Encouraged by this success, it rose to the supreme effort required by the assault on the wood, which has already been described. At 4 o'clock on the morning of Friday, the 23d, a fresh emission of gas was made both upon the Second Brigade, which held the line running northeast, and upon the Third Brigade, which, as has been fully explained, had continued the line up to the pivotal point, as defined above, and had then spread down in a southeasterly direction. It is, perhaps, worth mentioning that two privates of the Forty-eighth Highlanders who found their way into the trenches commanded by Colonel Lipsett, Ninetieth Winnipeg Rifles, Eighth Battalion, perished in the fumes, and it was noticed that their faces became blue immediately after dissolution. The Royal Highlanders of Montreal, Thirteenth Battalion, and the Forty-eighth Highlanders, Fifteenth Battalion, were more especially affected by the discharge. The Royal Highlanders, though considerably shaken, remained immovable upon their ground. The Forty-eighth Highlanders, which, no doubt, received a more poisonous discharge, was for the moment dismayed, and, indeed, their trench, according to the testimony of very hardened soldiers, became intolerable. The battalion retired from the trench, but for a very short distance, and for an equally short time. In a few moments they were again their own men. They advanced upon and occupied the trenches which they had momentarily abandoned. In the course of the same night the Third Brigade, which had already displayed a resource, a gallantry, and a tenacity for which no eulogy could be excessive, was exposed (and with it the whole allied case) to a peril still more formidable. [Illustration: The German rush across the Yser-Ypres Canal was checked at Lizerne and opposite Boesinghe. The shaded area on the map marks the scene of the battle. Within this area are Steenstraate, Het Sast, Pilkem, St. Julien, and Langemarck, all of which the Germans claimed to have captured.] It has been explained, and, indeed, the fundamental situation made the peril clear, that several German divisions were attempting to crush or drive back this devoted brigade, and in any event to use their enormous numerical superiority to sweep around and overwhelm its left wing. At some point in the line which cannot be precisely determined the last attempt partially succeeded, and in the course of this critical struggle German troops in considerable though not in overwhelming numbers swung past the unsupported left of the brigade, and, slipping in between the wood and St. Julien, added to the torturing anxieties of the long-drawn struggle by the appearance, and indeed for the moment the reality, of isolation from the brigade base.