Allpyral: An appraisal.

In Allpyral the alum which has been added to the highly alkaline-pyrididium extract of non-defatted pollen absorbs only 25% of the extracted nitrogenous material, the larger quantity having been discarded with the supernanant. Allpyral contains a relatively small amount of antigenic material compared with conventional aqueous or glycerol preparations. Chemical studies show Allpyral to be a product resulting from an unrealized concept and a faulty method of preparation involving injudicious use of alum.