64 BIOLOGICAL PHYSICS 



within, and without, the brain and cord, it follows of neces- 

 sity that unless a means of escape for the fluid is also 

 provided, a stasis and over-pressure must ensue, and this 

 provision we find to exist in the means of peripheral circu- 

 lation of the fluid and its release when, and where, required 

 by a continuous system of enclosed, yet open, spaces, or a 

 lymph vasculature, conterminous with the systemic nervous 

 system in all its parts, afferent and efferent, or sensory, 

 and motor, and sympathetic. 



This circulatory and excretional provision, by which 

 every exigency of intra-cranial and intra-spinal pressure is 

 met by immediate re-disposal or absolute displacement of 

 the cerebro-spinal fluid, necessitates a belief in the complete 

 non-existence of a histological and anatomical cerebro- 

 spinal meningeal " shut sac," inasmuch as a doubly 

 pervious space in unbroken continuation from the sub- 

 arachnoid and sub-dural spaces respectively accompanies 

 every nerve, from its exit from the cerebro-spinal cavity 

 until it finally terminates in the skin, the muscles, or the 

 sympathetic system. 



Thus, a system of continuous circulation, forwards, or 

 backwards, according to the prevailing local and general 

 structural necessities of intracrano-spinal pressure, can be 

 maintained by an ordered flow, due to the operation of 

 vital hydrostatics and dynamics along the lines of least 

 resistance, and not against immovable obstacles, and so the 

 safety and integrity of the great central nervous system can 

 be maintained by a definite histological and physiological 

 means, and not by accident. The truth of these assertions 

 is based on such facts as that the inter-neurilemmar spaces 

 can be penetrated to some extent by the injection of fluid 

 from within the arachnoid membrane, but more especially, 

 according to my clinical and pathological observations and 

 experience, that materies morbi, or viri, chemical and 

 material, are allowed to traverse these inter-spaces and are 

 deposited, at their terminations in the nerve terminals, 

 causing, it may be, a pathological manifestation there, in 

 accordance with the nature of the virus and the character 

 of the nerve terminal distribution in the skin or muscles 

 involved ; thus alcohol, arsenic, and certain bacteria leave 

 a trail from the centre to the periphery of the nervous 



