another, just a trace of some specifically organized substance, and this is at once deprived of its essential properties by means of the opposing defensive ferment. It might be thought that the same cells which give off the disharmonious material would themselves supply the ferments, and transfer their further reduction into the plasma; but at present there are no proofs for such a suggestion.
This view may be opposed on the ground, that it is difficult to understand how specifically directed ferments can be distinguished in boiled tissues. Many of the finer features in the structure of the substrate must surely be obliterated in the process of boiling. This probably holds only for the physical properties and hardly at all for the chemical. We may boil a substance having a composition A B C D, and another having a structure B C D A, for a long time; both would still retain their original composition or structure, although their physical properties might undergo alteration. Thus, for instance, their rotation might alter, and to this extent their biological behaviour might be affected. Thus there is nothing against the idea, that the substrate against which the ferment is directed may, in spite of its newly acquired properties, be still liable to attack by the ferment. With a key corresponding to a particular lock we can still unlock the latter, even though it has been badly damaged, provided only
