The awe-stricken Tommy slung the satchel over his shoulder, and on the word “Gas!” from the general thrust his hand into the haversack and pulled out--a very dirty pair of army socks. The fourth German attack of 1916 was made on June seventeenth in Flanders, near Messines; in fact, just north of the Wulverghem-Messines road. Like those of April, it was intensely strong, very short, and sent over in successive waves at intervals of about twenty minutes. There were really no fresh features about the show, but the cloud seems to have been even stronger than before. I had no personal experience of this attack, but the cloud must have been very strong, for it killed animals at “Plugstreet”--the only name we used in the British Army for Ploegsteert--three and half miles away, and was quite distinctly perceptible even at Béthune. At the “Piggeries”--the remains of a model farm in rear of Plugstreet Wood belonging to a notable French sportsman, a place well-known to so many British soldiers--a calf was found dead, after the passage of the cloud, with the body very much blown out. Dead rats lay in close proximity. Even farther back than this animals were seriously affected. The army mules in the line of the gas were seized with fits of coughing and kicked violently, making them even more difficult to handle than usual. It is probably not realised that horse masks are now issued on a scale sufficient to provide protection for all horses and mules, such as those of the first-line transport and the artillery, which have to approach anywhere near the lines. The present form of these respirators is that of a big bag soaked in chemicals which fits over the animal’s nostrils, leaving its mouth free so that the use of the bit is not interfered with. When not in use the horse respirator folds up very nicely and neatly into a canvas case which can be carried on the breastband of the harness or any place from which it can be quickly adjusted. Some of the animals take to these masks--“Horspirators,” some wag called them--quite quickly, but others are strenuous objectors; some of those hardened sinners, the mules, transforming themselves into masses of teeth and hoofs whenever an attempt is made to fix on the gas bags.