A Vegetable Extract Used as an Antigen for the Kahn Test: An Experimental Trial.

It has been shown that a substance with properties akin to those of syphilis " antigen " can be extracted from commercial soya bean flour (Stevenson, 1949). The most satisfactory method is the following: 25 g. commercial soya flour is extracted successively with 100, 75, 75, 75 ml. pure ether. The flour is then dried and weighed and extracted for one hour at 800 C. with 95 per cent. ethyl alcohol in the proportion of 5 ml. alcohol per g. of flour residue. It will be seen that this process is similar to that used to extract Kahn antigen from dried beef heart, differing only in the alcohol extraction (for one hour at 800 C. in place of three days at room temperature).