Every officer defending a trench against an enemy gas attack should endeavor to collect information whenever possible to be sent to headquarters regarding the capture of apparatus used by the enemy either for disseminating or protection from gas. If a gas shell attack is made, unexploded shells or portions of them should be sent; the time of day, duration of attack, color, taste or smell of gas used, effect on the eyes, breathing, and all other symptoms should be noted. New gases may be used at any time, and speedy information greatly helps the adopting of protective measures. The area of the gas attack is very large and will sometimes cover as far back as 12 to 15 miles behind the lines, although at that point it is not generally dangerous, but for three to four miles the gas has a killing power, and precaution should be taken anywhere within that length of the firing line the same as though in the firing line. Another nuisance resulting from a gas attack is the wholesale slaughter of rats and other animals that infest the trenches, and while a very unpleasant job, steps should at once be taken to gather these beasts up and bury them in some place, obviously for sanitary reasons. DUTIES OF A PLATOON COMMANDER AT THE FRONT GENERAL NOTES: The selection and training of section commanders is of the highest importance, and a commander must assure himself that the man selected has the confidence of the men as well as his own. A platoon commander should know his men and all about them, and keep a record in a book arranged in sections always kept up-to-date. This is easy to say, but harder to do, when the platoon changes day by day. He should know his drill and be capable of moving the platoon into any position easily and by the shortest possible route. He should know how to organize a task allotted to him, such as delivering over a working party, placing a line of sentries, arranging posts and reliefs, and occupying a line of trenches. He should be able to assume responsibility for all trench stores, bombs, periscopes, etc., handed over to him. He should know the geography of his battalion trenches, the position of company and battalion headquarters, and keep trained guides at hand who can find their way to all important points by day or night. GOING INTO THE TRENCHES Platoons generally enter by not more than two sections at a time, thus minimizing the danger from shell fire and delay at entrance to communication trenches. Before leaving billets, platoon commanders should explain fully to sergeants and sections commanders the extent of trench to be taken over and the steps to be taken in case they are caught by shelling or rapid fire going up to the trenches. Arrangements should also be made that if casualties occur among the soldiers, relief will proceed as arranged. IN THE FIRING LINE