Demonstration of the Vernes flocculation test for syphilis

Abstract

Fifteen to twenty cc. of blood are taken in the usual manner from a vein of the patient and collected in a test tube. The tube is then stoppered and placed in the refrigerator over night to allow the serum to separate. The serum is then decanted and centrifugalized for two minutes at high speed to free it from all traces of corpuscles; the clear serum being transferred to a fresh tube which is tightly closed with a rubber stopper and inactivated one-half hour at 55°C and allowed to cool for one-half hour at room temperature.

The antigen is prepared with the mechanical aid of the mélangeur: 6 cc. of the specially prepared alcoholic extract of horse's heart, called péréthynol, are dropped at the rate of 1 cc. per minute into a beaker containing 12 cc. of doubly distilled water, the suspension being stirred at the rate of 200 revolutions per minute. (See Fig. 1.) After the temperature of this suspension, which has been elevated by the stirring, has regained its original temperature, 21 cc. of doubly distilled water are added very slowly by hand, while the suspension is being mixed at the same rate, and the stirring continued a few minutes after all the water has been added.

It is most important that all solutions should be of the same temperature, between 20° to 25°C, before adding one to the other, and that the doubly distilled water be prepared in all-glass apparatus free from rubber or metal connections. For the test four tubes are set up for each patient and 0.8 cc. of inactivated serum placed in each tube. To two of these (the reaction tubes) 0.4 cc. of the diluted péréthynol suspension are added and to the other two tubes (the control tubes) 0.4 cc. of a control diluted alcoholic solution (1 cc. absolute ethyl alcohol to 5.5 cc. doubly distilled water).