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.

The use of raw milk was forbidden in the army, and condensed milk was issued instead. Sometimes "blown" cans of this were sent in for examination and found to be infected with gas producing organisms. Whenever such occurred, the report would be forwarded back through the system to England and the manufacturer would be apprised of the fact and checked up on his methods. Canned foods of various sorts were also brought in for examination, but nothing of a harmful character ever discovered. The food supply of the British Army, as a matter of fact, was of the highest quality and had been subjected to rigid examination by the Government inspectors during its preparation; practically none of it was ever found to be bad.

Another unusual problem arose out of the fact that several soldiers had contracted anthrax, both in England and in France, and the shaving brushes issued were suspected of being the cause. We undertook to search them for anthrax spores, but found it was too long and tedious a job for a field laboratory, for the brushes were full of spores of all kinds. Later on in England anthrax was actually found by other bacteriologists in some of these brushes, according to reports published.

These few examples taken at random will serve to demonstrate the varied character of the work of a field laboratory, and to show that a certain amount of experience is necessary in order to handle some of the problems affectively. We were peculiarly fortunate in our combined experience. Major Rankin, a first rate pathologist and bacteriologist of the government of Alberta, had been in charge of the government laboratory at Siam for five years previous to the war, and knew tropical medicine like a book, while Captain Ellis had carried on research work for three years in the Rockefeller hospital laboratories in New York and was thoroughly conversant with all the most recent work in vaccine and serum therapy. Consequently there was practically nothing that we could not tackle between the three of us, either in bacteriology, pathology, sanitation or treatment of epidemic disease.

Wherever an action was about to occur on the front the hospitals were evacuated of all sick and wounded in order to obtain the maximum number of empty beds. Consequently when fighting was going on the hospitals were very busy but the laboratory routine greatly decreased except in hygienic work. We therefore undertook scientific investigations of various kinds to keep busy and be of the maximum use.

At the suggestion of the D.M.S. of the army, Major Rankin made a survey of the army area for anopheles mosquitoes. The Indian corps was in our area at the time and he obtained the co-operation of the officers of the Indian Medical Service, who being particularly keen on biting insects collected many specimens for him. This variety of mosquito transmits malaria, and, as we were getting a few cases of malaria in troops who had been in tropical climates, it was important to determine accurately the varieties of mosquitoes present, particularly since the numerous ditches, canals and ponds of the country were ideal places for their multiplication. In spite of the anopheles mosquito being found everywhere, Major Rankin reported that he did not believe that there would be many new cases of malaria, develop in France and such proved to be the case.

Captain Ellis began an investigation into the grouping of the various strains of "meningococci"—the organism causing cerebro-spinal meningitis, with the ultimate object of obtaining a more efficient anti-serum for the treatment of this disease.

Apparatus designed to purify wash water from baths before turning it into the streams; designs for the building of small chlorinating plants near the trenches, and the construction of field incinerators for consuming garbage, were constantly being referred to us for consideration and suggestions; we thus had a variety of sanitary work of an interesting and useful kind, which helped to keep us busy.

The nature of our activities carried us through the area of shell fire, among the batteries and sometimes quite close to the trenches. We were free lances to all intents and purposes and frequently had to hunt out new problems to work upon. In travelling about in the course of our work we saw things more or less from the spectator's standpoint, and there were few things going on that escaped us.