390 DEATH AND DISSOLUTION 



fatty acids and soaps. This self-digestion is a consequence of the 

 lack of free oxygen in the tissues, which lack, as we have seen, 

 causes the accumulation of acids. It has been shown that a very 

 slight increase in hydrogen ion concentration so alters the tissue 

 constituents that they are readily acted on by cellular enzymes. 



In Chap. IX. we mentioned the interesting fact that the enzyme 

 which hydrolyses maltose builds up another carbohydrate, 

 isomaltose, which it is incapable of breaking down. In general, 

 when a synthesis is brought about by an enzyme, the product is 

 immune from being broken down by its builder. But, by the 

 hydrating effect of acid these synthetic products are converted 

 into isomeric forms which can be destroyed by the enzymes which 

 originally formed them. 



In addition to autolysis, micro-organisms present in the intes- 

 tinal tract or otherwise entering the body from outside, play a 

 large part in the dissolution of the organism. Putrefaction is 

 readily distinguished from autolysis by the odour of the products 

 of its action. 



Just as the material composing the body returns to the earth 

 to begin anew the cycle of life passing from soil bacteria to 

 plant, from plant to animal and from lower to higher animal 

 so the energy of the constituents of the body pass into the great 

 cistern of unavailable energy, " waste heat," from which we are 

 unable to draw supplies, but which by raising the level of the total 

 cosmical heat energy ever so slightly, contributes to the well- 

 being of all living things by raising, in imperceptible amounts, 

 it is true, the level of metabolism. 



