176 



PHYSIOLOGY 



existence has been definitely established in the animal body. The 

 greater part of them are involved in the processes of digestion in the 

 alimentary canal. The preponderance, however, of digestive ferments 

 in the list is due to the fact that we know more about digestion than 

 about the other chemical processes taking place within the cells 

 of the body. 



LIST OF FERMENTS 



Many other ferments will probably be distinguished with increase 

 in our knowledge of cellular metabolism. The long list which is here 

 given suffices to show how great a part these bodies must play in the 

 normal processes of life. A study of the conditions of ferment actions 

 is therefore essential if we would form a conception of the chemical 

 mechanisms of the living cell. 



It is important to note that all the changes wrought by ferments 

 can be effected by ordinary chemical means. Thus the disaccharides 

 can be made to take up a molecule of water and undergo conversion 

 into monosaccharides. If a solution of maltose be taken and bacteria 

 be excluded from the solution, it undergoes at ordinary temperatures 

 practically no change. If the solution be warmed, a slow process of 

 hydration takes place which is quickened by rise of temperature, 

 so that if the solution be heated under pressure to, say, 110C., hydrolysis 

 occurs with considerable rapidity. If, however, a little maltase 

 be added to the solution, the change of maltose into glucose takes 



