IO4 SPECIFICITY OF DEFENSIVE FERMENTS 



them exclusively by the manner in \\iiich they act, and 

 that is whv, in must questions relating to ferments 

 and their activity, we are only able to answer with con- 

 jectures. We may imagine that a ferment is directed 

 against a simpler product of decomposition, and yet 

 that it attacks at the same time a more complicated 

 molecule, in so far as the group through which it 

 attacks the substrate is actually present therein and 

 within reach. It only depends on whether the 

 ferment is able to find a group, corresponding to its 

 own structure and configuration, in the particular 

 molecule. We must, also, not forget that, in a 

 body of high molecular structure, the same group- 

 ing may recur many times. In any case we consider 

 it very possible that cases are met with in which 

 the optical method shows a decomposition, while the 

 dialysation process gives a negative result ; although 

 it must be admitted that, up to the present, not a 

 single case of this kind has been satisfactorily proved. 

 All these discussions would be superfluous, if we 

 only knew, on the one hand the nature of the fer- 

 ments, and on the other the components that are 

 out of harmony with the plasma. As it is, we are 

 simply faced with the fact that ferments, directed 

 against particular substrates, are to be found in the 

 blood serum under very definite conditions. What 

 is entirely new is the clear demonstration of the fact 

 that the animal organism, within certain limits, 



