682 GENERAL THERAPEUTIC MEASURES 



cells, or enzymes within the cells (chiefly of muscles), and 

 thus produces heat or energy. 



The other part is directly built into living protoplasm. 

 If the amount of circulatory protein is deficient, then the 

 organized protein is called upon, the tissues are robbed of 

 their substance, and the body emaciates. When a larger 

 amount of protein is contained in the blood, we have a 

 proportionately larger elimination of nitrogenous matter in 

 the urine, as equilibrium is soon established in the adult animal 

 of constant weight, so that the amount of nitrogen eliminated 

 equals that ingested. In young and growing animals 

 a portion of the nitrogen does not reappear in the urine, but 

 is utilized in tissue formation. This also applies to previously 

 :starving animals on being well fed. An excess of circulating 

 protein, besides being wasteful economically, is harmful in 

 causing various disordered conditions, resulting in the formation 

 • of products of imperfect oxidation. 



The vegetable proteids are transformed into bodies of 

 :simpler chemical composition in the stomach and are there con- 

 verted in part by the gastric juice, but chiefly by pancreatic 

 (trypsin), biliary and intestinal ferments in the intestines, into 

 peptone, proteoses, and possibly acid and alkali and native 

 albumin. 



The epithelial cells of the intestines possess the power not 

 only to absorb the peptone, but to transmute it into more com- 

 plex isomeric compounds, as serum albumin, serum globulin 

 ■and fibrinogen; special cells being employed in the formation 

 of particular compounds. 



Any peptone not so converted by the intestinal epithe- 

 lium becomes a poison when absorbed into the entero-hepatic 

 ■circulation, but its toxicity is destroyed by the liver cells. In 

 regard to the metabolism and fate of proteids, energy is not 

 only directly liberated by the decomposition of the energy- 

 producing protein in the muscle cell but is also formed by the 

 functional activity of cell protoplasm in which katabolic changes 

 occur. So that the tissue-building protein is eventually an 

 •energy-producer as well. Elimination of nitrogenous matter 

 is not increased by muscular activity, nor proteid metabolism, 

 as carbohydrates furnish the fuel for the mechanical work — 

 •with increase of CO, and H„0 elimination. The katabolism of 

 protein in muscles then goes on independently of, and is not 

 ■augmented by, muscular contractions. 



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