The Germans fully realized the formidable obstacle to the retreat of the Italians which this rain-swollen river constituted, and they made a determined effort to secure for themselves a passage across its upper course while the Second and Third Armies to the south were not yet behind the stream. There is a bridge a few miles west of the town of Gemona which was not being used by the retreating army because of its comparatively flimsy construction. The Tagliamento, then very high, was, like many mountain streams, subject to very rapid rises and falls. Therefore, part of the enemy advance-guard, which was following up the Italian retirement was pushed on ahead to try to obtain control of this bridge at Gemona, for use at any rate when the waters had sunk a little. This German detachment forced its way across the bridge with considerable courage, some of them being swept away by the swift stream pouring over it, but on the other bank they were immediately faced with stout resistance by the Italian rear-guard, and with their backs to the river virtually all the enemy who had crossed the Tagliamento were killed or captured. [Sidenote: Gallant conduct of the rear-guard.] The gallant and skilful conduct of the rear-guard of the Italian army is, indeed, the brightest part of the gloomy story of the retreat. [Sidenote: The Italian armies are on the defensive.] [Sidenote: The war now a struggle against invaders.] The cavalry, specially, played a distinguished part in covering the retirement. Charging machine-guns with the lance, and holding commanding positions until they were virtually cut off, these regiments had very heavy losses. A retreat where circumstances make it impossible to get the whole of the army away imposes upon the rear-guard a call for special self-sacrifice, since the moment never comes, when, the whole of the main body being safely past, it can break off the combat and itself retire, its duty done. In the withdrawal of the armies that were along the front in the Cadore and Carnic Alps, occasions of this kind occurred several times during the week throughout which the retreat lasted, when rear-guard detachments were completely surrounded. At Lorenzago a force in this position succeeded in cutting its way back to join the main body again; west of Gemona, however, the remnants of the Thirty-sixth Division were so thoroughly engulfed by the advancing Austro-German forces that, having used up all their ammunition, they were obliged to surrender. And so, gradually, not without moments of discouragement almost amounting to despair, the Italian armies, which ten days before had been fighting on Austrian territory with every prospect of carrying still further a series of victories that had lasted two years and a half, found themselves on the defensive far back of their own borders, awaiting the attack of a triumphant and advancing foe. It had been a terrible trial for them and for the nation at their back. Almost in one