82 THE GERM THEORY OF DISEASE. 



2d. Digestion is threefold in its forms : (a) Primary, (b) 

 Absorptive or Resorptive. (c) Nutritive or Assimilative. 



Primary digestion is the ordinary method by which food is 

 fitted for reception by the organism. It is accomplished by 

 a soluble ferment, or ferments, secreted by the organism and 

 thrown out (a) into a cavity, stomach or intestinal canal, into 

 which the digestible material is brought; (6) into the sur- 

 rounding media in which digestible material is suspended, or 

 upon digestible solids or semi-solids. 



Absorptive and resorptive digestion is accomplished among 

 the ordinary tissues, by a soluble ferment elaborated by the 

 tissues, under special circumstances: (a) For the removal of 

 tissues no longer needed, as roots of temporary teeth, of bone 

 during changes of form, and of other tissues after their purpose 

 has been served resorptive digestion. (6) For the removal 

 of substances accidentally lodged in the tissues, as animal 

 membrane and catgut ligatures, etc. absorptive digestion. 



Nutritive digestion is performed within the tissues them- 

 selves, and by them. It is the act of assimilation, the act by 

 which nutritive material is converted into tissue and formed 

 material. 



Primary digestion, in the higher animals, is performed in 

 the alimentary canal. This is accomplished by the aid of 

 certain substances known as soluble ferments. The term 

 soluble ferment is used to denote a very different thing from 

 an organic ferment. An organic ferment is always com- 

 posed of living cells, and is therefore insoluble. A soluble 

 ferment performs the act of digestion only, and is not capable 

 of reproduction ; while an organic ferment performs all the 

 acts of complete fermentation, and is capable of continuous 

 reproduction. All soluble ferments are products of the 

 activity of cell life, or of the life force in the cell form. In 

 the stomach it is found that certain cells, forming the peptic 



