Summary
Percutaneous or intraperitoneal previous treatment with pyocyaneus filtrates protect neither guinea pigs nor rabbits from a respectively subcutaneous or intraperitoneal infection with Bacillus pyocyaneus.
It is possible to protect both kinds of animals by repeated intrapleural injections of previously heated pyocyaneus filtrate against intrapleural infection with Bacillus pyocyaneus.
The resistance acquired in this way is restricted to the pleural cavity. Simultaneous metastatic infections of the liver and of the kidney are common findings.
In other cases the resistance is only a relative one; in spite of the previous treatment an infection of the pleura occurs, but the course of the disease is much slower than in the control animals.
The question of specificity of the action of the filtrates will be studied on a larger scale. Although an occasional increase of resistance caused by the unspecific filtrates has been found, the protection produced by specific filtrates seems to be more intense and more dependable.
Intrapleural injections with sterile broth have no prophylactic value against an intrapleural infection with Bacillus pyocyaneus: it is impossible to protect the animals by broth injections against such infections.
