138 BIOLOGICAL PHYSICS 



and treatment, it becomes imperatively necessary to 

 differentiate, in the first place, between the systemic and 

 sympathetic nervous systems, as to the part they respec- 

 tively play in their genesis and persistence, and whether 

 they are singly, or unitedly, concerned, because on this will 

 depend, to a great extent, the exactitude of our appreciation 

 of the diseased condition before us, as well as the success 

 of our remedial and ameliorative procedure. 



Roughly speaking, almost all external pain and sensory 

 disturbance emanate from the systemic nervous system, 

 while in the same way, almost all internal pain and sensory 

 disturbance emanate from the sympathetic nervous 

 system, the exceptions being where the affected parts 

 happen to be innervated, to some extent, by both systems. 

 It may, however, be taken for granted that sympathetically 

 initiated pain can only be realised through the systemic 

 nervous system in virtue of the existence of the nerui 

 communicanteS) and consequent intimate union subsisting 

 between the two nervatures. As types respectively of 

 the two orders of pain, we might cite those proceeding 

 from dermatitis and " bilious colic," so called ; the former 

 representing a 'visible peripheral sensory phenomenon, the 

 latter, a hidden sympathetico-systemic sensory phenomenon 

 each affording a strong contrast to the other in point 

 of character and intensity, and requiring for its relief, or 

 removal, the use of a different method of procedure. 



Our survey of the genesis and character of pain, or 

 perverted aesthesia, applies also to the motor aspect of the 

 systemic nervous system, and there we find the phenomena 

 displayed in all degrees of intensity, and over small, or 

 large, areas, according to the nature, and extent, of its 

 etiological factors : thus, in acute rheumatism, we have it 

 displayed generally, and less or more locally, when it may 

 involve muscle substance pure and simple, periosteum, 

 ligaments, tendons, joints, and bone, in all varieties and 

 combinations ; in fact, this series of pains and painful 

 affections constitutes one of the largest that the medical 

 profession is called upon to deal with. 



