Although the effect of the World War has by no means been to revolutionise military art completely, none the less it is incumbent upon us to draw from it a number of lessons both as regards the further development of our army and also as regards our mode of training. From the point of view of organisation it must first of all be realised that no organisation can possibly cover all the possible contingencies of war, and that, therefore, it is of the first importance to make it as elastic and adaptable as possible. In the course of the World War the attempt to preserve the original formations, and thereby to secure the continuous influence of the leaders over their troops, was found to be impossible of realisation, or at any rate it had to be restricted to the divisions. The latter became strategic units and were correspondingly developed; the army corps became in many cases an army-group, and the number of its divisions underwent constant fluctuation. The question of the expediency of the triple division of the higher units was relegated forthwith to the background in face of the imperative demands of the War. This is by no means a novel experience. Napoleon never hesitated to alter the number of divisions in his army corps. The latter were made up in accordance with the demands of the situation, the personality of the leader, and the number of subordinate units which were available. The War has demonstrated the necessity of equipping the infantry with a larger number of machine-guns than was provided for by us in time of peace. In defensive warfare, as we have already pointed out, the tendency has been more and more to husband the reserves of men, and to wage the battle in the foremost line by mechanical means, machine-guns and mines, backed up by the artillery. The field artillery, whose duty it was to work in the closest co-operation with the infantry, required not so much an absolute increase in the number of batteries as an increase in the number of batteries of howitzers. On the other hand, in the case of the garrison artillery, the engineers, the bomb-throwing companies, the railway, telegraph, and motor troops, and the flying corps, a considerable increase has proved to be necessary. It will not be necessary to increase the numbers of the cavalry in the future; but the cavalry will doubtless have to be kept at its present strength, which will perhaps make it possible in a future war to manage with a smaller force of reserve cavalry, so that the men and horses will be available for other purposes. In face of modern firearms and mass-armies the cavalry is very much restricted in its opportunities for reconnaissance, and to a large extent it has been superseded by the aeroplane. None the less, this long entrenched war, and the fact that in the course of it this valuable weapon has only been employed in the same way as the infantry, must not lead us to form false conclusions. At the