ORGANS FOR INTRODUCING FOOD. 23 



plasm. — Tlie manner in whicli tlie pabulum is brought 

 i:ito very close proximity to the bioplasm, or into actual 

 contact with it is very different in different cases. In 

 man and the higher animals this operation is provided 

 for by a highly complex apparatus deserving the 

 most attentive study. So important is this to the 

 well-being of the individual that, should any part of 

 its intricate structure be impaired or its action modi- 

 fied in any great degree, serious derangement of the 

 nutritive process results, and structural change of the 

 most important kind in organs of the highest import- 

 ance to the life of the complex being is occasioned. 

 In the case of the simpler forms of life the pabulum 

 is brought into the immediate vicinity of the bioplasm, 

 so to say by accident. A breath of air, a drop of 

 rain, may contain the pabulum which will provide for 

 the free growth of some of the simplest organisms, 

 which increase and multiply in so short a time. 



39. Organs for introducing food. — In man and 

 the higher animals most important oigaus minister 

 to the introduction of pabulum into the intestine 

 where multitudes of bioplasm particles are ever ready 

 to take it up and grow and multiply at its expense. 

 The introduction of aliment is not suffered to depend 

 upon our reason and thoughtfulness. If the demand 

 for food be not duly satisfied, the sensation of hunger 

 is experienced, and when this becomes intense, every 

 other desire, every other interest is in abeyance until 

 the demand for food has been satisfied. 



40. Distribution of nourishment. — The bioplasm 

 having taken up the nutrient matter from the diges- 

 tive tube undergoes change ; a part of it dies, and 

 some of its constituents, dissolved in water, pass into 

 the blood which flows in channels close to it. The 

 apparatus concerned in the distrihutiun of the nutrient 

 matter so dissolved to all parts of the body of man 

 and the higher aninials and plants, consists of tubes 

 so communicating that the contained fluid may tra- 



