decreased pressure, for all kinds of experiments on animals. It is a pity that hardly any investigations have been made in this direction.
Once we have demonstrated the existence of ferments directed against particular micro-organisms, then the question naturally arises, what influence is attributable to the defensive ferments in a special case. They may act defensively. But it is also possible that it is they which first produce the poisonous substances, when decomposing disharmonious material. The ferment is unable to "know" what will be the result, when it breaks down a particular substrate. It may be that the attacked substrate is quite harmless to the organism, and that injurious substances first appear during decomposition.
If further researches show that the organism defends itself successfully by means of definite ferments, then a road is marked out for therapy to follow. By the direct addition of the necessary micro-organisms, or of certain parts of them, we shall produce defensive ferments which are directed against them, and try to transmit these with the serum. We can determine, exactly, the moment when the defensive ferments appear. A particularly fine basis for experiments seems to be supplied by thromboses, which one might be able to attack effectively by means of properly directed ferments, and so bring about their absorption.
