[nicholls] medicine AND OTHER NATURAL SCIENCES 7 



are impossible and death of the cell is inevitable. The nuclear ma- 

 terial, or chromatin, is differentiated from the cytoplasm by one 

 capital peculiarity, it contains phosphorus. And reproduction can 

 only occur by the fusion of the male and female nuclear material. 

 Phosphorus, then, is in a very literal sense the light of life. 



When Pasteur, who was not a medical man, by the way, but a 

 chemist, published his epoch-making researches upon fermentation, 

 he opened up what has proved to be a most fruitful line of thought. 

 It has been discovered, for example, that bacterial activity for the 

 most part is due to fermentation processes which are initiated in the 

 course of their metabolism, and out of this has grown the great subject 

 of immunity. It has been shown, too, step by step, that many, if not 

 the majority, of the metabolic processes of the animal body are due to 

 the action of ferments or enzymes. To cite familiar instances, the 

 whole function of digestion, from one end of the gastrointestinal tract 

 to the other, is dependent on ferment action — ptyalin in the saliva, 

 acting on starch; pepsin in the stomach, acting on proteins; rennin, 

 acting on casein; trypsin, acting on proteins; amylopsin, acting on 

 carbohydrates; steapsin, acting on fats; the last three being found 

 in the pancreatic secretion; finally, the residue of the food, after run- 

 ning the gauntlet of these various enzymes, is farther acted upon by 

 putrefactive and other bacteria in the lower bowel. Again, the liver 

 cells elaborate a ferment that converts carbohydrates into glycogen 

 and vice versa. The white cells of the blood can produce a proteo- 

 lytic ferment, and the red cells contain an oxydase that is an important 

 link in the process of respiration. 



It has been determined about enzymes; that they may be intra- 

 cellular or extracellular in their activities: that if not actually of 

 proteid composition they are constantly and indissolubly asssociated 

 with proteid substance: that, provided the products of their activity 

 are not allowed to accumulate, their action continues until all fer- 

 mentescible material has been transformed ; that they are not destroyed 

 themselves in the process; that their action is often reversible. Further, 

 it is now known that the organism normally produces substances 

 antagonistic to ferments, in other words, antiferments. Thus, an 

 antirennin has been isolated from the blood; an antipepsin has been 

 noted in the gastric mucous membrane; and an antiferment has been 

 found in the pancreas, neutralizing the digestive powers of this organ. 

 Here at last we get an adequate explanation of the old puzzle, why 

 the various digestive organs do not digest themselves. 



We Avould observe that there is one great underlying principle 

 in all this. There is a constant tendency for the cells of the body to 

 reach an equilibrium. This law is exemplified not only in the indi- 



