348 BIOLOGICAL PHYSICS 



point out, and to prove, that within our bodies there are 

 two great acting, and determining, entities, which are 

 known as the sympathetic, and systemic, nervous systems, 

 inextricably blended for communal functional work, but 

 which are capable of separate, and independent, action, in 

 all individual functional effort, the two combining, in the 

 normal, or physiological conditions on the strictest principles 

 of reciprocity, inter-dependence, and independence, accord- 

 ing to systemic, or physiological, requirements ; and the 

 one, the sympathetic, acting continuously, and the other, 

 the systemic, acting periodically, or diurnally, according to 

 well-defined physiological conditions, and laws, while, in 

 conditions pathologically disturbed, the principles of action 

 are dominated, and determined, by the strongest, and 

 most effective, materio-dynamic impulses, with formative 

 results accordingly as these work out in the physiologico- 

 pathological struggle. 



During the developmental changes taking place in the 

 process of neuronogenesis, the neurons, as they are evolved 

 from the neuroglial matrix, become encircled individually 

 with a peri-saccular, and peri-axonal, sheath, containing a 

 layer of neural lymph which is projected along the axonal 

 processes, forming a fluid protection for their delicate 

 contained structures, and accompanying them to their 

 terminal extensions, and in addition, where they proceed 

 along the nerve trunks leaving the cerebro-spinal canal, 

 being received, and surrounded, with a neurilemmar 

 extension sheath, continuous with the meningeal linings 

 of that canal which, in turn, accompanies them to their 

 final, or terminal distribution in the skin, or muscles, or 

 along the rami communicantes into the sympathetic 

 nervature. 



Such neuronogenetic anatomico-histological arrange- 

 ments secure that every unit of neuronal structure is 

 encircled by membranous envelopes and floated in fluid, 

 and also that the completely evolved systemic nervous 

 system in all its parts, is surrounded by, secured to, and 

 protected from, its non-nervous related structures and 

 organs, free to perform its manifold functions, material, 

 dynamic, and physic, with security and precision, with 

 leakage of its specific materials and energy prevented, and 



