326 Researches in the Theory and Calculus of Operations. 



cranial brains and the sensational centres, for the elimina- 

 tion of the coordinating forces of the system, the cogni- 

 zance of sensation and the evolution of thought ; and lastly 

 to the fundamental digestive organs themselves, thus com- 

 pleting a ceaseless round of circulating movement so long 

 as tRe stomach retains its normal vitality and is conscien- 

 tiously fed from without. 



The present may serve as an outline exemplification of 

 the circuit of operations of one of these subordinate systems 

 or organical members of an animal body (fig. 43). B is the 

 digester containing food of the second degree of composi- 

 tion. The digester, charged with force brought by the con- 

 ductor s f from the reservoir A, furnishes a new component 

 which converts the mass into compost of the third degree 

 of composition. In this condition it is propelled through the 

 tube r to the organ C on the surface or limit of the circuit. 

 The substance of the organ is decomposed by the newly 

 arrived compound, and the organ is recomposed anew. The 

 force liberated by the act of decomposition is partly ex- 

 pended in expelling the matter rejected as exuviae in form- 

 ing the new compound, and the remainder is transmitted 

 through the conductor s to the reservoir A, to reinforce 

 and keep up the supply sent from A to B. Here B is a 

 stomach, r a duct, C a gland, s an afferent nerve, A a gan- 

 glion, and s f an efferent nerve. 



Commencing at the duodenal extremity of the digestive 

 canal, the chyme entering from the stomach suffers double 

 decomposition into chyle and fecal matter. The force liber- 

 ated by each successive impulse between the chymous and 

 bilious semifluids suffices to forward the movement of the 

 two resultants of the decomposition, and is quickened by 

 the pressure of the advancing material from the stomach; 

 while, as in other cases abundantly quoted, each successive • 

 decomposition is immediately followed by the restitution of 

 the immanent equilibrating forces (conservation of vis viva). 



