"Having given you full instructions as to the correct method of entering your respirators I will now tell you how to extricate yourselves. You must first be careful to ascertain that there is no gas left about. Tests are usually made (1) with a white mouse, (2) with a canary. "If the white mouse turns green there is gas present; if it don't there ain't. If the canary wags his tail and whistles 'Gee! ain't it dandy down in Dixie!' all is well, but if it wheezes 'The End of a Perfect Day' and moults violently, beware, beware! If through the negligence of the Quartermastering Department you have not been equipped with either mice or canaries do not start sniffing for gas yourselves, but remember that your lives are of value to your King and country and send for an officer. To have first sniff of all gas is one of an officer's privileges; he hasn't many, but this is one of them and very jealously guarded as such. If an officer should catch you snuffing up all the gas in the neighbourhood he will be justifiably annoyed and peevish. "Now; having given you all the theory of anti-gas precautions, we will indulge in a little practice. When I shout the word 'Gas!' my assistants will distribute a few smoke bombs among you, and every man will don his respirator in five motions and wend his way towards the gas-chamber, entering it by the south door and leaving it by the north. Is that quite clear? Then get ready. Gas!" * * * * * * * * Four or five N.C.O. Instructors suddenly pop up out of the gravel pit and bombard the congregation with hissing smoke grenades. The front ranks wake up, spring to their feet in terror and leg it for safety at a stretched gallop, shedding their respirators for lightness' sake as they flee. The rear ranks, who, in spite of themselves, have heard something of the lecture, burrow laboriously into their masks. Some wear them as hats, some as ear-muffs, some as chest-protectors. The smoke rolls over them in heavy yellow billows. Shadow shapes, hooded like Spanish inquisitors, may be seen here and there crouched as in prayer, struggling together or groping blindly for the way out. One unfortunate has his head down a rabbit-hole, several blunder over the edge of the gravel pit and are seen no more. There is a noise of painful laboured breathing as of grampuses in deep water or pigs with asthma. The starchy N.C.O. Instructors close on the helpless mob and with muffled yelps and wild waving of arms herd them towards the south door of the gas-chamber, push them inside and shoot the bolts. The R.A.M.C. Orderlies are busy hauling the bodies out of the north door, loading them on stretchers and trotting them across to the cemetery, at the gates of which stands the Base Burial Officer beaming welcome. The lecturer, seeing the game well in progress, lights a pipe and strolls home to tea. XXVIII THE CONVERT