Maitre Alem, defending the widow's gayish conduct after her husband's death, declared it to be natural enough. It had been shown to be innocent. He trounced the Press for helping to exaggerate the rumours which envy of Mme Lacoste's good fortune had created. He asked the jury to acquit Mme Lacoste. The Procureur du Roi had another say. It was again an attempt to destroy the 'system' of the defence, but by making a mystery of the fact that the Lacoste-Verges marriage had not taken place in a church he gave the wily Maitre Alem an opportunity for following him. The summing-up of the President on the third day of the trial was, it is said, a model of clarity and impartiality. The jury returned on all the points put to them a verdict of "Not guilty" for both the accused. VIII Another verdict may now seem to have been hardly possible. The accusation was built up on the jealousy of neighbours, on chance circumstances, on testimonies founded on petty spite. But, combined with the medico-legal evidence, the weight of circumstance might easily have hoisted the accused in the balance. It will be seen, then, how much on foot the case of the Veuve Lacoste was with that of the Veuve Boursier, twenty years before. It is on the experience of cases such as these two that the technique of investigation into arsenical poison has been evolved. In the case of Veuve Boursier you find M. Orfila discovering oxide of arsenic where M. Barruel saw only grains of fat. Four years previous to the case of the Veuve Lacoste that same Orfila came into the trial of Mme Lafarge with the first use in medical jurisprudence of the Marsh test, and based on the experiment a cocksure opinion which had much to do with the condemnation of that unfortunate woman. In the Lacoste trial you find the Parisian experts giving an opinion of no greater value than that of Orfila's in the Lafarge case, but find also an element of doubt introduced by the country practitioner, with his common sense on the then moot question of the accumulation, the absorption, and elimination of the drug. Nowadays we are quite certain that our experts in medical jurisprudence know all there is to know about arsenical poisoning. What are the chances, however, in spite of our apparently well-founded faith, that some bristle-headed local chemist with a fighting chin will not spring up at an arsenic-poisoning trial and, with new facts about the substance, blow to pieces the cocksure evidence of the leading expert in pathology? It may seem impossible that such a thing can ever happen again--a mistake regarding the action of arsenic on the human body. But when we discover it becoming a commonplace of science that one human may be poisoned by an everyday substance which thousands of his fellows eat with enjoyment as well as impunity--a substance, for instance, as everyday as porridge--who will dare say even now that the last word has been said and written of arsenic?