One day a young medical officer, so excited that he could hardly speak, rushed into the laboratory with a lot of dead fish. After some questioning we found that there were tens of thousands of dead fish in the Aire-La Bassee canal and, as this ran into the German lines, he suspected that the canal water had been poisoned by the enemy. We told him that we thought the fish had probably died from asphyxiation as a result of organic matter from a starch works being emptied into the stream. He went away unconvinced, to make a further enquiry and returned later in the day to report that the fish in the canal died every year in the spring when a certain distillery dumped its waste into the canal. Thus did former experience with starch mills pouring their effluents into Ontario streams and killing fish prove of unexpected use. The laboratory was used a great deal by the highly trained officers of the Indian Medical service, who were always wanting some unusual parasite or insect identified, and made a good deal of use of our library. A German high explosive percussion bomb was brought in one day for us to identify the explosive present. We did not allow the messenger even to lay it down but besought him to hold it tight and to keep moving towards the explosives laboratory seven miles away while we escorted him quickly and safely from the premises. The way some of those chaps handled bombs and shells made you tired. It would have been a great pity if that two hundred year old building had been blown up and the British Army compelled to pay for it. A poor soldier up and died one day without warning or preliminary sickness. They thought it might be poison, and his wife would have been deprived of her pension if the man had committed suicide. We were asked to examine the stomach contents to decide whether poison was present. No poison was found. We were sent a little vial containing a small amount of material and asked to determine the nature of the contents. The bottle had been found beside a dead German. It proved to be opium, and the owner had evidently been prepared for a painless passage across the Styx when such necessity arose. Occasionally we had to investigate possible cases of cholera among troops coming from India. One day we received a telegram to proceed to a certain place about ten miles away and report on the sanitary surroundings and particularly on the water supply of a place where an old Frenchman had died with "choleric dysentery." We found the place after some search, and discovered that the old man had died a month before, and that the suspected water supply, unboiled, had been used ever since by a certain headquarter staff without ill effects. Needless to say that was the best proof obtainable that the water supply was safe.