At first the work was very heavy and the numbers of wounded enormous, but once it was started, Mrs. Stobart was able to leave the smoothly working hospital in good hands, and to answer the call to help Serbia, then in such dire need. Accordingly, after spending some time in making her preparations, she travelled to Serbia in April, 1915, with a fresh unit. On arrival Mrs. Stobart began by establishing a camp hospital, entirely consisting of tents, at Kragujevatz. It was the first experiment of this kind which had been tried, but the advantages of healthy outdoor conditions, as opposed to the alternative of insanitary buildings, were soon proved, for the hospital, which had been requested by the Serbian medical authorities to undertake surgical work, entirely escaped the scourge of typhus. Unfortunately, this was not so with regard to typhoid, from which several members of the staff died in June, 1915, including the well-known author, Mrs. Percy Dearmer, who, though far from strong, had offered her services to the unit, and had already done fine work. During the first three months the hospital undertook both civil and military cases, and Mrs. Stobart organised a further invaluable and successful scheme in establishing roadside tent dispensaries in seven or eight remote villages. Altogether, within a few weeks, 22,000 civilians received surgical and medical assistance. At the end of September, 1915, came a signal proof of the confidence which Mrs. Stobart had inspired in Serbia. The army was preparing its fresh resistance to the second invasion, and the Bulgarians were on the eve of declaring war. Mrs. Stobart was approached by the Serbian military authorities and asked to mobilise a portion of her unit as a flying field hospital. She was appointed commander, with the rank of major in the Serbian army (the first time in history that such an appointment has been given to a woman), and the unit, which was called the First Serbian-English Field Hospital, was attached to the Schumadia division. After making arrangements for the continuation of the work of the Kragujevatz hospital, Mrs. Stobart chose for the ambulance column a dozen of her English women doctors and nurses, motor ambulance drivers, a cook, orderlies, interpreters, and about sixty Serbian soldiers. On October 1 the column started for the Bulgarian front, travelling by train, through Nish, to Pirot. But, after a few days of trekking in that direction, the column was ordered to move north with the division to within a few miles of Belgrade on the Danube front, to face the stronger enemy, the Germans and the Austrians. On October 14 the hospital camp was pitched within sound of the guns, and the first batches of wounded were received. But the stand of the Serbian army was destined to be a short one. Two days later, orders came to move southwards, and the first stage began of the great retreat, which was to continue steadily for three months.