COMPLEX VITAL PEOCESSES CONSTITUTING DISEASE. 51 



in the nutrition of the part, and is a condition which cannot 

 exist for any length of time without the occurrence of an organic 

 or structural change. The most familiar functional derange- 

 ments are the conditions of increased sensitiveness, irritability, 

 and contractility of muscular tissue, and tonicity, wliich is a 

 modification of contractility, — termed passive, in opposition to 

 active contractility, by Mr. Bowman. Of excessive contractility 

 we have examples in spasmodic colic and in chorea, where the 

 contractions are sudden, and alternate with sudden relaxations. 

 Contractions of this kind are termed clonic spasms ; and of exces- 

 sive tonicity, or tonic spasms, we have examples in the arteries, 

 when the pulse indicates a liard, unyielding condition of the 

 arterial walls ; in cramp of some of the voluntary muscles, and, 

 in an extreme degree, in tetanus. 



Opposed to the above conditions we have loss of sensibility, 

 anaesthesia, and paralysis. 



