l6 DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 



with the milk as sole nourishment, from the moment 

 of passing on to the mixed nourishment that is 

 peculiar to its species, the second important change 

 in the feeding of the growing individual is accom- 

 plished. The third stage of its evolution has begun. 3 



The cells must function quickly to prevent dis- 

 harmonious substances from entering the circulation. 

 To ensure the proper discharge of a duty so important 

 to the organism, the liver is placed between the 

 intestines and other organs. Within this important 

 organ the blood, still laden with the absorbed and 

 partly metamorphosed food-stuffs, comes into contact 

 with the liver cells. This material is once more 

 thoroughly sifted, and the blood is finally discharged 

 into the general circulation, freed from all substances 

 that would be out of harmony with the body and the 

 blood. 



The knowledge that digestion is the means by 

 which unsuitable products are prevented from passing 

 into the blood and the cells of the body is of the 

 greatest importance for our comprehension of the 

 whole metabolism of the animal organism. Thus, to 

 a certain extent, we may look upon the animal 

 organism as a whole in itself. All the cells of the 



From this point of view it is easy to see why lack of 

 its proper milk sets up disturbances in the suckling, and 

 particularly how dangerous are continual changes in the 

 composition of the food, seeing that the young animal is 

 not yet prepared for the reception of mixed nutriment. 



