Abstract
In earlier papers (1, 2, 3, 4) the authors have reported on the immunity developed by unprocessed tetanus toxoid in guinea pigs following the subcutaneous injection of the toxoid. When the unprocessed tetanus toxoid was tested on human beings by intracutaneous and subcutaneous injections it was found to produce annoying local reactions. This experience led to the development of the refined alum precipitated toxoid. The refined tetanus toxoid was prepared by precipitating the unprocessed toxoid with aluminum-potassium sulphate and washing the precipitate several times with sterile normal saline solution. The purified toxoid was then brought to its original volume with sterile saline solution following the method of precipitation and refinement of diphtheria toxoid devised by Wells, Graham and Havens (5). Antitoxin Development in Guinea Pigs. A study of the comparative antigenic value of the unprocessed toxoid and the refined toxoid was carried out in guinea pigs weighing 350 grams.