MUSCULAR SYSTEM. 233 



Q. What property predominates in the muscles of or- 

 ganic life ? 



*#. Sensible organic contractility ; but organic sensibi- 

 lity is also very conspicuous. 



Q. How are stimuli divided with reference to the sen- 

 sible organic contractility of the organic muscles? 



#. Into natural and artificial. The blood is the natu- 

 ral stimulus to the heart, the urine to the bladder, food 

 and faeces for the stomach and bowels. Artificial stimuli 

 are irritants applied after death, or in experiments. 



Q. How is the sensible organic contractility of this tis- ^ 

 sue affected by natural stimuli? 



*ft. It is altered by changes in the quality and quantity 

 of fluids. See how the heart is hurried when chyle enters 

 it after digestion, and likewise when fluids are thrown into 

 the veins. 



Q. Is this sensible organic contractility the same in all 

 the organs? 



ft It is not. It is peculiar, inasmuch as each organ re- 

 sponds to its peculiar or natural stimuli such is the blood 

 to the heart, the urine to the bladder. 



Q. What is the state of this property at different ages? 



A. It is most active in youth; it becomes less so in 



adult and advanced life. The action of the heart, bladder, 



and rectum at these periods of life, will fully illustrate 



this. 



Q. Does temperament present different states of this 

 property? 



*ft. In different temperaments, you see a predominance 

 of this property, in some over others. Having no common 

 centre or source of influence, as the animal muscles have, 



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