In any account of the German spy system one invariably harks back to Stieber when passing to a review of any fresh branch of the system. Psychologist as he was, Stieber recognised that such a system as he proposed to establish in France prior to the war of 1870 could be rendered more effective if women were employed in conjunction with men. Thus he requested that there might be sent from Prussia to France a certain number of domestic servants, governesses, women-workers, and others who might, by gaining access to the family life of the French people, pass on to the fixed agents information which might be useful. Further, he requisitioned the services of a smaller number of attractive-looking girls who were to be placed out as barmaids, and in similar positions, where they could incite men to talk a little too freely for the benefit of the Grosser General Stab of Berlin. Stieber reckoned that women could learn what men would miss, in many cases, and the event proved him right. He was careful, however, not to employ his women spies in positions of extreme trust, for he had learned, by the time that he was ready to organise his system, that the Prussian woman--it is unwise to include more--was not to be trusted with a secret. Out of the many failures to be credited to spies, most of all are laid to the accounts of women, mainly through the women in question having lost control of their heads through their hearts, and having become more or less infatuated with men whom they ought to have regarded as their prey, but whom they would no longer betray. It seems that the temperament in a woman which best fits her for spying also renders her likely to fall victim to her own affections, as far as her efficiency in espionage is concerned, for the German secret service, though it may overlook one mistake--no more--on the part of a male agent, disowns a woman spy as soon as she errs, without any exception. The case of Lison, who ruined Lieutenant Ullmo, is partly a case in point. Not that this vampire lost her head in the things she did, or acquired any undue affection for Ullmo; but she bungled her case after having rendered good service to the German secret service. The mistake was not overlooked--the German secret service no longer knew that such a woman as Lison existed when once the trial of Ullmo had opened. Her error put her out of the spy system for ever, and, no matter what became of her, she never received another pfennig from her former paymasters.