no reaction from the serum of an animal dead from true anaphylaxis, provided that the test was carried out after the total removal of all coagulable proteids, thus leaving the non-coagulable peptones and albumoses in the filtrate. This method, therefore, gives no evidence of any degradation product demonstrable by the biuret reaction (Pfeiffer and Mita).
The question was attacked in still another fashion by Abderhalden and Pincussohn. If the intoxication of anaphylaxis is produced by the rapid production of toxic cleavage products from the injected proteid, it is legitimate to assume that the serum of sensitized animals should possess ferments which rapidly accomplish this degradation of the proteid molecule. The experimental test was successful in demonstrating proteolytic ferments, but these ferments were not specific nor of very active nature; and later work by Gruber renders their relation to anaphylaxis quite doubtful.
Summing up the evidence which we have regarding the identity of proteid cleavage products and the causative agent or agents of true anaphylaxis, it must be said that while the assumption is theoretically tenable, a firm experimental basis for this assumption is yet to be laid. Moreover, investigators who unreservedly identify the disturbances caused by proteid constituents produced in vitro, with true anaphylaxis, are causing confusion in another direction. Not only is a perfectly well defined symptom-complex like anaphylaxis obscured by this extension of its scope, but a number of characteristic signs of anaphylaxis lose their significance. Before this can be discussed profitably, the original meaning of the word anaphylaxis as well as the functional disturbances and anatomical signs which characterize it, must clearly be kept in mind. On account of the importance of this, it may perhaps be permissible to give a short resume of matter already discussed.
Meaning of the Word Anaphylaxis, and Diagnostic Criteria.—What the word anaphylaxis was coined to indicate has already been stated; it means the symptoms and signs which are produced when an organism is resubjected to the action of a foreign soluble proteid. When horse serum, for example, is employed, the first injection causes no untoward effects; the second injection, however, gives outspoken and pronounced results which did not occur after the first injection, and these effects are only obtained when a proper interval has elapsed between the two administrations of horse serum. In active anaphylaxis there are three well-defined stages—sensitization, incubation and intoxication. In passive anaphylaxis, where a normal animal is sensitized by the injection of the serum of a sensitized animal, the same three stages are present, but the period of incubation is now shortened to a few hours. If, therefore, reactions are obtained in an animal after the second or so-called toxic injection which were absent when the first one was given,