DEFENSIVE FERMENTS OF THE ANIMAL ORGANISM 23 



stituent parts of the organism. To these belong all 

 such substances as are received from the outside as 

 nutriment, with the exception of those products 

 which may be ranged amongst the most simple 

 units, as, for instance, grape sugar. As sub- 

 stances " in harmony with the body,' we would then 

 term those which, when entirely recast, correspond 

 in their structure to the essential composition of the 

 particular species or individual. In addition to this 

 general conception, which only means that a sub- 

 stance is not absolutely disharmonious to the body 

 in general, we have undoubtedly to make a still finer 

 distinction according to the special features of the 

 compound in question. As early as the year 1906* 

 we had suggested the advisability of distinguishing 

 between substances which, though they are adapted 

 to the blood, are nevertheless out of harmony with the 

 varied cells of the body, and those which show any 

 features characteristic of the structure of the cells of 

 a particular organ. If our ideas concerning the 

 structure of the particular cells of an organ, and the 

 dependence of its functions on this peculiarity, prove 

 correct, then it follows that, as we have alreadv 

 emphasized, each kind of cell must have at its dis- 

 posal units of its own kind. We may then speak 

 of substances that are " in harmony with " an organ, 



4 " Lehrbuch der physiologischen Chemie," i Auflage,. 

 S. 292, Urban and Schwarzenberg. Berlin-Wien, igo6. 



