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. Many sad and depressing sights were witnessed, and one received many vivid impressions of what war means to an invaded country,--impressions which can only be attained by actual experience. Accompanied by the sanitary officer of the 19th division one morning I saw a very sad example of what ignorance of the essentials of hygiene can bring about. Down in a swampy spot on a branch of the canal was a little hamlet, and one of the tiny houses was occupied by a family of refugees from La Bassee. When we entered the house swarms of flies flew up from the table and buzzed about while we did our best to prevent them from settling upon us. The father of the family was in bed unconscious, with typhoid fever. The mother, dead from the disease, had been buried the day before. During the funeral the eldest daughter, a pretty girl of sixteen, sat up in a chair trying to look after the visitors. When we called she also was in bed delirious with the disease in the same room as her father.