These circumstances serve, in part at least, to explain the fact that the success attending the use of anti-bacterial sera has been much inferior to that in the case of antitoxic sera.
Pfeiffer (1894), and various anti-bacterial sera have been introduced.
In preparing anti-bacterial sera the lines of procedure correspond to those followed in the case of antitoxins, but the bacteria themselves in the living or dead condition or their maceration products are always used in the injections.
An important point with regard to the therapeutic application of an anti-bacterial serum, is that when the serum is kept in vitro the complement rapidly disappears, and accordingly the complement necessary for the production of the bactericidal action must be supplied by the blood of the patient treated.
Another property which may be possessed by an anti-bacterial serum is that of agglutination.