Tracked by a Tattoo by Fergus Hume

The evidence of Theophilus Binjoy: --

"I am a medical man; and in my early manhood, I practised in the village of Damington. I was present at the birth of Edward Fielding, and of Gregory Fellenger. I know about the mark on the arm of the real heir. Madaline changed the two children, and I said nothing as she promised to marry me. I was madly in love with her. She left the village, and deceived me. Afterwards I held my tongue lest I should get into trouble; also I hoped when the false Sir Gregory grew up, to have a hold on him. I was prevented from doing this by Madaline (whom I had discovered in Tooley's Alley, under the name of Mrs. Boazoph). She threatened to reveal the name of the true heir if I meddled with her son. I therefore did nothing. I saw the poisoned needle which Louis had made ready for an experiment. It was in a cabinet in the laboratory. Young Vaud came to Taxton-on-Thames nearly crazed with the death of Emma Colmer, whom he had courted as Emma Calvert.