A Study of the Fever-Producing Principle in the Typhoid Vaccine. ∗

Abstract

Conclusions

1. The fever-producing principle in typhoid vaccine and in broth in which B. typhosus has grown for 48 hours is not removed by Berkefeld filtration. The principle is, therefore, not bound to the bacterial bodies.

2. The principle is removed by a 200-second Zsigmondy filter and is, therefore, of approximately the same size as the principle previously found in reactive inulin and infusion-fluids.

3. Like “pyrogen” found in inulin and in infusion-fluids, it is removed by filtration through asbestos pads of the types of Seitz and Ertel.

4. On the basis of the clinical response provoked by intravenous injection, and the filtration characteristics, it is submitted that the fever-producing principle associated with B. typhosus and the “pyrogen” found in infusion-fluids and inulin are closely related substances.