A rather remarkable illustration of this fact is furnished by the trial of Marie Jeanneret, which took place at Geneva in Switzerland in 1868 and which deservedly ranks high among the _causes célèbres_ of the present century, both as a legal question and a problem of psycho-pathology. [At the time when this trial occurred, the writer directed attention to the peculiar and perplexing features of the case in _The Nation_ for January 7, 1869, p. 11.] Dumas in his novel _Le Comte de Monte Christo_, describes the character and career of a young, refined and beautiful woman, moving in the best circles of Parisian society, and yet poisoning successively six or seven members of her own family; but even the most imaginative and audacious of French romancers did not dare to delineate such criminality without ascribing it to some apparently adequate motive. Madame de Villefort administered deadly potions to her relatives under the impulse of a morbidly intense maternal love, which centred all her moral and intellectual faculties on the idea of making her son the sole heir to a large estate. Affection and social ambition for her offspring incited her to the murder of her kin. But the invention, which created such a monster of sentimental depravity, has been far surpassed in real life by the exploits of Marie Jeanneret, a Swiss nurse, who took advantage of her professional position to give doses of poison to the sick persons confided to her care, from the effects of which seven of them died.