid fluid therefore of the same character chemically, physically and cyto- logically as the ventricular fluid ? Why normally is the fluid practically limited to the subarachnoid spaces, and under what conditions does it become subdural ? Granting that fluid may escape by way of the Pacchionian granulations, is this the chief or only manner of escape ? If an important avenue, why are these structures lacking in the lower animals and in the human infant ? Are these granulations, there¬ fore, pathological processes, and if so, what are their precursors ? Are there other means of fluid absorption along the nerves by way of the lymphatics, and if so, how important are they ? How do the spaces in the pia-arachnoid develop and do the choroidal glands mature and secrete before or after their formation ? Are there faults of development at these meningeal outlets for fluid which can account for congenital hydrocephalus and for malformations such as spina bifida and cephalocele ? Are there analogies in the fluid circulation of the eye to which we may attribute the dis¬ turbances of circulation of the intra-ocular fluids ? It so happened that we came to attack these questions in reverse order, 4 upstream 5 as it were; and instead of beginning with the plexus, though this was not wholly neglected, attention was first paid to the portals of exit. Dr. Weed soon hit upon a satisfactory method of identifying](https://iiif.wellcomecollection.org/image/b29929209_0029.jp2/full/800%2C/0/default.jpg)
