On Dr. Mark's Desargues Configuration

In a paper published in the Journal of the London Math, Soc. 7 (1926) pp 86-93, Dr. Marr has shown that given six points on a conic there are ten points P such that the lines joining P to the six points touch a cubic curve at these six points. Recently in an additional note be has shown that these points form a Desatgues configuration He has not stated that this configuration is self-polar with respect to the conic, though this follows from his proof.