27 



Oh ! of course, it was very different. Perhaps so ; the spider 

 ate its food raw and we cooked it first. He was convinced that 

 the spider pre-eminently ate to spin ; many men spun to eat. 

 There was no penetrating the mysteries of Nature ; whether we 

 searched the starry spheres with a telescope, or examined the 

 spider with the microscope, we found the same omnipotent 

 wisdom, the same infinity. 



WEDNESDAY, FEBRUARY 22nd, 1899. 



fain, 



BY 



Mr. G. morgan, F.R.C.S. Ed., L.R.C.P. 



TAKING up the consideration of a central nervous system 

 consisting of brain and spinal cord, and of a sensory sur- 

 face of skin, Mr. Morgan set himself to explain the connection 

 between these two by means of the nerves, which are " practi- 

 cally the electric cables and the finer electric wires of the 

 nervous system, conducting impulses to and from the tissues and 

 organs on the one hand, and the nervous centres on the 

 other." The "first essential" of a nervous fibre is "its axis 

 cylinder or Axon, which is a cylindrical, or band-like, pale, 

 transparent structure, which, after being treated by certain re- 

 agents, shows itself composed of very fine homogenous or more 

 or less beaded rihn'llai:" This cylinder is enveloped in " its 

 own hyaline sheath, the Axilemma." The next essential of 

 the nerve fibre is an insulating material, surrounding the Axon 

 as gutta-percha surrounds the copper of an electric wire. This 

 insulator, which is "bright, fatty, and glistening," is called the 

 medullary sheath, or white substance of Schwann." Outside the 

 white substance of Schwann is the " Neurilemma," which forms 

 the outer boundary of the nerve fibre. 



Each nerve has its own blood vessels ramifying outside and 

 within its sheath, giving oft" smaller vessels that supply the 

 ultimate fibres. And it is through these small vessels that 

 certain neuralgic pains are caused when the blood is loaded 

 with the toxins of " malaria, or influenza, or other specific 

 disease," or has been robbed to a certain extent of its oxygen- 



