contained in the tissue. The appearance of defensive ferments, after the extraction of blood, is without doubt to be ascribed to the destruction of red blood corpuscles that results therefrom. Is it not possible that the absorption of plugs of fibrin that occlude the walls of the vessels may be connected with defensive ferments, and may not the latter also have a share in the organization of thrombi?
Defensive ferments, which decompose the albumen of blood corpuscles, may be produced by means of injections of hæmolytic blood, and herein lies a source of error which should never be underestimated. Only organs that are absolutely free from blood give conclusive results. Defensive ferments, which decompose the albumen of blood corpuscles, are frequently met with in carcinoma. Any extravasation of blood into the tissues, however slight, will give rise to this kind of defensive ferments.
Within the domain of pathology there is no field which would not lend itself to researches based on the methods we have described. We will call attention to some. In the first place we can try, by means of defensive ferments directed against certain kinds of cells, to discover those organs which are giving off substances that are out of harmony with the blood or the plasma. This would be the case, when a particular organ fails to complete its otherwise normal metabolism. But it is also possible that
