34 APPLIED PHYSIOLOGY 



engine. The process goes on so slowly that no flame 

 is produced, but the same amount of heat is produced as 

 though the same substances were burned in a furnace. 

 Some of this heat is used to warm the body, and some 

 is changed to power which enables the body to do work, 

 either of motion, or of manufacturing the various products 

 of the body or of thought. Oxidation is an essential 

 process of life; when it ceases for an instant life ends. 

 When the air is cut off from the body for only a minute, 

 a great feeling of suffocation comes on, and within two 

 or three minutes the body dies. 



Oxidation goes on in each cell, but especially in the 

 cells of the lungs and liver. It is a process of life, and 

 in a living cell it can be hastened or retarded according 

 to the needs of the body. 



By the oxidation within the cells of the body, carbonic 

 acid gas, water, and ashes are formed, as in a furnace. 



39. Oxidation of albumin. An ounce of albumin is 

 completely oxidized by an ounce and a half of oxygen. 

 The ashes which are produced are partly the sulphur of 

 the albumin and partly the nitrogen, which holds some 

 of the carbon, hydrogen and oxygen, combined in a 

 solid called urea. Urea must be given off by the kid- 

 neys and skin as fast as it is formed. When there is 

 not enough oxygen to burn the albumin entirely, other 

 substances resembling urea are formed, just as a stove 

 smokes instead of burning brightly when the draft is 

 closed. Some of these substances are very poisonous. 

 The albumin of the living cells is probably oxidized and 

 replaced continually. Much of the albumin of the food 

 is oxidized before it reaches the cells. 



40. Oxidation of fat An ounce of fat is completely 

 oxidized by three ounces of oxygen. So it will produce 



