The battery was found nestling in the midst of an orchard, but the M.O. who knew all about the water supply, was not to be found. Reluctantly I accepted from the Colonel an invitation to dinner, for the feeling was still strong in me that some danger was impending. Half-way through dinner there came the well-known scream of an approaching shell, which burst at the other end of the orchard. A second shell burst a little closer; a third came closer still, and a fourth rained shrapnel on the roof; all the others, with one exception, fell short, and the shelling was over for the time. It was just another one of those "intuitions." While the shells were flying we all kept on eating as if this were a usual everyday accompaniment to lunch, though I noticed that they watched me with as much interest as I eyed them during the process, each curious to know how the other took it. The varied nature of laboratory work in the army and its practical applications may be seen from the following examples:-- One day the O.C. of a hospital sent over a pint of tea suspected of poisoning 28 out of 29 men who drank it. From the history of the affair we did not believe that this could possibly be the cause, and after making a few rapid tests to exclude metals, we proved that the tea was not poisonous by the simple, practical test of drinking it, Major Rankin being the official tester. This method of making a practical physiological test rather astonished the British authorities. A German gas mask found on the battle field was submitted to us to find what chemicals were present. That mistakes were sometimes made by the Germans was evident when we found that the mask had not been treated with chemicals at all; some of the Huns at least had been unprepared for a gas attack. The clarifying apparatus on the British water carts was mechanically defective and usually broke at certain definite places. Recommendations were made by us after we had experimented with rubber instead of rigid connections, which resulted in all the water carts in the British army being equipped with rubber connections, the results being entirely satisfactory. A great deal of experimental laboratory and field work was done with chlorine gas and the efficiency of gas masks and helmets. Experimental physiological and pathological work was done on animals with chlorine and other gases, and on the drying out and deterioration of gas helmets and the chemicals used in them. Subsequently a Gas Service was inaugurated and all work of this sort carried out in special laboratories at G.H.Q. Quite a number of cases of nephritis occurred among soldiers, and arsenic was suggested as a possible cause. The laboratory was asked to examine a considerable number of samples of wine and beer to see whether traces of arsenic were present or not. None was found. A large quantity of wine found to be diluted with ditch water, and sold to our soldiers, was destroyed, and the vendors fined.