3 i 8 BIOLOGICAL PHYSICS 



potentiality, and contractility, of these muscle fibres, by 

 becoming, in fact, a nutritive pabulum, for their growth, 

 and maintenance. Moreover, it seems impossible to 

 assume that the very large amount of white, or medullary, 

 and axis cylinder, substances, which must be discharged 

 from the motor nerve " end plates," or terminals, can be 

 otherwise disposed of, than in supplying the nutritive 

 material necessary for the wants of the great muscular 

 system, and, so, of keeping up that intimate, material, 

 and functional, or materio-dynamic, union, of nerve, and 

 muscle, so essential for the proper discharge of the 

 complex duties, of meeting the requirements of volition, 

 as well as, those of conveying involuntary impulses for 

 automatic movements, single, and co-ordinated, alike 

 and that, therefore, this matter, or substance, does not 

 become effete, until it has discharged, or contributed to 

 discharge, the function of muscular contraction, with its 

 accompanying waste, when, we may take it that it is 

 discharged, or conveyed, into the systemic lymphatic 

 system, via the muscle tendons, periosteal textures, and 

 associated bone matrix, and medulla, and so into the 

 blood stream, for final disposal in contrast to the final 

 elimination of the, medullary, and axis-cylinder, substances, 

 characterising the sensory nerve terminals. 



In still further detail we would remark that the nucleus,, 

 in like manner with its parent cell, forms or secretes the 

 protoplasm of its body, that protoplasm being retained in 

 position by its encircling or containing wall, from which it 

 in turn passes or grows along, or as the axis cylinder 

 separated from the medullary or white substance by a con- 

 tinuation or prolongation of the neurokeratinous nuclear 

 envelope until it arrives at the confines of the indivi- 

 dual fibres, where it undergoes the process of final disposal 

 or elimination by the various forms of nerve terminal 

 arrangements, as effete, but not yet quite functionally 

 exhausted material. The organised materials composing 

 the medullary substance and the axis cylinder substance 

 alike circulate from the cells and nuclei respectively to the 

 boundaries of the nervous system on the skin and mem- 

 branes, in the substance of the parenchymatous textures and 

 within the sarcolemmar coverings of the muscular fibres, 



