Castaing was defended by two advocates--Roussel, a schoolfellow of his, and the famous Berryer, reckoned by some the greatest French orator since Mirabeau. Both advocates were allowed to address the jury. Roussel insisted on the importance of the corpus delicti. "The delictum," he said, "is the effect, the guilty man merely the cause; it is useless to deal with the cause if the effect is uncertain," and he cited a case in which a woman had been sent for trial, charged with murdering her husband; the moral proof of her guilt seemed conclusive, when suddenly her husband appeared in court alive and well. The advocate made a good deal of the fact that the remains of the draught prescribed by Dr. Pigache, a spoonful of which Castaing had given to Auguste Ballet, had been analysed and showed no trace of poison. Against this the prosecution set the evidence of the chemist at Saint Cloud, who had made up the prescription. He said that the same day he had made up a second prescription similar to that of Dr. Pigache, but not made out for Auguste Ballet, which contained, in addition to the other ingredients, acetate of morphia. The original of this prescription he had given to a friend of Castaing, who had come to his shop and asked him for it a few days after Ballet's death. It would seem therefore that there had been two bottles of medicine, one of which containing morphia had disappeared. M. Roussel combatted the suggestion that the family of Castaing were in a state of indigence. He showed that his father had an income of 10,000 francs, while his two brothers were holding good positions, one as an officer in the army, the other as a government official. The mistress of Castaing he represented as enjoying an income of 5,000 francs. He protested against the quantity of hearsay evidence that had been admitted into the case. "In England," he said, "when a witness is called, he is asked 'What have you seen?' If he can only testify to mere talk, and hearsay, he is not heard." He quoted the concluding paragraph of the will of Auguste Ballet as showing his friendly feeling towards Castaing: "It is only after careful reflection that I have made this final disposition of my property, in order to mark the sincere friendship which I have never for one moment ceased to feel for MM. Castaing, Briant and Leuchere, in order to recognise the faithful loyalty of my servants, and deprive M. and Mme. Martignon, my brother-in-law and sister, of all rights to which they might be legally entitled on my death, fully persuaded in soul and conscience that, in doing so, I am giving to each their just and proper due." "Is this," asked M. Roussel, "a document wrested by surprise from a weak man, extorted by trickery? Is he not acting in the full exercise of his faculties? He forgets no one, and justifies his conduct."